Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_planets.thumb.jpg.e76f0a73fd950ae15415beb032373794.jpg

Blogs

Featured Entries

 

Need guidance

Another short clear window in the early evening let me practise set up and alignment of the new AVX mount again. I ran through my new alignment process, including calibrating the StarSense to the OTA. I then repeated the process and the handset reported a final PA accuracy of 30" in Dec and 3' in RA. However, (and with clouds rapidly moving over) I managed to take another sequence of 30, 60, 90, 120 and 180 second shots to test tracking. Here's the 180s (which is heavily affected by high clouds), which is consistent with the others but shows the trailing best: Q1. I roughly measure the trail to be 14 pixels, or 26.6" at my pixel scale, so 0.15" per second. If correct, my maximum unguided exposure would be 13 seconds to stay within my 1.9" pixel scale. Would a PA error of 3' give this sort of trailing? Q2. I also noticed (or believed I noticed) that the mount seems to move when tightening the mount bolt. I think that this further tightens the accessory tray which pushes on the legs more. I noticed this when I calibrated the StarSense on Betelgeuse. Normally, my goto would then be bang on centre but when I slewed back to Betelgeuse it was a little way outside my crosshairs (using SGPro). I wonder if this is causing me problems and whether I need to attach the accessory tray at all? Q3. I also use anti-vibration pads beneath the tripod feet. Could they also slip when adjusting the mount? Q4. Whilst the length of trailing seemed proportionate to the exposure time, the direction was not always consistent, particularly in the shorter subs. I'm assuming this could be the affect of many things: PEC, wind, seeing. Is that right? I did get reasonable 120s exposures the previous night, so I know it's possible. However, I'm quickly concluding that having tested unguided I now need to quickly move onto a guided set up (skipping over drift aligning though I probably should learn how!). I have a ZWO OAG and ZWO ASI224 so time to bite the next complexity bullet. As it's likely to be cloudy until Monday at the earliest I can start working on that now. Spacing I think I've just got my spacing right for the ASI1600MM-C. Which for my reference was 66mm for the Skywatcher field flattener plus an additional 1mm for the filter (1/3rd of the 3mm filter thickness on the Astrodon 3nm HA). I achieved this spacing with: 11.0mm Skywatcher spacer ring (included with FF) 9.0mm FLO M48 to M42 adaptor (https://www.firstlightoptics.com/adapters/flo-m48-to-t2-adapter.html) 1.0mm delrin spacer 7.5mm Baader T2 extension tube (https://www.firstlightoptics.com/adapters/baader-t2-extension-tube.html) 10mm spacer supplied with ZWO camera 2mm male to male connector supplied with ZWO camera 20.0mm ZWO EFW 6.5mm ZWO ASI1600MM sensor distance inside body The OAG has a spacing of 16.5mm and comes with a M48 adaptor so I'm hoping I can just swap out the 9.0mm FLO M48 to M42 adaptor and the 7.5mm Baader T2 extension tube. How good does a polar alignment need to be for guiding? Would it be happy with the sort of accuracy I was achieving above or would I need to drift align and improve it further? I'm hoping that a single StarSense alignment routine will get me close enough that guiding will take over (having also read that guiding seems to like an error in PA so that it only has to correct in one direction). Tune in next week for what I expect to be a frustrating first attempt

Filroden

Filroden

 

Second light, a little wobbly

The forecast was spot on for a change. Clear all afternoon into the evening, clouding over later. So it was worth a good run at fixing the issues I had with my first attempt at polar aligning the new AVX mount and maybe, finally, getting some subs. I've noticed a few extra things this time: the tripod is much lighter than the Evolution one. They share the same legs so it's just down to the mounting plate and the accessory tray being much smaller. It's a one hand job rather than two for the Evolution. It still feels as solid. In fact, it was quite windy last night and it seemed to handle it ok. Likewise, the mount itself is lighter, though it's more awkward to carry. I do like that Celestron have now added carry handles to its latest mounts. The mount seems to remember the time/date. It must have an internal battery clock. I have to set the time each time I used the Evolution, so this is a nice quality of life improvement. Last night it took about the same 25 minutes to get set up and everything connected. I decided to use the USB hub and also connect the mount to the PC in the hope of testing mount control from within SGPro. This gave me even more cables to deal with. Having powered up and roughly aligned the mount using a compass, I checked my time, date and location data and set StarSense to auto align. It hung on the first slew with a message on the handset that it was trying to read the alignment. After repeating this a few times and getting the same result I restored the handset to factory settings, rebooted and tried again. This time it worked. It seems I'd saved alignments on the previous session and this was messing with the process.  I finally got aligned and slewed to Betelgeuse. It was in the field of view so I started the Polar Alignment routine. It slewed again (as expected) but no sign of Betelgeuse in the field of view. I did a blind plate solve and I was about one frame to the west. I adjusted the azimuth bolts and finally found the star and centred it. I ran StarSense auto align again and slewed back to Betelgeuse. No sign again! I took a test shot anyway, and was seeing significant trails even in a 30s shot. Something wasn't right. I'd forgotten to calibrate StarSense. I reset the alignment model and started again from the beginning. It seems to get a good alignment I need to complete a calibration step each time. So my new alignment process is: Roughly align the mount with a compass Set the mount to its home position Check time, date and location data in handset Run a StarSense auto alignment Select and slew to polar alignment star (close to meridian and ecliptic) Press Align to calibrate to this star, then move it into centre of cross-hairs using handset Run Polar Alignment, centring star using the alt and az bolts Run StarSense auto alignment once more Even with this, I can't have been spot on. I slewed to IC443 (bang on) and framed it. I then took a series of single exposures from 30s to 180s to see how well the mount tracked unguided. Here's the series with the same auto stretch. The 60s and 180s show trailing but I was pleased I could get a 120s sub without trailing. 30 seconds 60 seconds 90 seconds 120 seconds 180 seconds Having run these quick tests I wanted to gather some data so I set a sequence of 30 x 120s subs running on IC443 and went and caught up on some TV for an hour. By this time the clouds had come over so I packed up and transferred the files to the main PC for processing. After weeding out cloud covered images I found that about a quarter of the subs showed a lot of trailing. Also, between the first and last sub, the frame had moved significantly in RA and a small amount in Dec. I definitly need to spend a little more time on getting my PA right, maybe even running it twice. I also need to start guiding! IC 443 Jellyfish (if a little wobbly) Choosing the best 21 images (though some still showed trailing), here's a quick process of 42 minutes at gain 139 offset 21 and cooled to -20C on IC443 using the Celestron AVX mount, Skywatcher Esprit 80, ZWO ASI1600MM-C and the Astrodon 3nm Ha filter. It's noisy, the stars are elongated because of trails, but it's a image (and considerably better than the one I took on the Evolution)!

Filroden

Filroden

 

First light, first fail

The weather started to promise some clear spells throughout the day with increasing areas of blue sky visible. The forecast suggested the clouds would thin at lower levels with some high haze until late evening when a new band of clouds would move over. So I took the chance and decided to do a full set up and trial run at aligning the new Celestron AVX. Having already set it up once, though without connecting any of the electronics, I decided to work from my memorised check list. Moving all the gear outside and setting it up, with all gear fully connected took 25 minutes. The ground at the other end of the garden was also level to within a degree, so other than marking the patio stones for future set ups, there is little more I can do to speed up the process. Marking the counterweight bar saved me time. The addition of the StarSense did little to the balance in RA but I did need to move the scope a little more forward to get near to balance in dec. The bar on the Esprit just isn't long enough to reach full balance so I will either have to get an extension or add a little weight to the front of the scope. I found focus with my L filter and I could see Polaris within the field of view. This gave me comfort that I had the mount very roughly aligned. Goto alignment I decided to try StarSense in full automatic mode. I've always used the manual mode because I had such a limited view (partly obscured by houses and partly limited in altitude to below 60 degrees). Taking a closer look, I could see almost down to the horizon to the west (Venus could be seen just to the right of the house) so the houses only block about 100 degrees. Automatic worked a charm, never slewing to an area blocked by houses or fence. It seemed to follow a different pattern than for an alt/az mount, with some images taken just degrees apart from earlier ones. There must be a different optimal set of image spacings needed to model the EQ mount compared to the Alt/Az mount. I forgot to add an additional calibration image (which is recommended in the manual). In fact, it's so easy to use, I should probably be adding a few additional calibration points, particularly in the area I will be imaging. Polar alignment Now the moment I was dreading - polar aligning the mount. I used the polar alignment routine on the StarSense, choosing Betelgeuse as my alignment star (it was close to the meridian). I had a mild panic as the mount, which was almost pointing in the right direction, started to slew in the other direction. I wondered if I'd somehow got my north and south mixed up when setting up. Panic over, Betelgeuse must have just passed the meridian and the scope was coming at it from the other side. It did give me confidence that the mount could manage cable wrapping, as it always pivots around the north. I will still need to tidy up the cables as I caught them trying to catch on the tripod leg, the hand controller holder, and anything else around the scope. At this stage I think I also missed a calibration step. I think i skipped this and went straight into polar alignment mode.  I loosened off the mount knob so there was enough rotational play for the azimuth knobs to move it and, with my laptop showing a loop of 2s exposures binned 2x2, I slackened one knob and tightened the other a fraction to see which way the star would move. Once I got the right direction, I continued to slacken one and tighten the other, always 'pushing' the star, until I had it on one of the cross hairs. I tightened up the loose knob so it could no longer move. I repeated this in altitude though it wasn't quite as easy. Loosen one side and tighten with the other to push. Once the star was getting close to centre I increased the screen magnification to 200x and continued to fine tune. There was some play between the axis as I had to make a final small adjustment in azimuth to get the star completely central. Once centre I tightened up all the adjustment knobs and also tightened the mount, making sure this didn't move the star. Overall, I have to say this was very easy. Much easier than I imagined. It was very similar to how you aligned a star for goto alignment, just using the physical adjustment knobs rather than the handset controls to centre the star. The goto and polar alignment probably only took 5-10 minutes. I then completed another StarSense automatic alignment (as I'd moved the mount). This should give me a good indication of my polar alignment. Bad news It again quickly ran the alignment routine and I brought up the polar alignment error. 46' in RA and 6' in dec! And now clouds were starting to build, so I decided I wanted a few test shots. I slewed to NGC2239 and expected to see the usual pattern of stars on the laptop. Nope. The scope seemed to be pointing in the right direction but nothing in the 2s exposures seemed familiar. I increased the exposure length and it still wasn't recognisable. As the clouds were really starting to build, I decided to take a few test shorts at increasing exposure, starting at 15s and working up to 240s. I swapped to my Ha filter as the Moon was nearby. After the first two exposures (15s and 30s) SGPro started to give download failure messages. I'd seen this once before and the only solution was to close SGPro and open it again. I saved my sequence and new profile and reloaded SGPro. Clouds were now starting to cover the area around Betelgeuse so I would soon not be able to see anything. The area around Procyon was still clear so I slewed there. No bright star in the field of view (though again it was still roughly pointing in the right direction). I did manage to take 30s, 45s, 60s, 120s and 180s exposures before the clouds had closed completely. Enough for me to plate solve and diagnose my alignment issues. A quick inspection of the stretched images showed trailing in everything above 30s. Not surprising given the error reported by the handset. Good news I plate solved the 30s exposure of "NGC2239" and found I was a single field of view away. I also found that images were oriented 90 degrees to how I expected them to be (based on the Alt/Az mount). I had captured 8 (epsilon) Monoceros at the lower (west) side of the frame and just clipped into the Rosette on the top (east) side of the frame. I still did not know what I'd done wrong. I thought it might be because I tried one manual StarSense alignment before doing the automatic one, but the sky was still too bright to find enough alignment stars. I assumed that in trying to solve this and then running the automatic, that I'd somehow corrupted the model. The answer was much simpler and came to me this morning. I'd set the date wrong! So next time I need to: set the right date (mm/dd/yy) add some additional calibration points when doing the initial goto alignment add one additional calibration on the star I'm using for polar alignment sort out my cables So now: My confidence set up will be easy in comparison to alt/az: 7/10 (+3) My confidence extra effort will result in improved images: 8/10 (no change)

Filroden

Filroden

 

Unboxing and set up

Unboxing The mount arrives in one double-boxed package. Inside were five boxes of various sizes, designed to fill the full space. This did mean that two of the boxes were significantly over sized for their contents, but these were protected with padding. There are good unboxing videos already available such as the one below so I did not take photographs. There are two large boxes, for the tripod (including eyepiece tray) and the mount (including hand controller in a neat little insert pocket in the polystyrene). A third box holds the counterweight and the two remaining boxes have various accessories (azimuth bolts, counterweight bar, power cord, etc). Warning: I'd noticed in the unboxing video that the counterweight can easily fall out of its box so when I picked it up I made sure I held both sides of the box! My first impressions of the mount were: the tripod has the same sturdy 2" legs as my Evolution but because the mounting plate was much smaller and the eyepiece tray is designed to be removed between uses, it takes up much less space. I'd estimate it takes about half the volume as the Evolution tripod. This will make transporting it much easier. It will lie much flatter in the boot of the car leaving much more space for the mount and scope. there are many more pieces than the Evolution. Setting up the Evolution simply means taking out the tripod, tightening the tray and then lowering the mount onto the plate. The mount is rotated so that three screws under the plate can be tightened to lock the mount in place. Done! This time, it looks like the set up will be much more involved. the mount design (small base with a downward protruding altitude knob) means it is not as stable when being stored. The Evolution mount has a large, flat base so it sits solidly on a shelf when not in use. This mount will need some thoughts for storing it securely. Set up I'd read the manual in advance (downloading the PDF from the Celestron website (http://www.celestron.com/media/796147/Advanced_VX-Manual-F.pdf) but I took the time to go through the printed manual included in the box. The initial set up was relatively easy. I took out the tripod, leaving the legs at their shortest (it helps me keep the scope inside the shadow of my garden fence) and tried to roughly align it north using the compass on my phone. I also tested how level the mount plate was. Though not needed to be level, it does simplify adjustments to alt and az during polar alignment. The plate was within 1 degree of level which was good enough for me. I attached the azimuth bolts to the mount, screwing them in just far enough so they were secure but the didn't impede the area where the alignment peg would sit. I assume they are removed during transit to make it easier to box the mount. I tightened the RA and dec clutches on the mount (which were left loose during transit). I sat the mount onto the tripod. It fits nicely. Putting the Evolution mount onto the tripod takes a little jiggling for it to seat itself. The AVX drops in with little effort. I pushed the central mounting knob under the mount plate upwards to connect with the mount and then screwed it in so the mount was held firmly in place. I then unscrewed it a little, so that there was some play, which is needed during polar alignment. I attached the accessory tray, which helps tension the tripod legs. I did not like that the v shaped spurs of the tray looked like they could mark the tripod legs when tightened. I will have to see if this is an issue over time. The spurs on the Evolution were more rounded and fit the legs smoothly so this never concerned me before. I attached the counterweight bar then removed the safety screw and slid the counterweight about halfway up the bar before reinserting the safety screw (with one had firmly holding the weight) before tightening the weight itself.  I snapped on the hand controller holder onto one of the legs. Note: at this point the manual goes through the process of attaching and balancing the scope. It is not until the very end that the manual mentions that you need to connect the dec motor to the RA motor using the supplied short cable. Without this cable, the mount cannot drive in RA! I would have thought this step should go much earlier in the manual. With great trepidation, I then attached the scope to the mount. Even though I knew this would be secure it still feels so wrong to have so much weight being held by two lateral screws! I then proceeded to try my first balancing of the scope. I loosened the clutches and rotated the scope so counterweight bar was horizontal and the scope was parallel to the ground, locking the clutches once finished. I then loosened the RA clutch, holding onto the scope for dear life. I slowly released my hold (waiting to catch the scope as it moved) to see which way the scope rolled. Nothing. Mild panic. I tested that the scope could move in RA. Yes, there was a little resistance but it moved freely and easily. I guess I was just very lucky and I'd already put the counterweight in the right place. I tested this by sliding the weight further down the bar and tested again. This time it did roll, so I returned the weight to its original position and marked this with some tape on the bar so it would be easy to balance in the future. I then tested dec. The scope did roll this time and I needed to push the scope a little forward. I will probably have to move it further forward once I add the OAG and guide camera, and have the StarSense attached. The next step would be to connect all the electronics and testing motor control from within SGPro and via Stellarium. I had many cloudy days and nights ahead so I decided to dismantle the set up and see how a more normal set up would be. My initial impression of set up confirmed my worries that this would take longer than setting up the Evolution. There are a number of additional steps that I need to take which might add 5 more minutes at the start of a session. However, as I would normally set up in the afternoon, this shouldn't be an issue. However, it would take a similar time to take down, when I'd also be more tired, so I will need to practice. The biggest set up differences will be: roughly aligning the tripod, hopefully to be speeded up once I've done my first PA and I can mark the paving slabs attaching/detaching the accessory tray each time, though this can be done indoors if I need to do a hasty take down balancing the scope, which will be quicker now I've marked the bar and will (once I have the full imaging train attached) mark the dovetail. I now need to test the motor control and then attempt my first alignment. As it stands: My confidence set up will be easy in comparison to alt/az: 4/10 My confidence extra effort will result in improved images: 8/10

Filroden

Filroden

 

An Evolution

Although this has been posted elsewhere I think it might be useful to show how my imaging has (hopefully) improved as I gained experience/equipment.   A Year of DSO Imaging with an Alt/Az Well, I seem to have attempted my first DSO images in December 15 and January 16 so it's been just over a year of trying to image with the Alt/Az mount. My first DSO target was M42 which I've shared previously but my next target was the Rosette Nebula which I don't think I've shared. I thought it would be nice to see how it progressed over the year. Image 1: Rosette Nebula through the 9.25SCT using the Canon 60D - no sign of any nebula but look at the resolution of those stars. If you find HD46150, a 6.8 magnitude star that forms the left of the middle pair of stars that make the famous rectangular shape inside the nebula you can see two companions so close they are almost touching. I think this serves as a clear example of why a long focal length SCT is not suited for DSO imaging on an Alt/Az mount! Image 2: Now with the Esprit 80 with the ZWO 1600MM. I did a terrible job at removing the background and removed most of the nebula in the process (and still left a nasty ring of gradient). Though at least there is nebula to see now! It shows how nice the field of view of the refractor is. Whilst this image has been cropped, it retains probably 90% of the area of a single sub. Image 3: same data as image 2 but with better processing. I was able to do a better job at removing the gradient and start to bring out some of the detail within the nebula. However, the stars are starting to dominate. Image 4: my first attempt with a narrow band filter. I love how this image is so much cleaner that an equivalent amount of data collected with the L filter (see above). With very little noticeable gradient this was such as easy image to process. Image 5: my first try at adding RGB data to the Ha data in image 4 resulted in an almost monochrome tinted version. I had very little usable RGB and the luminance of the Ha data swamped it, leaving it lacklustre in terms of colour. Image 6: with a little more data and some helpful processing advice I managed to get a better RGB version. This blends the Ha data into R and L using one of PixInsight's many scripts. Image 7: and with an extra 30 minutes data, and further processing improvements. This is back to being a simple HaRGB with the Ha replacing the luminance. Just a small amount of additional RGB data meant I could push it much harder and for it not to be washed out. It seems 40% of the improvement I've seen over the year is equipment, 40% better processing and only 20% improvement in skill at actual data capture. If you'd asked me at the start of this journey I would have though capturing the data would be the hardest part. It is hard, just not as hard as processing it! It's also interesting to see how, with each additional dataset, I've had to crop more and more of the image to remove stacking artefacts caused by rotation. And, to set a baseline for future EQ imaging, here's my current 'best' version of the Rosette. My plan is to start my imaging with this (if the weather improves before it moves out of my viewing range) so I can compare the results.

Filroden

Filroden

 

Background

After over a year of owning and using a Celestron Evolution mount, initially with the 9.25" SCT for visual and planetary imaging, but more recently with a Skywatcher Esprit 80 for DSO imaging, I finally took the step of ordering a Celestron Advanced VX mount, taking advantage of the ridiculous sale price at @FLO. I'd always been hesitant to move to an EQ mount even though I knew it's advantages for imaging. Just the thought of all that extra set up gave me a cold sweat. I loved the ease of the Evolution mount. It took about 5 minutes to set up, another few minutes for the StarSense to do its magic and align itself and in short order I could be focused and imaging. Over the course of the year I added more to my equipment list: I bought the StarSense to speed up alignment. It's a luxury that isn't needed but it got me up and running so quickly. I purchased PixInsight and BackyardEOS. Both made great improvements. BackyardEOS made taking images so much easier, and the quality of my processing started to improve using PixInsight (and gradually got better as I found more tutorials and guides). I purchased the Skywatcher Esprit 80. This was a revelation in terms of being able to image. The SCT was great for visual and for planetary/lunar imaging but would not work for DSO imaging. The Esprit was amazing. It's much wider field of view was ideal for the targets I loved. I swapped my Canon EOS 60d DSLR to a mono ZWO ASI 1600MM-C with electronic filter wheel and a set of LRGB filters. I hated the noise of the DSLR and the processing difficulties. I also didn't like its lack of red response (not bad, just not very good). I knew the ZWO ASO1600 would be great with an Alt/Az mount as it worked well at shorter exposures. I purchased Sequence Generator Pro. I needed a replacement for BackyardEOS now I was using a new camera. Having tried a few options, this was the one for me. It was a little more tricky to wrap my head around the idea of profiles and sequences, but once I'd figured it out, it worked really well for me. I added a Lakeside focuser to the Esprit so that I could automate focusing within SGPro. I purchased an Astrodon 3nm Ha filter. Again, this made a massive improvement to imaging. Still within the 30-60s exposure lengths I could squeeze out of the Evolution mount, the image was so much better than from my LRGB filters. I'd purchased all of the above knowing that they would work with any mount, so once i made the step up to an EQ mount, I'd be all set. I ordered a Celestron AVX mount along with the ZWO OAG (which would work with my ZWO ASI224 camera for guiding). I chose Celestron for two reasons: I already has the StarSense to aligning would be easier, and I liked that you could align on any star rather than Polaris. I had two set up locations, at either end of my (small) garden. I have limited visibility with street lights to the north and houses blocking the view from the SSW through to the NW. However, I had a good easterly view - ideal for Alt/Az imaging as field rotation is lowest to the east and west. I would normally set up outside the kitchen which really limited my view to the south but meant I could stretch the cables through the window and sit inside in the relative warmth. If I needed a more southerly view I could move the mount to the other end of the garden but it meant also setting up the laptop there too. I tried using a remote PC but the WiFi strength was too flaky and I had yet to set up any network cabling. I intended to continue to use both locations with the EQ mount. I would gain a wider view because I could now aim the scope above about 60 degrees altitude (the absolute limit for my Evolution mount with the refractor plus imaging train). I finally decided to try an EQ mount for three reasons: Being able to image above 60 degree altitude Eliminating field rotation which was slowly meaning I was losing up to 40% of my field of view because of cropping stacking artefacts The price, during the recent sale, became too attractive I also opted for an OAG. My plan was to continue with shorter exposures but I already had a suitable guide camera and having the option of improving my tracking even over 60s and adding the option of longer subs should I choose seemed a sensible decision. My plan was to test unguided imaging using the StarSense polar alignment routine only, hoping to get good 60s subs, then to progress to either improved alignment using the drift method (unlikely) or adding guiding (more likely).

Filroden

Filroden

 

Lowestoft Pier

Well I've made a start on constructing my permanent backyard telescope pier by drilling the 6mm. mild steel laser cut 200mm. dia. disc to take the three levelling threaded studs and the 12mm. bolt for fixing my pillar extension tube to the plate.  My investment in new drill bits and cutting oil turned out well, particularly as I have no pillar drill and had to accomplish the task using my trusty handheld Black and Decker.  I am trying to minimise the costs involved by using as many bits and pieces that have spent many a year languishing in my shed.  Using the extension tube, which I already possessed, saved me the cost of a 'puck' and after rooting about in my shed I found some reinforcement bar and most of the timber I required for formwork to cast the reinforced concrete pillar. By coincidence my friend Mr. Lidl had reduced the cost of a small angle-grinder to £9-99  and as I had given my larger disc-cutter to one of my sons, largely because I could no longer pick it up let alone wield it in any purposeful way, I parted with the cash and now have an effective machine for cutting the reinforcement.  I have borrowed an arc welder from another son so I can weld the reinforcent together- excellent!. As a fair weather astronomer and sometime builder I'm awaiting a warm dry spell before putting the formwork and reinforcement together and mixing and casting the concrete (two pours). Looking out the window I guess this might be a while! Last night about 1.00am the sky over Lowestoft was dark and transparent. Jupiter was big and briight due south and most of the usual culprits for this time of year were visible through my handheld 11x80 mm. Helios biinoculars. I still could not find the comet lurking somewhere between the Great Bear and Hercules although I could easily see fuzzies of the same magnitude. I think I'm losing it!  

Hawksmoor

Hawksmoor

 

Moray skies

Cold clear night tonight, finally got to see a few planets as a first.    Northern lights around 9 pm and Mars and Uranus came through pretty clear but the cold got to me after about a hour observing. Came out after 11 pm to watch Jupiter rise from the east.  Stayed for another hour before fingers dropped off.  I'm still learning the sky and how to use my equipment but overall I had a good night.    Hot chocolate then bed lol 

Jam_70

Jam_70

 

ah well

i have been waiting for tonight all week, clear skies predicted and virtually no moon, slept all day so i could stay up all night, only to wake to cloud and clearskies changed from green to orange, and red for the rest of the week and my pentax adapter just arrived too. sigh...

M106

M106

 

8 BILLION YEAR OLD PHOTONS

Chris’s Backyard Astronomy.  January 2017.   A view beyond Earth’s lifetime   Happy New Year to everyone.  This month I am going to concentrate upon one topic only; something that came to my attention at New Year.  The item in question is described as a QUASAR and makes a year in my life appear extremely insignificant.   Eyewitness report:   “Almost Older Than Time. Would we be able to see it?   On Monday the 2nd of January we gathered in Chris's back garden observatory to spot a tiny pinprick of light that had been travelling 8 billion years, yes that's right 8 BILLION YEARS to reach us! Chris had done his homework, mapped out its position and identified a few pointer stars to help us in our search. The bright moon and lovely Venus stayed handily behind the house so a reasonably dark, clear sky helped us in our search. Our luck was in, the pointer stars in the shape of a triangle were in the (telescope) field of view and using averted vision I spotted our faint target, impossible to grasp the enormous distance through space and time the photons from this QUASAR had travelled. Once spotted it was easier to see it again as we all took turns to look at this black hole in action; a successful night, thanks Chris.” Susan Feist   Quasi Stellar Radio Sources (QUASAR)   The name was adopted originally because such objects were first observed by ‘seeing’ their radio waves and so they were assumed to be stars.  Remember, telescopes are not just available to see things with your own eyes but some are capable of detecting lots of other forms of energy.  The Jodrell Bank telescope near Manchester for example was once the greatest radio telescopes in the world.     Jodrell Bank Radio Telescope: Image credit mattbuck   Up until the 1960s a multitude of radio wave sources out in the sky were listed and catalogued.  Critical to identifying these objects were to accurately log their precise position and then try and get identification too with a powerful visual telescope.  This proved possible in some cases and as a bonus it was possible to catch the light and determine the spectrum of the object (see my previous column).  Once you have the spectrum you can find out a lot of important information.   However, visual recognition and thus scientific interpretation of some of these QUASARs eluded astronomers.   3C 48   I quote a lot of numbers and acronyms but really it’s not that complicated. QUASAR 3C 48 was the 48th entry in the 3rd Cambridge catalogue of radio sources.  In 1960, using a huge 200 inch telescope, astronomers Sandage, Matthews and Bolton finally pinned this particular radio source to a 16th Magnitude star.     Mount Palomar 200-inch telescope. Image credit: Coneslayer at English Wikipedia   A refresher on magnitude   Remember, the magnitude scale works counter-intuitively in reverse. Each step is a change of about 2.5 times in brightness.  For example, to us the full Moon looks about 60,000 times brighter than the bright star Vega. On the other extreme QUASAR 3C 48 is about 10,000 times DIMMER than the dimmest star we can see with the naked eye!   Object Magnitude Brightness we see on Earth The Sun - 26 Midday Sun Full Moon - 12 Moonlit sky Venus (now) - 4 Bright evening ‘star’ (now) Jupiter - 2 Yellowish star like Vega (bright star) 0 5th brightest star in the sky Yildun + 4.5 Star just visible with your eye Neptune + 8 Farthest planet appearing reasonably bright in a 10 inch ‘scope 3C 48 QUASAR + 16 At the limit of a very large amateur ‘scope   Capturing the light from the QUASAR to enable a spectrum to be examined was some feat in those days but they did so.  Sandage though was quoted describing the spectrum as “exceedingly weird”.  What followed was a 3-year period of doubt and false reasoning because the spectrum just could not be interpreted within the range of known objects.   In 1963 two other scientists, Schmidt and Greenstein, re-examined the spectrum of 3C 48 from 1960.  Schmidt had previously examined a spectrum of a similar object (3C 273) and was thus experienced in these matters.  What he immediately concluded was not weird but that object 3C 48 showed a “redshift of 0.37”. So, now we need a recap on redshift.   Hearing an ambulance   Recall the last time you stood by as the ambulance sped towards you and then away from you.  We are all familiar with characteristic change in pitch of the siren.  As it approaches you the pitch gets higher then as it leaves you the pitch gets lower.  The lowering of the pitch as the sound source moves away from us is due to a ‘stretching’ of the wavelength caused by the speed of the ambulance relative to us. This is the Doppler effect and applies to all types of radiation including light.     Normal spectrum above and red-shifted spectrum below.  The tell tale absorption lines are moved to the right. Credit: Georg Wiora (Dr. Schorsch) via Wikimedia Commons   So Schmidt was saying that the spectrum of QUASAR 3C 48 told us that it was (and still is) moving away at truly phenomenal speed! As we have discussed before, the painstaking work of Edwin Hubble in the 1920s enabled a connection to be made between the speed that an object is receding and its distance.  On doing the maths 3C 48 was located at 4 BILLION LIGHT YEARS distant.   Ancient photons hit Bishop Monkton   This dramatic distance estimation created disbelief in the astronomical community.  Knowing how bright the object looks to us (Magnitude +16) and also knowing its distance, enables us to quite easily determine its true brightness close up and thus its power.  The calculation for most QUASARs shows they have the luminosity of 10 Trillion (10,000,000,000,000) Suns, easily one of the most energetic objects in the Universe!   As you may imagine this stimulated a decade long argument as to whether the observations were true or were these QUASARS just objects in our own galaxy that demonstrated weird physics?  In more recent times, advancements in technology have enabled astronomers to study ‘normal’ galaxies in the region of these QUASARS and confirm that indeed they are very distant objects.   On the 2nd January 2017 a group of villagers and friends congregated in my humble shed known as the Observatory and eventually, one by one caught a glimpse of light that has taken 8 BILLION years to get here.  I stumbled across a reference to QUASAR 4C 11.69 also known as CTA 102.  It is in the constellation of Pegasus looking west from the village at the moment.     The old 9 inch SCT telescope used to spot the QUASAR   This particular QUASAR was originally falsely classed as a magnitude +17 variable star.  Variable stars are quite common but are usually quite regular in their variability.  Not this one!  Recently its magnitude has changed from +17 to nearly +11, which is an increase in brightness of 250 times.  Think about this for a moment.  This is an object that is TWICE the age of the Earth, more than half the age of the entire Universe as we know it and visible in my 9 inch telescope.  Surely this is the most powerful and most distant visible object any of us will witness.   Its brightness currently varies quite substantially on a daily basis so what is it?  CTA 102 was discovered in the early 1960s from its varying radio source but was laughingly thought to be signals from an extra terrestrial intelligence and American folk rock band The Byrds wrote a song about it in 1967 called ‘Younger Than Yesterday’.  It is in fact a giant black hole at the centre of a distant elliptical galaxy and its brightness is determined by what it is currently consuming.  So the recent huge increase in brightness is a burp of cosmic proportions quite possibly as it gulps in stars or even other galaxies.  I write this in the present tense but it is highly likely this object ‘died’ eons ago and no longer exists.     A QUASAR; a disk of stellar material feeding a huge black hole and artist’s depiction of data via NASA’s Spitzer and Chandra telescopes. Credit: Nasa JPL   The village group found it a challenge to observe but with careful attention to excluding all other light sources and using averted vision I believe all present witnessed the 8 BILLION year old photons.  Retiring to the kitchen to consume a well earned cuppa, some of us had another peek about an hour later and it had significantly increased in brightness in that time so obviously it had done similar to us.   What next?   A few days later, from the observatory I captured a star field image to show the QUASAR CTA 102 here in the centre of frame against known reference stars.  This is a stack of 20 x 30 second exposures.     QUASAR CTA 102 approximately Magnitude 12. 8th January 2017; Chris Higgins   CTA 102 is now going out of reach. If it is still belching at the same rate in the Autumn we should check back then to see if it has satisfied its hunger.  Feel free to join me.    Follow my Twitter feed for regular updates on this and new topics from the backyard observatory.   Twitter: @owmuchonomy Astrophotos: https://www.flickr.com/photos/blue5hift/sets

Owmuchonomy

Owmuchonomy

 

First glimpse of Orion Nebula

got my first ever 'close up' glimpse of Orion Nebula this morning  considering the moon was streaming down and the local car park had both sodium and halogen floods blasting into the sky, and Orion was skimming the horizon, i didnt think i'd see anything more than Orion's belt, but the nebula was there, a hazy white patch in the sky... Wasnt 100% sure at first, but after ruining my vision checking my atlas, yep all the stars matched, spent an hour and a half gradually freezing solid in the hope it would resolve a little better, but it wasnt going to happen  cant wait to try again when the moon has gone and i'm out in the sticks; trip to north wales at end of the month is in order i think! exciting times for a newbie     Scope: Star Watcher 200P dob w/ SkyWatcher Super 10mm w/ Moon & Sky Glow Filter Sky: [SW London] 100% Clear, Moon 97%, Light Pollution bad

M106

M106

 

starting Dew control build

Neoprene, along with 2 x 48W heat cables for the primary mirror and main tube body, and 2 x ~8w heaters for the secondary mirror and eyepieces; 12V PWM controlled (mains power for now, battery later) NB: this is a prototype design based on reading other peoples ideas, no idea if or how well it will work for avoiding fogging Waiting for heater components to arrive, for now just the neoprene...    

M106

M106

 

First light

Beautiful clear skies over London tonight, first test drive of my new scope is done; amazing view of the moon, large mountainous craters on the edge which i've never seen before, can actually tell that the moon isnt a perfect disc at all; very happy Going to try and spot M42 soon, its nice and clear to the naked eye, fingers crossed... However... while i can already see the potential of the mirrors, the eye pieces are absolute rubbish, significant color shifts on the edges of everything, and that doesnt inspire confidence for looking into deep space; will be getting a pair of new ones asap, X-Cel's probably, or starguiders, we'll see what my bank balance is like at the end of the month! Not especially disappointed though, all the reports i'd read had prepared me for rubbish eye pieces lol   I would like more control over focus too, i bought a little device (not sure what its called) for my old refractor, which was essentially a focus with a very low gear, making focus very easy: i saw a version of the 200P with something similar built in, can anyone tell me what its called? And if there is one for 1.25" eyepieces? This looks interesting: http://www.365astronomy.com/Dual-Speed-1-10-Microfocus-Upgrade-Kit-for-Skywatcher-Crayford-Focusers.html Anyone tried it? Or have a better solution, 10:1 seems good though   No photos yet, still need and adapter for my dSLR, and a decent low light 1080p cmos/ccd   Scope: Star Watcher 200P dob w/ SkyWatcher Super 25mm & 10mm Sky: [SW London] 100% Clear, Moon 92%, Light Pollution bad

M106

M106

 

arrived

Newbie deep sky enthusiast with a new Skywatcher 200P (sorry dob mob, didnt have the patience for unboxing shots) Here it is... feel like it should have a name? Was fairly easy to put together, although the spanners didnt fit the nut that holds the base, and the screw driver only properly fit the screws for the EP holder; thats pretty bad imo, and makes me wonder what else they may have skimped on... but given its one of the UK's favourite scopes, i'm hoping nothing to serious The tube itself is metal, i was expecting plastic (confusion from reading soooo many reviews and listings for 100 or more scopes lol), i think i would have preferred plastic too as i'm now going to have to consider condensation allot more carefully on those cold nights; no 5 minutes grab and go with this scope in the winter i think, we'll see!   Question: Hot or Cold? Is it better to just let the scope cool down somewhere with dry air before taking outside, or would a heater be better? Heat cable should prevent condensation quite nicely, wrapped around the tube, but from the little i understand heat + astronomy isnt a good thing, maybe that only applies to the atmosphere high up where its visually more disruptive? Anyway here it is...name coming up eventually...     Clear skys expected from 9PM monday night, fingers crossed for first light then; will see how my Pentax dSLR does shooting through it too (not expecting much there tbh, no tracking on this scope, although i might get some decent moon and sun shots one day)

M106

M106

 

How the Hubble Space Telescope changed astronomy

From the beginning of the human race, to nearly only 400 years ago, everything we knew about space would be observed from the naked eye. Then Galileo came up with his telescope, and the world awakened. We learned Saturn had rings. Jupiter had moons. Within just a few years  of that, our entire understanding of the Universe changed. In the next few centuries, telescopes became more complex, of different sizes, lengths, and powers. Hubble is up in space, the ultimate viewing spot. Unhindered by weather, light pollution, or any other inconveniences, it is used by scientists to study the great cosmos. For 26 years now, the HST (Hubble Space Telescope) has been enthralling us with its spectacular images of nebulae, galaxies, and other space phenomena. However, the telescope does more than just take pictures all day for us to enjoy. The HST was a combined NASA(National Aeronautics and Space Administration) and ESA (European Space Agency) project, which went up with tons more scientific instruments than just a powerful camera.

Since being put in orbit, over 4000 astronomers have used it to publish ~13000 scientific papers on various topics. The HST is truly a marvel of civilization. When Hubble went up, it had a flawed mirror, which was sending back blurry images. After a 1993 servicing mission, the flaws were rectified, and from then, it's been taking pictures of all the amazing things we know it for. It's been used to look at other planets, their moons, further galaxies, and nebulae. It's been used to find water on planets, moons, and other asteroids. It's been used to map Pluto, the furthest planet from us (now a dwarf planet). NASA's New Horizons mission will rival the HST, but it will take 9 years to get close enough to Pluto to give any challenge to the HST.
It's been used to calculate the lifespan of the universe, Hubble helped astronomers nail down the age of the universe with an accuracy of about 5 percent. Our Galaxy, the Milky Way is set to collide with the Andromeda Galaxy, speeding towards us at the speed of a bullet. We know this all thanks to Hubble. Check out the gallery below to see what kinds of amazing pictures the HST has taken over the years, and also check out my original blog over at http://hridaysabir.blogspot.in/ to keep up with the latest topics I write on.  

HridaySabz

HridaySabz

 

Enjoying my Sky-Watcher Heritage 100p

So I've recently purchased this little gem. It is so good! Surprisingly showing me Venus and Mars in great detail. The scope boasts a 4" aperture with a 400mm focal length(quite short tbh) but gets the job done with messier objects. it has this beautiful red finish which I shouldn't include as a feature but it sure does look gorgeous. Unfortunately it has only seen the sky once due to the bad weather here  but the views were worth it.  

Samibotss

Samibotss

 

Into the Sunset....

My EQ-2 mount is nearing the end of its useful life. It has suffered a screw shear on the Dec. Slo-Mo controls, and now the handle of the main mount bolt has disintegrated. Although I would like to repair the mount, and keep it in operation, unfortunately, it is getting left behind in my astrophotography journey, and a replacement was due within a year or two. The recent disasters have only highlighted the need for this, and so a replacement is on its way! More next week....   ===========IN MEMORIUM============                                  EQ-2 (2012-2016).                         A Wonderful Telescope Mount.       Who Passed Away While Drift Aligning On The Front           Path, And Who Will Never See The Stars Again.                                 WE WILL MISS YOU

JohnSadlerAstro

JohnSadlerAstro

 

Ray tracing on GPU & prospects for stacking

Recently I’ve dusted off my old ray tracing code, done some OpenGL reading/refreshing, and implemented real-time ray (and path) tracing on GPU. It turns out the present-day GLSL (OpenGL shading language) is capable enough, and even an integrated Intel graphics has acceptable performance. Video: https://www.youtube.com/watch?v=2lAmO1Ghtn0   The most important part is the ability to use the hierarchical scene graph (tree); thanks to this, ray tracing’s time complexity is only O(log n) w.r.t. the number of scene objects, as opposed to O(n) for hardware rasterisation (i.e. what today’s GPUs normally do). Even though GLSL doesn’t allow recursion, it’s simple to search the tree iteratively and even without simulating a stack (which would eat up precious GPU registers – I’ve tried that too). Now that I feel more confident with OpenGL, GPU acceleration for Stackistry will probably arrive in the not-too-distant future. The quality estimation and the shift-and-add phases should be easiest to port into GLSL. Even if we remain strongly IO-bound (due to all the shuffling of images between RAM and GPU memory), I think a performance boost by a factor of several is possible.

GreatAttractor

GreatAttractor

 

November 18, 2016

№ 11 / November 18, 2016 / Home / 1955-2035 JST / Cold & clear / 15x70, 8x42 I went outside before moonrise to find The Golfputter, and I succeeded. I saw a shooting star pass from south to north just below M31. The last 10 minutes were consumed by a conversation with the next door neighbor, who'd stepped outside for a cigarette. CONSTELLATIONS:          And / Ari / Aur / Cas / Cep / Per / Tri DEEP SKY OBJECTS: Kemble 1 (As/Cam)             - M31 (SG/And)                     - M33 (SG/Tri)                       Same hazy patch M36 (OC/Aur)                     - M37 (OC/Aur)                     - M38 (OC/Aur)                     - M45 (OC/Tau)                    Naked-eye only.   I doubt I'll ever resolve more than two points of light. Mel 20 (OC/Per)                 - NGC 752 (OC/And)           I liked it! It appears as a widely distributed patch of stars; I pictured them as grains of sand being disturbed by the Golfputter. Golfputter (As/And)          First sighting! It's distinct, but unlike Kemble's Cascade, doesn't suffer when viewed through lower magnification. 

Kainushi

Kainushi

 

Spectrometer Mark 2

After completing my current oil painting blitz, I spent some time today completing 'Spectrometer Mark2' in the 'clean room' or the kitchen as my wife likes to call it.  The primary reason for the redesign is my desire to use either my QHY5v or QHY5-11 as the imaging camera, without dedicating either camera to capturing spectra.  So a modular approach seemed sensible and the ability to experiment with different diffraction gratings was also an objective.  Mark1 was virtually built for 'nowt',  Mark2 has required the expenditure of a few quid mainly on purchasing an extra mounting bracket for the QHY5 (I already had one in my bag of astro bits and bobs).  I made the base from hardwood samples  handed down from my late and great mate Barry Shulver.  The tilt and turn mechanism, for holding the diffraction transmission grating, was fashioned from a camera holder and tripod obtained from everyones favourite country 'Poundland'. I used an on-line transmission grating calculator to work out the diffraction angles for different gratings and basic trigonometry to calculate the distance between the gratings and the cameras chips to fit the first order spectrum on the chip.  Hopefully, if I've got it right , it should work ok - so watch this space for my continuing 'Chad Valley' exploits in 'Off World Spectra'!  

Hawksmoor

Hawksmoor

 

November 7, 2016

№ 10 / November 7, 2016 / Home / 1941-2000 JST / Cold and clear / Waxing moon (46%) / 8x42 & 10x50 Another brief sojourn. I was irritated when I began because I've felt as if I've neither learned nor see anything new lately. So, I stared at Alpheratz (α And) for a while to calm myself, and discovered that it's surrounded by several stars; I counted approximately 10. Taken as a whole, it looks like a folded napkin or a newspaper folded into the shape of a boat. I practiced hopping from α to δ to β, and from there up to M31, and this is a surer way of finding the galaxy than my previous method which was little more than pointing the binoculars at Cassiopeia and sweeping to the right (South) hoping to come across it. M31 itself is to the left (North?) of the trianlge of stars: HIP 2948, 32 And, & υ And; within this triangle of bright stars, I counted six or seven dimmer ones. I enjoyed the little time I had outdoors, and with reluctance returned indoors to complete the paperwork I have to prepapre for work tomorrow. The more I use the 8x42 and 10x50, the more I appreciate them. The Moon is almost half-full, and it was having a negative effect on the visibility of the stars. The smiling face in Auriga was barely discernible, but none of the OC's were visible.  CONSTELLATIONS: And / Aql / Aur / Cas / Cyg / Del / Peg / Per / Sge DEEP SKY OBJECTS: Cr 399 (As/Vul)             Diminished by the moonlight Kemble 1 (As/Cam)      HIP 18505 (bright star in the middle), NGC 1502 & NGC 19139 only Mel 20 (OC/Per)           Looked good; it wasn't adversely affected by the moonlight M31 (SG/And)              No less beautiful because of the smaller aperture NGC 869 (OC/Per)        Meh NGC 884 (OC/Per)        Meh NGC 1502 (OC/Cam)   Visible Stock 2 (As/Cas)           I couldn't make it out

Kainushi

Kainushi

 

November 4, 2016

№ 9 / Nov. 4, 2016 / Home / 1928-1946 JST / Cold breeze; canceled because of clouds / 15x70 A brief session, cut short because of the clouds that came in from the west, and covered everything. I had hoped to locate M56 and M57. I stared at Lyra for 5 minutes, but could not detect anything. Deneb's disappearing behind the clouds was the last thing I saw. CONSTELLATIONS:      Cas / Lyr / Sge DEEP SKY OBJECTS: Cr399 (AS/Vul)               Nice, until the clouds came Kemble 1 (AS/Cam)       Good until the clouds came M2 (GC/Aqr)                  Seen before the clouds arrived; it looked good; the shopping cart was distinct M11 (OC/Scu)                Low in the west, and negatively affected by clouds and horizon scum M13 (GC/Her)                Mostly obscured by clouds M31 (SG/And)               Greatly diminished Mel-20 (OC/Per)            Okay until the clouds arrived NGC 663 (OC/Cas)       It was conspicuous, and pleasant to look at until the clouds came NGC 869 (OC/Per)       Good until the clouds came NGC 884 (OC/Per)       Good until the clouds came NGC 1502 (OC/Cam)   Good until the clouds came Stock-2 (OC/Cas)         Good until the clouds came

Kainushi

Kainushi

×

Important Information

By using this site, you agree to our Terms of Use.