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Showing content with the highest reputation since 26/07/19 in all areas

  1. 22 points
    I am always fascinated by this target, and am always surprised just how much focal length it takes to really get close in on the pillars. This was taken with a 5" scope, so I was not expecting too much. I know the stars need some work--believe me, they were much worse. Kind of too late now anyway as I just have the JPEG. Obviously this is a crop, and at first glance I say Woe--too big on the screen. But each time I look I end up changing my mind on a down sample and size reduction. I look the forward to capturing this with the C11--but its not an easy one for me to get--maybe next year. EDIT: It reduces in size when you click on it. TOA 130 with ASI 1600 Ha 49 5min OIII 25 min SII 25 min
  2. 19 points
    Before starting an imaging run I now do some test images with different filters, exposures, and binning to see which combinations work best. When I examined the OIII 1800s bin 2x2 test image I was surprised to see an asymmetric outer shell with intricate structures, and so factored this into my image capture plan. This is the result. There is also a very faint diffuse OIII shell that is even further out from the core. I found processing this to be a real challenge, with 7 filters, and exposures varying from 30 sec bin 1x1 to 1800s bin 2x2. Integrating images with such extreme dynamic range was also a challenge. I was concerned by some lighter parts of the sky background, but after checking with other images available online it became clear that this was integrated flux nebula. This is a total of 57 hours of integration. Captured on my dual rig in Spain. Scopes: APM TMB LZOS 152 Cameras: QSI6120wsg8 Mount: 10Micron GM2000 HPS
  3. 19 points
    After watching the launch for Cape Canaveral I knew CRS-18 would pass over the UK as the ISS had done an overhead pass only 30 minutes earlier, the only doubt was if the cloud cleared and it would be high enough to be illuminated by sunlight. Well it was spectacular, the RCS thrusters we’re pushing out circular plumes of glowing blue gas as the course corrections fired as the Dragon capsule, second stage and the two tumbling side shrouds passed over. If you look very carefully there are two or three pinpoints of light behind and to the left, any ideas as to what these might be? All to quickly it moved into the earths shadow and faded from view but ai was still able to track it for a short while. Mel
  4. 18 points
    Lobster Neb from Yea Victoria Australia Imaging Scope TS130APO Camera QSI583WSG Astrodon Narrowband Filters HOO mapped. 4hrs integration
  5. 18 points
    IC2944 aka Running Chicken Nebula is a stellar nursery located in the Centaurus constellation. IC2944 is an open cluster and an emission nebula. Took the photo in June 2019 during my visit in the Kalahari desert in Namibia. Photo Details: HA - 11 x 5min = 55min OIII - 10 x 5min = 50min RGB - 3x5min for each channel at BIN2, 45min Total Exposure: 2.5 Hours Telescope: ASA 12'' F3.6 Mount: DDM 85 Unguided Camera: FLI 16200 Mono Filters: Astrodon My Flickr Page: https://www.flickr.com/photos/101543943@N04/? Thanks for watching, Haim Huli
  6. 17 points
    I finally had time (and clear sky) to photograph Saturn I wanted to do it for a long time! This is a combinaison of 3 x 1 min videos (about 6000 frames I think), with the ZWO ASI224MC and Sky-Watcher 4" Maksutov, on the AZ-GTi. Acquired and processed with the usual suspects: Sharpcap, PIPP, AutoStakkert and Registax. And the final touch in Photoshop I'm not an expert at processing, so I'm sure there's a lot to learn here. Feedbacks welcome! Seeing wasn't excellent, about 3-4/5. I'm also once again very impressed by the AZ-GTi, the tracking was extremely precise after a quick 2 star alignment. I imaged the Tycho crater on the Moon for 5 minutes, and it stayed right in the middle! It's a really nice little mount for a very portable setup.
  7. 17 points
    Laurin Dave and I shot two panels of luminance (18x15 minutes each) and an hour per colour per panel. I already had a deep OIII and Ha set 'in stock' and an RGB layer of an hour per colour per panel so we put them all together. In my existing HaOIIIRGB version I think I pushed too hard, trying to get narrowband depth in a natural colour image. It was never a very happy image. In this processing I decided to settle for less depth in the faint stuff and a more natural look. The brown dust on the right hand side is, we both feel, genuine. I've seen it every time I've shot colour on the Veil and the star count is also lower against the browns, consistent with the presence obscuring dust. Perhaps this dust is even being compressed by the expanding shock wave creating the Broom? I actually lowered the saturation of the browns in this version. Total exposure over 30 hours. Tak FSQ106N/Mesu 200/Atik 11000 mono. There is neither noise reduction nor sharpening in this one. Data calibrated using master bias, bad pixel map and luminance flat for all filters. AstroArt, Registar, Pixinsight and Photoshop CS3. Olly and Dave.
  8. 17 points
    I had planned on doing a mosaic of the Cygnus loop, but for whatever reason, it didnt work out.. Horizontal panels lined up, but could not get them lined up on the vertical plain.. Probably not enough overlap. Ill revisit again at some point. Went for the Witches Broom.. Overall, it came out quite nicely. Really liking the OSC with the Quadband Filter! Details: SW Esprit 100 SW EQ6-R Pro Mount (guided) ZWO ASI071 OSC Altair Astro Quadband Filter 21 x 300s Exposures (Total = 1hr 45min) Processing - PI and PS
  9. 15 points
    A few clear hours gave me the opportunity to get my NEQ6s polar aligned last night, and once the first was done I left it collecting unguided subs of M27 whilst I started on the second. Unfortunately I couldn't get my Altair camera working on the second so I had to stop the first and pinch the ASI174MM off it. But never mind! This is the first DSO image I've captured for many years. It needs more and longer subs, and the stars are a little eggy, but I don't care :) 19 x 60s unguided, ED80 and ASI174MM. James
  10. 14 points
    The Southern Pinwheel Galaxy M83 from the 6th of April, Mandurah Western Australia, conditions poor. This was my 3rd attempt with the first two attempts being much worse than this. 198 x 30 seconds, ISO 1600, 24 darks. Stacked in Sequator, edited in PaintDotNet and Fitswork. Sony a5000 Antares 6" achro refractor SkyWatcher EQ6 Pro
  11. 12 points
    Well, not an observatory as such, more an observing area. A ROR or a dome were both non starters as our garden is quite small and a housing to accommodate a refractor 79" long, with room for me as well, would be too big. My wife was almost willing to accept the ROR, but I decided not to ' push it ', and created this area instead. The trellis, viewed from the Conservatory will fairly quickly be covered in the Passion Flower and Clematis both of which are growing vigorously. I bought some canvas type material and hung it on the inside to shield light from my house and from my neighbour's security light, which seems to be on more frequently now, sometimes all night. It all works very well, no light visible and is actually quite cosy, not to mention fragrant from the various planting. I now have power to the pier, and everything except the telescope is covered over with the..er..cover. I just need a plastic box in there to store the curtains during the day. The corner table for my eyepiece box, I cut from a kitchen worktop thrown out six years ago. I rarely recycle anything deemed 'possibly useful '. It takes just a minute to carry the 5" from conservatory and locate it on the mount in the correct position, flick the switch, and away, so I am pretty happy really.
  12. 11 points
    When we last updated our website we included an offer to price-match competitor prices wherever possible. Today we have made our offer more prominent and easier to use. Every product description now has a blue 'Request a Price Match' button. Simply click the button then enter details of the price to be matched. We will endeavour then to reduce our price or (if it is a one-off) email you a discount code that will lower the price when at the Checkout. Nice & easy Please don't be embarrassed to click the button...
  13. 11 points
    A planetary nebula in the constellation of Cygnus - close to the Crescent Nebula. Only relatively recently discovered (2007) because of its extreme faintness hidden in bright hydrogen clouds. Also known as PN G75.5+1.7 43 hours total integration, captured from Extramadura, Spain. Scopes: APM TMB 152 F8 LZOS Mount: 10Micron GM2000 HPS Cameras: QSI 6120wsg8 APM TMB 152 F8 LZOS, 10 Micron GM2000HPS, QSI6120ws8
  14. 10 points
    About 2 hours of data with 20 bias and flat frames. Stacked in APP and processed in PS. Photographing nebulas in a Bortle 8 area with an unmodified DSLR and heavy setup on a light mount can be really challenging...
  15. 10 points
    Attached are Jupiter and Europa, Saturn, Copernicus Crater. All taken with ASI120MC, SW150/750 and 2x Barlow.
  16. 10 points
    Later it just got enjoyably better with a slight Milky Way at the zenith. A check showed sqm of 19.47, ace for the edge of town. Spent most of the time on Cassiopeia, enjoying the open clusters here . Went for a few lesser known King and Cr clusters. Of these King 12, King 21 , Cr 463 and Cr 36 stood out from the field of stars. Pleased to attach details below, makes a change from the norm ! Into Lacerta and the spectacular sparkling NGC 7209 and NGC 7243. Then a horizontal view , laying down to look at the views overhead and that theatre of Wonder from Cassiopeia to the front of Pegasus. Over to Perseus and the lovely triple Σ 162 (SAO 37536) . A great view of Σ 314 (SAO 23674) showing lovely twins 1.5" apart. Always a wonder to get an insignificant star then observe at high magnification. A brilliant challenge is ψ Cassiopeiae (SAO 11751), tease out the companion to give a triple group. Iota Cass. gave a great view. Pleased to attach a few bits of Cassiopeia. A wonderful calm, dry and warm few hours, under , Clear skies ! Nick.
  17. 10 points
    As poor as this is I thought i would post it as it is probably impossible from the UK and far from ideally placed out here in central Bulgaria. This is only 40mins as I didn't want to waste too much time on it as it was never going to be wonderful through the haze. Normal gear Canon 40D and 805mm apo on an AZ EQ 6. Guiding was fairly awful this low down and fully understand why Olly from a similar latitude does not recomment to his guest shooting around the Antraes area which is in fact about 5-6 degrees higher in the sky. Be kind I know it's not great, Alan
  18. 10 points
    Seeing was better for Saturn later in the evening. I still had to use an IR luminance channel to pull out the detail. Jupiter is in twilight and the seeing was very unsteady. Oval BA visible on Jupiter. Peter
  19. 10 points
    This is 41 mins of Ha, 37 mins of OIII and 4 mins of Red! Clouds and (low) aircraft conspired to ensure that essentially the same amount of subs were consigned to Trash! Taken with a Samyang 135mm + ASI1600MM-Pro at 139 gain, offset 56. Guiding was troublesome probably due to poor seeing. There is minimal cropping so stars at the extreme corners are not a good shape; possibly a shortcoming of the Samyang? The Ha and OIII were 120s and 180s duration and were pre-processed and combined in APP as a multi-session image. Red were just 60s. Ha, OIII and Red were processed in PixInsight and combined in PixelMath. Finally there was a small amount of noise reduction in PS and a very slight colour boost. As ever critical comments are welcome. Thank you for looking. Adrian
  20. 10 points
    AG Optical Convergent FA14 Moravian G3-16200 Mount:10 Micron GM2000 HPS II Astrodon B 50mm: 10x600" bin 1x1 Astrodon G 50mm: 10x600" bin 1x1 Astrodon L 50mm: 39x600" bin 1x1 Astrodon R 50mm: 10x600" bin 1x1 SkyEye Obsevatory
  21. 9 points
    I finally managed to capture everything I wanted for this target and as I have been advised, I stacked and calibrated in pixinsight. It is a mixture of 300 and 600sec subs shot with the QHY183M through a SW130pds and AT106. Roughly 50x300sec and 40x600sec for each filter. The Oiii filter is giving me these huge halos and not so very small stars which I'm finding hard to tame. I will try to add a little of the Ha as luminance layer to see if I can make it better. Emil
  22. 9 points
    Planets, on nights of good seeing, will be considerably crisper. DSOs will show more structure, globulars will be more striking and more resolved, holding up at higher magnification. Stellar images will be smaller and tighter. Nice but not entirely life-changing. My one scope? A six inch refractor. Actually my TEC isn't quite 6 inch at 140mm but it will do the following: With a full frame camera, moderately widefield imaging... With a small pixel camera, fairly high res deep sky imaging... Visual: Sharp planetary views and beautiful DS ones which, though not 'large reflector deep' have that seductive refractor sharpness and contrast. Olly
  23. 8 points
    It's been two months in the making. And despite vacations, crappy weather, and equipment reconfiguration, I'VE FINALLY FINISHED! This image consists of 30 hrs each Ha and Oiii (3nm) as well as 1hrs each of RGB data for the stars. I shot the RGB data the past two night during the full moon so a little more data was needed. I originally thought 30 min each would do the trick but 1hr each produced much more colorful stars. This is my longest project to date so I tried to be pretty meticulous when it came to post processing, especially in getting that outer Oiii shell to show. I call it the energy shield! Anyways, I hope you all enjoy! The Crescent Nebula (Description by Nasa's APOD) - "NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This sharp telescopic portrait uses narrow band image data that isolates light from hydrogen and oxygen atoms in the wind-blown nebula. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. Visible within the nebula, NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life this star should ultimately go out with a bang in a spectacular supernova explosion. Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000 light-years away. " Eqiupiment: AT8RC CEM60 ASI1600mm-pro Astrodon HA/OIII/RGB QHY5L-ii autoguider phd, spg, pix, ps, dss Exposure details: 180x600s (ha) 180x600s (Oiii) 60x60x RGB (ea.) Dates: 7/4, 7/5, 7/6, 7/7, 7/9, 7/28, 7/29, 7/30, 8/1, 8/2, 8/3, 8/4, 8/6, 8/7, 8/11 8/12, 8/13, 8/14, 8/15,
  24. 8 points
    No doubt we have all looked at Ptolemaeus, Alphonsus and Arzachel many times but what intrigued me was to the north of Ptolemaeus lying between Herschel and Glyden is a long valley running slightly west of north. The more I looked at the area the more intrigued I became and so began the sketch. As usual I got carried away and kept sketching all sorts of detail, all over the area. So far I have been unable to find out any information about this valley. The terminator was fascinating – various shades of black??? Key features laid out at the eyepiece and then the sketch completed later. I have done two versions – my normal graphite pencil on white paper and then coloured pencils on black paper (need to develop this technique). On both I have used a white gel pen to enhance the white. Mike PS Looking at photos of the region this valley (Glyden valley) seems to be a very steep sided V-shaped valley, hence its very black shadow contrasting with the sunlit portion. Tried to imagine walking along it - awe inspiring with steep sides towering over.........Also noted it is on the Lunar 100 list.
  25. 7 points
    Spotted these on Facebook Marketplace for all of £12. They looked like a copy of my dream bins - the Nikon Nature 8x30 E II - and they were only a mile or so from my house so took a punt. You know what? They’re rather nice; great colour rendition, very sharp, light and have that wonderful perception of depth a really good porro bin will give you. It’s always a bit of a chance with Russian optics but find something good and they can prove excellent value for money. These are keepers. Don’t suppose anyone can identify the maker?
  26. 7 points
    Sun popped out for a bit this afternoon. After a bit of visual white light visual I found the seeing was pretty good for the time of day so decided to pop the Ca-K diagonal in and grab an FD despite the lack of activity.
  27. 7 points
    Last fall I bought a SW120ED, and said, fully believing, that it would be my last refractor. I should have stayed off these boards! I have bought several Borg scopes from Ted Ishikawa, the U.S. importer, over the years, and have been pleased with them. I didn't need one this aperture, but somehow the Fluorite bug got under my skin, and 18 years to-the-month after Ted sold me my first one, I landed this gem. I tell myself it fills an aperture-gap in my arsenal, and that helps. I admit, to myself, and to you my viewers, I am not to be believed regarding telescope acquisition limits henceforth and forevermore, Amen.
  28. 7 points
    Hello This is my version of M16. Just about see the pillars of creation Finally a couple of clearish nights over the past few weeks. Almost forgot how to set up! Telescope - 102mm APO ES refractor on a AVX mount Camera- Canon 70d unmoded iso800 with a IDAS-D2 filter. Duration 4.5hours - 300s lights., Darks, flats and bias frames also taken Guided with PHD2 and processed in PS Cheers thanks for looking. Of course any improvements welcome Dean
  29. 7 points
    I've been doing some testing using Starnet's Pixinsight module for creating starless images for processing, and I'm nothing short of blown away. Free, just a single click needed, with incredible results. It can only be used on non-linear images, but the results are so impressive that I might just get rid of my linear processing routine (deconvolution, MLT) as it recommends for untouched stretched images to be used; can use both colour and grayscale images. Created by Nikita Misiura, it can also be obtained free as an executable for Windows and Mac: https://sourceforge.net/projects/starnet/files/. 4 hours of IC 1396 (Elephant's Trunk Nebula) in Ha: 18.5 hours of IC 1805 (Heart Nebula) in Ha: IC 1396 Bicolour (Ha 4h & O3 6h):
  30. 7 points
    Astro darkness is still about half a month away, and I wanted to build a cloud warning system. With the addition of an environmental sensor, this became a simple weather station. It is based on an infrared thermometer and a Bosch environmental sensor: MLX90614-BAA https://www.sparkfun.com/products/9570 BME280 https://www.sparkfun.com/products/13676 Arduino UNO a small piece of perf board, two resistors (4k7) and a capaciter (100 nF) The cloud warning system measures the sky temperature and the ambient temperature. If the sky is clear, these two temperatures differ (sky cooler than ambient). If they are about the same, the sky is probably clouded. Nothing original with this probably, other than a creative use of home ventilation parts. Housing projects of this kind is always somewhat of a challenge. The enclosure must protect the sensors from bugs and dust, but at the same time not shield them too much. I came up with the idea to use home ventilation covers and an aluminium strip to build a well ventilated box. The inside is lined with a course filter. The IR sensor is hot glued to the top of the enclosure. Both sensors use I2C communication, so they are easy to hook up to an Arduino. (The IR sensor is the green part, and the environmental sensor is the red part. Note the two resistors that pull SCL and SDA high.) I also added a 100 nF capaciter across the power wires. The sensors are connected to a piece of perf board that holds the resistors and capacitor. I just modified the example code from SparkFun for each sensor. At the moment the weather station reports sky temperature, ambient temperature, relative humidity, and air pressure every 10 seconds. (The values marked with red are after blowing into the enclosure for a few seconds. I am aware that the IR sensor and environmental sensor report different ambient temperatures, but the difference is too small to bother me.) Next step is to make the station talk to INDI. I will probably use an open source protocol for this, so I don't have to write my own INDI driver software.
  31. 7 points
    This was a test run of Hypercam 174m. The skywatcher autofocuser broke so I got shoddy focus and I was trying to avoid sun burn, so could not correct the tilt totally. But happy with the cam, got 70fps, a contrast to the 3fps i got with my old cam and laptop.
  32. 7 points
    Yesterday, I managed a quick observation of Jupiter before the clouds covered the sky. Despite the average seeing, it was clear that the astigmatism was gone. The telescope works as when the cable sling was loosened. Good!
  33. 6 points
    The center star was very much overblown, used PS to tame the star back. Shot with ASI1600mm at 300 gain and 50 offset and 30 seconds. The gain was too high, but made lemonade out of lemons. I had 400 each of Ha and O-III and did a Bi-Color.
  34. 6 points
    Apologise for the delay in the update (had a few hiccups along the way) but the pier is now complete. Some changes were made to the original plan which I'll explain. The drawings were created using fusion 360 by @angryowl who I have to give a massive shout out for doing all the hard work (one of which being bearing with much of my nonsense but I'm happy to report he is tough as nails and has survived ) The pier now does not have a hole on the side for tightening and loosening of the center bolts. The pier now also has 4 slits on the pipe because the bolts from the pier adapter were falling perfectly in line with the pipe walls so slits had to be cut to accommodate the bolts. The slits were made slightly wider so that the nuts can be tightened using a wrench. The base plate is 12mm thick and a 460mm x 460mm. The corners were rounded off because i didn't want any accidents when the kids would be playing in the garden. The holes are 16mm and 300mm apart The total height of the pier from the base plate to the top of the pier adapter will now be 1150mm which means the pipe will now be cut down to 1096mm. The inside of the pipe has been given 2 coats of black hammerite paint. The center bolt as i mentioned will now act as a pivot and the top pier plate is tapped. M12 bolt is used Here's the pier now getting it's final 2nd coat and drying
  35. 6 points
    Luke Talley was one of the engineers at IBM working on the Saturn V flight computers (LVDC). Destin spent some time with him and the gear at the museum in Huntsville. So much of interest here. The video is 45 minutes long but it's worth every minute. Fascinating stuff and this guy is an absolute treasure.
  36. 6 points
    Just getting some good views of Jupiter with the 8" f8, unexpected clear skies. GRS is just coming in to view, but towards the other limb on the SEB I can see quite a big white oval. Anyone else out there seeing the same?
  37. 6 points
    New CEM60 now in the new observatory and combined with a William Optics ZS 73 APO + 73A flat. All the images are a combination of 6x300s subs @ 800 iso with a mono D5100, 7nm Ha Baader filter inside the 73A flat. Processing in PI + tweak in PS
  38. 6 points
    The North American Nebula is situated in the constellation Cygnus close to the star, Deneb. It represents a large area of ionised Hydrogen gas which is comprised of both this object and the Pelican Nebula. Being a Hydrogen emission nebula, it is an attractive photography target especially using a Hydrogen filter and is ideally placed being close to the Zenith. It is not known what star is causing the Hydrogen to ionise, however if it is Deneb then this object is c1,800 Light Years away. The dark area representing the 'Gulf of Mexico' is actually an interstellar dust cloud located between the observer and NGC 7000 which is blocking out the light of the nebula. This gives the object the distinctive 'North American Continent' shape. Moving along to 'Mexico' we can see an area along the 'west coast' where the gas has started to consolidate into a star forming region. The following image was taken on 3 August 2019 between 00.44 BST and 02.33 BST. It is comprised of 35 two minute exposures and calibrated with 25 dark, flat and dark flat images. These were stacked and processed using PixInsight. Equipment used; William Optics Z61; 2" Astronomik Ha 12nm filter; ZWO ASI 1600mm Pro Cooled camera set at Unity Gain and sensor temperature of -15c. Mounted on an HEQ6R-Pro. Guiding with PHD2 and image captured using Astrophotography Tool (APT). Thanks for looking in. John
  39. 6 points
    Quite a promising start , but after an hour cloud drifted in along with the idiot two doors away and his back garden plastic and rubber fire. Had a useful look at Cygnus, ψ Cygni ( SAO 32114). δ Cygni ( Rukh) lovely secondary just out of the glare. 17 Cygni ( SAO 68827) in a great wide grouping. Σ 2588 (SAO 48866) . Looking through my old notes, I found ΟΣ 410. I recorded this as a wide binary . Switching to x216 ( 5.5mm Meade UWA) and the secondary easily split open. I had this down below 1", but it was rock steady and quite mesmerising. Great to see some early darkness , been nearly a month after the heavy rains and low pressure . Getting great seeing helps , under clear skies ! Nick.
  40. 6 points
    So true. Just have an SGL whipround and buy me one and then you can all come round and use it for free!. I already have a suitable mount.
  41. 6 points
    Me for sure, found his Observers Book of Astronomy back in 1969, read it 5 times. Alan
  42. 5 points
    Hi, this is my first proper attempt at an LRGB image. I chose the North America Nebula and framed the shot to capture the Cygnus Wall. What do you guys think? Do the colours look good? I think my focus was off slightly for the red channel as the stars look a little bloated? 120mins integration time 1x1 binning. WO Z73 + Altair 183m Pro Tec + Baader LRGB filters Thoughts, comments welcome as I really want to learn and improve! Thanks
  43. 5 points
    Disclaimer: I don't do DSLR AP, but understand what happens, so will try to explain. Let's first talk about what ISO is. ISO is in principle multiplicative constant. As such it does not impact your image in any way with regards to SNR - which is important thing in AP. If you have some sort of signal that is let's say 100 units, and associated noise is 10 units (photons / electrons, whatever), and you apply high iso - you will be multiplying with some number like 10, so resulting signal will be 1000 and noise will be 100. Signal to noise ratio remains the same. Image remains the same once you scale it to display range 0-255. So in principle nothing major happens with high / low ISO with regards to captured data. On the other hand, there are things that happen when you change your ISO settings - read noise depends on ISO, and usually low ISO has higher read noise, and higher ISO has lower read noise. This will have some importance later in discussion. Another thing that ISO does is change your effective full well capacity. Let's say you have 14 bit DSLR. This means that digital values produced by your camera can have values in range 0-16383 (integer values). Actual signal that pixels detect can and usually is higher than this. In order to map hole range that pixel can receive to limited range of 14 bits - you need to divide it with something. Let's say your actual full well capacity is 60000 electrons. You need to multiply that with 0.25 to get values in range of 0-15000. Such values fit 0-16383. But when you select higher ISO, you will be using only portion of your true full well capacity. Sometimes with very high ISO you might end up having less than 14bits effective full well capacity. For example if certain ISO has multiplicative constant of 2, then actual electron count from 0-8191 gets mapped to output of 0-16383, and you end up having smaller effective full well capacity. Now back to your question about blow out. Only thing that makes a difference between stacking a few longer subs vs many shorter subs (of the same total exposure) is read noise. Or to be precise, how "important" read noise is. There are a few sources of noise (shot, thermal, LP, read noise) and difference between few longer vs many shorter comes down to how "big" read noise is compared to other noise sources. Maybe best way to illustrate this is by using triangles, as noise adds as linearly independent vectors: If read noise is close in magnitude to other noise sources like LP noise this happens: Total noise is larger than both read noise and LP noise. But if read noise is far less in magnitude to some other noise source - in this case LP noise, than this happens: So difference that read noise makes gets minimal and there is almost no difference between few longer subs vs many short subs. With lower ISO you will effectively have larger full well capacity, and LP signal levels will not occupy significant portion of the range, so single sub will not look blown out, but lower ISO will have larger read noise - which means you need to again swamp your read noise with LP noise in order not to make difference. What all of this means is: yes you can change ISO but there won't be any significant improvement in stacking result. If you have high background LP signal at 90 seconds - just use those exposures - going longer simply won't produce better results.
  44. 5 points
    I was looking for a better Lunar map on my phone the other night, and discovered this app, LunarMap HD which provides excellent zoomable maps and charts. The only thing it doesn't do which I would like, is show the terminator in relief rather than just as a line. There is an iOS app call Moon Phase Photo Maps which does this very well but it doesn't seem to be on Android unfortunately. A couple of screen shots attached.
  45. 5 points
    I almost didn't bother with these after seeing @Aussie Dave's recent Saturn - before I noticed he's 'aussie' Dave and not having to struggle with the planet being at 15 degree altitude, camera at 24-degrees (temperature) and the seeing being like boiling water. But tehre were some moments of slightly better seeing, scroll down for the results First run at Jupiter was ironically one of the best, and caught the red spot and Ioop with it's shadow just on the point of leaving the disk: One of the last Saturn's was best as it neared its 'highest' point: Finally, a rather crummy image of Saturn, a stack of nine long-exposure frames (the darn planet then disappeared behind a roof!) Definitely Titan, Dione and Rhea, I'm sure Tethys is there and even a hint of Mimas! Wait until it is higher up and I can get a thousand frames! 2019-07-22-2215_3_pipp_Saturn_l4_ap25.tif
  46. 5 points
    Hello to u all from "Hoth". I see its customary here to introduce yourself as a new member so here I am. I am pretty much a rookie when it comes to this hobby. I have had a lot of things going on over the years. I am a security / network equipment tech by trade, and what claims most of my time off is the work I do as a musician. The night sky always fascinated me tho. When I was a kid I used to put up a ladder onto the garage roof where I lived and lay back and watch the sky for hours. As for instruments to actually use for this, I always saw as unobtanium. However... In my early 30s one time i had some cash to spare, almost on impulse, I bought a skywatcher refractor. Dont remember the model, but it's a 70mm lens and about half a meter long. I got it in the mail, and it lived in the trunk of my van for some days until I one day took it to my office. Hehe - I didnt want to tell the missus I had spent money on a telescope. Haha so it sat in my office for a month or so before I brought it home and thought- she will understand. I brought it into the living room and asked her if she liked my telescope. I explained - it was not spendy and I always wanted one and figured now was a good time to get one. She wasnt overly enthusiastic about it - because she didn't see the value in it. But as time went by I took my oldest kid outside an evening with a full moon. He was amazed and frankly so was I. I shot some pictures of the moon just pointing the phone cam to the eyepiece. Showed it to her and she was also amazed. I was hooked instantly. So I set the scope up in our living room. After standing there at a window for a couple of days, the missus asks me - Is that one gonna stay there now? A simply - yes of course- was the answer, and here I am. Been watching YouTube videos to learn this, but I miss a real community, and found this place on pure chance. First thread I read coming from google was about some guys here discussing some eyepiece question asked on CN and after reading that I decided - no way I'm going there, I'm staying here - looks like it's a bunch of good guys here and I like the fact that its kept family friendly! I'm sorry for the lengthy introduction, but I thought I'd do it the proper way hehe. Any questions, feel free to ask. See you around
  47. 5 points
    Great Stuff Stu! What a fantastic scope by the sound of it! I've certainly split it with my 127 mak (true aperture 119mm) - smaller than this the secondary will merge with the diff ring of the primary I imagine, but maybe still visible in nights of exceptional seeing. This is a stacked image of Zeta Her with my 127 Mak, together with a simulation using Aberrator for 119mm aperture:- Chris
  48. 5 points
    Here's a couple from Tuesday. Not much surface activity, but a couple of proms. Taken with ASI 174 mono, Quark Chromosphere+/- 0.5x reducer and SW Esprit ED80 I've stuck to monochrome rather than false colour; I find PSE doesn't always produce consistent results. pc387
  49. 5 points
    This is my last image before heading back to the cloudy skies of Scotland for a few days. Biclolour rendition - 10hrs in each of O3 and Ha. I've tried to minimalise the processing this time and used my Ha as a final layer to add back in the detail. ****No stars were harmed in the production of this image!! @wimvb the Starnet++ module is very good. I tried it on this image and the results are excellent, it just didn't suit this picture. Thanks for looking. Steve
  50. 5 points
    This is 93mins of 3 min subs on 3 nights, all the 3's. Conditions varied a fair bit and last night was by far the best but was using gap in the trees time for M17, which I will add to further. It is nowhere near as good as the shot from a member the other day from similar latitude but he had a F/L advantage over me of about 400mm. Same old gear at the moment Canon 40D modded, and 805mm APO on AZ EQ 6. Spent what seemed an age getting PA back to something like only to kick the tripod, yet again whilst putting the roof back in place, life! Please feel free to offer advice, I personally feel it's a tad orange but was told that is fairly normal as there are a lot of orange star in the background, I could have taken it out but decided not to. Hope you like it, Alan.
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