Padraic M

5 hours ago, andyofastro said:

Thank you for your reply.  I'll blink through the calibrated frames tonight to see what I can see.  As a wider question about imaging with Newtonian's and when to take flats:  I would like to gather imaging time over multiple nights, which may necessitate removing the rig from the garden between imaging sessions.  I am therefore assuming that I should be taking flats before removing the scope between imaging sessions.  I am also assuming that those flats should only be used to calibrate the images from the same night.  Then, only after all frames from multiple nights are calibrated with their corresponding calibration frames (Darks, Flats, Dark Flats), should the calibrated frames be stacked together?

Yes indeed, that's a good and commonly used plan. Just also fyi, most stacking software allows you to group lights by session, and assign calibration frames to each session so you don't need to manually calibrate each session before stacking the outputs. I use Astro Pixel Processor and it handles this almost seamlessly. DSS has a way to do it too. 

4 hours ago, Altair8389 said:

2) Another issue, is there a light leak problem with this reflector ? I noticed when getting a dark frame, the dark frame was NOT DARK. In fact doing a dark in the daylight led to a white out in the frame. I notice maybe you need to cover the primary mirror cell, maybe the focuser tube or front of the scope. Is there a common thing you have to do ?

Oh yes there is indeed! The 150PDS is a nice scope to image with, but it took quite a while to get all of the niggles sorted out up front, including the light leaks.

Three places to seal when taking darks:

1. Cover the front of the OTA (obviously!). The standard cover should be enough but I usually throw a sheet or a black sack over it too.
2. The primary cell 'rear' end of the OTA. People recommend stretching a black swimming cap over the end. I use a woolly had because I don't have a swimming cap! I just leave it in place permanently, as if it's leaking light during the daytime, it stands to reason that it also leaks light, no matter how little, at night.
3. Most importantly, cover the focuser draw-tube. Best bet is to wrap it with tinfoil; enough to stop light getting in between the drawtube and the holder. Again, I leave this in place permanently. Wrap it well, but make sure that it can still move freely for focusing.

The best way to test is to put your capture software on loop, set the scope up as you would for taking darks, and shine a really bright flashlight all over the OTA. You will see the leaks quite clearly in the captured frames.

I now never have a problem taking darks with the camera in situ, which I like to do so that I'm not impacting alignment or rotation by removing it.

That's no moon....

🙂 I've seen it too!

Definitely check on focus. I find that adequate focus is hard to achieve without an electronic focuser (others disagree) but either way, sharp focus makes a big difference. Cloud tends to reduce overall contrast, rather than sharpness.

Do you need those filters at all? Less glass between you and the target tends to be better, unless you have a specific reason. And, of course, once you have your setup dialled in, many times more subs will be required!

Just a quick thought - focusing your guide camera can be a bit tricky, and if it's well out of focus you can get a sea of noise. Luckily, it just needs to be done once as long as you don't knock it out of position as fine focus isn't really that important for the guide camera.

Your log file seems pretty clear alright, although it doesn't mention horizon limits but it stops tracking 22 minutes before the flip. Is there a message telling you it has hit limits?

I assume that your light frames from before that time are clear, and correctly platesolved over the Orion nebula?

Can you check your limits settings in ASCOM? If you disable limits entirely will it work? If your limits are correctly set at -90/+90 then maybe there's some mistranslation between ASCOM and the new NINA version so upgrading your ASCOM platform sounds like a definite plan.

So stupid questions first - is the power light on on the PSU; is the red light on on the cigarette lighter plug? Is the Amp meter reading anything?

Is the power light on the HEQ5 coming on? If it's under-voltage, the red led will blink. If there's no led light at all, then you've probably got a cable/connection issue.

If you have a flashing HEQ5 LED or solid led, then use the handset Utilities menu; there's an option to display the voltage into the mount. It should be 12V or more.

Sometimes I have an issue with those cigarette plugs. There's a small ring around the positive tip of the plug that unscrews to take the plug apart. Make sure that it is fully tightened; and obviously make sure that it's fully inserted.

But the state of the various lights and LEDs will tell you where the problem is.
i.e.

- no light on the PSU: faulty PSU/not switched on/plugged in etc. 
- no LED on the cigarette plug: plug faulty or not fully inserted
- no light on the HEQ5: faulty cable (hopefully) or faulty HEQ5.
- flashing LED on the HEQ5: undervoltage (poor quality power cable probably)
- Solid LED on the HEQ5: check the voltage on the handset, but possibly a faulty HEQ5 motherboard, but the handset display will normally tell you if you have a HEQ5 motherboard fault.

hth, let us know how it goes.

Absolutely should do the job. I use the bigger 30A cousin and with HEQ5 (or NEQ6 Pro), cameras, dew straps, mini PC, etc., it never goes above 4A draw. Holds the voltage steady well above 12V too.

54 minutes ago, GalaxyGael said:

Nice one, decent fov at 750 mm. About the max fl for me too with 3.76um pixels. 

Thanks Colm. Agreed, the FOV is ideal or this target. I just cropped out the stacking artefacts. Thought about different composition, especially given the 533's square format but don't think it would add much.

I have some old data including Ha that I may incorporate to see if I can bring out any more detail.

This year's iteration of NGC2903, and definitely the best. I hadn't set out to image it again, but it was a matter of dodging the clouds and the moonlight so targets are limited. I wanted to get some RGB Orion data, but it looks like galaxy season has started early! 

4.75 hours of RGB as 57x 300s.

Bortle 2, 60% moon, 30% cloud.
Capture: SW 150PDS, ASI533MC Pro, NEQ6 Pro, Nina, phd2.
Processing: AstroPixelProcessing, Siril, Gimp.

3 minutes ago, ollypenrice said:

A year of change, for me, collaborating with Paul Kummer and a joint RASA/OSC CMOS/Avalon Linear rig under Paul's robotic control. I'm just the on-site mechanic and do the post-processing. The RASA has opened up new targets (very faint ones) but the best we've done, technically at least, is this widefield Pleiades.

It's a large image so, to see the real point of it, you'd need to follow this SmugMug link, go to full screen and then click to enlarge. https://ollypenrice.smugmug.com/Other/DUSTY-DARK-AND-MILKY-WAY-TARGETS/i-RXwsZdg/A

Huge thanks to Russ Croman, author of StarXterminator, BlurXterminator and Noise Xterminator, software packages which have transformed post-processing.

Olly

Wow! Amazing depth.

A really poor year generally with one cracking spell over the summer holidays in August which I spent fettling a new OSC setup based on a SW 150PDS and a ASI533MC Pro. Got a selection of images (and very little sleep) that week, but this IC5146 Cocoon Nebula is my favourite. I've had practically no imaging nights since then due to weather

Yes, snags can be part of the game, but I haven't had your experience with the handset cable. I have the same ferrite block and still have it on the mount end rather the handset end. I don't know if there would be any issues with reversing the cable - I suspect not, but as a point of info, I also have a NEQ6 and the block is also mount-end, and the cable is not reversible.

On which tripod leg have you mounted the handset? If it is on the North leg maybe that's your problem. Mine is on the 'SW' leg (counter-clockwise from N) and as I said, it never snags.

I think they are likely to be dead pixels in the camera - hot pixels in this case, where the pixel is 'always on' or 'always bright'. You always get them on DSLR sensors, and I'm sure other sensors too, and you may get more as the sensor ages. Your calibration frames will sort them out.

If you don't have calibration frames for this particular run, you could try stacking using 'Sigma Clip' algorithm, it's pretty good at removing artefacts like this. Otherwise, Gimp Clone or Heal is your friend!

Dithering is important too, but even better if you don't mix them into the stack in the first place (by calibration).

+1 for the HEQ5, it's a very solid tracking mount for astrophotography. The 150PDS is also a great scope - great value for money, good-sized aperture, easy to use, good quality optics. It will give you years of enjoyment. Not perfect though, and you will find info on the web about some simple mods that make a big difference. The main issue that I had when I started with mine was that they leak light through the focuser and from behind the primary mirror. A black swimming cap is recommended over the back-end,  and I use some tin-foil wrapped around the focuser draw-tube. Looks very low-tech but it works for me (although I use a woolly hat because I didn't have a swimming cap! 🙂  )!

If you enjoy tinkering, there's no end of fun to be had with a HEQ5 and a 150PDS.

As mentioned above, the ZWO camera will work well for planetary, using Firecapture or Sharpcap. Stick with the DSLR for DSO until you can afford a cooled ZWO, and use BackyardEOS or Astrophotography Toolkit (APT) for DSO capture. Take a look at APT, it's very good. NINA is great for DSO capture, but last I looked it didn't support DSLRs. (afterthought: the latest version of Sharpcap has greatly upgraded its DSO capture capability but as I'm firmly in the NINA camp by now, I haven't looked at it).

Superb image! Really pops.

I'm sure Beverly Lynds never saw it like this, but it would be interesting to see the resolution on the original Palomar 48" plates. The catalog lists LBN 532 as brightness of 1 (brightest on a scale of 1-6) and colour of 2 ("equally visible on Red and Blue plates). LBN 531 is brightness 3, colour 3 ("more Red than Blue").

Very nice image David, I think I prefer the normal processing. Purely personal preference of course, both are great.

2 hours ago, maw lod qan said:

I saw the area of the deep field image described as being the equivalent of you holding a grain of sand at arms length.

 

I have to say that this description didn't really mean that much to me so I tried an experiment. 

From here https://webbtelescope.org/contents/media/images/2022/038/01G7JGTH21B5GN9VCYAHBXKSD1 we know that the Webb Deep Field image is about 2.4 arcmin across. From Stellarium, I can see that M51 is approximately 11'12" x 6'54" - so almost 7' across in its narrowest dimension.

Here's an extract from my latest M51 image with an overlay of what I believe to be the field of view of the Webb NIRCam wide field image. 

NIRCam's pixel scale is 0.031" (short wavelength channel) or 0.063" (long wavelength channel).

2 hours ago, gorann said:

I have not followed all the entries on this thread, so maybe this has been discussed: JWST is an IR telescope and I got quirious. Has anyone here tried IR astrophotogtaphy? Googling it gives rather few entries, but this one got me interested:

https://www.cloudynights.com/topic/554666-nirha-preview-of-horsehead-project/

This chap has experimented with an IR-pass filter and a mono sensor to capture galaxies from Tokyo centre with reasonable results. It's on my list of things to try as part of a narrowband setup in Bortle 8 at some stage.

https://satakagi.github.io/IR-imaging-of-galaxies-under-light-pollution/

http://uwakinabokura.livedoor.blog/archives/9101874.html

11 minutes ago, wimvb said:

Apparantly the various instruments  have a fov of about 1-2 arc minutes, the angular span of a ”grain of sand at arms length”. To me, that makes the deep field image even more impressive.

Someone on the NASA broadcast today said something like "we can't capture dark space" which I took to mean that wherever JWST was pointing, that 1-2 arcminutes (squared) is full of galaxies. That's a lot of galaxies.

Perfectly acceptable @Mark Jo, and actually desirable. As said above, a charged 12V battery is actually over 13V. I use a https://www.nevadaradio.co.uk/product/nevada-psw-30/ psu which provides a fixed 13.8V output.

The danger with using a 12V supply is that as your equipment draws current, the voltage will drop, and if it goes much below 11.5V you will see some strange behaviour from the electronics, especially your mount. We've all spent hours on cold dark nights trying to fix erratic hardware when using cheap or under-powered supplies.

My #1 rule now is if really strange things are happening, check the supply voltage. 9 times out of 10 I have accidentally switched the PSU output from 13.8V fixed to the adjustable voltage setting (easily done with a big switch on the back!).

I have an external 240V socket with a 5m extension cable to the mount. Nevada 30A is located at the mount - in a plastic crate if I'm going to leave it unattended. I use the cigarette socket output with a Lynx Astro cable to a PPB Advance on the mount. The Nevada outputs 13.8V which is plenty for all of the electronics. I know that some people object to the cigarette plugs and sockets as the quality can be variable but I haven't had any issues, certainly not with Lynx Astro cables. The PPBAdv powers mount, dew heaters, imaging camera, PLL focuser and mini PC. I have enough USB sockets between the PPBAdv and the PC.

Edit: the whole setup doesn't draw more than 3-4A even when slewing.

Next step is to encase the camera in concrete...  🙂

12 hours ago, david_taurus83 said:

To check, put the cap on and connect camera to PC and run a series of looped exposures. Note the average ADU value in the histogram/statistics. Then shine a very bright torch on the camera where you think it may be leaking in light and check the ADU value. If it goes up, you have a leak. If it stays as it is, no leak.

I did this with my 1600MM recently and found no leaks in the camera. Found plenty in my 150PDS newt 😞

@BrendanC has an interesting conversation ongoing at present elsewhere on SGL (can't remember the post link) and Vlaiv has suggested ways to analyse if you do indeed have a light leak in your darks. Current consensus seems to be that the camera is fine; the scope leaks; darks aren't materially impacted but flats are.

Not sure what difference there is, if any, between the 1600MM Cool and the 1600MM Pro (I have the Pro) but the Pro certainly does have some amp glow so I'm in the 'darks no bias' school. I've never suffered from light leaks through the camera though, as far as I'm aware.

I have a 150PDS and it leaks from every joint, and I'd expect the 130PDS is similar. The lens cap on the front is fine; a hat over the primary end is also fine. The focuser draw-tube is tricky, especially as it has to provide some flexibility for focusing. My current solution is a strip of tinfoil wrapped snugly around the focuser joint. It's working fine for me now. I don't cover the camera.

I've never noticed issues in darks due to light leak, although intuitively they will be impacted if there is environmental light while you're capturing them. This really means, if you haven't light-sealed your OTA, that you take darks in the dark, or off-scope with a covered camera. My biggest impact from the leak was while capturing flats as the light from the flat panel illuminated the focuser tube and caused an off-centre 'swipe' mark across the image. 

I now have reduced the issue to the level where (if it's not gone entirely) it is negligible compared to any one of my many other problems!! 🙂

I don't have any leaks (again, that I'm aware of) with my refractor Esprit 80. I'd be interested in hearing how you get on with the Lacerta.