Swillis

Thanks for all the advice @alacant, I've finally had chance to finish reprocessing this and its looking better now. HH is definitely clearer now. The debanding worked well before stacking, but it didn't cope with the Orion nebula well as there were dark vertical bands above and below it but another round of debanding on the stacked image appeared to sort that out. The manual processing was easier than I thought, and will use it again in the future. Thanks again!

Haha, hadn't noticed the original post date 🤣

Rotating by multiples of 90deg should be fine and not result in loss (pixels are square after all). Anything other than 90 and the software has to make a guess at what the pixel value should be. Presumably stacking software has to do this to some extent when rotating images? Happy to be corrected if I'm wrong, this is based on experience of a piece of equipment at work.

I'll pass this on to support my funding application 😅

@alacant thanks for all the tips. I have started looking into using Siril manually so hopefully better results will be on their way. Was that image using the snapshot I posted? Goes to show how valuable experience is in processing. I tried using per sub background extraction. Is this usually a good idea? @Astro Noodles yes, I am pleased with it 👍 Thanks

Hi, Thanks for the nice comments. @alacant sorry if my description wasn't clear, I used the bias frames for bias and dark. I think this is what was recommended for Canon DSLRs? Although I could have misunderstood. I will try the banding reduction in Siril, but might be a few days before I get chance to have a go. Also 500 subs takes a long time to stack. I don't have guiding so don't think I can dither? Although I probably have a fair amount of 'natural' dither from a fairly poor polar alignment due to no direct line of sight to Polaris. @Sterrenland it's great when these objects start to come out of the dark. The reaction from my wife when she saw the stacked image on the computer was 'its amazing what you can see that from our garden'. @RoloFanatic they are from the way the aperture closes is a camera lens. The 'classic' 4 spikes are from the secondary mirror supports on a newtonian reflector. @Astro Noodles it think it was the 4,5,7th Jan. That run of decent night's after all the cloud. No mods just stock. @Elp yes liking the wide field, might go a bit wider next time. I guess that's why the samyang 135 is so popular, and I'm very tempted to invest in one. Thanks again

Here is a snapshot of the autostretched image showing the coloured bands on the image. Happy to upload any other files if anyone thinks they would be useful in diagnosing the problem. Thanks

Hi all, So it's not really my first image, but it's the first one since I upgraded from a barn door to a star adventurer. The barn door was fun to build, but took a long time to setup and with two little ones about I need something a little quicker to setup and take down. The star adventurer is my first real investment in astrophotography. I'm using a Canon 350d DSLR and a 75-300mm lens which I already had, so I wasn't expecting anything fantastic but I'm pretty pleased with the final result, even if there is plenty of room for improvement in data acquisition and processing. Here it is (yet another newbie takes a pic of M42) Approx 500 X 30sec exposures over three nights stacked with flats and bias (bias used as darks) in Siril. After I applied background extraction, and photometric colour calibration I noticed some strange vertical colour banding on the image. Not sure what's causing this or if anyone has any ideas? I've tried a different set a flats but it's still present and if I take only a single nights data it's still present. I managed to remove it during the histogram stretch, but without the banding I would have probably got more detail. Thanks for looking, just wanted to finish by saying thanks for everyone help with previous questions, you really are a very helpful and knowledgeable bunch. Also Siril is great!

@DaveHKent Worth trying Siril for processing. I'm a beginner myself and have a lot to learn about processing, but I kept hearing about Siril and how it is better to do certain bits before stretching. So far I'm very pleased with the results even if I know there is more detail there than I have brought out. Also it's recommended not to take darks for Canon DSLRs. Just take bias and use that for bias and dark frames. Apparently Canons have part of the sensor masked off which is used to subtract the dark current, so darks frames are not required.

With a good polar alignment you should hopefully be able to get 1-2min exposures but it will also depend on the focal length your planning to use. I have the 2i but have only gone up to 30sec exposures using 160mm focal length since I don't have a view of Polaris. If that's the same 75-300 lens I have then I would recommend taping down the zoom ring as it has a habit of slipping.

Hi all, My father in-law is looking to get a telescope for his birthday and is looking at the Starquest 130p https://www.firstlightoptics.com/sky-watcher-starquest/sky-watcher-starquest-130p-f5-parabolic-newtonian-reflector-telescope.html I think the 130 is a good scope to start with, but I wanted to know if anyone had experience of the mount? Is there much wobble? Should I suggest a sturdier mount (depending on budget)? The other issue is that it is out of stock for approx next 3 months!

Thanks @vlaiv, and sorry @Astro Noodles for hijacking the thread

@vlaiv thanks Not sure if I'm looking at the right thing. I opened the files in SIRIL but I'm not familiar with it yet. If I go to image information>statistics I get 257 mean for bias (2403 max) and 257.3 mean for dark (4095 max). Not sure if these are ADUs or not?

@happy-kat thanks, I had been reading that thread. Very interesting. @The Lazy Astronomer it was all left connected and the focal length was taped down throughout so hopefully it hasn't shifted. I'll give it a go and see what I get 🤞 Thanks

@vlaiv any idea if this applies to any Canon DSLR? I have a 350d, not sure if that's considered a bit 'vintage' 😅 Thanks

Hi, I'm using a DSLR, Canon 350d with a 75-300mm lens. Quite a basic setup. I don't have flats from each session. I'm assuming a set of flats covering all sessions would be better than none? The darks were taken straight after the lights. But I had read recently about differing views on of they should be used for DSLRs. I then read in another thread this evening that Canon DSLRs don't need them as they have internal dark calibration. Not sure if that's the case with the 350d or just more modern ones!

Hi, I have a couple of nights of data from a dslr which I plan to stack in DSS. From what I understand I need to put my flats and bias frames in the main group and each nights light and darks into their own group? That way the flats and bias get applied to each group but the correct darks are associated with the correct night lights? Thanks in advance

@reezehYes certainly is an older model. Had it for a long time, and know that high ISOs were very noisy even as you point out in daylight. Maybe I'll get to upgrade one day, but for now it's serving me well as I get started in AP. I think the links @ONIKKINEN provided give me a good rational starting point (as a scientist I like a nice graph!) Thanks

Thanks Elp, What camera is that with? I guess with most things in this hobby a bit of experimentation is required, but enough clear nights would be helpful to try things out😅 A good starting point is always helpful Thanks 👍

Looks like you've had plenty of great advice here. As mentioned by many above, with so much to learn it is a good idea to keep it simple. With that in mind you could go even simpler than suggested, if you have a DSLR and lens you could start with that and add a mount. Either something simple such as a star adventurer (or similar), or as you mentioned you preferred to 'buy once' then get the mount you want to run your intended equipment on and learn the basics before moving onto something bigger/more demanding/complicated. There is lots to learn from setting up, through taking images, guiding and processing if you can smooth the learning curve out a little that should go a long way to keeping your interest going. When you talk to your family friend it may be a good idea to ask for their story of how they got into AP and what gear they started with. Best of luck

Thanks for the swift reply they look like very useful resources. Looks like 400 it is then. 👍

Hi, pretty new to AP and I was interested in how everyone chooses what ISO to use? Is this more camera/scope/lens or target based? I'm guessing LP will have a big part to play here also? I have a Canon 350d with a (kit) 75-300mm lens on a star adventurer. ISO 800 (maximum is 1600). Using what I have to get started... From what I understand ISO shouldn't matter for signal(?) As it effectively multiplies the signal, same number of photons reaching the detector. But also read noise goes down at higher ISO? So we should use highest possible ISO

Well they all look better than my effort so far. Looking forward to getting more data once the clouds clear. @Stu Wilson love the Look of the diffraction spikes

Worth a go with the webcam, if it works great and anything to build on that interest. Probably worth testing it out first or getting it setup without your daughter about, least of all so she doesn't hear all the swearing when it all goes wrong, but watching for ages as you try to set it up will do nothing for that enthusiasm. With our 4 year old, I've found binoculars on a tripod to be very good (easier than lifting her up to the telescope eyepiece). Your not going to get the magnification of a telescope, but it's easier for them to see through with two eye pieces (certainly for a 4yo) and good for looking at the moon and showing Jupiter's moons. Even a pair of kids binoculars are able to show them a bit more than they can see unaided. Also, I have heard that the small table top dobs are really great for kids. I plan to look into these in a few years if my daughter interest continues. Good luck, I hope her enthusiasm continues.