alacant

Hi Nice shot. You've some nice detail emerging. Why not just remove the halo? The extraction takes most of the bg magenta with it too. This is with the .jpg. On a linear file, this would be far better. Cheers

Remember what we're trying to achieve... 1. We're trying to minimise lateral movement of the mirror relative to its cell as the telescope changes angle as it tracks the sky. This prevents the collimation changing. 2. The mirror clips are no longer needed, rendering cleaner stars. It must NOT be held rigidly, rather as @Craig aquite correctly notes, it should be allowed to expand freely as the temperature changes. Hence the need for sealant which does not harden over time or with temperature. IF you're uncertain of the suitability of a given sealant, leave a blob of it for a few days or so out in the conditions under which the telescope will operate and check for yourself. At the same time, let's not overthink this too much; anything is better than using the SW cell as it is and if you do get it wrong, the process is easily reversed. Cheers and HTH

Hi I can't, sorry. It seems rather country specific. Not sure where you are, but here is the Spanish version which we use. It's nothing special and is available at supermarkets; the ones which sell light bulbs and hammers as well as pasta and beer. The main property is that it doesn't continue to harden over time. Cheers

Hi What issue is it causing where it is currently positioned?

Hi If the filters are as close to the sensor as possible, you'll know you need to go bigger when they're blocking so much light that flat frames fail to correct the field. Cheers

Hi You have something -probably very simple- missing or have overlooked. All we can do from the information you have given forum-wise is guess what that maybe. By far the easiest way to get guiding working is having someone alongside who knows what they're doing. Your local astro club will be only too pleased to help. Cheers and good luck.

Hi Don't overthink it! A 1/4 unc bolt to hold the camera and a choice of Vixen or Losmandy. If at some stage you need portrait, a sturdy steel bracket. The 800d works fine with the asiair pro. We'd recommend a usb cable to connect: it's a mini-usb at the camera end. (note: Not tested with the older plastic asi verson.) Looking forward to seeing your mw results. Cheers and HTH

Hi You are trying to calibrate too far away from the equator - meridian intersection but anyway, most if not all the settings for your guiding arrangement are incorrect, except maybe the pixel size for the zwo. I'd strongly recommend starting again. Make a new profile with the camera and mount attached and live with the mount guide speeds for RA and DEC both at 0.9. Take ALL the default values. Change nothing Focus the guide camera and slew south around DEC zero and within say 30 minutes of the local meridian. Make certain the mount moves using PHD2's manual NSEW controls (watch the stars move on the display and/or listen for motors). Finally, slew N for a few moments. Now calibrate. Hopefully that will get you calibrated. Cheers and HTH

Don't know where you are, but there must be an astronomy club/gathering/meeting somewhere close. When getting low end gear up to ap standard, they're a god send! Cheers and good luck.

Hi That isn't coma, it's astigmatism; some Baader cc examples are better than others You can see that the corrector is doing its job on the coma as it distorts the coma-stretched stars back into shape. Going to 60mm may help but also fatten the stars centre field as may ensuring the front element of the cc isn't pinched. Assuming the secondary checks out OK (substitute one of known performance) and you have good perfect collimation, the only definitive method of curing both aberrations is to go with one of the 4 element ccs. Or just accept it and correct in software. Over a 533 sensor, it should be relatively slight anyway.. Cheers and HTH.

The best is the original prescription GPU. A search avoiding the term 'TS' shows it available here. There's also a used one here. For the 130pds over aps-c we use 52mm cc to sensor. At focus, this needs 10mm removing from the inner focuser barrel to prevent its intrusion into the light cone. That's ap. I've never looked through a PDS, with or without cc. Cheers and HTH

... and more helpful to the beginner. The biggest concept I've had to come to terms with in ap is that for me at least, pragmatism is the only way forward. Example. When I first started, I wanted to know how to stop the focuser slipping on my ed80 and how to prevent stars looking like big blue blobs. I didn't want endless commentaries about pinions/crayford/chromatic this/ lateral that... Most disconcerting also was that the very guys who had recommended certain hardware (in the days when the only recommendation was an ed80 and a heq5) had never been anywhere near the stuff they were recommending, let alone have any notion of how to fix it. The software side was even worse. If you really are serious about getting online with ap material, perhaps hands on with what beginners use and ask is probably the only niche left in the already overcrowded ap influencer market. There are many examples on this very forum where seeing it done would be vastly superior to reading about it, but still nowhere near the level of understanding you could gain from simply going along to your local astro club and fixing your 80ed with someone who knows what they're doing. Cheers and good luck.

Hi 600d, so dither at least 10 pixels between frames and lose both dark and camera sourced bias. Instead, simply pre-process by subtracting the offset (2048) from both the flat and light frames before registration. Stack with one of the clipping algorithms. Siril makes these tasks easy. Working with the linear stack, crop the frame edges and extract the background before photometric colour calibration. That will clean the background and so go some way to avoid artefacts introduced by other software😉 Cheers and HTH

Hi Stick a yellow filter, available cheaply, before the sensor. A #8 will control the blue without removing it completely. A #12 or 495 long-pass will remove most of it. Former preferred. If you're looking for a software method, split to rgb, use deconvolution with stars+halo selected on b only, then recombine. Cheers and HTH

Hi Use one of these and one of these. That gets you connected. If you're ok with the images, that maybe all you need😉 HTH

Apart from the eos circuitry which introduces its own artefacts when combined with conventional dark frames, the impossibility of matching the varying temperature of your dark frames with your equally temperature variant light frames introduces more noise rather than help eliminate it. 700d? Same here, so simply enter: =2048 in the field where you would normally enter the location of your master bias file. ... about dark frames on a 700d? Really? I'd guess the authors had never been near a DSLR. In this game theory, whilst maybe interesting to some, is of little use to those wishing to retain what remains of their hair. Cheers and HTH

Hi Dark frames of any type on a DSLR are bad news. Forget. Don't use... etc. DSLRs employ sizeable offsets. To prevent the flat frames over-correcting, this should must be removed. Don't know what camera you have but on e.g. recent eos models this is easily achieved by simply subtracting a constant bias of 2048. Don't forget to do this for the light frames too. No need to shoot separate bias frames. No nonsense, open-source method for this? Siril. Cheers and HTH

Hi Lovely shot. You have captured detail right into the difficult bright bits. Beats anything I've seen over 60s. Cheers

Hi You don't mention how you deal with any offset, but your description is consistent with incorrect or absent bias subtraction. The easiest way is to deal with this is to simply subtract a constant value corresponding to the offset you used. The more laborious, applying dark flat frames. Cheers and HTH

Hi We use and recommend DSLRs. True, a few years ago, early models were insensitive and noisy but technology moves rapidly. They are rugged, affordable and above all most have a decent aps-c sized sensor. A dedicated camera this big is going to cost far more than a DSLR. The images they produce are easy to process and of more than acceptable quality. From experience, we do not recommend going used for camera. Which DSLR? You don't need a top of the range model as most of the daylight shooting wizardry therein will never be used. Any Eos model with the 18mp sensor works well when astro-modified. We use mainly 700d and 4000d. The 24mp models are also good but we had trouble with the earlier 750d models. AFAICT, all newer and subsequent models are fine. Anyway, HTH you decide.

Hi Stu, everyone As always, lovely detail from the fast reflector.. To get this really good, perhaps have a look at tilt, bottom left and something which resembles a distorted dew shield, top right. Any ideas? Should be easy to locate and put right. Cheers and HTH

More nebula-safe stars. Alas, there are -perhaps disqualifying- dark bits. l to r ngc869, ngc884 and ngc957 in Perseo. Thanks for looking. eos700d + asahi takumar 200: ~90min, ISO800: st 1.8.527

Another go. This time in the nebula-safe area of Perseo. NGC 1245 Thanks for looking. eos700d: 90 min ISO800: st 1.8.527

Hi everyone Nice to see so many stars. We spend €enormous to be able to take images thereof. Then obliterate them to death! Here is HD34452 and friends in between the -not easy to avoid- gas and dust of Auriga. Thanks for looking. eos700d + Bresser-150: 90 min, ISO800:: st 1.8.527

Hi You've probably hit the mount limit at the meridian. Set RA to a few minutes after. Cheers