StuartT

Ah. That's a mistake. It's actually 4.97ms and the gain was 0. (corrected now). Sharpcap camera data Gain=0 Exposure=0.00492 Reason I was confused is that I took one the following night at 1ms (I think I was trying to freeze atmospheric effects as much as possible). But thanks for the tip that it doesn't need to be quite that fast.

Doing a lot of experimenting at the moment to figure just what works best. And plenty of clear skies to try it out! Fairly happy with this one from the 17th. Best 20% (1000 frames in total). Gain = 0, Exposure 4.97ms, Esprit 150mm ED APO. No filters

gorgeous!

Outstanding! I've only used my 150mm frac at native length for the moon. But it looks like adding a Barlow is def worth doing. I guess you keep the exposure nice and short? like 1ms?

Thank you. Unfortunately they don’t ship to the UK

I need a cap (preferably metal) to cover the camera end of my focal reducer, but I'm not having much success finding one online. I need M48 with a female 0.75 thread. Any ideas? Thanks

That's interesting. I have been using zero gain becuase I thought you lose dynamic range at higher gain levels. Is that not right? I have clear sky tonight also, so I am going to try higher gain (which will allow me to use nice short exposure times). Thanks Yes, I used to use Autostakkert3 for stacking, but I found that Registax does a very slightly better job (comparing directly with the same images and the same wavelet sharpening settings)

Interesting. Thanks. I assumed that the histogram was a guide to correct exposure. Fortunately, I just looked back at last night's capture (with which I got this image) and see that Gain=0 Exposure=0.00492 So I just managed to sneak under your threshold vlaiv 😃

Any advice anyone? Is this curve looking right for a good exposure? I'm assuming the white bar at the bottom needs to be about 30-40% along the x-axis, but am I right to check the 'logarithmic' box? Thanks

Thanks. I just left it and it did eventually finish. Here is the product of its labours (3128x3128px)

I shot some admittedly rather large .SER movies of the full moon tonight on a 2600MC Pro at 3800x3800. They're 5000 frames and about 50GB each. Registax is taking absolutely for ever just to align them. I haven't even started stacking yet. I read somewhere that if you set too many align points it gives it too much work to do. Is that true? I set 383. Is that a reasonable number? What are the practical upper limits of Registax? Or will it cope provided I just wait long enough?

Those of you who use SharpCap for lunar, can I just check that my histo should be set to logarithmic to get the right exposure to be 30-40% ? Thanks

thanks. Info added to the OP now.

and with the same setup four nights later. This time 600 stacked frames (the best 20% of a 3000 frame movie)

Reach for the lasers Olly!

thanks SO much @vlaiv . Really appreciate you taking the time to advise me.

great! Thanks so much. I shall bin 2x2 from now on then. I can set that in NINA easy enough. I think it will also reduce my file size yes? Not really sure how I would bin after the images are taken. I thought binning was a camera setting? But maybe there is image processing software that can do this? I use SiriL for stacking and processing, with a little Photoshop at the end to remove gradients.

Actually @vlaiv I can't see any difference in the two versions - either in terms of signal or noise! But clearly you can, so I shall take your word for it. So I guess all I need to do is reduce the size of my images after I have finished processing them. I can do this in Photoshop - so just resize down to 66%. Thanks. One last thing... you said the word 'need' suggests I have a choice in this. But the 0.96 is a function of my camera and my focal length, so I don't really have a choice. Unless I can find a camera with larger pixels (which you advised against). So I guess just resizing down to 66% is the solution

Thanks again @vlaiv I don't know how you know all this stuff, but it's truly impressive. Unfortunately, I don't really understand much - if anything - of what you actually wrote. I am clearly out of my intellectual depth here (and I am a scientist!! 😬 ) I don't really know what you mean about finding out if my images are oversampled. I don't know how I would measure FWHM (which I think is the size of the stars, right?). But all my images are shot with the same rig (so at 0.96"/px) so perhaps you can tell me if they are oversampled? For example, https://stargazerslounge.com/topic/387610-m33-and-m42-last-night/ https://stargazerslounge.com/topic/386331-final-image-of-the-eastern-veil-nebula-for-this-year/ https://stargazerslounge.com/topic/385080-eastern-veil-with-l-extreme/

Thanks for this @vlaiv and sorry you have had to repeat yourself. So first thing is, my camera is colour, so it sounds like what you are saying is that there is not a lot of point in binning as it won't improve my images in any meaningful way. BTW - According to this, 0.96 is not oversampled.

I currently have two ZWO cameras. They both have a pixel size of 3.76 um. With my Esprit 150 and reducer this is giving me a pixel scale of 0.96 which is just about OK (slightly verging on the oversampled). But I also have a 20cm SCT with a focal length of 2030mm, for which both cameras would definitely be oversampling. So.. for the SCT, should I (a) try and find a camera with bigger pixels? If so, any recommendations? Or (b) should I just use 2x2 binning on the existing cameras? Is there a difference between the two approaches?

I think I have the exposure right now. This was stacked from the best 30% of a 1000 frame .SER Esprit 150ED with 0.77x reducer (808mm FL, f/5.4) EQ6R-Pro mount ZWO ASI 2600MC Pro Captured in SharpCap 3.2 @ 7 frames/sec Stacked and wavelet sharpened in Registax, de-greened and levels adjusted in Photoshop

Nice clear night here last night.

I decided to try out swapping the various channels in an image to see what kind of effects I could get. This is purely for artistic/aesthetic interest, by the way. I am not claiming that the different versions of the image actually 'mean' anything. Just in case it's of interest, here's what all the various channel swaps look like from an original image of M42 I took last night

Maybe take up astrophotography instead? (then you can stay indoors) 😉