speckofdust

Obviously you already have the subframes as fits files, so you can omit the file conversion step.

I am not an expert, but when I used it recently, it gave me very good results for the same process that ended up with hot pixel trails in deep sky stacker. This is the process I follow: You need to put all your images ( light frames, darks and flats in separate sub folders named "Lights", "Darks" "Flats"- the names should be exactly those, otherwise it wouldnt work) in one single folder . Then head over to siril, use each of the tabs in sequence--File conversion, sequence, pre-processing etc.. While in file conversion, select the "change directory" button and select your "Lights" subfolder. Then click on "Add" with the plus sign that is to the right of the source box and add the files. If you have colour Light frames, add them all in one go and give a sequence name eg: light and then click convert. If you have separate R, G and B subframes, only add the individual channel frames and convert them under separate sequence names. Also do the same for your darks and flats. Once this step is complete, move onto the next tab- Sequence. You select all of the sequences generated in the previous process one by one and give a name and click "export sequence". before you do that you can reject the frames that you dont like by viewing them individually in the viewing window that would appear. next move onto Pre-processing tab. here you can choose your master dark and flat files and pre-process your sub-frames then move onto registration- fairly straigtforward process. Then plot- here you will see how your frames are differing in quality from the median line. Keep the median quality number in mind Then move onto stacking- you can either stack all your subframes or a smaller set. You can use the + or - symbol next to the "stack this set of images" to choose the number you want to get as close to the "median quality number " from the previous "Plot"tab. and then click start stacking which will give you the final stacked images for R, G, B etc There will be a number of options to choose within each of the tabs, but the good thing is that if you hover your mouse cursor over the options, there will be very clear explanation to guide you, so with some trial and error it should work. Having said all that I did not get good results when I pre-processed with dark and flat images- absolutely no idea why that happened, so I stacked without the darks and flats and got way better result than with DSS ( with dark and flat). May be I will figure it out one day or someone here can help.

stunning image. Inspiring me to work hard and do better.

Thanks Vlaiv for your advice, will give it a go with the sigma clip, can I ask what tool would you suggest instead of DSS then. thanks

hello all, would appreciate your advice. as you can see in the attached images, the stacked image of 7 Ha subframes is full of elongated hot pixels but the sub frame does not have any of these. The subs were stacked in deep sky stacker with darks and flats. funnily enough, the rgb frames from the same session did not have this problem. cooled camera asi1600 mm exposed for 10 minutes. Thanks for your help. I read a recent post which was discussing a similar issue and they mentioned something to do with dithering{ I am not sure what it is though}

Fantastic image. well done

amazing result

hello and welcome to the astronomy world! Few obvious things to check first- is the dust cap off the main tube? secondly, is the finderscope aligned in line with the main telescope tube? if it is out of alignment even by a small amount, the views you get in the finderscope and main scope will be very different. You can check this by focussing the telescope at a bright big object like the moon and then see if the finderscope has that object at it's centre of view. If possible you can try this on distant ( at least 100 to 200 m away) terrestrial objects in the day time. and also it's worth checking that you have adjusted the position of the eyepiece using the rotary focusser to bring the object into focus. BW

Isn't this something to do with parallel axis theorem. There was another video on the same subject, using mobile phones to demonstrate it, trying to flip them face forward.

Thanks Olly, your advice on adjusting the histo using the marquee selection really worked well. I was doing edge cropping previously and as I could not find a way to crop all the 3 RGB images in the same way, it created problems with matching the data when overlayed. I took dark flats as per your advice and restacked the images, but unfortunately that did not do anything about the vignetting/ amp glow. I will certainly look it up to find a solution as it is very difficult to get a good contrast between the target object and the dark sky around it. Thanks

Hello all, Could someone please look at the problems I am having with image capture and tell me what I am doing wrong? As you can see from the attached images (labelled "histo......." ), my histogram always has a little bit of unwanted extension in front of the foot of the main curve. These images have been captured with the same setup ( HEQ5 Pro mount, SW Evostar 80ED Pro, ZWO Electronic filter wheel with Baader LRGB filters, ASI1600MM cooled with no field flattener or reducer) and then stacked with Deep sky stacker using dark, offset and flat frames. There have been no manual changes to the position of the camera or the mount during image capture session and usually I would get all LRGB images in the same session. But the frames are not aligned in the same way when creating individual LRGB stacked final image which leads to that little extension in the histogram curve. I end up cropping the individual final LRGB images to get rid of that little extension and then have to manually align the LRGB images in photoshop. Also I have noticed quite a significant amount of what looks like vignetting on the right hand side of the images. It is not circular like you would expect to see with vignetting. So I am not sure if this is something to do with anything on the surface of the filters. I have looked at the filters and they look clean to me. Also, the pattern of the abnormal vignetting seems to be the same in the R, G and B images and probably in the L images as well, but it is not seen clearly in L. I have stretched the images to extreme to make the "vignetting" problem obvious. Any help would be really appreciated