Image processing (and stacking)

[Arcturian]

I've read about how people stack images to build a more intricate image, I also know this is done with different filters, but i'm wondering is there any way on a DSLR that you can take multiple images and stack them to create a better picture

What do you guys process images on, photoshop? I've got a photoshop 11 license, have downloaded some software called RegiStar, which allows you to split astroimages into RGB copies, and (i think) allows you to stack different images. I'm sure there are a few other functions but I've only looked at it at a glance because I haven't received my T-Ring adapter to mount the camera. When I do i hope the software will take on some use

TL;DR What can be done to improve & process astroimages & on what software?

Welcoming any tips/questions for someone starting out on astrophotography & image processing.

[jgs001]

For imaging with a dSLR, you want to use DeepSkyStacker for stacking the files the camera produces. You need to do this even when not using coloured filters, as the stacking process helps increase the signal to noise ratio. The help file in DSS is very good at the details of the input files needed.

Once stacked, then off to photoshop for the stretching and further processing.

I've not looked at/played with RegiStar so I cannot comment on it I'm afraid.

[Astrosurf]

I assume you want to do Deep Sky Objects (DSOs) like nebulae and galaxies? If so, you would ideally need a mount that can be autoguided to enable you to achieve shots (subs) of several minutes. If not, and your mount tracks well, you might get 30-60 seconds of a bright object like a globular cluster. You would take at least 15 of those. 25+ is best! Then take darks (to be explained later . . .)

You would then stack those in Deep Sky Stacker as John said.

But if this is your first foray into astro imaging, I would strongly advise you to read the imager's bible first!

http://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html

Alexxx

[Arcturian]

Once stacked, then off to photoshop for the stretching and further processing.

What exactly is stretching? I know there will be a tonne of Photoshop astro guides, but is there any few things in particular that you guys find really enhances the image in photoshop, because yeah, I could and eventually will end up fiddling with every feature on photoshop to see what works and what doesn't, but if there are some things that are strongly recommended then I may aswell learn them first. I've booked your imagers bible link and will delve into it later tonight

[Arcturian]

Sidenote: When am I able to edit my own posts? Nothing major, just that I should have been more clear who i was replying to at what time

[jgs001]

Pretty much... it's all about curves... the data is buried in the black point of the histogram displayed and you have to pull it out to reveal the detail.

I started out using this guide that MartinB posted

http://stargazerslounge.com/topic/9392-3-primer-how-to-stretch-the-histogram-using-levels-and-curves-long-download/

There is no one answer for any image, as photoshop has several ways of achieving any particular edit, adjusting an astro image is as variable. On various occasions, I've thrown away numerous edits as I didn't like where I was going with them, and started again. I have never yet been able to reproduce what I've achieved before, even on the exact same data.

[Cornelius Varley]

Sidenote: When am I able to edit my own posts? Nothing major, just that I should have been more clear who i was replying to at what time

When you have reached 250 posts.

[PeterCPC]

Nebulosity is also good at stacking but requires more user input. I think that it gives better results though. 

Peter

[Arcturian]

Hoping my T-Ring arrives tomorrow, until then is there any way I can practice on DeepSky Stacker? I'm going to redownload Photoshop and practice, no reason why I can't do that, right? Just use any old image, will this help me at all or will working on a piece thats already processed be so different that it's not worth it?

Please do let me know about practicing on DSS, if it's possible & maybe even some tips on what to do

[jgs001]

Have a look at http://stargazerslounge.com/topic/36308-basic-widefield-with-a-camera-and-tripod/... you can have a go with kit lens etc. 

If you're thinking of mounting your 1000d on the 130, there may be some focus issues, insufficient inward travel... I've no direct experience of the 130 focus as I've never used one, but it's something I've read numerous times on here.

[Arcturian]

Have a look at http://stargazerslounge.com/topic/36308-basic-widefield-with-a-camera-and-tripod/... you can have a go with kit lens etc. 

If you're thinking of mounting your 1000d on the 130, there may be some focus issues, insufficient inward travel... I've no direct experience of the 130 focus as I've never used one, but it's something I've read numerous times on here.

Noted, i'll know by the end of the week

So I've reinstalled Photoshop 12, read a tutorial on Curves, played around with an image of M42 - the Orion Nebula. Went pretty well, managed to make it look significantly different, and not in a bad way.. when you said its all about curves, jgs, do you really mean 'ALL' about curves, surely there is other things to do too? First astroimaging tutorial i read did lead me straight to curves though to be fair.

[Tinker1947]

Take a stroll through this site Doug does some nice video's to get you on your way.....

http://www.budgetastro.net/

[jgs001]

You can run some noise reduction and sharpening if needed, but curves is your workhorse tool.

Sent from my GT-I9300 using Tapatalk

[lensman57]

I've read about how people stack images to build a more intricate image, I also know this is done with different filters, but i'm wondering is there any way on a DSLR that you can take multiple images and stack them to create a better picture

What do you guys process images on, photoshop? I've got a photoshop 11 license, have downloaded some software called RegiStar, which allows you to split astroimages into RGB copies, and (i think) allows you to stack different images. I'm sure there are a few other functions but I've only looked at it at a glance because I haven't received my T-Ring adapter to mount the camera. When I do i hope the software will take on some use

TL;DR What can be done to improve & process astroimages & on what software?

Welcoming any tips/questions for someone starting out on astrophotography & image processing.

It looks like as if you are a refugee from the world of terrestrial imaging,  so I go  slow so you can pick up the basics.

In astro imagery, AP, you have either Planetary Imaging or Deep Sky Imaging.

in Planetary Imaging you can use your telescope and eyepiece together ( eyepiece projection mode ) or use the telescope as a very long teleohoto lens with your imaging device ( 90% of the time it is a planetary camera or webcam ) and this is called prime focus imaging.

In either prime focus or eyepiece projection mode you'd use the high speed planetary webcam to capture and download a tremendous number of frames,  I have done up to 3500 at speeds up to and beyond 60 FPS on to your hard disc. You will then use planetary imaging software ( AS!2, Registax 6, etc ) to stack and combine the frames to give a single composite frame which you will then process  using an astro imaging software ( Registax 6 ) for wavelet application and detail extraction. You need to combine a lot of frames to combat the noise and build the Signal / Noise ratio so you can stretch the data in your stacked frame. BTW, when you stack a large number of frames  you   are building Signal, the final stack has a very wide Dynamic Range that can not be displayed on a computer screen so it looks as if it has been "compressed" ,stretching involves procedures to expand this seemingly " compressed" data.

In Deep Sky Imaging ( DSO imaging ) you only use your telescope and imaging device in prime focus mode, anything else is a fools game. As DSOs are extremely  dim  and quite often large ( the span of the Andromeda Galaxy,M31, is  about7 full Moon diameters though usually only the core and the surronding areas are captured ) the use of a webcam with it's very small sensor is not practical so enter the DSLR and the very expensive Cooled CCDs. The principal of stacking a relatively large number of frames still applies but as the DSOs avery dim the sub frame exposure lengths need to be very long ( inorder of tens of minutes and at times hours at least ) so for this to happen the use of Equatorial Mounts guided by a guide scope and camera is necessay to keep the target in the same place as the earth rotates and moves around the Sun.  Hope this helps a little.

A.G