I was under the impression that programmes such as registax could be used to stack photos of faint objects in order to produce a brighter image. I am using a Canon Rebel digital camera which produces JPEG images.

The loading and processing with registax v4 went fine.  But the stacked image is not any brighter than the original ones. What should I do next?

At the end of the processing, the cropping feature is available but not the "View full image" option which would help if one wants to crop the image. At least the "View full image" option was available at the beginning  of the process. 

Any help would be appreciated

Although I've never used it myself, I've seen other people post about DeepSkyStacker. Maybe you can give that one a try? From what I understand, stacking's main purpose is to reduce the noise in the image. Have you tried adjusting your exposure times?

Sorry I couldn't be of more help.

Joe

use DSS, you can put the final image in R4 a little bit and play with layers function and linear stretch

Thanks guys. I looked up DSS.  You are right, DSS and I guess, Registax are used to  increase the signal to noise ratio only. The author of DSS states clearly that it does not increase brightness.

I am still puzzled by the word "stack" which seems to imly "add". If the same pixel in three photographs receives respectively 9, 10 and 11 photons, the stack it seems responds to 10 photons, not 30. Indeed random noise will be less important in the result. But is it not really an average rather than a stack? Or is my reasoning all wrong?

Anyway I hope that with reduced noise I can stretch histograms etc to take advantage of the "stacking" and brighten my images.

main a idea with stacking is getting a better S/N ratio- this allows you to further stretch the image- read over the DSS help files, it has examples in it- what do you use to final process the image? neither DSS or R4 can do this

Hi Tasco

I looked at DSS but am still with Registax for the moment. I found that I could enhance the color of M8(for example) by the "saturation" option. What do you mean by final processing? I know that some people use Photoshop etc but just what does it do?

it just gives you more tools to tweak the final image with (Photoshop)- you also have ATN's and 8bf files you can add for added tweaks- i usually just stack with DSS and then throw it in PS- i also got images plus and Maxim DL for stacking, but i prefer the efficientcy and simplicity of DSS

I have never touched Photoshop so please bear with me...I still don't know what are those tools to tweak the image...and what are ATN's and 8bf files?

Thanks

well i mean in photoshop, it can do unworldly final adjustments,- curves, levels, saturation, color balance- etc etc, by ATN's and 8bf files i mean PS add-ons, heres an example on an ATN set (action) http://actions.home.att.net/Astronomy_Tools.html  photoshop has a high learning curve- but learning the basics is pretty simple

Now I know what you mean... amazing what you can do with those programmes!

If you would like to do Photoshop style processing, but don't want to pay the high price, try GIMP at http://www.gimp.org/.

 

 

Try a book called Photoshop Astronomy by Scott Ireland. It tech heavy and not for "quick fix" types.But it makes art out of your blurry unprocessed pics, well worth the price (30 buck I think)