Stacking

[Jason1970]

Hello,

Im can now stack, align and follow all the instructions on Harry's videos. Great

However just a bit confused on the following:-

Should I calibrate or dedayer first? Which is first please?

Thanks

I have been advised to use as many dark frames as posible since this would reduce the noise. To be honest i cannot really tell the difference with and without calibration. Im using around 4 dark frames compared to around 15 light frames.

Thanks

Astro psycho.

[Nocturnal]

Hi Harry,

flat fielding (just one component of calibration) is completely independent of noise or dark current. It has everything to do with illumination differences across the field of view. For long FL work like your 1800mm I can see how the 'curvature' is limited. With the 80mm refractor I'm not sure given how bad it was with my M110. I assume you took a flat field and measured it before deciding not to bother with them. Since we're trying to bring out minuscule value differences in our processing I think that it's crucial that illumination differences are accounted for. A 10% drop is intensity from center to corner might not sound like much but once you start stretching the edges will get dark and the center bright.

It's true we all decide on our how how to process our images but it's important we understand how things work so we make decisions based on facts and measured numbers. This is especially important when advising new members to 'the sport'. So my advise remains that Jason should take a flat field and see what the curvature is like. Then think for a moment what that curvature will do to his images if he doesn't correct for it. It might be minimal, it might be problematic. Hard to say from here. But now he's on his way to measure and decide for himself.

[Cheyenne]

See the thread that I started in the General topic about image calibration. http://pixinsight.com/forum/index.php?topic=1273.0

[Harry page]

Hi Jason

Ok lets start at the begining



Are you using flats with your Images

Harry

[Jason1970]

HI Harry,

No i havent. I know I should but still havent.

I have darks,Bias and light frames.  If the Flat frames really make the difference then i will shoot myself cause i tried to make the image better cant, nevertheless the lagoon image i have is my best. I will reduce the size of it shortly and post it here within the next 15 minutes

Regards

Ja

[Jason1970]

Here we are, my first!!  . Hope u like it!!

Thank you

[Harry page]

Hi Jason

You are lucky with the sx camera that darks mostley are not needed ( I have done subs up to 15 mins )and I have never used any darks
So if do not have any flats do no calibration at all,  it is not needed and might even cause more noise

So just debayer your images and then stack away

Regards Harry

[Harry page]

Hi Jason

Can you post a larger image so we can see some detail

But she looks a bit green, where did you debayer ie PI or Maxim


Harry

[Jason1970]

Hi Harry,

I coloured them in PI. It does look too greenish, thougt it should be reddish,

When I used SCNR it looks back to monoghrome.

Where can I post this imge bigger?

Cheers

[Harry page]

Hi Jason

There are 4 setting on the debayer module , you need to play with these till you get the right one ie when its red
Once you know the setting it will always be that

Max post size is 128k so you have a bit more to play with

Harry

[Jason1970]

Here we are.

Thanks Harry, It always nice to have people to help, especially on this prosessing stuff.  Big thanks

Jason

[Harry page]

Hi Jason

Looks like we are getting there

What we need is a bit less green

You will need a web page at this rate

Show use again when its red


Harry

[mmirot]

Hi Jason,

Welcome to PixInsight Forum!

Little to add to what others have already said about your questions. StarAlignment is an automatic image registration tool specifically designed to align deep-sky images (as its name suggests it uses stars as registration references). ImageIntegration is the tool you must use in PixInsight to combine (stack) your frames. Both StarAlignment and ImageIntegration implement state-of-the-art algorithms, especially the new versions that come with the next release of PixInsight, due in a few days.

Unfortunately we still lack an image calibration tool, but this is going to change very very soon I fully agree with the suggestion about DeepSkyStacker - it is a top notch application.

Finally, as Harry has pointed out Sander Pool's Debayer module (you'll find it on the Process Explorer, under the ColorSpaces category) is what you want to convert your raw FITS files into regular RGB color images.

Let us know if you need further help with these or other tools in PixInsight.

Can the images sets and modules for calibration(soon), registration   and  integration be placed in the image container?

[Jason1970]

Thanks for your comments

[Nocturnal]

Max: image container works for debayering. I tried it the other day.