Help - Basic guide to processing please

[malc-c]

I have no idea what's going wrong with my post processing. I've taken 5 x 90sec images of M31 with a DSLR at 1600 ISO, plus 1 x 90 second image at the same ISO through the scope with the end cap on. Each of the 5 images have a fair amount of data in them in that you can make out the shape, and form of the galaxy and can distinguish the dust lanes. They also have a decent quality about them. (although they seem to have a green tinge when viewed on this forum)

I've tried DSS, Registax etc but the results are appalling and no where near as detailed at the original image. I've tried tweeking the image in Photoshop, trying to make the background darker and bring out the ring detail a little better, but still no joy.

I've acquired a copy of MaximDL and on opeing can see it's full of options - so many I don't know where to start. Can anyone offer some basic suggestions as to what I should do to stack these images and how best to process them to get something a little better than a single image

[steppenwolf]

MaximDL should make a very good job of this although I did use Registax for a couple of years when I started out with my DSLR and although designed more for Lunar/planetary work, it did work very well.

As a rough guide to stacking in MaximDL, select File - Combine Files and choose the images you want to stack. Choose 'Auto Star Matching', and 'SDMask' then click OK. This will stack your images in readiness for further processing.

This will give you a good base to start from so get that part right first and then we'll help you with the further processing.

[malc-c]

Steve,

Thanks for your input.

I've opened up Maxim, but didn't have the option from FILE to combine, however under PROCESS there is an option to STACK, which brings up a popup to select images, and a tabbed option to combine and select the options your stated. This grouped the images, and on clicking GO the results (scaled down to suit forum regs on images) can be seen attached to this post... Uhmmmmm

Forgot to mention that this is from the RAW CR2 files, and yes that cross hatching effect is real and not an artifact of re-sizing the image for the forum

[steppenwolf]

Right, maybe you don't have the batch combine function in your version - is this a 'lite' version or the full version of MaximDL?

The matrix that you are seeing is the Bayer Matrix that holds the colour data in encoded format. I had assumed that you already had individually coloured images. Your first task will be to de-Bayer this Matrix either in MaximDL or in the software that came with your DSLR. In Maxim, load in the first image and click on Colour - Convert RGB. For now leave the percentages at 100% and experiment with the X and Y offset until you get a colour image that has the right hue to it.

Then repeat for each of the other images leaving them all on screen. When they are all colour converted, click on Process - Combine and Choose 'Auto Star Matching', and 'SDMask' then click OK. This will stack your images in readiness for further processing.

[malc-c]

Steve, thanks for holding my hand on this one

The version is 5.03. The images were RAW direct from the camera (Canon D400), and I used a CLS clip filter to reduce light pollution which may be why there is a green rather than orange tint to the JPG images ?

OK I'll pre-process the CR2 files to take out that matrix and try again

[malc-c]

OK for quickness I just selected the pre-set for my camera from the RGB option and let it use the auto defaults just so I could get some idea of how the process works. The RGB box had no sliders just value boxes in which you could type in numbers (345 for example for each RGB option) - anyway, having don that I saved as uncompressed fit file and then used them in the combined process you described above.

Whilst the image is somewhat heavy on the blue, it's shows some promise

[malc-c]

What can I say... received a PM from Steve inviting me to call him. A 45 min phone call and he walked me through processing an image in Maxim and PS. -

Whilst I choose to use the auto levels in the de-Bayer process for quickness and this was really just a "mess about" to get an idea of how the tools work, I'm really happy with the result, especially the detail in the dust lanes

Steve, many thanks for your support, and I'll go and do my home work you suggested

[steppenwolf]

Tee hee, this is the first sight I've had of the finished work as I was working blind and getting you to try things in a logical sequence but I think you've cracked it Malcolm! Well done - I will be marking your homework so be sure to get it in on time

[WhiteShiva]

Wow, well done!

[malc-c]

Guys,

It's been a while since I tried this, and to save Steve being on the phone longer than required, I didn't take notes... Can anyone put me straight on the process again:

I think its:

1) - open each RAW file in Maxim and debayer via the "colour > convert to RGB" option then save the FIT images

2) - Choose the option in maxim to align and stack using the settings Steve mentioned above - select the FIT and let it combine them into a single image called group1.FIT

It's at this point I get lost. I remember Steve suggesting stretching the histogram in some way before opening it in Photo shop or PixInsight and then using curves... but thats where my fading memory lets me down.

Also I took 4 darks at the same time, and can't remember how to use these to remove the hot pixels etc...

I've got 14 x 300sec subs of M31 as a result of my guiding trials last night, plus 4 darks that I wish to process, but none of my results turn out like the one above

[steppenwolf]

Malcolm,

Adjust the 'Screen Stretch window' (the button looks like a sketch of a mountain) to adjust the image so that it looks 'about right' being careful to ensure that the left hand slider does NOT encroach into the histogram and save the image as a 16 bit TIF file remembering to click on the 'stretch button' in the save dialogue box followed by 'OK' in the 'Stretch' dialogue box first.

You can now import the TIF image into PhotoShop.

[Earl]

Quiet a fair bit of dust lane detail when a few HDRWavlets are applied.

[malc-c]

Earl, that's never my image above ??? - Is it ?? - Wow !

If it is then I wonder how good the guided shots will turn out and....

Steve thanks for the info - I'll start another run through shortly

[Gunnar]

Hi.

Wery nice image. What a great improvement you managed to do on that pitchure.

I found this tutorial, very useful.

Astrophotography by Tom Diana - Photoshop Techniques

It helped me to make this image out of andromeda.

3min X 1600 Iso lights, stacked in DSS and processed in PS. Telescope Skywatcher 190-MN.

Were did you find the Maxim software, is it freeware?

Gunnar

andromeda original stack WEB.tif

[malc-c]

Thanks for the links, I'll take a look shortly. That's a stunning image - how may subs at 3min did you use

Were did you find the Maxim software, is it freeware?

Gunnar

Regret not... but the web being the place it is I guess it could be

[malc-c]

Well I think I'm getting there... but this was simply the stacked images, no darks. Also, as I use a clip LP filter the images seem to be biased towards the blue end of the spectrum.

Anyway, I'll post up the image here together with a link to the 16bit tiff, hoping that one of you imaging guru's can transform this into something worthy

micro-heli.co.uk/test1.tif

[malc-c]

last tweak...

[Gunnar]

Malcolm!

I tok 20 lights but used only 7 of them, the rest was going to the bin. Unmodded Canon 500D / homemade dewshield and dewheaters / no filter at all / no darks / no guiding... that`s why only 7 images... I suppose

I am figuring about wich guidecamera to buy now Has to be one of those stand alone models.

Gunnar

[Earl]

last tweak...

HAHA... you wish once you start you just cant stop...

[malc-c]

Still can't get my head round this processing lark... I'm processing subs taken earlier this week. I've ten 180 second exposures @ISO800, and five 180 second darks of the same exposure. I converted the RAW files to RGB in Maxim, then selected Process, added the files and applied the same rules above - went to stack / align and it reported it couldn't align the files...

Tried DSS - net result was OK but plastered in red dots as if it added the hot pixels rather than removed them. Finally I took a single JPG and just processed it in Photoshop... here's the net result. (single 180sec @ISO800) Now if a single sub looks this good... I can only wonder what data could be pulled from a stack of 9 further subs !

[malc-c]

I was about to give up on this processing lark when I thought I would give one more thing a try. I downloaded Nebulosity and in no time at all have stacked five 180second subs with a dark and produced this image (re-sized to suit forum regs) in black and white.

I love this program.. Even without going into it's settings it produces reasonable results 1st time and it wasn't as challenging as Maxim

[Earl]

I recommend you download a trial of Pixinsight, and go through Harrys tutorials he provides demo images also.

Only problem been is that PI does cost, but its worth it.

[Quatermass]

I use deepsky stacker and photoshop both together do a good job ;-)

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