First Galaxy

[saysme]

Hi Guy's,

Captured my First Galaxy Last night :). Just when I was getting extremely frustrated with my 3.38 polar alignment I went back to a simple 3 star and found myself lest then a degree in each plane so figured with a bit of Guiding Courtesy of PHD I 'might' be able to image something.

Just an addit from my previous post the image plane error was largely corrected by squaring the secondary mirror , Thankyou all.

The image is of Silver Dollar Galaxy NCG253, and has 65 mins of data collected in 1-2-3min subs, in iso's 800 through to 6400 Could have should have probably collected more data at the high end to help wash out the noise, used darks for the first time which helped. Haven't actually applied any noise reduction (after thought) and it shows :rolleyes:

All processing was done manually with JPEG's in PS-CS5. Overall I'm pretty happy with the result. I think I can improve this image several was but time forbids it.

Firstly the images where captured in RAW but iphoto kept transfering them to PS in JPEG. I haven't used masks in the image stack but rather adusted the opacity of the layers to try and keep the detail. Keen to give it another workover when uni is done.

[alistairsam]

Nice effort Steve. There is some nice detail in the lanes.
Do you have the frames saved as raw as well? if so try processing the raw frames with DSS as well. you'd get better results than with jpg's.
The Canon software that comes in a CD helps to browse raw frames and select the good ones. Can't remember what its called.
or you could use the jpg's to choose your frames, and then use their raws in dss.
Have a go at checking your collimation as well. that would improve the stars in the corners. Look forward to more.

[saysme]

thanks Alistairsam,

I think the coma in the corners is because my coma corrector is not set at the right distance, though collmination has been a big issue for me. I do all my processing on iMAC so until I cough up the funds I'm out of luck, tried to process using lynkeos but it was an epic fail particularly when trying to add the dark frames.

I can up load the RAW frames directly to Adobe Bridge which will / would have been much better, then open them up as a group and batch process them in Adobe camera RAW, ready for stacking.

Question when applying dark frames, do you do additional noise reduction? If so before or after you subtract the dark frames?

[alistairsam]

Are you able to run up a windows instance in parallels? if so DSS will make the stacking much easier and it takes care of noise reduction with your darks.
usually, colour correction and post processing is done on the stacked image not individual frames.
not sure what is available for the mac though.
I've read there are pros and cons to using in camera noise reduction. I haven't tried it myself.

Edit: from what I can see, there seems to be field rotation more than coma, Coma usually is radial from the centre, yours might improve with better polar alignment. I'm no expert, but minor tweaks in your collimation, better PA and DSS should see you getting some great images, not that this was bad. its actually quite good.

[Vegeta]

Nice Image, great detail in the arms :thumbsup:

[saysme]

A bit field rotation was likely, not quite PA, and the first guide star I found was a bt up and to the left. My home made guiding setup is a bit rudimentary but it was cheap. LOL, sometimes I feel excited when I find a guide star thats not A-centuari.......seriously! Though I now have my guide scope on a micro adjustable camera tripod head which as made life much easier.

[saysme]

I have played with this image bait, as you do, added some flats. I never really understood what they did until I used them. and reworked the levels. Still far from perfect and still has field rotation but the colour is heaps better.