help on producing images using dss and adobe photoshop

[philip57]

Hi,

After quite a bit of help on forums i am gradually getting to grips with imaging. However i think i need help to go further.

I have recently imaged M31 and an struggling to get a good final image using dss or photoshop. I polar aligned and guided using PHD and had reasonably good graph throughout( within 1 pixel line)

I stacked 36 90second images iso800 and 9 dark 90second images using my c9.25 with focal reducer. See attached image im msg below, click on there will send you to the image in flickr. I cant find any other way of attaching an image here

I have tried using curves and levels etc in both dss and adobe but cant really produce a much better image than the raw one that you can see.

I feel its my processing ability thats lackening and not the amount of raw material. I would be interested to see the results of other people processing using my image. I would then know to try harder in imaging or processing.

PS i also noticed in my final image that the stars as you get nearer the extremes of the image are trailed

Philip

[philip57]

[philip57]

click on the image icon and it shoud go to the image in flickr

[Jessun]

Hi philip57!

Well, I see your image now but I'm pretty convinced you should be able to upload an image under "Go advanced". Make sure your picture falls withing the size limits for each format. Browse, upload, wait, close window, done!

I am a total newbie here and I have sometimes found it hard to get answers here quick enough but I think it comes down to the fact that nearly every question has been asked before and the answer is hiding somewhere on this massive forum or other forums or in software tutorials on youtube etc, so snoop around.

You learn the hard way sometimes but that knowledge sticks! In terms of material vs processing you quickly get a feel for what other people have accomplished using x ammount of exposure with x equipment under x conditions using roughly x software routines. It will give you a hint what could be possible with your results. Remember that as soon as anyone starts moving levels and curves and all the other fancy bits they effectively become artists and they do their impression. Maybe not how you wanted it.

I'd keep at it if I were you, start from scratch a few times, try stacking with different parameters, try stacking all subs and then just the best ones etc. It's satisfying to learn! Some of the results you see here are processed by Jedis!

As to your trailed stars do they often trail radially like they're doing the jump to light speed and then it's optical and just the properties of your particular image train. Trailing in any other fashion and as far as I know polar alignment is at fault, or something got bumped after PHD calibration. Try comparing the first sub with the last to fugure out what mobvement you have going on.

Spontanousley although being a total 0 on the matter I'd say that there should be loads more there, and that you could try from scratch with what should be a rather bright image produced by DSS to get the target looking ok, then work on the background. A jet black background like yours is hard to do with just levels and curves without dimming all the faint stuff that makes out the galaxy.

M31 is famous for being tricky too! I know, I'm still stuck on it! Haha

All the best!

/Jessun

[cgarry]

click on the image icon and it shoud go to the image in flickr

Am I missing something, I can't see an image icon...

Cheers,

Chris

[cgarry]

After looking through the page's source code I found a link to Flickr.

My thoughts:

M31 is not a good target for you scope/camera combination. You are really just looking at M31's core.

90s subs are a little short, though I think you should be able to pull out a bit more detail from the stacked image than you describe. Are all the subs actually being included in the stack?

I have a C9.25 and x6.3 focal reducer and get exactly the same trailed stars at the corner of images taken with cameras with large sensors. I know of 1 other person with this combination and they get this star trailing too, if fact I do not know of anybody who has made this combination work!

Are you able to put the stacked image (.tif file) directly out of DSS somewhere to share it?

Cheers,

Chris

[philip57]

Hi again,

I have had some very helpful comments today. i am going to open account in sendspace.com and upload the raw image there. Will send message as soon as done.

Philip

[philip57]

message removed

[cgarry]

My processing skills are not up to this task I fear. I have had a go with PixInsight but really struggled to get any detail out.

A big issue I see is that a large sensor with your scope and focal reducer suffers from a lot of vignetting that would ideally be corrected with flats. PixInsight's DBE tool would normally be able to do a good job at this in the absence of flats, but does not work well on this image because the entire image has a gradient from M31 itself which we do not want to remove.

Anyway, this is all I could get from the data:

Cheers,

Chris

[Quatermass]

I have worked quite a bit on m31 to try and improve on it from last years efforts and I have kept a detailed account of it all in my blog. Theres also some new photoshop tutorials going on there if its any help to you. Its a good way of sharing what Ive been learning for others on the forum and its good to share knowledge.

[BlueAstra]

Please list your equipment setup. Are you using an equitorial mount? The trailing looks radial, so could be field rotation due to an Alt/Az mount or bad polar alignment. Is your focal reducer spacing correct? You probably need longer exposures to pull out the detail.

[dph1nm]

I spend a year fiddling trying to improve images of M31 at 1200mm FL without flats. Waste of time! Took some with flats and M31 came out almost perfect first time.

NigelM

[philip57]

thanks for comments so far and the image cgarry has done is about the best i can get as well. Its really frustrating. I have also used flats and darks. Flats have helped to lessen vignetting but even after using flats and darks i cannot get any more detail.

My setup. Imaging with c9.25 on HEQ6 mount( i know the c9.25 is not the best for M31 but i should still be getting much better data/detail than this), focal reducer6.3 and canon 450d with astronomics clip in CLS filter inserted in camera. Guiding using PHD, which shows a good guide throughout the imaging

30 x 90secs lights stacked in deep sky stacker. I have also used 6 flats and 6 darks resulting in no further improvement of detail just less vignetting. I have tried processing in both DSS and Adobe Photoshop.... i just cant seem to tease any real detail out using curves and levels.

Philip

I am not sure what else i can try to get more detail. Somewere in my setup and processing somethings not right.

Someone has said try imaging with the astronomic cls filter taken out of the canon450d, but i thought this clip in filter should improve longer imaging of deep sky objects.

[philip57]

Hi again.

i have had a friend whos much more up on astrophotography has come up with a reason why i cant get much detail after stacking to process good images.

He has said that in the canon450d menu the long exposure reduction and the high iso speed reduction should be turned off when stacking mulitiple images in DSS. I have had both turned on, i cant wait to try imaging this way.

Do other people turn off these 2 functions.

Philip

[Jessun]

Yes.

It's the noise reduction you mean. Both these go off under custom settings. I wasted lots of time doing long exposures with these enabled and it all went to waste!

EDIT: And do take loads of more images. Can't be stressed enough I find. Take 3 times as much and stack again! It is really rewarding.

/Jessun

[Quatermass]

You need to take at least 30. Darks and flats and offset\ bias shots with about 60 subs and you will get much better results with a good clear dark sky. Seeing conditions make a big difference for sure. Flats and darks do improve your image if you take the right amount so dont skimp on them even though they are a pain. See the tutourial on my blog about bringing out the detail on dust lanes you might find it helpful if you use photoshop ;-)

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