set up for M13, Andromeda and Ring Nebula

[alcol620]

Hi folks

Advice required as per imagining settings to capture M13, Andromeda and the Ring Nebula.

My set up is an 8SE scope with a Celestron f6.3 reducer, Canon 1100d moded camera

using APT software, what would be your suggested exposure and ISO setting and how many light and dark images  would be appropriate?

Thanks for your advice

[kalasinman]

M13 is too low right now (at least for me in Thailand). Ring is too tiny for my camera lens, so I'll take a flyer at M31. A start with ISO 400 and 300s or longer subs at the largest aperture you can manage should be a good start. How many? There seems to be a theory that with more than 30, increases in data are better obtained with longer subs. Best examples I've seen  take two sets and stack them using a layer mask to emphasize the fine detail w/o blowing out the Trapezium.

--Jack

http://www.astropix.com/HTML/J_DIGIT/LAYMASK.HTM

[MattJenko]

If you are on the EQ5, then you have a tracking EQ mount and should be able to do up to 60 second exposures before tracking errors will creep in. If you are guiding, this will be longer. I would suggest doing as many 45 second exposures as you can fit in, with 20 dark, 20 bias and 20 flats (if you can work out how to do them...). Use the lowest ISO you feel comfortable with, I tend to use 400 or 800.

If you are on your SE mount, do 30 seconds or less.

However, the moon is out to play at the moment, and this means deep sky objects are going to be washed out.

[alcol620]

Thanks folks for taking time to provide feedback, duly noted for future use.

Had a play around the other evening and even with the Moon out I managed to get images of M13, Andromeda and the Ring Nebular. Only took a few frames at 20/30seconds ISO 400/800. However, images must have been of poor quality, although I could see stars, Deep Sky Stacker couldn't and would only stack 1 frame? With only 1 frame stacked I could improve the image slightly in Photoshop but nothing of any detail or clarity. However, I was well pleased at actually getting the images even if they were poor quality. Also pleased that for the 1st time, my set up got images right in the middle of the eyepiece when using the mount Goto.

[MattJenko]

Getting good goto is a good result and quite rightly satisfying. In DSS did you try adjusting the % slider to tweak how DSS determines the number of stars? It might be why it cannot stack them. This option is when you are doing the Register stage.

Funnily enough, I tried guiding for the first time ever last night under the full moon and also got some pretty decent looking subs of some open clusters in Cassiopeia. Am hoping I can process out the rather obvious dust bunnies and assorted rubbish in my images with some hastily taken flats, but my confidence is not high!

[Owmuchonomy]

Hi, just a comment on your hardware.  Your set up is too long (FL) for M31 unless you are happy just imaging the core for practice.  A FL of around 300mm will capture it fine as its apparent size is around 3' across (thats the equivalent of 6 full moons).  M13 should be fine as will be the Ring although the latter is bright and small so I would try it without the reducer if you can get your exposures long enough without tracking errors.

[alcol620]

Thanks for further comments, Matt, yes I did use the slider and got a few stars to show. Further research on the web, suggested that focus  may have been a problem as DSS won't include stars that are a bit out of focus. I ran DSS again with alignment turned off and it stacked the few frames that I had. However, the stacked image showed each star as a row of star points. Suggested that my tracking was very poor on the scope. Not sure that the star images should move much for 20/30 second exposures??

Chris, still at the practice stage trying to get "something" but point taken

[D4N]

If you stack without registering that's what will happen. Unless you guide and don't dither registering the light frames is essential.

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

[alcol620]

Hi D4N I thought I registered the 4 frames I had, but I switched off 'align' (in DSS). It did stack the 4 frames but they came out as 1 image with the 4 images over layed but not aligned.

[D4N]

Registering is basically aligning so if it's turned off your not going to get a good image.

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

[alcol620]

Hi D4N

When I registered the 4 images originally and started the DSS processing it did a run through and told me that it could only stack 1 image. And it duly produced a Tiff image of 1 image. When I turned off alignment and ran DSS again I could see it registering 4 images and then ran through the stacking process. The Tiff image produced was a composite of the 4 images, but with the 4 images slightly offset from one another.

[D4N]

Yeh that would be normal with alignment turned off. So for some reason DSS isn't finding stars to align, could be something in the settings or it could be focus.

One thing you could try is in the Raw/fits options at the bottom left you could try increasing the brightness, the camera is outputting 12 or 14 bits in a 16 bit file format so you should be able to stick a 4 in there without losing data. If it causes over exposed stars just set it back to 1.

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

[alcol620]

Hi D4N  Did what you said using 4 brightness instead of 1, but only wanted to stack 1 frame. Turned the wick up to 10 to see what happened on it found 67 stars at 3%. I ran DSS at this setting and it completed the stacking and gave me what looked like an improved image, although the stars don't look particularly round. I have tried playing with the image in photoshop but can't get anything worthwhile, although I can see there is something there. The Youtube videos seem to magic images out of nothing, obviously my skills need honing.  I have read all sorts of info on photoshop but can't get nothing from the image. Is there someway I can copy the Tiff image somewhere, where someone with expertise can manipulate it?? Obviously the file is much to big to load on here?

[D4N]

It does look a lot like images from nothing when you start stretching the image. The image was already there, just not bright and not enough contrast to see.

67 stars is certainly enough to register and stack.

When you only stack one light frame all you are doing is calibrating it with the bias, dark and flat frames. This removes noise.

Once you start using more light frames then you start to add signal to the image and get detail.

Have you started adding the other light frames in again or still on the single frame?

TSED70Q, iOptron Smart EQ pro, ASI-120MM, Finepix S5 pro.

[alcol620]

The latest image I have produced from DSS has stacked the 4 light frames and 2 darks. They are 20s ISO400 and the Moon was out so I shouldn't expect too much! But although I have tried photoshop curves and levels I don't seem to be able to bring too much out of the image although I can see the brightness around the centre of Andromeda and can see (or I might be imagining) a dust lane. Really looking to see if someone else who knows what they are doing can get more from the stacked image.

[kalasinman]

I'd suggest you aren't getting enough data to capture fine detail. Attached is a single sub x300seconds ISO400 f/8. Longer exposures are best, or failing that increase  ISO.

[D4N]

Yeh 80 seconds won't reveal much detail, take more and you should start to see a result.

Sent from my iPad using Tapatalk

[alcol620]

Hi folks 

have attached a jpg of the 4 frame stacked output from DSS. No Photoshop tweaks. Comments please. I know I need more frames, longer exposures etc. but what can be brought out of the attached?

[D4N]

Most of the fine detail is lost in the JPEG conversion but I did a quick background extraction and histogram stretch to see if anything is there.

You can see dust lanes on the left and the bright smudge top middle is M32.

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[alcol620]

Hi D4N Thanks for all your help. Very encouraging. Is there any way I can send you a copy of the DSS produced file to play around with?

[D4N]

You could put it on dropbox.

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[alcol620]

How do I do that, presumable have to open an account?

[ollypenrice]

Going back a bit, you can model your focal length and chip size on many planetaria to see what the framing will give you. The software throws up a frame of the correct size on the screen. I do this in SkyMap Pro but I think it can be done in the free Stellarium. This is always my first step in planning an image.

Olly