Astro Picts.

[tkerr]

Here are a couple of my astrophotos.


The Pleiades (Messier 45) In Taurus.
Camera: Canon EOS 50D.
Lens: Celestron C80ED f/7.5 Refractor telescope (600mm Focal Length).
ISO 800
Stack of 45 x 180 second exposures.








Messier 31 The Andromeda Galaxy
Camera: Canon EOS 50D
Lens: Canon EF 100-400mm L IS USM, at 300mm f/5.6
ISO 800
Stack of 25 x 180 second exposures.




Telescope mount used was the Celestron CG5-GT Computerized mount.
Autoguiding with Stark Labs PHD Autoguiding software.
Image stacking with Deep Sky Stacker
PP with Photoshop CS5

[PaulM]

Hi Tim,


In laymans ( read I

[tkerr]

Generally, it's usually a matter of the Aperture of the objective lens.
A majority of astroimages are done with a telescope, but not all. I guess it depends on what you are trying to accomplish. A camera lens is usually smaller and will give you a wider field of view. Using the 100-400mm gives me more flexibility than using a fixed focal length telescope. But the telescope has a larger aperture and longer focal length which will have greater light grasp and resolving power.(Greater Detail), and increased image scale.


BTW, you don't need a telescope mount to take pictures of the night sky. You will if you want to do something like these two pictures, but there are other things you can do also.


[View:http://www.youtube.com/watch?v=6JvzlMhZavc&hd=1]

[Baker]

What program/software do you use to make your time lapse?


Here is a shot I took a couple of weeks ago. I believe it is 70 thirty second exposures stacked together.








IMG_1634-IMG_1697 by Chris-Baker, on Flickr

[Jon Ruyle]

Nice shots of the andromeda galaxy and pleadies. I like the color in m31. I haven't been able to get nice color like that in my pics.

Generally, it's usually a matter of the Aperture of the objective lens.

Exactly. Many people get hung up on focal length, but with a large, high pixel density CCD, there is a lot of latitude for adjusting effective focal length. (Though admittedly, for a very wide angle picture, one needs a wide angle lens).


An interesting question, though, is which is preferable when there is overlap? Eg, would an 800mm f/5.6 L be preferable to say, a 140mm AP refractor? I don't know the answer . Most of us don't have both, so we make do with what we have


I took a couple of pics last night with my little scope. I'll post them when I get them processed.

[tkerr]

What program/software do you use to make your time lapse?
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Currently I use Pinnacle Studio HD Ultimate 14. when I first started creating time lapse I would just use Windows Movie Maker. But I didn't like the rendering and limitations so I had to look for something else.


How did you stack you star trails image, Photoshop Or Startrails?

[Jon Ruyle]

Here is one of the pictures I took last night from my yard in Wonder Valley, CA:


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5DII (long exposure NR on) + 9.25" Edge HD (2350mm @ f/10) + Astrophysics Mach 1 GTO mount


10 exposures, 4 min each, stacked with Deep Sky Stacker.


I had some trouble with tracking: though autoguiding, I experienced a slow steady drift. Don't know if it was differential flexure, mirror flop, or what, but 4 min was about as much as I could do. I never had such problems with my refractor.


Seeing was lousy, but it was a nice dark night. I looked at galaxies through the big telescope while the small one was taking pictures. My idea of a nice evening!

[tkerr]

Here is one of the pictures I took last night from my yard in Wonder Valley, CA:


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5DII (long exposure NR on) + 9.25" Edge HD (2350mm @ f/10) + Astrophysics Mach 1 GTO mount


10 exposures, 4 min each, stacked with Deep Sky Stacker.


I had some trouble with tracking: though autoguiding, I experienced a slow steady drift. Don't know if it was differential flexure, mirror flop, or what, but 4 min was about as much as I could do. I never had such problems with my refractor.


Seeing was lousy, but it was a nice dark night. I looked at galaxies through the big telescope while the small one was taking pictures. My idea of a nice evening!









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Very nice, A lot of detail in the galaxy. However, I wonder why you are using the Long Exposure Noise Reduction rather than shooting dark frames. Using the cameras long exposure noise reduction often removes data that you might otherwise want, i.e. small faint stars and some of the fainter detail in the outer reaches of the galaxy and surrounding areas.
Additionally, on my monitor it looks like the dark points are clipped a little too much. Space is dark, but it's not pitch black.
I can see the tracking error, but all in all even considering what else I mentioned it's a very nice image, the resolution is great.


How do you like that New Edge HD?


Didn't you shoot any darks, Flats or Bias?
Even if you don't shoot darks or flats, I feel bias frames are a minimum necessity for image calibration and stacking.

[doggiedoc]

Really Awesome Jon!


Paul

[Jon Ruyle]

Thanks, Paul.


Tim-when yous say the dark points are clipped to much, do you mean I subtracted too much or not enough? On my monitor, space looks totally black.


As for darks and flats, I can't either to work right with DSS- maybe you can help.


When I dark frames in DSS (instead of in camera NR), I get little streaks all over the picture. I think it has to do with the fact that I'm getting a little drift (separate issue), but I don't know. I haven't heard of other people having the problem. Of course for the darks I use the same ISO and exposure time and make sure the temperature is close.


Whenever I've tried flats the thing always overcompensates (gives me a bright edges and a dim center). Maybe I'm doing something wrong.


My refractor has almost no vignetting, so I never needed flats. The 9.25HD has comparatively a ton of vignetting, so flats are more important now. If I am to be serious about this, I suppose I need to figure all these problems out- either by getting it to work with DSS or using a different program.


Other than that, the jury is still out on the 9.25. I only get the drift I was talking about with the 9.25, so if it is caused by mirror flop, that means thge clutches aren't working very well, which would be pretty annoying. But the problem seems to uniform to be mirror flop. If it is differential flexure, it is still a strike against the 9.25 because it is so hard to set up an off axis guider with it. I might go with one of the inexpensive RC's if I had it to do over again, but no doubt they have their own problems.


The 9.25 *does* have pinpoint stars to the edge of the field, I'll give it that.