2nd attempt - Sword of Orion

Started Dec 6, 2012 | Discussions thread
eyeport
Regular MemberPosts: 196Gear list
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Re: 2nd attempt - Sword of Orion
In reply to RustierOne, Dec 8, 2012

RustierOne wrote:

eyeport wrote:

Not the best sky as half moon was present. Shoot with a Canon5Dmk3 with 500mm and 1.4x extender attached. Image stacked using Photoshop because tripod only. Only wish I had the tracking mount.

Any technical advice will be greatly appreciated.

That's a very good shot, Felix! I for one sometimes like the saturation cranked up high like that. Its amazing what you've captured without a tracking mount.

My experience with tracking mounts recently has been with a home-made barn-door mount:

http://www.dpreview.com/articles/2705562354/building-using-a-tracking-mount-for-astrophotography

which produces good results with my 8mm fisheye and 55mm film lens with 2-1/2 minute exposures. The disadvantage of such a mount, is the lack of any way to guide the exposure to compensate for errors in polar alignment and tracking rate. These sorts of problems become important as the exposure increases and for longer focal lengths, like with your lens. Other than the home-made version there are some commercial mounts:

  • Vixen Polarie
  • AstroTrac
  • Losmandy Starlapse System

There are probably a few others. In my opinion, the best results (particularly with long focal length lenses and telescopes) is a equatorial mount with slow motions on both axes. An example of this is a camera, piggyback on a telescope. The telescope is trained on a guide star, which is kept centered on crosshairs by the slow motion controls. The image is taken through camera lens only - not through the telescope. Of great advantage is the capability of autoguider inputs like what razor2277 uses.

Here's an example of what can be accomplished piggyback:

Comet Hale-Bopp, Pentax 200mm f/4.0, 15 min. exposure; Fuji Super G 800 Plus, April 9, 1997

Tracking was provided by an old 1981 Celestron-8, fork mount, with slow motion controls. Hale-Bopp was one of those once-in-a-lifetime "Great Comets". We may have another one coming - C/2012 S1, which will be brightest around November 2013.

http://earthsky.org/space/big-sun-diving-comet-ison-might-be-spectacular-in-2013

So I would strongly suggest that all astrophotographers gather equipment and perfect your skills - you never know when another great one could pop up unexpectedly.

Best Regards,
Russ

Wow thanks for the informative reply Russ. I think I will probably need some commercial mounts that will be able to support a canon 500L lens. The home made one looks awesome though but unfortunately its only limited to wide space. Still, I wish I had one of these.

Yes will certainly geared up for the upcoming comet shots, and certainly do lots of practice in the meantime.

From what I have read online piggyback astrophotography sometimes can be difficult because the lens piggybacking on top is at a slightly different axis from the telescope?

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Regards,
Felix Wu
Creationheart Photography
www.creationheart.com
Canon 1Dx, Canon 5D Mk3, 16-35L II, 35L, 85L, 100L, 135L, 70-200L IS II, 500L IS, 580EXII x2, PWplus3 x3, ThinkTank Airport Takeoff, Thinktank Retrospective LC3, Shootsac

 eyeport's gear list:eyeport's gear list
Canon EOS-1D X Canon EOS 5D Mark III Canon EF 15mm f/2.8 Fisheye Canon EF 35mm f/1.4L USM Canon EF 85mm f/1.2L II USM +5 more
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