by Jeff Crilly
http://home.crilly.org/astro/300D/macholz.html
(thats with an un-modified 300D)
I have a bunch of these (some 5 minute), and darks, etc, but havent had time to dark-subtract/stack/process them. However, the single 3 minute exposure seemed acceptable enough (though not great).
It is just amazing what a THREE minute exposure can bring out.
THREE minutes to get the shot... yet, I was up there all night. Whasup with that?!
Heck, one could do this with an EQ1 mount, or (hmm) a EQ table and big dob... if (and this is a big IF) for that THREE minutes all is going just right (no wind, jiggles, bumps, PE, etc).
THREE minute exposure... sheesh.
THREE minutes to get the shot... yet, I was up there all night. Whasup with that?!Um, foreplay?
Ok... that was good.
Heck, one could do this with an EQ1 mount...
Before I go off to the store and slobber all over the cameras I cannot afford, and thereby reduce any chance of the above to zero, tell me, was this on your Xmas mount? Was wizardry involved in polar alignment? Was it guided by anything? Something (probably great pictures like this one) makes me want to try photography.
Ok.. there were witnesses to the picture taking... so I guess I cant hide anything...
It was indeed done on the AP900.
I arrived late at FP... there was a "public" program... lots of kids around... hence I couldnt setup until the place cleared out (not safe to drive in the dark with kids and TV crew around).
I saw the comet in binos... There wasnt much time before it would be getting low in the western light washed horizon.. so I setup the mount rather quickly.
For polar alignment I simply "eyeballed" polaris in the polar scope bore hole, without the polar scope in place.
I then piled on the telescope, camera, guidescope, etc. Quickie balance.
Guiding was done with the ST7E piggyback above the FSQ-106. Fyi.. the guidescope was that 80mm f6 "shortish tube" that michelle sold me at the SJAA auction. I guided on the comet nucleus.
So.. no.. there wasnt alot of polar alignment.. but since the comet is moving, one (imo) needs to guide on the comet itself. Any polar alignment is going to be moot. In fact, misalignment may actually help (!).
Also, fyi, the canon 300D camera came (used) from another TACo in socal.
I know it's madness. Please stop me now.
Yes. It is. madness.. I tell you. I apologize.
Seriously, though... given the results one can get with short exposures using modified (IR filter removed) DSLR cameras, I do wonder if wide field astro work can be easily done with very inexpensive mounts. maybe not an EQ1, but say an LXD55 or Orion astroview may be sufficent. I havent experimented with these, but if one can get good tracking for 3 minutes (even with manual guidescope corrections), then one can get as good results as with a more expensive mount capable of hours long guided exposures.
It really depends on the object being photographed -- bright stuff is going to work ok.. dim stuff will require many subexposures and better guiding during the subexposures.
Fwiw, I've yet to be able to have decent enough conditions to put the AP900 to really good use -- like 2 hour exposures using the medium format camera. Where it really shines, I expect, is when one puts a longer focal length OTA on it... say a C11.
Posted on calastro Jan 26, 2005 13:35:37 PT
Converted by report.pm 1.2 Jan 27, 2005 23:31:55 PT