Brent, Chuck and Dave, Thanks for the comments. I probably ought to have you look at it with me. I am able to get round stars with flares. When I attempt a star test it looks round when the collimation is correct. This makes me wonder what I am seeing. I see the problem at it's worst when viewing a bright star or planet. For example, I was 78 - 406X. I could get a good focus on the planet and could see good surface detail. The planet was surrounded by a halo of light that seemed to be oscallating, possibly by my eye moving around. Bright stars never appear to come to focus even when other stars appear to be points. When I first set up the scope at Monte I discovered that the secondary was not centered in the tube. Since I used a laser to collimate, I was able to tip both mirrors and get good images of galaxies and nebula. Stars and planets were awful. I have fixed the allignment problem and now just have the halo, which I think made Mars look like a comet with a big nucleous. Dave
Dave, coma is never present in the very center of the field. If you see problems at high powers, dead-centered, you don't have coma, but someting else. The halo description sounds like spherical abberation. --- DunnDave@aol.com wrote:
Brent, Chuck and Dave, Thanks for the comments. I probably ought to have you look at it with me. I am able to get round stars with flares. When I attempt a star test it looks round when the collimation is correct. This makes me wonder what I am seeing. I see the problem at it's worst when viewing a bright star or planet. For example, I was 78 - 406X. I could get a good focus on the planet and could see good surface detail. The planet was surrounded by a halo of light that seemed to be oscallating, possibly by my eye moving around. Bright stars never appear to come to focus even when other stars appear to be points. When I first set up the scope at Monte I discovered that the secondary was not centered in the tube. Since I used a laser to collimate, I was able to tip both mirrors and get good images of galaxies and nebula. Stars and planets were awful. I have fixed the allignment problem and now just have the halo, which I think made Mars look like a comet with a big nucleous.
Dave
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FYI, Just in case anyone was as confused as I was - (though I know that's not possible ;-) :The SLAS meeting is next Tuesday the 23rd @ 7:30pm, not this evening. I believe, among other things, there will be several short presentations from members with their impressions of the recent Mars Opposition. dlb P.S. Sorry if this is a duplicate...I've been having some problems with my email account
Dave, I'm interested in attending... where is it going to be held? Cheers, James Helsby
James, It will be held at the 10th East Senior Center in Salt Lake at 7:30pm on Tuesday, the 23rd. The address is: 237 S 1000 E, Salt Lake City, UT see: http://www.slas.ws/location.htm On Tuesday, September 16, 2003, at 04:11 PM, James Helsby wrote:
Dave,
I'm interested in attending... where is it going to be held?
Cheers,
James Helsby
From: "David L Bennett" <dlbennett@mac.com> Date: Tue Sep 16, 2003 3:07:03 PM US/Mountain To: "Visit http://www.utahastronomy.com for the photo gallery." <utah-astronomy@mailman.xmission.com> Subject: [Utah-astronomy] Meeting Next Tuesday Reply-To: "Visit http://www.utahastronomy.com for the photo gallery." <utah-astronomy@mailman.xmission.com>
FYI, Just in case anyone was as confused as I was - (though I know that's not possible ;-) :The SLAS meeting is next Tuesday the 23rd @ 7:30pm, not this evening.
I believe, among other things, there will be several short presentations from members with their impressions of the recent Mars Opposition.
participants (4)
-
Chuck Hards -
David L Bennett -
DunnDave@aol.com -
James Helsby