What are the advantages of each and which ones to your guys/gals prefer? Is there a visual advantage to a thicker mirror or are they about the same? I was thinking of upgrading to an 18" dobsonian reflector. The StarMaster 18" telescope seems a little more portable than the 18" Obsession. I can't lift the Obsession 80 lb mirror box. I'd need a trailer or truck to haul the 18" Obsession. Which would you guys/gals pick and why? Debbie
Depends on 3 things: 1: How much can you lift repeatedly? 2: Thermal control. Thick mirrors take longer to cool and usually require active thermal management (fan) 3: Support. Thin mirrors need perfect support from their mirror cells. Each is capable of superb imagery, if you observe all the caveats. Once you reach a certain aperture, thin is the only option. In small scopes, go with thick unless you decide to flex it ala Kelley/Adler. For an 18", though, my personal choice would be thin (I'm getting old...) C. --- UTAHDEB@aol.com wrote:
What are the advantages of each and which ones to your guys/gals prefer? Is there a visual advantage to a thicker mirror or are they about the same?
I was thinking of upgrading to an 18" dobsonian reflector. The StarMaster 18" telescope seems a little more portable than the 18" Obsession. I can't lift the Obsession 80 lb mirror box. I'd need a trailer or truck to haul the 18" Obsession. Which would you guys/gals pick and why?
Debbie
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I have the 18" Starmaster and we used it to cleanly split Beta Delphinus (.5 arc sec) at 1000x at Wolf Creek. I think both Starmasters and Obsessions are excellent telescopes. Because of the passive cooling system and the thin mirror there is very little cool down time required with the 18" Starmaster. I have had no extensive experience with the Obsessions. The Obsession moves easier than the Starmaster and that can be good or bad depending on the wind conditions. The Starmaster has an excellent GOTO system and I think Obsession is now developing one or has already. According to Starmaster's web page they have an 18" in stock so you don't have to wait a year. Clear Skies Don Colton -----Original Message----- From: utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com [mailto:utah-astronomy-bounces+djcolton=piol.com@mailman.xmission.com]On Behalf Of UTAHDEB@aol.com Sent: Thursday, January 29, 2004 1:42 PM To: utah-astronomy@mailman.xmission.com Subject: [Utah-astronomy] Thin Mirrors vs Thick Mirrors What are the advantages of each and which ones to your guys/gals prefer? Is there a visual advantage to a thicker mirror or are they about the same? I was thinking of upgrading to an 18" dobsonian reflector. The StarMaster 18" telescope seems a little more portable than the 18" Obsession. I can't lift the Obsession 80 lb mirror box. I'd need a trailer or truck to haul the 18" Obsession. Which would you guys/gals pick and why? Debbie
participants (3)
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Chuck Hards -
Don J. Colton -
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