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MACandhisCanon
journeyman
Reged: 10/12/09
Posts: 8
Loc: Trobajo del Camino, Spain
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Hi to everyone Actually I've an Skywatcher 12" F5 Newt, but It's too heavy (only a few) for my SW EQ6 mount (Orion Atlas) I had an idea, I've seen the Hubble Optics lightweigh sandwich mirrors and they look pretty for my project (I want to change the Skywatcher mirror by a Hubble Optics mirror), but I need some extra information about these mirrors.
Somebody have a lightweigh mirror from this maker?
Which quality can I spect from these mirrors?
How much can be the weigh of one of these mirrors?
Thanks.
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There is not closed doors, there is not impossible pictures, you only must learn how to do it, or you don't have all what you need
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dave b
Post Laureate
Reged: 05/10/05
Posts: 3548
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in the 12" size i dont think you will save any weight over the mirror you have now.
even if you saved a pound, you would have to add a pound of counterweight to keep your scope from being top heavy
every hubble (except one) test result ive seen has been a rough mirror - your skywatcher very likely has better optics already.
Hubble Sandwich with much Stig
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dave bonandrini
30" f/5.2 Dobsonian
President of GCAC
Astromart Moderator
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MACandhisCanon
journeyman
Reged: 10/12/09
Posts: 8
Loc: Trobajo del Camino, Spain
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Ok Dave, thanks for your reply, Project aborted, I'll take the "B" project, reinforce the EQ6 mount.
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There is not closed doors, there is not impossible pictures, you only must learn how to do it, or you don't have all what you need
Edited by MACandhisCanon (10/21/09 12:41 PM)
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bertb
journeyman
Reged: 10/10/08
Posts: 7
Loc: Achterveld, the Netherlands
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I have a massive 12.5 inch F5 HO mirror, it is 25 mm thick and it is 4.4 kg.
However, the specs in the HO advertising(s) are to good to be true. In the advertising it was a 0.98 strehl.
Mine was not that good: 1/4.8 PV and 0.93 strehl
Still not a bad mirror. I paid only $ 275 for it (e-bay)
Bert
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mark cowan
Vendor (Obsidian Optics)
Reged: 06/03/05
Posts: 2159
Loc: salem, OR
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Hi Bert,
Quote:
1/4.8 PV and 0.93 strehl
This isn't a viable combination of specs, SFAIK. Unless it was tested interferometrically and had one bad spot but was otherwise nearly flawless, an 0.93 Strehl is more like an average 1/16 wave PVW; a 1/4.8 wave PVW is more like an 0.85 Strehl...
Best,
Mark
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MACandhisCanon
journeyman
Reged: 10/12/09
Posts: 8
Loc: Trobajo del Camino, Spain
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Then, I can understand that purchase a HO mirror is like a lottery ¿Really?
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There is not closed doors, there is not impossible pictures, you only must learn how to do it, or you don't have all what you need
Edited by MACandhisCanon (10/21/09 05:09 PM)
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