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Hubble Optics Sandwich Mirrors

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#1 hoptoit

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Posted 22 May 2019 - 08:16 PM

I looked through a 20" f/3.7 at TSP using my Parracor 2 and Televue eyepieces.  The company rep had it set up just outside the vendor building Saturday night.  The rep with the aid of a friend were using a wireless laptop for goto.  When near an object they would use a 32 mm eyepiece and an on scope paddle pad to center object with drive motors.  The 32mm view was not impressive.  When I installed my Parracor 2 and 27 Panoptic and 13 Ethos,  the views were pretty good. We looked at galaxies near zenith. M104 and the Whirlpool.  I was curious if anyone else had any experience with their mirrors.  


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#2 Astro-Master

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Posted 22 May 2019 - 10:08 PM

I was observing in the Anza Borrego Desert last year with my 18" Obsession when a guy showed up with a Hubble Optics 20' F/3.7.  I never looked through one before that night.  He was using a binocular viewer with a barlow to bring it to focus, he had M51 in the scope, but the power was to high to see the whole galaxy.

 

We tried my 17 Ethos with the TV Big Barlow for a power of 221x.  It looked really nice, those mirrors cool very fast.  The problem was the altitude bearing was so stiff it was a pain to move, and the azimuth bearing was to loose.  The star images looked good, but we didn't look at the planets.  There was no baffles on the upper cage to block stray light, so the contrast was diminished.

 

When he looked through my scope, he was amazed how smooth the scope moved, and how well it was baffled for stray light.  On the drive home I was thinking how lucky I was to buy a used Obsession.

 

I've seen a few posts on CN about the hit or miss chance of getting a good mirror from Hubble Optics.  I think its better to save your money and buy a good used premium Dob. than to rush into buying something that will cause you grief.



#3 J A VOLK

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Posted 22 May 2019 - 11:20 PM

Image in the center of the field should certainly be sharp with a 32mm (60x), however without a coma corrector at f/3.7 off-axis the image quality will fall off very quickly due to intrinsic coma.

#4 starman876

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Posted 23 May 2019 - 09:27 AM

I had bought a 14" mirror from them some years ago only to find out it was not over coated.  I sure hope they over coat their mirrors now.  I do know they claim a very high strehl  ratio on their mirrors.  



#5 starman876

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Posted 23 May 2019 - 09:24 AM

Interesting,  I have been looking at their gear wondering if they were a decent scope.  I once bought one of their 14" mirrors.  I found their mirror was not over coated.  That was right after I tried the first cleaning  and left the mirror badly streaked.  




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