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Celestron Compustar 8" - Truth

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#1 deraj

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Posted 09 October 2012 - 05:17 AM

I found out from a friend of a friend of a friend that he was selling his Celestron Compustar 8. I read in Backyard Astronomer's Guide that:

"Almost Any Schmidt-Cassegrain Produced in the Mid- to Late 1980s During the Comet Halley era, optical quality slipped terrible, giving SCTs a bad reputation that persisted for years."

Does anyone know any truth to this? Is it directed at this make and model?

It's for sale at $580 and includes these accessories:

with standard Starbright enhanced optical coatings; 2000mm f/10
- Compustar fork mount drive system with full dual axis control
- 12V DC Computer and telescope drive power control unit - 120V -12 V transformer for use at home
- 8x50 Polaris Finder scope with illuminated reticule eyepiece and right angle or straight through connections
- 2" Mirror Diagonal with 1.25" adapter
- 32mm Sirius plössl eyepiece with rubberized eye guard
- Celestron Ultima Equatorial Wedge
- Celestron Heavy Duty Field Tripod
- Foam-lined Custom Storage and Shipping Case
- Lens Shade8" Celestron
- Orion LaserMate Deluxe culminator

#2 Jon Isaacs

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Posted 09 October 2012 - 07:19 AM

Does anyone know any truth to this? Is it directed at this make and model?



Hi:

I think there is some truth to that... I recommend downloading Uncle Rod's Used SCT Buyers Guide

"Uncle" Rod Mollise is the man when it comes to SCTs, he has written two books and has an extensive knowledge of Celestron and Meade SCTs. He hangs out in the Cats and Casses forum here on Cloudy Nights.

Uncle Rod does discuss the Compustar and puts it on his list of SCTs to avoid... :(

A few comments:

- Older SCTs like the Compustar are obsolete, parts are not available from Celestron so if something does go wrong with the mount, it may not be repairable.

- "Fork on a wedge" SCTs can be awkward to use and are prone to vibration.

- Price wise, this is not too far away from a used Nexstar 8SE which is likely to have better optics and a modern GOTO mount.

Jon

#3 GOLGO13

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Posted 09 October 2012 - 07:38 AM

Great information Jon! Certainly helps in this situation!

#4 deraj

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Posted 09 October 2012 - 07:48 AM

Indeed, great info. Thanks for your help.

#5 orion61

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Posted 31 December 2012 - 12:15 PM

There is some mis-conseption that ALL the scopes were bad during that time, I bought a New C8 SPC8 and it had wonderfull optics!
I believe more Good tubes were made, but there were some that slipped through the cracks. the bad one I saw was a Super C8 that sussered a high degree of Spherical Aberration
5 Pretty rings around the star.LOL Best to look through any scope from that time OR GET A Guarentee that the optics do not suffer form Astigmatism (worst issue) or S.A.
Some other issues are Zones shown as bands in the defocused
Stellar image, Also some were rushed through that had
a somewhat rough surface showing up as light scatter.
But remember these were still the minority,
Remember the C8 production back then went from a Normal 100 or so a Week to roughly double that, The HAD to use virtually everything that came down the line to make demand quota, also polishing and figuring time had to be cut down,
there were also some less experienced workers involved in the extra shifts.

#6 orion61

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Posted 06 March 2013 - 01:52 PM

To add to the above post Celestron Hired Tom Johnson back
in 1987 to replace the master Blocks that had worn down, thus adding to the slipping quality. The Compustars were made from 1987 and up for about 8 years.
1987 is also the time Celestron was producing one of their finest optical series the origonal Ultima. I have never looked through a bad Ultima or Compustar system, just the opposite!
1984-1986 were the questionable years for quality.

#7 GeneT

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Posted 06 March 2013 - 10:36 PM

There is truth to this concern. I bought a C8 during that time frame. It had excellent optics. If you purchase such a telescope, check out, or have someone check out the optics. Years earlier, I had purchased a Dynamax 8. It had poor optics. Some have posted on Cloudy Nights that their Dynamax 8's have excellent optics. Again, it is a matter of verifying the quality of optics of the telescopes with poor track records before buying one. You may find a gem in the mix, and get it at a good price.






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