Jump to content


Photo

Please help me identify this C8/Vixen SCT

  • Please log in to reply
9 replies to this topic

#1 Ruimteman

Ruimteman

    Vostok 1

  • -----
  • Posts: 110
  • Joined: 03 Apr 2012
  • Loc: Tokyo

Posted 20 November 2012 - 10:37 PM

Hi experts!
Please help me identify this C8. Is it a C8+ or an Ultima? Any idea when it was made?
Thank you!
Ruimteman

Attached Files



#2 Ruimteman

Ruimteman

    Vostok 1

  • -----
  • Posts: 110
  • Joined: 03 Apr 2012
  • Loc: Tokyo

Posted 20 November 2012 - 10:38 PM

Second picture.

Attached Files



#3 Ruimteman

Ruimteman

    Vostok 1

  • -----
  • Posts: 110
  • Joined: 03 Apr 2012
  • Loc: Tokyo

Posted 20 November 2012 - 10:39 PM

Third picture.

Attached Files



#4 Ruimteman

Ruimteman

    Vostok 1

  • -----
  • Posts: 110
  • Joined: 03 Apr 2012
  • Loc: Tokyo

Posted 20 November 2012 - 10:39 PM

Last one!

Attached Files



#5 Eddgie

Eddgie

    Voyager 1

  • *****
  • Posts: 13174
  • Joined: 01 Feb 2006

Posted 21 November 2012 - 12:03 AM

I do not think that this scope was originally a GEM mouted scope. I believe it is a 90s era OTA that was removed from its original fork.

There are two pan head screws visible in the picture on the side of the mirror cell. These heads of these screws appear to be "tipped" to one side like the screw holes are not flush to the wall of the mirror cell.

I believe that the SPC8 (GEM mounted scopes) did not have these screw holes present and that when it was de-forked, someone put these screws in the holes to fill them up.

I owned one of these that had been deforked. I filled the holes with hex head screws that would recess into the holes, but before I did, I had the same Pan head screws sticking out of the side.

Hope this helps.

#6 Eddgie

Eddgie

    Voyager 1

  • *****
  • Posts: 13174
  • Joined: 01 Feb 2006

Posted 21 November 2012 - 12:09 AM

The Pan head screws were used to attach the declination castings to the OTA. These castings were where the altitude bearings attached to the fork. When you defork, the castings come off with the scope OTA, then you simply remove the two pan head screws on either casting and the castings each come away from the OTA.

Again, I think the scopes that were originally sold for GEM mounting did not have these holes. Only the fork mounted scopes had these holes.

I could be wrong of course.

Here is an article by Rod Mollise that shows pictures of what I am talking about:

Pictures showing dec castings on fork mounted C8 being converted to GEM use

#7 Ruimteman

Ruimteman

    Vostok 1

  • -----
  • Posts: 110
  • Joined: 03 Apr 2012
  • Loc: Tokyo

Posted 21 November 2012 - 07:16 PM

Thank you Eddgie, lots of good information! :)

#8 Jaimo!

Jaimo!

    Apollo

  • *****
  • Posts: 1368
  • Joined: 11 Oct 2007
  • Loc: Exit 135 / 40° North

Posted 22 November 2012 - 12:48 AM

Definitely not an Ultima, the Ultima has a silver U-shaped handle under the the visual back, it's nice handhold to steer the OTA.

The dovetail does look "non-Vixen" with the phillips head screws attaching it to the OTA, typically Vixen would use a hex screw.

Jaimo!

#9 Geo.

Geo.

    Gemini

  • *****
  • Posts: 3028
  • Joined: 01 Oct 2008
  • Loc: Upstate NY

Posted 24 November 2012 - 10:13 PM

I think what you have is an early G8. I've only seen one of these. They were sold on the first Synta CG-5s, but the dovetail bars were from Vixen. The carrying strap is also Vixen made and was original on the SP-C8. I don't think they were original on the G8. The optical tube is of the type introduced in 1989 as the Ultima 8. The Ultima was the first C8 with the non-finned rear cell casting. It is about a pound and a half heavier than the former design. Folks often refer to this type as the Ultima, even though it technically may not be. The OTAs were all made on the same line. I believe StarBright multicoatings were standard at the time the Ultima type went into production. The screw holes for fork mounting mean nothing all C8s until the gray painted models (about 2007) were drilled for forks. The gray tubes intenede for GEM mounting omitted the fork mount holes and added an extra set of holes for the narrow dovetail bars. The Vixen bar had flanges wide enough to be drilled for the 1.75" spaced holes found on the lower surface of all C8 rear cells.

These early CG-5s could be had with servo motor drive system very similar to the one developed for the 1990 Ultima mounts. It was a step above the later more common Synta stepper drive system.

#10 orion61

orion61

    Aurora

  • *****
  • Posts: 4813
  • Joined: 20 Oct 2007
  • Loc: Birthplace James T Kirk

Posted 26 November 2012 - 04:35 PM

That is a(90's) Celestar ota with an old Super Polaris 8 strap/camera adapter... I had each..






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics