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Started by IGastaldo, 08/26/2003 11:01AM
Posted 08/26/2003 11:01AM Opening Post
Hello all!

Well, being that I'm not an optical engineer, I have a question for the ones that might be or know the answer to this...

We are all familiar with the SCT Reducer/Corrector lenses that attach to the visual back thread to convert an f/10 SCT to an f/6.3 for example...

If you had no capability to attach this rear cell corrector, is there another product that you could use instead? can it be attached somewhere else in the light path? like a 2" reducer/corrector that would fit in the threads of a 2" eyepiece? possible?

Thanks for reading, this is just something I thought about, never seen, and wanted to know if it can be done, or if it exists...

Clear dark skies!


Ivan Gastaldo 8)
Coconut Creek, FL

Ivan's Observatory
Lat 26N 16' 48" Long 80W 10' 48"
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CCD Imaging and Processing/Deep Sky - Moderator
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Posted 08/26/2003 01:36PM #1
Hello, Ivan.

I'm not sure if you're looking for any/all possibilities, or if you're truly looking for an eyepiece-installed solution. So, how about this:

An SCT-specific ruducer/corrector can thread onto a 2-inch SCT-thread adapter.
An SCT visual back (either 1.25- or 2-inch) then attaches to the r/c.
The visual back then accepts eyepiece or diagonal.

The major limitation will be spacing between the eyepiece and the r/c. Non-SCT scopes will likely *not* be able to focus using 2-inch diagonals behind the r/c.

SCT-thread adapters can be purchased from APM or Scopetronix. Other retailers likely carry them as well.

Hope that helps.
Best wishes.
Posted 08/26/2003 02:46PM #2
Hi Ivan,

This same issue was discussed at length in the Yahoo NexStar GPS group and the concensus is to use a VSE adpater #A2LT in front of the reducer/corrector. This part goes into your telescope adapter ring. On the back of the corrector you screw in an SCT-thread to 2-inch adapter from Tele Vue, I believe the part numbers are ACC-0003 and ACS-0004 but not 100% shure. This allows the use of any 2-inch device behind the reducer/corrector.

Take Care,

Jose Suro
Tierra Verde, Florida