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Terry Wood

Jupiter (clearer) Nov 5th 2023 w/Mewlon 180c

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12" Tinsley f/16 Classical Cassegrain OTA - Reduced $900

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For sale is a 12" Tinsley f/16 Classical Cassegrain OTA only. This OTA was likely made in the 1960's.

The 12" Tinsley OTA has been refurbished, and the optics appear to be diffraction limited. You can view a video of the moon taken with this OTA by messaging me for the link. The mirror photos in thid ad were taken prior to proper mirror cleaning, I will try to get photos of the cleaned mirror without removing it.

The retrofit of the Tinsley included adding fully adjustable collimation: tip/tilt of rear plate and the adjustment of primary mirror. This did not change mirror separation, but took up about 7/16" of backfocus, and the telescope still reaches focus with the diagonal without the focuser bottoming out. The original secondary adjustment was left original because it works perfectly.

The moon photos were taken with the Tinsley using a ZWO ASI174MM camera at 4877mm FL (prime focus), both on nights of poor seeing. This instrument performs extremely well visually, much better than these photos.

  • 12" Tinsley OTA, $2800 (now $1900) includes FREE shipping UPS ground in the 48 lower states. The 12.125" by 2" thick primary mirror is quartz and has two chips in it, one of the edge, and one mostly inside the shadow of the secondary mirror, and this does not effect performance. Includes all the original Tinsley accessories, the guidescope is not included. Also, the mount is not included, it has a pending buyer.

There's a lot of information to discuss, so feel free to contact me via Astromart message, and I can answer any questions.

Discounts would be available for local pickup, cash sale, and meeting somewhere reasonably close to Casper Wyoming.

I am selling this because I have too many projects, and I have more OTA's for the observatory to hold. Also, I can scale down a little bit to even a 10" CC which would fit better in my building. These Tinsley's are rare and a 12" Tinsley Cassegrain sold in 2006 on Astromart for $4000.