TeleVue .8X Reducer for TV102 Telescopes
This TeleVue .8X focal reducer and field flattener is made specifically for the TV102 and new TV102iis telescopes and can be used for imaging for up to 43mm diagonal formats.
It threads directly to the TV102iis 2.4" focuser, and can be attached to the TV102's 2" focuser with an optional Televue RAD-1074 adapter (see accessories tab for more info). This accessory requires the appropriate Tele Vue adapter to connect your camera (choices can be found in the "Accessories" tab, above).
Televue Product Number: RFL-4087
- Additional Information
SKU TE-RFL-4087 Manufacturer Tele Vue Barrel Size 2.5" Warranty 5 Year Warranty
Customer Reviews 1 item(s)
- Works great with 127mm f/7.5 triplet
I got this for my new Explore Scientific 127mm triplet, for imaging with my Canon 40D and 450D. (Mainly daytime terrestrial photography, of birds. I didn't expect this reducer to be perfect, since it's a one size fits all 800-1000mm and very hard to find reviews, but I was very pleasantly surprised. It provides 0.7934x reduction (even better than 0.8x, bringing my scope down to 755.7 mm @ f/5.95 it yields a tack sharp image, with no added aberrations that I can see.
The corners in APS-C 22mm by 15mm format are nearly as sharp as the center (still pixel sharp, with a nearly rotationally symmetric point spread function, and the focal plane is *almost* flat using the Televue Wide T-Adapter. The curvature of the corrected focal plane is on the order of 1/16 turn of the fine-tuning knob (7.7:1 ratio, so about 1/120 turn of the coarse focusing knob — a tiny fraction of a millimeter of tube travel on the ES127's Crayford focuser to get the corners in focus after focusing on the center, which is very close to flat.
The reducer (with TE-RAD-1074 screwed on adds almost exactly 60 mm of focus path length. On my ES127, this means that infinity focus is about 25 mm out with the reducer (it's about 85 mm out without it. To give myself the maximum terrestrial close focus, I might buy a 1 inch screw-on extension tube and use a 2 parfocalizing ring on it.
I think with a negative spacers on the order of 1 mm or less I could get the focal plane flatness even more perfect, but that would require a thinner Wide T-Adapter (since there's no such thing as a negative spacer.
Given that this was designed for a Televue scope, not Explore Scientific, I am impressed... and I expect that this reducer/corrector is going to be my workhorse for imaging with the ES127.
1= Houston, We Have a Problem & 5= It's Out of This World
- Included Items
- Televue .8X Reducer RFL-4087
- Five Year TeleVue Warranty
- Questions & Answers
Product QuestionsCan this reducer be used with CCD cameras such as Imaging Source cameras or is it for DSLR only?
ThanksQuestion by: Robert on Mar 15, 2015 11:27:00 PMYou can use this reducer for other cameras besides DSLRs, but the spacing from the glass in the reducer to the CCD camera must be exactly the same as for a DSLR so threaded spacers will often be needed to move the CCD camera back far enough from the reducer.Answer by: Chris Hendren (Admin) on Mar 16, 2015 5:27:00 PM
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