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70/80 mm refractor choice


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I have a redcat 51 which is my travel scope. Now i want a refractor triplet in a range 70-80mm. But i don't want to loose the focal length by using reducer [removed word] flattener. In india not many  branded scopes are available. I have to choose in between WO / TS Photoline / Explore Scientific /Sky watcher  . WO triplet scopes have problem that they use their own reducer [removed word] flattener in GT series. So the focal length will be decreased, which I don't want. Please advise.

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With The WO Z73 you can use just a flattener so no reduction (not a triplet though) and the same with the TS optics Photoline 80mm. I'm also annoyed that there's not a flattener for the 81 GT!

 

William Optics Adjustable Flattener for ZS73 | First Light Optics

 

Teleskop-Express: TS-Optics PHOTOLINE 80mm f/6 FPL53 Triplet APO - 2.5" RAP Focuser

Edited by Rustang
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Universal Flattener like this one https://www.firstlightoptics.com/reducersflatteners/hotech-sca-field-flattener.html, can be used with a wide range of refractors between f/5 and f/8 (sometimes even f/9). TS Optics and Sharpstar also make one. So you can combine it with any 70 - 80mm refractors you like. The main problem with this kind of setup is that you will have to work out the correct spacing between the flattener and the camera through trial and error yourself.

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I use a TSFLAT2 with both my AT72ED and TS-Optics 90mm FPL-53 triplet to flatten their fields for visual use.  There is no change in their focal lengths.  I've seen images showing it works well for astrophotography as well.

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