Tak flatteners and reducers

[LewisM]

I have an OLD Tak FC-100 (original model, not the recent D versions). Finding a specific focl reducer or flattener for these is nigh on impossible, and the price for the new D flattener and reducer is insane (even grey market price).

Put simply, the FC-100 is a fantastic doublet. Not quite colour free, but darned close. As such, I want to do galaxy and semi-deep imaging with it. I intend to use the Vixen FL102S reducer with it (makes the Tak f/5.3, which is not too shabby), but flattener is another story.

Anyone think that the TSA 102 flattener would be effective with the FC-100? The native focal length etc of the old FC-100 is the same as the TSA 102, and there is only a 2mm difference in effective aperture, so I think this would seem to be a reasonably good match.

Opinions?

It's a $520 flattener, so it's not just a case of Buy it and try it :)

[Larryp]

Lewis, have you asked Claude if it will work?

[LewisM]

I sent an email a while back - maybe 3 days ago. Time will tell.

If I use the FC-76 flattener, it is cheap enough, but also need the M72 to M55.6 step down adapter and so on.

Maybe just buy an Orion flattener and try that :)

[beren]

Claude must be away sent him a email the same time and hasn't got back, he's usually pretty quick replying. Are you on the uncensored tak yahoo group ? Someone there might be able to help

[LewisM]

Claude says the TSA102 flattener and reducer won't work well with the old FC100, but I will throw it to the Tak group when I get approved.

Might just try the rather inexpensive Orion refractor flattener and see if it works, or better yet, the Televue one.

[LewisM]

Hans,

Thanks, and that is the one that SCARES in price. I will try the Vixen reducer first and see what happens, but primarily, I need to flatten more than reduce.

[gregbradley]

I find generally speaking that flatteners are way less sensitive than reducers. I use a 4 inch FS152 Tak flattener for example that works perfectly well on my TEC180 and my AP140 2 quite different scopes (although both oiled triplets). And that is using the very large 16803 sensor and I get perfect stars to the corners.

The problem with flatteners is not usually whether they work or not but rather whether they vignette or not. That depends on what size sensor you plan to image with. APS sized sensors are not that demanding but 35mm are. So a 67mm diameter flattener may vignette. Generally you need a 4 inch focuser to handle a 35mm or larger sensor.

Greg.

[Octane]

Let me know if you get approved.

My request to join the group was declined. I even gave a valid reason to join the group.

H

[LewisM]

H,

Errr, yes, I was approved and posting already. Ya did something wrong :)

Greg, it will be used with the FC-100 and FLI ML8300, so I don't THINK a 67mm should vignette, much at least. The FC100 drawtube is 72mm Tak standard, which is a 3" drawtube.

Time will tell - just need to decide WHICH flattener.

[Octane]

It's the name.

H

[LewisM]

I was thinking there was an "American bias"