Help me find a field flattener?

[bokchoy ninja]

Hello, I currently use the following equipment:

1. Explore Scientific 80 mm Essential ED Triplet Refractor OTA.
2. High Point 2" Camera Adapter.
3. Celestron Nikon T-Ring for 35mm SLR Cameras.
4. Nikon D7100.

I notice that my stars are very elongated at the edges of the frame. Will this field flattener work with my setup, between the OTA focuser and my dslr's t-ring?

https://www.highpointscientific.com/hotech-sca-field-flattener-sca-fft58

Will I be able to thread filters into it, between the flattener and the OTA?

Would I need any spacers or anything, or would it be straightforward?

[david_taurus83]

I have one of those. Yes, you can thread 2" filters into the nosepiece. Spacers, you'll have to experiment. Start at 55mm and see how you get on. It's not enough for my current setup. Its somewhere between 70/80mm for me. Still working on it!

[bokchoy ninja]

1 hour ago, david_taurus83 said:

I have one of those. Yes, you can thread 2" filters into the nosepiece. Spacers, you'll have to experiment. Start at 55mm and see how you get on. It's not enough for my current setup. Its somewhere between 70/80mm for me. Still working on it!

What scope and camera do you use with it? Would you recommend this flattener?

[alan potts]

As a pure field flattener the Hotech SCA I feel works very well indeed, you can get them from FLO. I use it with a Canon camera on a 800mm F7 scope, I believe they can handle F5-F8, I bought it on the recommendation of a very fine on site imager .

[david_taurus83]

8 hours ago, bokchoy ninja said:

What scope and camera do you use with it? Would you recommend this flattener?

I use a WO GT71 420mm F5.9 triplet. I think the Hotech spacing is dependant on focal length more so than focal ratio. Alan's works at the quoted 55mm. Explore Scientific do a flattener for your scope. Have you considered that?

[DaveS]

I have one between my Megrez 90 (F/6.9) and ASI1600 camera. currently it's set at 55mm, but I may need to push it out another mm or so.

[bokchoy ninja]

How much spacer length do you guys have to leave between the focuser and field flattener, for an 80mm f/6?

 

I'm worried about the total length becoming ridiculous

[DaveS]

Here's a photo of my set up.

Looks to be about 65mm, but YMMV.

[bokchoy ninja]

2 hours ago, DaveS said:

Here's a photo of my set up.

 

Looks to be about 65mm, but YMMV.

Nice. Any issue with flexing?

Edited May 19, 2019 by bokchoy ninja

[DaveS]

No flexing that I've noticed.

[bokchoy ninja]

27 minutes ago, DaveS said:

No flexing that I've noticed.

Cool. Which scope do you use?

[DaveS]

WO Megrez 90, alas no longer made, but it's an ED doublet 90mm f/6.9. With the flattener the colour correction is pretty good.

[900SL]

To bump this one, did anybody use the Hotech SCA flattener with the WO GT71 and what was the backfocus distance if so (I would be using APS-C)

 

Many thanks  

[900SL]

bump

[900SL]

Ok I heard back from TS, the Flat 2 with suitable adapters will work with the GT71 as a 1.0 field flattener apparently. Not tested this yet.. 

Anybody used the Flat 2 as a general field flattener?