Field flattener for CMOS photometry

[Kevin West]

The scope I am buying has a field flattener with it.
I have seen that some are described as flattener/reducers, but this is not a reducer.
Is this this of any use in the photometry optical train?

My proposed initial system will be: StellaMira 90mm ED triplet, FL 600mm, CMOS camera ZWO – AISI 1600
I plugged this into:
https://astronomy.tools/calculators/field_of_view/
and it returned a FOV of 1.69 x 1.28 degrees
Long term I’d like a big jump to a Celestron C11

[Grant Privett]

I don’t see why not – but am happy to be corrected if I am wrong.

I use a coma corrector on my telescope and do photometry.

Just be sure to always do dark subtraction and flat fielding.

[Andy Wilson]

Hi Kevin,

A field flattener should work fine for photometry. There is a chance it might improve your photometry if it reduces any distortions in stars towards the edge of your field of view. Though the effect is probably going to be negligible.

If it is the one on the FLO website, then it also acts as a x0.8 focal reducer, so your focal length goes from 540mm (f/6) to 432mm (f/4.8). It would be a good idea to check the sky pixel size of this setup, though in all probability this will be about whether or not you bin the pixels.

Cheers,
Andy

• This reply was modified 8 months, 2 weeks ago by Andy Wilson.

[Kevin West]

Thanks for the replies

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