Megrez 90 Owners

[PeterO]

Greetings All,

I'm about to get a Megrez 90 and would like to know what attachments I need to fit a Canon DSLR. I understand I will need the WO x.8 flattner/reducer, and I already have a T Ring do I need any ext tubes?

cheers, peter

[citivolus]

Beware the WO Flat 3 with the Megrez 90, you'll get unacceptable astigmatism. The Flat 2 has been theorised to work better, however I have not seen a specific test done to confirm this, nor do I know how much vignetting you will get. Flat frames will compensate, but the knowledge that it is there may not be acceptable for some :)

I use a Borg DGL 0.85x reducer and it does a much better job of correcting the image. Borg manufactures the rings necessary to use it in a 2" focuser, as it uses larger threads to prevent vignetting. I purchased mine from Hutech and they were able to advise all of the adapters necessary for my usage. Be warned, it is twice the price of the WO.

I have heard that there is a Televue that also works, but I think it is a similar price to the DGL.

An extension tube should only be necessary when doing terrestrial photography if I recall correctly, as your focal point will get shifted back. As I always have an extension tube around, I can't remember if it ends up getting used or not.

Regards,
Eric

[Robert_T]

Hi Eric - I'd been looking at the Megrez 90 too, but the description on the Andrews web site page suggested that it was the flat 3 that was optimised for it and not the flat 2:shrug:

[citivolus]

Yes, WO keeps claiming that the Flat 3 was designed specifically for the Megrez 90. I've yet to hear an owner of one who believed that!

Regards,
Eric

[Robert_T]

Thanks Eric, you'be probably saved me a costly mistake:)

[PeterO]

Ditto for me too Eric, thanks.

peter