QHYCCD

Televue Parrcorr & QHY8?

Televue Parrcorr & QHY8?
« on: October 13, 2007, 02:34:27 AM »
Hi

I'll be using a QHY8 soon, hopefully, and am intending to have it unusually connected to the telescope:

http://www.projectgalileo.info/gallery/v/Equipment/Imaging/dscf3512.jpg.html

...in the position where the current Televue Powermate is (sticking out to the left of the filterwheel).

Will I need to use a Parrcorr in case I get severe vignetting?
(details of Parrcorr here:
http://www.scsastro.co.uk/it060016.htm
)

The filterwheel contains 1.25" filters.

Regards,

Dez.
« Last Edit: October 13, 2007, 02:58:05 AM by zedkatuf »

MMys

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Re: Televue Parrcorr & QHY8?
« Reply #1 on: October 16, 2007, 06:16:25 AM »
Using QHY8 with 1.25" filters (or something wit 1.25" diameter) in path will cause very strong vigneting and black corners. This is not useful setup to utilize capabilities of QHY8. I recommend you to rebuilt whole imaging chain to at least 2" diameter on path to the QHY8 camera.

You can use paracorr still in this case, it improves sharpness of image of axis noticeably.
« Last Edit: October 16, 2007, 06:18:25 AM by MMys »
Vixen VC200L V.I.S.A.C., homemade Newton 185/610+Paracorr, Borg 77ED refractor,  optionally with EDF4 reducer, Modified EQ6 mount, Modified EOS 300D, QHY8 ccd camera, MII G2-8300 mono CCD camera, TVGuider.

Re: Televue Parrcorr & QHY8?
« Reply #2 on: October 16, 2007, 08:28:55 AM »
Using QHY8 with 1.25" filters (or something wit 1.25" diameter) in path will cause very strong vigneting and black corners. This is not useful setup to utilize capabilities of QHY8. I recommend you to rebuilt whole imaging chain to at least 2" diameter on path to the QHY8 camera.

You can use paracorr still in this case, it improves sharpness of image of axis noticeably.

OK, I guessed that might be an issue.  I've decided to use a Baader MPCC atached to the back of the 4 inch piggy-back Skywatch refrator, and screw the QHY8 directly to that (well, via an off-axis guider), as hopefully the large barrel of the 4 inch refractor will accomodate the APS format CCD.