Back to forums

qhy 294m and 10 f/4 newton

QHYCCD QHY294M Pro Equipment Reflectors
5 replies•70 views
Jan_F avatar
Jan_F avatar
Dear all,

just one question. Do you think that a QHY 294M with the CFW3ZSM (36mm filters) fits to a 10 f/4 Newton? Or would you guess that the distance between filters and sensor is too large, such that it causes vignetting?

Another point is the point in rotator. I have mixed feelings about rotators and fast Newton Telescopes. What do you guess?

All the best
Jan
Engaging
andrea tasselli avatar
andrea tasselli avatar
You can likely get away with 1.25" filters so 36mm is plenty. I don't use rotators and the good ones are expensive anyway and with the other stuff sitting on the CC I think you'll be short-charged for backfocus but this also depends on what CC are you going to use.
Jan_F avatar
Jan_F avatar
Dear Andrea, thanks for the comment,

but I meant something different.  I know that 36mm work well for the 10 f/4 Newton with other cameras (e.g. 268m). My question was regarding the special design of the QHY 294M. The cam has a built in (simple mechanical) rotator BETWEEN the filter wheel and the actual cam. So, the distance between sensor and filters is relatively large, and there is no way to change this. I am wondering whether this can result in issues, which may render it a little difficult to generally use this cam with my Newton.

All the best
Jan
Well Written Insightful Respectful Concise
andrea tasselli avatar
andrea tasselli avatar
Yes, I went to great lengths to assess that camera for my 12" f/4 and conclused that it can be used as the front flange adaptor can be removed and replace with a low profile one. Still, even with the orginal adaptor it's 17.5mm backfocus. I'm talking about QHY FWs here and I'm not sure what else you have in mind.
andrea tasselli avatar
andrea tasselli avatar
At any rate you get 55 mm of BF to play with so that should be enough for nearly all scenarios.
Jan_F avatar
Jan_F avatar
This sounds good. Maybe, there was just a misunderstanding. It's nice that it works on your 12'' f/4.
I hope I can also get some clear skies soon, as I have the camera currently at hand.

All the best
Jan