Flip Mirror System

[leon]

Hi All

I would like to ask about a flip mirror arrangement.
I know that this may sound dumb, but i have never laid eyes on one, let alone used one.

Would this be used, so one can focus on a star field for instance, without having to look through the view finder of the camera attached to the scope.
to get sharp focus, for astro photography.

I was hoping to use one of these with my ED80, and Digital SLR.

Thank You. Leon

[Merlin66 (Ken)]

Yes. It's basically a star diagonal where the mirror moves out of the light path and allows a camera to be mounted on the other face. The Meade one comes with a spacer and helical focusser to allow you to get both the guide eyepiece and the CCD in focus. Once this is done you can then flip between them to check the object is still in the centre of the field etc before exposure.
Downside is that it takes up about 50 -60mm of back focus so is more suitable for a SC telescope than say a newtonian.

[Dennis]

Hi Leon

As Merlin has pointed out, be careful with the "back focus" of your telescope. Have a read of this website:
http://www.taurus-tech.com/background.htm
to get a better understanding of back focus before you make a purchasing decision.

Cheers

Dennis

[Lester]

Hi Leon,

I bourght a flip mirror for my Meade SCT 14", planning on using it with focal reducer f6.3, and off axis guider and then camera. Well the news is it will not focus. And now Astro-Optical supplies are looking into it because I might be hanging too much out the rear of the SCT. The whole idea of the flip mirror is to make it easier to find DSO to photograph. I am in the process of finding 3 adapters to fit the system together with the focal reducer after the flip mirror and off axis guider.

I am not very happy.

Hope you have better luck, or can try one before buying if a mate has one near by. The concept is good.

[leon]

Thank you guys, for your help, i'll do some more resesrch on the subject, i think.
Thanks again. Leon

[leon]

Hi Dennis,

Just had a long look at that site you recommended, well worth the effort. thank you for the link.

[EzyStyles (Eric)]

my experience with flip mirror system is i can't get focus on my 8" F/4 newt. is there any other way to get focus besides moving the primary mirror closer to the focuser?

cheers

[Merlin66 (Ken)]

If you don't want to move the main mirror or secondary, only real options are to use a transfer lens. This can either be a barlow which will increase you effective focal length and f ratio or a positive lens which will maintain the current EFL. Either of these would be placed between the secondary and the focusser. You need some data on the FL of the lenses to work out the correct position and relative spacing.

[leon]

sounds like to much buggerizing around for me, i'll just do it the way i have always done.

Thanks anyway, people..