Can anyone recommend a flip mirror

[g__day]

I've been thinking that I'd like to set my 110mm refractor up so its simply to convert between visual and imaging by adding a flip mirror into the system.

I envisage my set up would be OTA -> moonlite focuser

primary light path would be a large enough flip mirror - guess I need a 2" light path (not the 1.25" models like the Orion one Bintel sell) - into a COMA corrector -> Canon DSLR

secondary light path would be a tube extender of roughly the same length as the COMA corrector -> eye piece with a helical focuser on the flip mirror to make the both Camera and eye piece's focus points parafocal.

The only models I common see that have helical focuses on one light path seem to have 1.25" eye piece connectors to the main OTA e.g.

http://www.bintel.com.au/Astrophotography/Astrophotography-Accessories/Orion-1-25--Flip-Mirror/1230/productview.aspx

I wonder that this would chop a DSLR's imaging chip.

Can anyone offer advise of what I am trying to achieve please?

Thanks, Matt

[ZeroID]

I've certainly thought about a similar setup myself and from one of my current setups you're right, the 1.25" will vignette a DSLR feild considerably. Flip mirrors are one answer but I'd imagine the price for a 2" would be pretty horrific. I've been having thoughts about a DIY beam splitter system but it's still just an idea.

[Stardrifter_WA]

Hi Matt,

Have you looked at the Sliders from Van Slyke Instruments. Sounds like this may be what you are looking for. http://www.observatory.org/sliders.htm

There was a review in July 2002 S&T that explains their sliders.

Cheers Peter

[Merlin66]

One significant issue with flip mirrors (and I have a few of them!) is the quality of the mirror.
If you want to use the straight through for imaging and drop the flip for visual you really want a first class mirror - as good as any you'd get in an expensive diagonal.
I have (many) Vixen flip mirrors, which have the advantage of having a male T thread on both ports so you can add whatever you like/ need....BUT the mirror is rubbish! Ok to find things, then flip it out to expose the camera but NBG for quality visual. Same goes for the Brightstar (and it's clones)
I don't know about the sliding version from Baader....
I do have an "interesting" slider version (China?) which has a pretty good mirror, but I haven't see any others...
The BEST flip mirrors IMHO were the Meade. I have both the 1.25" and 2" versions and they use the same high quality mirror used in the diagonals. Unfortunately now out of production, but available 2nd hand.
(These can be left on the scope as a diagonal.....)
Beamsplitters - Hmmm I've built many and use many for spectroscopy....the quality (3mm+ thick) plates are very expensive and only 1/4 wave...the beamsplitter cube gives 50/50 which doesn't suit all observers or their needs and again is only 1/4 wave(at the best)
There may be others, but I haven't found them yet.
HTH

[DannyV]

Hi Matthew,
Here's the one I've found is the best, and Ive tried both the other local ones.

http://tinyurl.com/mvfjq5a

The trouble with the others is the focal length is too long and if you need anything else in the chain you can't get focus.

This one is a bewt. It's fairly heavy, but very well engineered.

[g__day]

The Meade looks interesting - as do the Van Slkye sliders and the weird unit Danny posted above - I wonder when configured as an OAG if the prism is out of the light path of a DSLR?

[DannyV]

Yes it's above the DSLR light path if you just pop it down a small way. I'll use it in flip mirror mode with a MallinCam video camera on top and my EOS 60da on the main path

[g__day]

Status check:

Telesckop Service 2" Flip Mirror - on wait list (ponder when they come back in)
Meade - End of production - wonder if any has surplus
Van Slkye - doesn't have a threaded focuser on the eye piece and would really desire this feature!

More searching on the way!

[DannyV]

Hi Mat,
I checked with OPT:
Hello Mr. Vagg,

Thank you for your reply.

We do not have any on order at the moment so it may be several weeks before we order more. If your friend wants to place his order online, we can get him in the system and process his order accordingly.

Sincerely,

Jason Farmer
OPT Internet Sales Manager