Here's a shot of my binoscope. It's 25cm F/5s. Other than the fact the images are in stereo, it is more or less a conventional dobsonian(s). It's made from aluminium, plywood & foamboard. The UTAs rotate in order to adjust the interpupillary distance.
The mirrors are both GSO mirrors, & the focal lengths are almost identical. They need to be matched within 2% or thereabouts, otherwise the images will be different sizes & won't merge successfully.
Drool! Please Sir, may I have a look through it one day?
Great Phil!
So focus each eyepiece separately, then rotate one or both UTA to get IPD correct? Which is why some talk of using helical focussers instead of draw tube.
Any further adjustment needed for individual users to "match" the images?
Of course you can look through it Erick, it is a sociable telescope.
Initial collimation is a three-step affair:
1. collimate one side
2. collimate the other side
3. tweak the left-hand mirror with those knobs to merge the images at the eyepiece. It only takes a tiny, tiny adjustment. It is not such a ***** once you have lived with it for a bit.
Then as you surmise, you focus each side separately & rotate the UTAs to get the right interpupillary distance. Which is indeed why helical focusers can work well on these scopes, since they focus without changing the IPD & remove one iteration from the process. I nearly went down this route but in the end just used the most easily available bits (I had half the bits already since I cannibalized a 10" monocular to build it).
If I can add there , the focus IPD thing with Crayfords is no issue, just a matter of always follwing the routine. Just rough focus each eye first. Then set you IPD , then touch up fine focus : the fine focus is maybe a few tenths of a mm so doesn't upset the IPD .
We had 6 people from Macarthur AS looking through Paul Shopiss' 12" binos , they were complete newbies and had no trouble with the adjustments.
A note on focal length differnece for bino mirrors. 2% differnce is the where the brain might start to not co-add images in stereo. I prefer to allow a figure of half that, consisting of 0.5% margin for eyepiece FL difference and 0.5% for mirrors. Which means ideally 6mm for a 50" focal length scope. Mirrors matched in production allow them to be much closer than that.
I have finally got around to posting some pictures of my scopes.
I only recently acquired the ST2000-XMC and had to use the diagonal until the extender arrived. I haven't had much of a chance to use it yet but will post my results when I do.
I bought the ZS 80 for my girlfriend so she could share my passion for astronomy.
Last edited by Blaznee; 28-10-2007 at 03:19 AM.
Reason: Grammar correction
My most useful piece of equipment..... Allows me to comfortably use the rest of my equipment much more often.
Early evening with alpha/beta centauri setting.
250mm F6 home made on an EQ6 pier mounted. Tube is standard concrete forma tube. Diagonal holder and wooden mirror cell is also home made.Bintel Crayford 10:1 low profile focuser with Skywatcher electric focuser. Bintel Finder altered to right angle with a 25.4mm bintel star diagonal. 32 and 25mm Bintel GSO plossl, 20 and 14mm Meade series 5000 plossl and Orion 2x shorty barlow.
Steel Pier has 20mm thick top and bottom plates, 150x150x6mm column sitting on a concrete block 500mm square at top tapering dowm to 1200mm square at the bottom embedded about 1500mm in the ground.
Couldn't make the observatory any bigger, not enough backyard
Ok here is my pityfull setup.
One skywatcher 120mm achromat with an meade 70mm on top for guiding.
Made the tripod legs last week (sturdy and adjustable).
and it all works so well. 
