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Posts Made By: Jim Schoonover

April 24, 2003 10:30 PM Forum: Off Topic Discussions

Do ANY of the Arabs have a mind of their own?

Posted By Jim Schoonover
Sorry, fellas, but I feel the same as Herb on this. I do understand all of the posts, that they do what they do because they are now free, etc. But when thousands of these marching (protesting) newly freed citizens are chanting loudy "Death to America"; they've lost me, because that is an extremely counterproductive, and dumb thing to do, even from their perspective, considering everything.

April 28, 2003 10:07 PM Forum: Equipment Talk

Casse-fractor telescope design

Posted By Jim Schoonover
Ron, you should take a look at the Sept '99 Sky & Tel.
There's an article on a fellow who built a Mersenne telescope, using a 20" f5 parabolic primary, a convex paraboloidal secondary, and a Tele Vue 4" Genesis refractor. The secondary takes the converging light from the primary and turns it back into parallel light. The refractor then views that light, and brings it to a focus, using the refractor's lenses, focuser, and eyepiece. He also built a 30" Mersenne scope utilizing a Tele Vue 140 refractor. The observer can sit in a chair while observing. Pretty neat.

June 10, 2003 11:29 PM Forum: Astro Binoculars

What size and mag bino...

Posted By Jim Schoonover
Wow, tripod mounted huh, my neck hurts just thinking about it!
And hand-held binos are pretty much limited to roughly 50mm and smaller for most folks, as your arms get tired and you just can't hold them steady for very long.
For extremely quick looks, my wife and I use a pair of 7x35 wide angle Bushnell's I won several years ago at a company dinner. Nice and light; wear them aroung your neck and they're always there for that quick look. We like the rocking lever focus on these too, very fast.
But the aperture is really too small for tripod mounting.

June 12, 2003 09:17 PM Forum: Equipment Talk

Ouch!

Posted By Jim Schoonover
If you were standing just three inches more to your left, you would have been in real trouble there buckaroo!
When I was building my 36" I had the roll off roof open about two feet to let in some light. It was cloudy, so I thought it was ok. I smelled something burning, couldn't figure what, until I saw smoke coming up off the indoor/outdoor/office carpet. The mirror burned a 6" diameter hole in the carpet about four feet to the side of the scope. I can imagine how dangerous that would be at big star parties with hundreds of scopes set up out in the open daylight.

June 19, 2003 10:38 PM Forum: Astro-Physics

Astrophysics

Posted By Jim Schoonover
Amen, Brother. Let us all chant now, "apo,apo,apo,apo,apo,apo,apo,apo,apo,apo". Ah, I feel better already.

June 24, 2003 02:58 AM Forum: Equipment Talk

Looking for LARGE finderscope. Recommendations?

Posted By Jim Schoonover
Hi Paul, I know this may sound unusual, but I use a 6" F8 Skywatcher refractor (Celestron, ect) as a finder. It works great. I use a 2" TeleVue 40mm wide field eyepiece, and find that I can actually 'see' those faint fuzzies that escape smaller finders.
And you can find one for around $300 used including mounting rings. Best finder I've ever used, bar none.

September 1, 2003 03:20 AM Forum: Equipment Talk

Fans blowing across mirror

Posted By Jim Schoonover
I tried two 4" fans blowing across the face of my 36" mirror. Didn't seem to help much. Then I added three fans blowing onto the back of the mirror and one fan blowing across the 11" secondary mirror. I also installed a dual temp thermometer, and can say that this setup definitely cools the optics down faster than without fans.
I think it really depends on how fast the temp drops where you are located and where you store your scope (house, garage).

October 1, 2003 04:24 PM Forum: Equipment Talk

comments on optical tubes?

Posted By Jim Schoonover
I own a 10" LXD55 UHTC. The optics are ok, just don't expect $4,000 performance from an OTA worth about $550. Also, for ccd work, the standard, mostly plastic focuser will have to go. So, plan on spending some extra bucks for that.

October 8, 2003 07:32 PM Forum: Equipment Talk

FeatherTouch vs. Clement focuser.

Posted By Jim Schoonover
Chris, I believe the choice between the two focusers you mentioned depends on how small a secondary diagonal you are planning on using. Since you've mentioned that the scope is for visual use only, and if you are trying to keep the secondary obstruction as small as possible, you will need a focuser that is extremely short in height. The Clement wins that contest. Otherwise, if you are using a fairly standard sized secondary for your scope, then the shortest Feathertouch would be fine. Either will work great, but the Clement will allow focusing closer to the tube using a smaller diagonal.

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