Posts Made By: Tom Hole

http://www.astromart.com/articles/article.asp?article_id=100

for the buck:

http://www.astromart.com/classifieds/details.asp?classified_id=286571

Having a hard time coming up with a reason not to buy one.

Tom

New binoviewers:

27mm dielectric, broadband beamsplitter
broadband coated Bak4 prisms
102mm path length
individual diopter adjusters

$199 which includes a pair of ep's (no corrector, though)

I couldn't resist and bought a pair with ep's from Burgess Optical. I'll let you know what I think when they arrive.

Tom

BTW, run the numbers for that in my clear aperture spreadheet at f/6.

Just a nice story about my Starmaster:

http://www.tomhole.com/Starmaster%2011%20EL.htm

Tom

"I am seriously debating purchasing a binoviewer and am wondering how much wider a feild of view I can actually get with it?"

The best you can do is equal the current FOV. A binoviewer will not increase your FOV and in some cases (when a corrector is required to reach focus as in a refractor or newt) it decreases it.

"can I get a binoviewer for $100? or is this a pipe dream."

You can get one for $200 with a pair of EP's from Burgess Optical, but you won't see much with it until you add a corrector to it, which can add anywhere from $20 to $500 depending on what you are looking for. For widefield, you'll need to spend at least another $130 for a low power corrector (1.3x) and that will decrease your TFOV by about 23%.

Also, those $200 binoviewers will completely vignette any ep with a field stop larger than 18mm or so. That's about a 23mm plossl. Your 32mm plossls will have about a 35 deg AFOV in the BB's.

Plan to spend more if you want to keep those low power wide field views.

The binoviewer forum might be a better spot for this.

Tom

So we have telescopes that can find galaxies billions of miles away in the dark all by themselves. They have sattellite receivers and 28 gozillion object databases and they always know where I am and what time it is, even though I may not.

So howcum I still have to collimate my telescope? Put Bob's servomotors on the secondary and/or primary, put a special ep in the focuser and let the 'puter align everything to within a gnat's butt. Seems trivial compared to figerin out that at 17:11:24.45 UTC I was at N38 24 45.35 W76 54 23.37. Maybe I'm being unreasonable.

Tom

On a tip from Tom D, I picked up an older Celestron 2x barlow that was really long (5.5"). It kinda screwed onto the nosepiece of the BB and I measured the mag at 2.7x or so. Better than a short barlow was giving me, but not as low as I hoped.

So, the lowest power I can get is 170x with the 24 Pans. The lowest unvignetted power I can get is 240x with the 17 WA's. Not the best options, but at least I get to look at stuff with the BB's.

I pulled the Starmaster out and put the BB's in with the 17mm WA's from Bill. Oila! It focused. First view was the blue and gold double in the northern cross (I'm sure they have a more proper name, but blue and gold are my alma mater's colors). Whoa! It's now a foursome. That's not good. I wiggled the ep's around and got it down to the normal two stars. I suspected the set screw ep holders might cause merging issues and they did. It's easy enough to wiggle the ep and get them to merge. I used the diopter adjusters and as I rotated the right one, the image would merge and unmerge. Looked kinda cool, but not a desirable characteristic in binoviewers. A wiggle of the ep gets them merged again. This phenomenon is to be expected as the set screw pushes the ep against one side of the ep holder thus, uncentering it. As the ep rotates, the center of the focal path rotates around the center of rotation causing the image to unmerge. This is a minor annoyance, but one that new binoviewer folk should be aware of. It will drive you batty if you don't know what is going on.

On to the double double. Wow! Nice split! Then I remembered I was at 240x. I would hope they split nicely there. I put the 24 monocentrics in and still a clean split, as expected. The 24mm ep's were actually 24 Pans but they vignetted down to about 40 deg AFOV or so. That confirms the baffle acting as a field stop theory.

The skies are crystal clear and fairly steady. I anticipate a wonderful evening with the BB's and the eclipse. The 170x I can get with the 24 orthos will be a bummer. I'll have to pull out the Denks for a wider FOV.

No obvious spherical or chromatic aberrations noted during a star test. Not steady enough for a critical test, but at least there wasn't any obvious issues.

Hope everyone else gets to view the eclipse as well.

Clear skies,

Tom

Equipment used (ranked in order of best view):

MK1 Mod0 Eyeballs
12x36 image stabalized binoculars me in a lounge chair
16x70 binocs on pmount and me in a lounge chair
11" dob w/ binoviewers

Something special about sitting in a comfy lounger and just taking it all in with my native equipment. The 12x36's were a close second.

Tom

Just got the Nov issue of Reader's Digest and the That's Outrageous column was on the elimination of honor rolls and valedictorians in schools across America because it makes the folks who aren't on those lists feel bad.

The thought is that school should be a non-competitive, happy place that nurtures learning in as low a stress environment as possible. To be honest, that certainly sounds happy, happy, joy, joy. My question is what happens to these kids when they finally get out of happy land and into the real world? Will what they learned in school have helped or hurt them?

Tom

I don't consider the gay population in the same manner I consider the minority population. IMHO, being gay is a choice, not unlike choosing to drink, do drugs, smoke or carouse. Being black, hispanic, Asian or other is not by choice. Being gay is. This is my opinion.

I think Timothy's ire would have been better spent championing a different minority. There are many from which to choose, but only one that supported his morality slant.

Tom