May 2002 - Utah-Astronomy - mailman.xmission.com

Re: [Utah-astronomy] Fwd: Re: Thanks
by William.H.Fenton＠Dartmouth.EDU 23 May '02

23 May '02

Re: astronomy software You can't lose with XEphem. Free, open source and the best thing out there. http://www.clearskyinstitute.com/xephem/

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Bruce's compact parallelogram
by Chuck Hards 21 May '02

21 May '02

Bruce says he will get together with Patrick sometime soon to get some photos of his compact, spring-balanced parallelogram. He goes on to say that he designed it some time ago, and thinks he got the idea from a commercial mount, but can't remember specifically. He also said that while he thinks it's great for a personal mount, he feels that it doesn't have quite the range for a star-party, where the heights of attendees could range to extremes. Nevertheless, I'm fairly sure he's bringing it to Binopalooza. >From memory, I'd say it should work fine for people from about 4'-6" up to about 6'-2" or so; probably about 90% of the general adult population. Since this range depends on the tripod used, and it is made for commercial tripods, YMMV. Look for photos on Patrick's site soon. Chuck __________________________________________________ Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience http://launch.yahoo.com

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Oberwerk/Bear 15x70mm
by Chuck Hards 21 May '02

21 May '02

It appears that list messages are beginning to trickle through again. Weekend observing conditions were poor. Although crystal-clear skies looked promising around sundown, a persistant high haze and cirrus prevented a serious attempt to discern a difference in throughput between the Oberwerk and Bear binoculars. Just looking around, however, through the few "sucker holes", I could detect no difference at all in brightness between them. (Yes, I'm sure someone will tell me that it was crystal-clear at 3:30 am!) This tends to support my experience that one multi-coated surface among perhaps twelve (in these binoculars) doesn't increase throughput substantially enough to be noticed visually. Further testing is called for before I can really say with certainty "that's the way it is", due to the lousy seeing. Again I looked hard for a difference in field of view. This I can say with absolute certainty: There is no difference. The fields are exactly identical. I did feel a bit silly looking for this difference after I discovered that both have the same specification, by their respective distributors. I've been looking for differences between identical twins. These are the same binocular, made by the same manufacturer, but imported by different distributors. About the only difference so far, on my personal units, is that the Bear has ever-so-slightly less mechanical slop in the focusing mechanism. In practice, I could not see any negative effects of this with the Oberwerk. It felt fairly tight, just not as tight as the Bear. I'll keep comparing them as weather permits, and report any visual differences at all if I find any. In my opinion, and this what I want to stress, Bear owners have no reason to feel that they hold an inferior product to the Oberwerk. I'm still curious, Ron, as to whether you had a chance to repeat your comparison, and if you still stand by your pronouncement. If so, I would like to examine the same two units you used for your tests. I would be willing to drive to an OAS star-party for this, given enough notice. -Chuck __________________________________________________ Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience http://launch.yahoo.com

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RE: [Utah-astronomy] Oberwerk/Bear 15x70mm
by David Dunn 21 May '02

21 May '02

Ron, They are still around and you are welcome to use them. I will even leave them uncollimated for you. Dave -----Original Message----- From: karen vanderhule [mailto:nitesite@lgcy.com] Sent: Sunday, May 19, 2002 11:35 PM To: utah-astronomy(a)mailman.xmission.com Subject: Re: [Utah-astronomy] Oberwerk/Bear 15x70mm > .Chuck; It will be a little hard to repeat the comparison as the Obies went to Australia last January with the owner.( Steve if you are still following events here why don't you weigh in on this, my visual acuity is in serious question?). But the Bears are still around( I think?). Dave Dunn,do you want to present exhibit "A" at the future bino event? As a side note, are any of you locals going to RTMC this coming week? We are loaded up and will be leaving Tuesday for the event. Will check e-mail Monday night to find out who to look for. Ron > > > > I'm still curious, Ron, as to whether you had a chance > to repeat your comparison, and if you still stand by > your pronouncement. If so, I would like to examine > the same two units you used for your tests. I would > be willing to drive to an OAS star-party for this, > given enough notice. > > -Chuck > > __________________________________________________ > Do You Yahoo!? > LAUNCH - Your Yahoo! Music Experience > http://launch.yahoo.com > > _______________________________________________ > Utah-Astronomy mailing list > Utah-Astronomy(a)mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy(a)mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy

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Re: [Utah-astronomy] compact parallelogram bino mount
by Josephine M. Grahn 20 May '02

20 May '02

Jim, Sorry, I was not trying to make an engineering comment, just a "user observation". Of course the legs have to have a certain spread for stability, and there is a relationship between the spread of the legs and the length of the parallelogram, along with the height at which you expect to use it. I was only trying to point out a potential drawback to saving weight by making a short parallelogram. The final choice should be based on your expected uses and needs. If you are backpacking, or have limited space in your vehicle, then size is a top priority. If you are making it to use at public star parties, then you may decide that it is more important to make the design more "idiot resistant". If the binoculars at one end and the weight at the other end define an arc that is as big or bigger than the arc of the legs, it is visually easier to avoid stumbling over the legs. Jo At 01:11 PM 5/20/2002 -0700, you wrote: >hhhmmm, I would have expected that the longer arms >(crutches) would require a wider spread of the legs to >prevent tipping over. If the parallelogram arms are longer, >are you saying the legs can be closer together? Seems like >it would be the reverse, intuitively. >Jim

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Re: [Utah-astronomy] compact parallelogram bino mount
by Josephine M. Grahn 20 May '02

20 May '02

Jim, Regarding compact bino mounts, I have a full pennies worth of advice :). If your tripod legs open up as wide as the parralelogram, and you set them up at a star party, some klutz is apt to trip over them, (I won't name any names but her initials are J. G. ). If you make the parallelogram a bit longer, it really helps..... Jo > I would like to build one and >like the idea of the adjustable Aluminum crutches, but >wanted one more compact than the crutches make. Just my 4 >cents worth (keep the change). > Jim Stitley

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List test
by Joe Borgione 20 May '02

20 May '02

Is this thing up? I've sent a couple of postings in the past 24 hours and haven't seen them in my mailbox. Joe Borgione May 19, 10:00 am

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First Impressions - Oberwerk 15x70 binocular
by Chuck Hards 20 May '02

20 May '02

The Oberwerk 15x70mm arrived today, just in time for the weekend! They ARE Bears; Rich's suspicions were correct. That is, they are made by the same Chinese factory, re-labled for a different customer. The soft case is the same, the instruction manual (multi-folded, generic sheet) is identical, the neck strap and cleaning cloth are identical. The only difference, aside from the silk-screened graphics and cosmetic differences on the rubber armor, is that the Oberwerks have a multi-coating on the front surface of the objective only. All other optical surfaces have single-layer MgF2 coatings, including the eyepieces. The apparent fields are identical, the true fields are identical. Both display the same ever-so-slightly-curved focal plane, and edge-of-field distortion begins to show up at the same distance from the center of the field, at around 2/3 of the distance from the center. The distortion is very mild, and probably won't be noticed by 95% of the people who use either binocular. As an aside, I've NEVER seen a binocular with no distortion near the field edge, regardless of cost. True, some high-dollar brands have a larger distortion-free zone, but the field always deteriorates near the edge. The eyepieces are identical with the Bears. Fold-down eyeguards makes seeing the entire field of view possible with glasses, if your prescription is not too strong. Focusing is tight and smooth, but there is a tad more "slop" with the Obies than the Bears, which do not "rock" at all, even when racked all the way out. There is a bit of "rock" evident on the Obies. Focusing the Bears requires slightly more finger pressure than the Oberwerks, so my impression is that the Bears are just a tad "tighter". Right diopter adjustment. I would mention that I have seen one of the Bears purchased last fall, with the eyegards eroded-off, because the owner kept them folded-down all the time. The rubber eventually cracked and separated at the fold-line. He considered the eyeguards a nuisance anyway, since he wears a strong eyeglass prescription. The same could happen to the Oberwerks, so be warned. Keep the eyeguards fully extended when not in-use, to maximize their lifespan. Right now, I have both pair tripod-mounted, looking out my window at birds in a tree only 100' away. I can not detect any difference at all in the image between the two units, either in fidelity or brightness. The throughput test will have to come under the stars, where the front-surface multi-coating would pay a better dividend. I'll have to chase down dim stars on a referrence chart for this comparison. The seller's on-line ad stated that a tripod-bracket was included, but I did not receive one. I'll check that out via email with the seller. Instead I got a second neckstrap with "Oberwerk" stitched on it. For now I am pleased with these binoculars. I didn't relish selling my duplicate pair of Bears, and it now seems that I essentially have them back, with a coating bonus. Although 50% more money than the Bears, the price is still very, very low for a 70mm binocular, especially when you consider this is a standard-stock item, and not an overstock or discontinued model, which the Bears were. Barring any surprises under the stars, I am recommending the Oberwerk 15x70mm binocular as an excellent value and reasonably well-made unit. Get your order in, Rich! Stay tuned for part 2, "Under the Stars with Obie & Bear" Chuck __________________________________________________ Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience http://launch.yahoo.com

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Can anyone help?
by Patrick Wiggins 20 May '02

20 May '02

Hi, I just heard from Mike Gubler in Tooele that he's having a problem with his 16" Meade S/C and the customer service folks are being less than helpful (gee, where have I heard that before...?) The main problem is the paint on the inside of the tube of his 18 month old scope is peeling off in large sheets. Some of it has been sticking to the mirror. He'd like some advice on recoating the inside of the tube and cleaning the mirror. If you can help, please contact him at mgubler(a)trilobyte.net. Patrick

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15 x 70 binoculars
by Richard Tenney 20 May '02

20 May '02

Hi all, In my poking around the web looking for binocular info, I found what may be the OEM equivalent of the 15 x 70 "Bear" binos that Chuck Hards favorably reviewed not long ago (and demo'ed at a recent SLAS meeting). While these are more expensive at $150, they are in stock and probably have some kind of limited warranty... See the attached query I sent Chuck on them. The name these are sold under is "Oberwerk". Let me know if any of you are familiar with this brand or these particular binoculars. Thanks, -Rich Note: forwarded message attached. __________________________________________________ Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience http://launch.yahoo.com

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