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RE: [Utah-astronomy] Comet Catcher
by David Dunn 18 Feb '03

18 Feb '03

John has coated all four of my mirrors. I have been pleased with all of them. I haven't finished the 16" scope yet but the mirror looks good. I plan to have the 16" done by the end of March. Last time I went down there I had him show me the equipment and process. It was real interesting. The only complaint that I have heard is that he doesn't have a set fee schedule and sometimes has charged different prices for coatings on two mirrors of the same size. Dave -----Original Message----- From: Brent Watson [mailto:brentjwatson@yahoo.com] Sent: Monday, February 17, 2003 4:51 PM To: utah-astronomy(a)mailman.xmission.com Subject: Re: [Utah-astronomy] Comet Catcher Chuck, No I didn't do any throughput testing. I do think the contrast increased slightly, but the secondary color also is more apparent (My estimations). John Ross does this in his basement at home. He is retired from Hiill AFB where he did this for a living. Therefore, he has no brochures, no web site, and works from word of mouth only. He will do any coating, including aluminum and gold. Some folks around have a different opinion as to quality, but Ihave had no complaints with his work. He can do up to about 16" optics. Brent --- Chuck Hards <chuckhards(a)yahoo.com> wrote: > Hey, guys, MgFL2 will only work for ONE wavelength- > thus the current rage over multi-coatings. > Hopefully > this one wavelength is centered in the visual > spectrum- I didn't get that far before sleep > overtook > me. > > It is an interference coating, so thickness is > critical. The idea is that the reflection off the > glass surface itself is 1/2 wave out-of-phase with > the > reflection off the coating surface, thus they cancel > out, no reflection at that wavelength. (For > multiple > wavelengths, you must use different materials & coat > them to the thickness appropriate for the desired > wavelength.) > > Now, you may ask, OK, no reflection, but how does > that > contribute to total throughput? After all, the > relfected light is being cancelled by phase > shifting; > it's not being re-routed back through the glass to > the > focal plane. > > We have entered the weird, counterintuitive world of > quantum mechanics and probabilities...apparently, if > no light is lost to reflection, it must be going > through with the rest! I know, I don't fully > understand it either. > > But make sure that Mr. Ross knows what wavelength > you > want to dampen- that will determine the coating > thickness. Just seeing a blue tint on your glass is > indicative of- a blue tint. > > Brent, did you do any throughput tests, before and > after? > > I'd like to see Mr. Ross's work. Does he have a > website, or brochure perhaps? A local source is SO > convenient! > > Chuck > > --- Greg Taylor <astronomus_maximus(a)yahoo.com> > wrote: > > Great! I will do that. I am generally vehemently > > opposed to uncoated optics (oh no, a strong > opinion > > ;) > > ). > > > > Greg > > > > --- Brent Watson <brentjwatson(a)yahoo.com> wrote: > > > Greg, > > > > > > I just fot back from Wyoming and saw youe post. > > You > > > can have magnesium flouride applied by Joh Ross > in > > > Clearfield. He coated all four surfaces of my > > > refractor and the 12"window in my 10". His > phone > > > number is:825-2130. His address is 423 Marilyn, > > > Clearfield, UT 84015. Taking it to him is > easier > > > than > > > trying to find the reference! > > > > > > Brent > > > > > > > > > > __________________________________________________ > > > Do you Yahoo!? > > > Yahoo! Shopping - Send Flowers for Valentine's > Day > > > http://shopping.yahoo.com > > > > > > _______________________________________________ > > > Utah-Astronomy mailing list > > > Utah-Astronomy(a)mailman.xmission.com > > > > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > > > > > > __________________________________________________ > > Do you Yahoo!? > > Yahoo! Shopping - Send Flowers for Valentine's Day > > http://shopping.yahoo.com > > > > _______________________________________________ > > Utah-Astronomy mailing list > > Utah-Astronomy(a)mailman.xmission.com > > > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > > > __________________________________________________ > Do you Yahoo!? > Yahoo! Shopping - Send Flowers for Valentine's Day > http://shopping.yahoo.com > > _______________________________________________ > Utah-Astronomy mailing list > Utah-Astronomy(a)mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy __________________________________________________ Do you Yahoo!? Yahoo! Shopping - Send Flowers for Valentine's Day http://shopping.yahoo.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy(a)mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy

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Origin of the Moon
by Marilyn Smith 17 Feb '03

17 Feb '03

The February issue of Discover magazine has an article exploring theories of the origin of the moon. Describing one impactor theory, the article says: "The mega-meteor is so huge it takes half an hour to plow fully into the planet (earth)." Wow. That would have given someone enough time to go grab the Nikon to squeeze off a few shots. Bob Grant

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RE: [Utah-astronomy] Binopalooza
by Kim Hyatt 17 Feb '03

17 Feb '03

There is a nice Forest Service campground right by the hightway, about 2 miles below the top of the ridge where we usually set up. I believe there is a group site, and of course there are primitive toilets, but the campground is in a poor location for observing (high horizons). Dave Bennett has posted a map - I believe it is on the SLAS website. -----Original Message----- From: Chuck Hards [mailto:chuckhards@yahoo.com] Sent: Monday, February 17, 2003 2:12 PM To: utah-astronomy(a)mailman.xmission.com Subject: Re: [Utah-astronomy] Binopalooza Right now, all sites are under consideration. Any facilities there these days? I haven't been there in 17 years. C. --- Kim Hyatt <khyatt(a)smithlayton.com> wrote: > Chuck and others - have you considered Wolf Creek > pass for a binopalooza? > Especially if it's held later in the year, Wolf > Creek is a dynamite site. > Last year Dave Bennett and I were able to drive up > there in late May (as I > recall). > > _______________________________________________ > Utah-Astronomy mailing list > Utah-Astronomy(a)mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy __________________________________________________ Do you Yahoo!? Yahoo! Shopping - Send Flowers for Valentine's Day http://shopping.yahoo.com _______________________________________________ Utah-Astronomy mailing list Utah-Astronomy(a)mailman.xmission.com http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy

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Comet Catcher
by Greg Taylor 17 Feb '03

17 Feb '03

I recently aquired an old celestron comet catcher for use as a super finder on the big scope that I am building. After a few minor repairs, it works very well. My only quam is that the corrector plate is uncoated. Is there anywhere quasi-local where I could get at least a magnesium flouride coating put on it? Greg --------------------------------- Do you Yahoo!? Yahoo! Shopping - Send Flowers for Valentine's Day

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RE: [Utah-astronomy] Some recent postings
by Chuck Hards 17 Feb '03

17 Feb '03

--- Jim Gibson <xajax99(a)yahoo.com> wrote: > > Chuck > Nobody takes you serious! Well, that sure explains a lot! ;) C. __________________________________________________ Do you Yahoo!? Yahoo! Shopping - Send Flowers for Valentine's Day http://shopping.yahoo.com

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Binopalooza
by Kim Hyatt 17 Feb '03

17 Feb '03

Chuck and others - have you considered Wolf Creek pass for a binopalooza? Especially if it's held later in the year, Wolf Creek is a dynamite site. Last year Dave Bennett and I were able to drive up there in late May (as I recall).

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miscellaneous
by Kim Hyatt 17 Feb '03

17 Feb '03

I've been away from my desk at work and unable to respond to some of the comments I've seen posted until now. Chuck, I find your knowledge of astronomy, your enthusiasm for our "sport" and your construction and observing skills to be staggering (makes me jealous). I hope neither you nor anyone else who chooses to comment on this site will take offense as did one recent respondent. I'm confident that I have never read anything to which most persons would take offense. I've long noted in my years of SLAS membership that you have to take some people with the proverbial salt grain or you just can't have any fun. Regarding the "strange lights" observed by Garth Evans - this sounds suspiciously like an observation of anticrepuscular rays, or rays of light visible during twilight hours that appear to converge on the horizon opposite the sun at the anti-solar point. Crepuscular rays are those that appear to rise above the horizon before sunrise or after sunset just above the point where the sun will rise or has just set. They are usually caused by clouds beyond the horizon and are simply the clouds' shadows on the atmosphere. On rare occasions when atmospheric conditions are right, these rays can be easily traced across the entire sky to the opposite horizon. I have photographed them only two or three times - some of these photos I've shared at SLAS meetings. If the atmospheric physics are not well understood, they can truly appear "strange." (Please, no offense, anyone.) Incidentally, observations of crepuscular and/or anticrepuscular rays are also indications of a not-too-transparent sky, and even though the sky may be otherwise clear, transparency can be dramatically reduced. Kim A. Hyatt, AIA SL&A Architects 331 South Rio Grande, Suite 304 Salt Lake City, Utah 84101 801.322.5550 x122

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Another Moon site
by Patrick Wiggins 17 Feb '03

17 Feb '03

On the subject of Moon sites, here's one I've found useful: http://www.lpi.usra.edu/research/lunar_orbiter Patrick

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Re: [Utah-astronomy] Moon watcher
by UTAHDEB＠aol.com 16 Feb '03

16 Feb '03

I was also a "lunar snob" until I bought my refractor in Nov 2001. I look at the moon in a different light now. Sometimes I even observe under full moon although my targets are different than when I observe under new moon. Debbie

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Moon watcher
by Jim Gibson 16 Feb '03

16 Feb '03

To all: I have found the moon to be totally fascinating. My 5" meade does a fine job of letting me investigate many of it's features. I just ran across this link and find it very valuable: http://www.lunarrepublic.com/atlas/index.shtml Hope you enjoy it. Jim --------------------------------- Do you Yahoo!? Yahoo! Shopping - Send Flowers for Valentine's Day

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