February 2006 - Utah-Astronomy - mailman.xmission.com

Any chemists out there?
by Patrick Wiggins 23 Feb '06

23 Feb '06

I just received an email from the local Burning Man contingent (really fun group, btw). They've decided to form a non-profit group called Element 11 and in their announcement they note that: "Element 11 refers to the number of salt on the periodic table." While I used to be married to a genius chemist neither the chemist nor the genius rubbed off on me so I may be wrong but I don't think salt is an element but rather a compound made up of the elements sodium and chloride. Any chemists out there that can confirm (or refute) that? Thanks, Patrick

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Re: [Utah-astronomy] Expedition
by astrodeb＠charter.net 22 Feb '06

22 Feb '06

Hi Joe, I'm planning on going out to my friend Jim's house in LaVerkin Thursday night. He will have his 25" Obsession on his driveway. Friday night I may go out to Anazasi Plateau near Rockville, UT if the weather is warm enough. I haven't been out there since early November but I had a blast last time so I'm eager for some really dark skies again. Be sure and take the hand warmers. A must this time of year! By the way, here is the weather.com forcast for Rockville. It's a little cooler than St George but not much. http://www.weather.com/outlook/health/allergies/weather/tenday/USUT0218?x=1… Debbie ---- Olhomorto(a)aol.com wrote: > Hi Joe, > > What I'm hoping for is a Messier Marathon expedition to the Wedge in March! > I thoroughly enjoyed what we did last year. Do you think it will happen > again?! > > Mike Bailey > _______________________________________________ > Utah-Astronomy mailing list > Utah-Astronomy(a)mailman.xmission.com > http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy > Visit the Photo Gallery: http://www.utahastronomy.com

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Re: [Utah-astronomy] Expedition
by Olhomorto＠aol.com 22 Feb '06

22 Feb '06

Hi Joe, What I'm hoping for is a Messier Marathon expedition to the Wedge in March! I thoroughly enjoyed what we did last year. Do you think it will happen again?! Mike Bailey

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Re: Recurrent nova RS Oph
by Chuck Hards 22 Feb '06

22 Feb '06

I'd be interested in hearing if anyone who observes this star perceives the purple coloration noted by Wallerstein during the 1958 eruption. > From: Canopus56 <canopus56(a)yahoo.com> > Recurrent nova RS Oph (Nova Oph 1933), normally a > mag > 11 object, has re-erupted for the first time since > 1985 as a naked-eye object at ~mag 5 __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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What's in a name?
by Chuck Hards 21 Feb '06

21 Feb '06

Re-reading Sagan's "Broca's Brain", I laughed out loud when reading this passage, concerned with the story behind naming Martian surface features: "Another suggestion, made by a European savant, was to name each volcano "Mons" (mountain) followed by the name of a principal Roman deity in the appropriate Latin genitive case: thus, Mons Martes, Mons Jovis and Mons Veneris. I objected that at least the last of these had been pre-empted by quite a different field of human activity. The reply was: "Oh, I hadn't heard." I guess some astronomers really don't get out enough. ;) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: Watch caps
by Chuck Hards 20 Feb '06

20 Feb '06

Hopefully we won't be needing the cold weather clothing too terribly much longer! I found this bargain if you're having trouble finding a watch cap: http://www.sportsmansguide.com/cb/cb.asp?a=245180 Factory seconds, but who cares in the dark, as long as it keeps your head warm... __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: [Utah-astronomy] Re: Insulated overalls
by Olhomorto＠aol.com 16 Feb '06

16 Feb '06

Chuck, thanks for the tip. Mike Bailey

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How to estimate equivalent exposure time when using Wratten filters
by Canopus56 16 Feb '06

16 Feb '06

How do I estimate the equivalent exposure time for a series of planetary filters in a filter wheel. Assume as a hypothetical, that one has taken a satisfactory luminosity image and would like to cycle three visual-photo planetary filters through the wheel - and make an equivalent exposure: Filter Transmission Filter Factor (1/Trans) 08 Yellow, Light 0.83 1.2 21 Orange 0.46 2.7 25A Red 0.14 7.2 The following is what I think the answer is, but would like some confirmation from more experienced amateurs. Using the basic exposure equation: t1 = F1_ratio^2 / ( ISO_speed * Brightness_B ) and Covington's _Astrophotography for Amateurs_ Appendix A modification applying a filter factor representing the optical density of a filter: t1 = F1_ratio^2 / ( ISO_speed * Brightness_B / Filter factor1 ) and then dividing two equations, one for t1-Filter factor1 and a second for t2-Filter factor2, you can simplify to: t2 = F1_ratio^2 / ( ISO_speed * Brightness_B / Filter factor2 ) t1 = F1_ratio^2 / ( ISO_speed * Brightness_B / Filter factor1 ) t2/t1 = 1 / ( (1/Filter factor2) / (1/Filter factor1) ) = 1 / ( Transmission%2 / Transmission%1 ) t2 = t1 * ( Transmission%1 / Transmission%2 ) or alternatively, t2 = t1 * ( Filter factor2) / Filter factor1 ) So, for example, if I take a correctly exposed luminosity image (Filter-factor1 = 100%) at 100 secs, and then turn the filter wheel, the estimated equivalent exposure times should be: Filter Filter Factor t1 t2 No filter 1.0 100 100 08 Yellow, Light 1.2 100 120 21 Orange 2.7 100 270 25A Red 7.2 100 720 Does this look right? - Canopus56 (Kurt) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: Insulated overalls
by Chuck Hards 16 Feb '06

16 Feb '06

For some reason I've been thinking only of mechanics & ranchwear, when hunters have all kinds of insulated clothing options: http://www.sportsmansguide.com/cb/cb.asp?a=249237 There may even be some options in military surplus. (Mike Bailey, are you out there?) __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Re: Re: Recurrent nova RS Oph
by Chuck Hards 16 Feb '06

16 Feb '06

I found it interesting that Wallerstein wrote that it was not known with certainty if RS Oph was a double star. Today, conventional thought is that recurrent novae are due to a main-sequence star losing mass, mostly hydrogen, to a white-dwarf companion. It accretes on the surface until a critical temperature is reached, at which time nuclear detonation occurs in a runaway reaction. The accreted material is blown-away into an expanding shell around the white dwarf, and the cycle begins again. This is also the cause of some planetary nebulae. Thanks for digging up that paper, Kurt. > From: Canopus56 <canopus56(a)yahoo.com> > Read Wallerstein's 1958 paper on the violet color > during the 1958 eruption: > > http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1958PASP...70..537W __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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