April 2011 - Utah-Astronomy - mailman.xmission.com

Re: [Utah-astronomy] Polar Diamond Ring Asterism with Polaris misc images
by Canopus56 29 Apr '11

29 Apr '11

Jay wrote: > Very appropriate given the goings on of the day in Great Britain. Nice shot! LOL. That had not even occurred to me. Even the diamond part of the asterism is appropriately sized for a royal wedding. This is a nice asterism that is easily seen - at least the ring part - through binoculars at any suburban rural transition site. It's a good target for kids who show up at star parties with binos hanging around their necks. - Clear Skies, Kurt

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Polar Diamond Ring Asterism with Polaris misc images
by Canopus56 29 Apr '11

29 Apr '11

>From playing around with a tripod mounted Canon Rebel Xsi yesterday. Clear Skies - Kurt Image at 5:30am unlabeled http://www.slas.us/gallery2/main.php?g2_itemId=4226 Labeled image at 12:30am http://www.slas.us/gallery2/main.php?g2_itemId=4223 Chart http://www.slas.us/gallery2/main.php?g2_itemId=4220

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Dob Help?
by Mark Shelton 29 Apr '11

29 Apr '11

Hello all, I am just getting ready to cut my trusses for the dob I am making. The question I have is where to make the eyepieces I have come into focus. I have read that you use a 2" eyepiece racked all the way in and cut your trusses when it just reaches focus. Then I ready just the opposite. You should cut your trusses so everything is in focus with your eyepiece racked all the way out. What are your feelings on the matter. I feel I should make eyepieces come into focus in the middle of the travel of the focus-er. ?????? Thanks for your help in this matter. Mark Shelton

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MeAde etx
by Ron Vandrehule 29 Apr '11

29 Apr '11

I have a real money saver for you, my Meade etx 60 mm & a 2x barlow. 50.00. Leave the money in the coffee can on my back porch. ::)) Sent from my iPhone

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Filter Help
by Troy Davidson 29 Apr '11

29 Apr '11

I have two filters that, as far as I can tell, do the same thing. One is an O-III filter, and the other is an UHC filter. Both of these seem like they do the same thing. Can some one help me out in understanding what these are good for, and if both do the same thing? Thanks. ++++++++++++++++++ Troy Davidson, KF7MTE www.istroyworking.com

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Photopic Sky Survey
by Jay Eads 28 Apr '11

28 Apr '11

http://skysurvey.org/ [image: zoom in]*Zoom In* The Photopic Sky Survey is a 5,000 megapixel photograph of the entire night sky stitched together from 37,440 exposures. Large in size and scope, it portrays a world far beyond the one beneath our feet and reveals our familiar Milky Way with unfamiliar clarity. Just go to the site, click on the image of the Milky Way and WOW! You can even zoom in. I like this one. I got it from Bad Astronomy over on Discovery.com -- Jay Eads

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Re: [Utah-astronomy] Dob Help?
by Wayne Sumner 28 Apr '11

28 Apr '11

For anything closer than infinity, you need to be able to rack the eyepiece out. Put your shortest focal length eyepiece in the focuser, then back it out just a bit to be safe. Your longer focal length eyepieces should work just fine as long as you have enough travel in your focuser. Wayne A. Sumner Math/Physics/Astronomy/Engineering Boy's Tennis Coach Northridge High School Davis School District (801) 402-8610 >>> Mark Shelton 04/28/11 4:31 PM >>> Hello all, I am just getting ready to cut my trusses for the dob I am making. The question I have is where to make the eyepieces I have come into focus. I have read that you use a 2" eyepiece racked all the way in and cut your trusses when it just reaches focus. Then I ready just the opposite. You should cut your trusses so everything is in focus with your eyepiece racked all the way out. What are your feelings on the matter. I feel I should make eyepieces come into focus in the middle of the travel of the focus-er. ?????? Thanks for your help in this matter. Mark Shelton _______________________________________________ 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.slas.us/gallery2/main.php

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GPS may be inaccurate for a few days
by Patrick Wiggins 27 Apr '11

27 Apr '11

While intended mainly for pilots I thought I'd repost this here since a number of folks here use GPS and it looks like the effects of the test could reach the ground. patrick http://download.aopa.org/epilot/2011/110426utah.pdf FEDERAL AVIATION ADMINISTRATION FLIGHT ADVISORY GPS Testing ACC GPS 11-07 April 28, 2011 – May 13, 2011 Wendover, UT GPS testing scheduled as follows may result in unreliable or unavailable GPS signal. A. Location: Centered at 402602N/1132936W or the BVL VOR 145.44 degree radial at 21.3NM. B. Datesandtimes: 28 APR – 29 APR 30 APR - 06 MAY 09 MAY – 13 MAY 1700Z – 2000Z 2200Z – 0000Z 1700Z – 2000Z 1700Z – 2000Z C. Duration: Tests will be conducted continuously during times requested above. D. During testing, the GPS signal may be unreliable or unavailable within a 395NMR centered at 402602N/1132936W or the BVL VOR 145.44 degree radial at 21.3NM at FL400 and above, decreasing in area with decrease in altitude to 355NMR at FL250, 260NMR at 10,000 FT MSL, 265NMR at 4,000 FT AGL and 225NMR at 50 FT AGL. E. Pilots are strongly encouraged to report anomalies during testing to the appropriate ARTCC to assist in the determination of the extent of GPS degradation during tests. The NOTAMs discussed in this advisory may change with little or no notice. Pilots are advised to check NOTAMs frequently for possible changes prior to operations in the area. NOTAMs will be published at least 24 hours in advance of any GPS tests.

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Apologies
by Steve Fisher 27 Apr '11

27 Apr '11

Sorry everyone for conducting "business" here. I replied not realizing we were still on list. Steve

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Re: [Utah-astronomy] Utah-Astronomy Digest, Vol 98, Issue 79
by Michael Vanopstall 27 Apr '11

27 Apr '11

Joe -- It doesn't really matter. I was trying to say that the closer the full moon is to midnight on Saturday, the more likely that the inaccuracies in the older computations are to have an effect. I was actually wrong on that: the Julian moon tables are fully four days behind. Thus, it is more likely than not that the dates do not coincide. So being close to midnight doesn't matter. That is more consistent with what I've experienced -- it seems like a rare year when Orthodox and Western churches observe on the same date... The moon tables are made based on a lunar calendar that isn't exact. It's just made up with more-or-less alternating 29 and 30 day months to approximate moon phases. So deep down, there's a Christian lunar new year that no one (that I know of) celebrates. So even the modern, Gregorian computations are wrong in some years, since the moon's actual (synodic) period is about 29.5 days. It's slightly more, so the ecclesiastical lunar calendar has, I think, an extra 30 month day. It was both factors, the slipping of the equinox and the moon being off (in the 16th century, the equinox was 10 days off and the moon cycles were about 3 days off) that motivated the creation of the Gregorian calendar. Anyway, the time zone is irrelevant: there's not an actual computation of the new moon to the minute, hour, second, or anything like that. The new moon is just, by convention, on the first day of some "month" of the church lunar calendar. ---- Rev. Michael A. van Opstall Department of Mathematics, University of Utah Office: JWB 313 opstall(a)math.utah.edu

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