October 2010 - Utah-Astronomy - mailman.xmission.com

M57 +73PSW-3
by daniel turner 27 Mar '13

27 Mar '13

Mark your calendar for early evening May 7. Their will be a close encounter between the Ring nebula and periodic comet 73P. The comet will be close to earth so its exact position in the sky will depend stongly on your location on the globe. Go to spaceweather.com and use the link at the bottom of the page for "Observable Comets". 73p is in the list and includes orbital elements and a link for daily ephemerides. DT __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Purchase advice on Canon Digital Rebel XS, XSi
by Canopus56 02 Nov '10

02 Nov '10

I am getting ready to buy my first DSLR and I would like to buy a Rebel XS or XSi. This would be a general purpose camera but I want to cross-purpose it as an astronomy camera. I feel the cheaper XS model meets my needs. I am unclear on: 1) For time lapse night time photography of a large sky section with the 15mm lens, how do you get the images off the camera in real time since it only holds 4 shots? 2) Other advice of comments are the purchase are welcome. Thanks - Kurt

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Re: [Utah-astronomy] 2003 UV11 What if it hit Salt Lake City
by Jay Eads 01 Nov '10

01 Nov '10

David, There was a study in 2007 by Sandia Labs out of Livermore CA (where I grew up) found at https://share.sandia.gov/news/resources/releases/2007/asteroid.html that shows that the size of the Tungska event is actually smaller than orginally thought. Tungska's object created a yield of 3-5 megatons, which is revised down from the 10-20 megatons of earlier. Thus the size of the object would be about 60% less. How often is still up for grabs from what I've read but I'm sure they are more defined. I think Shoemaker estimated Tunguska events around every 300 years. From the Sandia study it looks like even smaller ones could still do major damage over a major metropolitan area. -- Jay Eads

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ISS this evening
by Patrick Wiggins 01 Nov '10

01 Nov '10

Challenging pass of ISS this evening (challenging because it occurs right at sunset). Here are data computed for my place but should be good for all of most eveyone on this list (well except for Rob but he'll probably be drinking something cool on a beach somewhere at the time <g>): Sunset 18h27m Appears 18h23m55s 3.3mag az:236.4° WSW horizon Culmination 18h28m52s -4.1mag az:324.4° NW h:72.8° distance: 370.6km height above Earth: 356.3km elevation of sun: -1° Disappears 18h33m36s -1.1mag az: 52.4° NE h:1.2° patrick

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Updates to Using Setting Circles webpage - Goto and Manual
by Canopus56 31 Oct '10

31 Oct '10

I have made the following updates to my ongoing page on using manual setting circles - which has expanded to other SAO reference lists to support GOTO star synching in support of GOTO DSO locating. The general intended purpose of these lists is to support GOTO DSO locating at urban and suburban star parties by supporting the GOTO star-sync method of DSO location (described below). The intent is to support fast slew and accurate GOTO location so telescope operators may make a more fluid presentation of a series of multiple targets. I. Bright-Star-to-SAO cross-reference list for the LX200 and N41 observing points Table: Cross-reference Bayer-Flamsteed-to-SAO for 1822 stars brighter than mag 5.5 visible above -40° dec http://fisherka.csolutionshosting.net/astronote/plan/mansetcir/html/LX200SA… This table (file: LX200SAOXRefTable.pdf) cross-references bright Flamsteed and Bayer stars by constellation to SAO numbers that are: 1) Are brighter than mag 5.5; and, 2) Are north of -38 North. The table is sorted by constellation. Therefore, if a bright Bayer or Flamsteed star in a constellation of interest can be seen, its SAO number can be quickly found, and then the telescope operator can use the SAO number to slew the scope to the bright star. For urban star parties, a smaller set of stars under mag 4.0 and 3.0, also included in the list, is more useful. The purpose of this table is to increase the pointing accuracy the GOTO star synch method. Most computer GOTO telescopes, unless perfectly aligned cannot accurately slew more than 30 degrees. At the light-polluted sites, success in finding faint DSOs is problematic for most irregular users given the small TFOV of many scopes like the f/10 LX200, e.g. about 1/3 degree at 25mm. By the synch method, the telescope is first slewed to a bright naked-eye star within 5 to 10 degrees of the target. Then handbox is synched to that bright star. Then the telescope is slewed to the DSO faint fuzzy target. Since the slew distance is small, usually the slew error is sufficiently small that the faint fuzzy DSO is within the eyepiece apparent field-of-view. Additional versions in csv and Excel 2003 format are available by linking off the main webpage url at http://fisherka.csolutionshosting.net/astronote/plan/mansetcir/ManSettingCi… II. Caldwell-Messier Cross-Reference list to nearby bright synch stars with SAO numbers Table: Messier and Caldwell list slews from bright stars above -38° dec by Messier Caldwell number sorted by constellation http://fisherka.csolutionshosting.net/astronote/plan/mansetcir/html/Messier… This table is a re-sort of my March 2010 version. The original version was orderd by RA and DEC. This version is sorted by constellation which makes the table more useful on a given observing night by (file: "MessierCaldwellSlewsbyConstellation.pdf") stating cross-references between the DSO to the closet Bayer star and that Bayer's star SAO number. This table can be used with the synch method to resynch align GOTO scopes to a nearby star before slewing to a faint fuzzy DSO. The first table of bright-star-to-SAO cross-references was created using an amateur developed full cross reference table for the LX200 SAO star catalogue consisting of approximately 37,000 rows. (url: http://www.starxref.com/star_xref.htm ). This larger list was narrowed by magnitude and whether they were observable from Utah. Gatter's list is well-known and reputable in the amateur community, but I have spot checked 20 of the entries in my narrowed lists and they appear accurate. That yielded the table of 1822 stars (file: "LX200sAOXRefTable.xls"). Although the 1822 entries cover about 32 pages, a double-sided printed list would be 16 pages and would be a managable hard-copy when using a consumer grade GOTO scope. The second Caldwell-Messier SAO cross-reference list was originally developed by myself in 2007, when I initially based the cross-references on HD star numbers. In 2010, I updated the table to include SAO cross-references. Here, the table is resorted by constellation - a much more useful order for making star party presentations. Please email me with any corrections. Clear Skies - Kurt

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Re: [Utah-astronomy] Purchase advice on Canon Digital Rebel XS, XSi
by Canopus56 31 Oct '10

31 Oct '10

Dear group, Thanks for all for the many informed comments on the Canon camera series. That was just what I was looking for; what a wonderful resource you guys are. Looks like buying a used XSi off the KSL classifieds is the way to go. I'll probably also be buying one of those digital shutter controls, so when doing wide-field sky time lapse photography, I do not also have to haul out laptop. Does anyone know if Inkleys or Pictureline sells the T-ring adapter for the camera body locally, or should I go ahead and order it off of Scopestuff.com ? Thanks again - Kurt P.S. - Patrick - Yes, may I borrow the ST-6 for a few weeks. I have a several uncooled astro cameras and, even with the ST-6's old serial port, it would be nice to add a cooled camera. Let me know what would work for a hand-off time. I am on the UofU campus during the week, so maybe a hand-off after one of your physics classes would be the best method.

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Re: [Utah-astronomy] Happy Haloween! -- Killer Rocks in Space
by Canopus56 31 Oct '10

31 Oct '10

Joe, Thanks for a wonderfully well written review of this astro-hazard topic. Your many years of journalism experience really shine through. - Kurt

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Re: [Utah-astronomy] 2003 UV11 What if it hit Salt Lake City
by Canopus56 31 Oct '10

31 Oct '10

Joe - Yes, please go ahead quote me. - Kurt P.S. - For impact damage, there would also be the "light dusting" (applet's language) of 1.5 inches diameter rocks [traveling at near the speed of sound]. Link to applet authors' journal article about the applet. http://impact.ese.ic.ac.uk/ImpactEffects/effects.pdf P.P.S. - You might also want to remind the 2012 conspiracy theorist types that NASA was reduced to risk of the Aphosis impact in 2032 to a non-event like 1-in-250,000. http://www.nasa.gov/home/hqnews/2009/oct/HQ_09-232_Apophis_Update.html Similarly, some 2012 conspiracy theorist types are hyping 433 Eros, an asteroid that NASA landed a probe on in 2000, as an impact threat in 2012. In January 2012, 433 Eros will pass at 70 lunar distances from the Earth - in other words no chance of impact. See http://en.wikipedia.org/wiki/433_Eros

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Re: [Utah-astronomy] 2003 UV11 What if it hit Salt Lake City
by Canopus56 30 Oct '10

30 Oct '10

Joe wrote: "Kurt, a Richter scale 7 is a major earthquake. Wouldn't there be a lot of damage just from that? Thanks, Joe" Yes, there seemed to be a disconnected between the web application's description of the light physical damage to buildings and my personal experience of magnitude 7.0 earthquake in 1971. But no worries, the other major damage is the flash burn from the fireball that would be 10 times the sun's mean brightness. At 100km distant from the impact - let's say Nephi or Spanish Fork - anyone outside would suffer first degree burns over 100% of their body, and the town, if not shaken down, would burn down. - Clear Skies (and since its near Halloween), Kurt "Death from Above" Canopus56

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Sun Image
by Jay Eads 30 Oct '10

30 Oct '10

This isn't the Great Pumpkin Charlie Brown, but a fantastic image of our sun! I thought this was rather cool. It is an image of the sun taken by astrophotographer Alan Friedman. It is taken on this equipment: http://www.avertedimagination.com/images/littlebigman.jpg The image was shot on October 20th, 2010 in H-Alpha. Here's the link to the interactive image: http://www.avertedimagination.com/img_pages/not_the_great_pumpkin.html Click on the sun and you'll get two gray boxes that you can click on and get closer images. Here is something else to think about: "See that little bright spot on the plume on the left, where two plumes are next to each other, just above the Sun’s edge? *That spot is the same size as the Earth*." Remember, a million earth's could fit inside of the sun! Anyway, I thought this was cool and I know many others also take such wonderful images of our nearest star. Here is Alan Friedman's gallery if you want to take a look at his images: http://www.avertedimagination.com/latest_1.htm Some are really cool. Enjoy. -- Jay Eads

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