December 2007 - Utah-Astronomy - mailman.xmission.com

Re: [Utah-astronomy] Misc nature pic added to Gallery
by Kurt Fisher 09 Dec '07

09 Dec '07

Joe wrote: > I can't see beauty in it [the snow] anymore. . . . > I'm glad you're not jaded by snow! -- Joe I don't get out into the Wasatch anywhere near what I did in the 80s or early 90s. But the ocassional hike, telemark turn or diagnol stride up a side trail can still get my heart fluttering - in a good way! Astronomy is just an extension of that - keeping your eyes open and up to nature. - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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RE: [Utah-astronomy] Utah astro wiki update: 1-5-2008 asteriodoccultation
by Kurt Fisher 08 Dec '07

08 Dec '07

Dale, Thanks. Occult Watch looks like another good option. All this is pretty amazing software. Occult4 doesn't return the occultation that you mentioned. Could you post some details so I can check out the entry. I'd like to figure out why it did not come up in Occult4? One the thing I like about Occult4 is that you can search for potential asteroid occultations against the fainter UCAC2 catalogue. This increases the chance of finding an asteroid occultation that you do not have to drive a 200 km to watch. The brighter Tycho2 entries (< mag10 in that mag 11 catalogue) seem to happen infrequently for any one North American location. It looks like it will be a good year for grazing lunar occultations. Leafing through my 2008 RASC Handbook (at pp167-172) over lunch, preliminary there are three potential observable lunar grazes in 2008 that cross over or near SLC County. (No. 45 - 2/21 - 33km dist from SLC); No. 95 - 4/14 - 2km dist; No. 210 - 12-17 - 3km dist). I took a quick look at these in Occult4 adding the driving distances from SLC in the preceding paranthetical. I'll check these 2008 grazes out in more detail using Occult4 later in the month. The lunar occultation graze on 2-21-2008 at 4:25 UT across a mag 7.8 star near the lunar north pole occurs during the near full Moon and would not be useable. But as it happens, the 4:25 UT occultation (4:38 UT in Occult4) frutitously occurs during the February 21 (Feb. 20 9:38 MST) total lunar eclipse when the Moon will be in the Earth's umbra. See the 2008 RASC Handbook at p. 138. Maybe the lunar graze of this mag 7.8 star will not be washed out by the full Moon. SPOC will be opening for the special eclipse event. Running the gaze through Occult4 using SPOC's coordinates and altitude shows SPOC is 13km north of the graze centerline. I believe Patrick will be distributing the 2008 handbooks at the solstice party. - Kurt P.S. for lurkers. Another option for bright star and grazing lunar occultations by the Moon that doesn't involve using software is to download the city specific table for 2008 from: http://www.lunar-occultations.com/bobgraze/f.zip in http://www.lunar-occultations.com/iota/iotandx.htm The lunar graze maps for 2008 (reproduced in the 2008 RASC Handbook) will also be available at that site, but have not been posted yet. There are three types of occultations described in this thread: 1) occultations by asteroids of stars used to determine the size of the asteroid, 2) total occultations of binary and multiple star by the dark limb of the Moon used to determine the separation of a members of a multiple system, and 3) grazing occultations of the Moon's dark limb by single stars used to create a partial profile of the topography of the Moon's limb. _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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Seeking copy of Mardsen's Catalogue of Cometary Orbits
by Kurt Fisher 07 Dec '07

07 Dec '07

Hi, I'm looking for a copy of Mardsen's Catalogue of Cometary Orbits. An outdated version would be okay. Can't seem to find one at any local Utah library. I'm looking for a table that would include both the perihelion distance in a.u. and the maximum observed diameter for the comet's coma. This is related to Comet 17P Holmes. I understand that there is a relationship between the perihelion of a comet and diameter of the coma. As a comet gets closer to the Sun, the pressure of solar wind causes the coma size to shrink. Short period comets that do not get close to the Sun at perihelion can have larger comas because there is less pressure from the solar wind pushing against the dust ejecta from the nucleus. Apparently, the Mardsen's catalogue put out annually by the Harvard Center for Astrophysics may have the right table but they restrict distribution to paper to keep up their royalty revenue stream. Anyone have an copy of this that they could lend me? - Thanks, Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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Utah astro wiki update: 1-5-2008 asteriod occultation
by Kurt Fisher 07 Dec '07

07 Dec '07

Added to the utah astro wiki current events page, background on the Jan. 5 7.19.9 UT or 12:19am MST occultation by asteroid 4368 Pillmore of 10.8 mag star UCAC2 29623669, probably the same as TYC4843-01058-1. http://www.utahastronomy.com/Current_observing_events#January_2008 Unfortunately, the maximum duration of the occultation is 1.5 seconds. Therefore, the usual use of these occultations - to prepare a 2D slice map of the outline of the asteroid - is so short that useful data probably could only be retrieved by a few club members equipped with 10 inch apetures and video cameras with intensifiers operating at 30 frames per second. Nonethless, this occultation provides an opportunity for club members who have not done asteroid occultations to get some experience in this observing skill from the relative comfort of their urban backyards during the cold winter season. Using a small goto alt az telescope or DOB, you can try to see the star blink-out at the appointed time. A sample of what these occultations look like can be seen in a YouTube of a 3 second occultation of iot Cnc in April of this year. http://www.youtube.com/watch?v=FYvW7Y7N0tI Salt Lake County is well positioned to observe this short 1.5 second occultation - the ground track runs east-west between I-215 south to the Point of the Mountain in Salt Lake County. In Tooele County, it runs between SPOC and South Mountain and in Wasatch County between Rockport and the north end of Heber Valley past the Jordanelle Dam. Being a novice at asteroid occultations, corrections and comments on the background provdied in utah astro wiki entry are welcomed. Enjoy - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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Shuttle launch postponed to 7:56am Fri
by Kurt Fisher 06 Dec '07

06 Dec '07

Shuttle launch postponed till 7:56am MST Friday. [http://www.nasa.gov/mission_pages/shuttle/main/index.html Dec. 7 also is the 35th Anniversary of launch of the last manned moon landing - Apollo 17. - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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Is the clear sky alarm down?
by Dale Hooper 06 Dec '07

06 Dec '07

Hi, I haven't received a clear sky alarm for about two months now. I know the skies have been bad - but they haven't been THAT bad. Is anyone else signed up for clear sky alarms and have you received any recently? I've tried to contact Mark Casazza who runs the Clear Sky Alarm Clock site ( http://clearskyalarmclock.com/v2/Referers.php ) but perhaps I've gone about it the wrong way. Thanks for any help and clear skies, Dale.

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Misc updates to Utah Astro Wiki
by Kurt Fisher 05 Dec '07

05 Dec '07

Updated section on high-accuracy time synchronization with a discussion of the Garmin 18 GPS and the KIWI-OSD video labeler. The relatively inexpensive Garmin 18 plugs into your laptop and can synchronize your laptop to GPS time while at a remote site. http://www.utahastronomy.com/Observing_resources#High_accuracy_time_synchro… Updated handy tables for observing with a table of the number of effective observing hours per month for Salt Lake City. http://www.utahastronomy.com/Table_SLC_UT_Effective_Observing_Hours Effective observing hours equals potential dark sky hours or lunar observing hours times the percentage of average monthly time with clear skys per Utah climate records. See also handy tables generally at - http://www.utahastronomy.com/Observing_resources#Handy_Tables - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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Re: Comet 17P 12-4-2007 pic added to gallery
by Kurt Fisher 05 Dec '07

05 Dec '07

Tyler and Joe, > Nice image Kurt. . . . Thanks for posting the image. Thanks. These are all just quick pics - unguided short 2.8 sec x 4 exposures with a telephoto lens kludged onto a DSI Pro I. Something I can grab and go with at 10pm or 11pm when the 16% clear weather window in December cooperates and that only takes a few minutes to make an image with in 40 deg temperatures. More to document the comet between weather fronts rather than going for a skillful image. But hopefully it will inspire those of you with the _real gear_ to take another pic. If you do get a clear weather window, don't forget to try for Comet 8P, which I understand presently can be acquired inbound as a faint mag 9 fuzz ball about 3 degs PA 350 north of rho1 rho2 Cep. Haven't seen it myself. http://www.utahastronomy.com/Current_observing_events#Comet_8P_Tuttle_12-14… - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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Comet 17P 12-4-2007 pic added to gallery
by Kurt Fisher 05 Dec '07

05 Dec '07

12-4-2007 6:48UT (12/3/2007 11:48 MST) http://gallery.utahastronomy.com/v/kurt/solarsystem/Comet+17P+Holmes/040.PN… http://gallery.utahastronomy.com/d/10832-2/040.PNG K. Fisher 12-4-2007 labeled with stars and photometry http://gallery.utahastronomy.com/v/kurt/solarsystem/Comet+17P+Holmes/041.pn… http://gallery.utahastronomy.com/d/10835-4/041.png and to Utah Astro wiki Comet Holmes current events page at: http://www.utahastronomy.com/Comet_17P_Holmes_2007 The comet was about 1 deg PA 180 south of iot Per. It is now about 1 deg in diameter or a physical size of about 4.5 million km. Mag was between 4.5 and 5.0. It is still visible with the naked-eye in a mag. 5.0 sky from Little Mtn. - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

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Comet & sky great tonight
by Patrick Wiggins 05 Dec '07

05 Dec '07

When I got home tonight the sky was overcast so I was surprised when Bruce Grim called a few minutes ago exclaiming about the comet. I hustled outside and, sure enough, it had cleared off and the comet was _still_ easy naked eye. Maybe it's time to start calling Comet Holmes the comet that would not die. I'm currently imaging a few MPs and the crystal clear images are telling me the seeing is superb. And as a bonus: No Moon! What a night. pw

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