February 2009 - Utah-Astronomy - mailman.xmission.com

Roger Sinnott's article "A Spreadsheet for Polar Alignment"
by Naz & David 22 Feb '09

22 Feb '09

Kurt, Do you have a copy of Roger Sinnott's article in the Sept '91 S&T issue "A Spreadsheet for Polar Alignment" pp 299-301? Does it work through the math a little bit? I want to calculate the RA and DEC drift of a star as a function of alt and az polar misalignment, I have the spreadsheet you put together that goes the other way. Cheers David

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Re: [Utah-astronomy] Roger Sinnott's article "A Spreadsheet for Polar Alignment"
by Canopus56 22 Feb '09

22 Feb '09

Replied offline: Consistent with the practice back in the days of Visicalc, Supercalc, Multiplan and Lotus-1-2-3, the formulas [in Sinnott's article] are listed in a table on the second page. I could not find an online spreadsheet, so I hand-typed the formulas into the Excel spreadsheet that you downloaded. Enjoy Kurt P.S. - Chris Lord also has an extensive of papers - but they are pretty hard to follow: http://www.brayebrookobservatory.org/BrayObsWebSite/HOMEPAGE/BRAYOBS%20PUBL… True Polar Alignment for an Observatory Class Equatorial http://www.brayebrookobservatory.org/BrayObsWebSite/HOMEPAGE/PageMill_Resou…

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Re: [Utah-astronomy] Urban Obs Rep 2-20 10pm 2-21 2am MST
by Canopus56 22 Feb '09

22 Feb '09

Thanks, Jim. I left a couple of notable clusters off the list - Christmas Tree and the M67. - Kurt

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Comet Lulin
by Raeburn Kennard 22 Feb '09

22 Feb '09

I have posted to my album on the SLAS Gallery three photos of Comet Lulin taken the morning of Sat., Feb. 21 from my back yard in Draper, UT. http://www.slas.us/gallery2/main.php?g2_itemId=464 These are 30-second exposures using a Nikon D40X on a tripod (no tracking, so objects are "moving"). I used a 55mm lens with f4.0, and iso setting at 800. The first photo is unedited. The other two are cropped to frame Gamma Virgo (I think) and the comet. The first of these two cropped photos (No. 9a) was taken about 30 minutes prior to the second cropped photo (No. 17a). The rapid movement of the comet relative to the nearby star is evident when comparing these two photos. I would welcome any enhancements that people might achieve by using Tyler Allred's editing techniques, as explained in his excellent lecture last week. Raeburn Kennard rkennard(a)kmclaw.com<mailto:rkennard@kmclaw.com>

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Lulin FIT files
by Patrick Wiggins 21 Feb '09

21 Feb '09

I got 6 "quick and dirty" 1 minute exposures. All washed out the way them came out of the camera (the comet is bright) and since I guided on the comet (which is moving quickly) the background stars are trailed. Should anyone care to try and salvage something from the FIT files you'll find them at: http://users.wirelessbeehive.com/~paw/temp/LULIN2009FEB21.zip patrick

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Urban Obs Rep 2-20 10pm 2-21 2am MST
by Canopus56 21 Feb '09

21 Feb '09

Last night being moderately warm with clear skies and good transparency, I pulled out a small 4 1/4" computer controlled short tube reflector for an evening of urban astronomy. Urban astronomy involves double stars and bright open clusters and not faint galaxies lost in the urban light pollution glare. Tonight, I was getting used to a new scope and decided to do a showcase open cluster tour in the anti-spinward unfolding Orion-Cygnus Arm that runs north-south along the east side of Orion from Orion to Canis Major and Puppis. (Although boring for most of the advanced amateurs on this list, the target detection confirmations at 127mm apeture from a light polluted location may be of use.) My other major goal of the night was to try practicing urban dark adapted observing techniques, i.e. - consistent use of an eye-patch and an Orion dark cloth hood. (My specific site in the aves is outside my back door and is riddled with intrusive neighbor "afraid of the dark" house lamps. ZLM was 18.1 mpsas per the Sky Quality Meter (4.1 mag). Transparency was much improved from a session on the previously night of 2-19 to 2-20. First, I tried unsuccessfully a second time to detect Comet 144P Kushida. Although on target, I concluded that 125mm of apeture was not enough to detect this comet from light polluted skies. Next, I skirted up to NGC 1647 - an open cluster on the east leg of Tau's horn for a quite telescopic limiting magnitude test. On of the first "projects" that I did on returning to astronomy in the early 2000's was a high-precision map of NGC1647 for TLM test purposes. NGC1647 Map http://members.csolutions.net/fisherka/astronote/observed/NGC1647/NGC1647_P… In this light polluted urban environment at v4.1, the 127mm reflector reached down to mag 10.4 The open cluster tour began high in the western sky with showcase open cluster M35 (NGC2168, 5.1v, 30' dia., dist. 0.816 kpc). A two-dimensional map from a north galactic pole view looking down on Sol and showing the clusters described in this post can be found at: http://members.csolutions.net/fisherka/astronote/observed/Reports/20090221O… Cluster M35 cluster had good resolution at this apeture and light pollution. (I didnot make a note on the visibility of nearby open cluster NGC2158. NGC2158 is about 15 arcmins from M35. At a distance of 5 kpc, NGC2158 (8.6v, dia. 5') is the most distant open cluster visible in amateur class telescopes and is located in the Outer Arm. I will try for a detection tonight, weather permitting.) Next was M50 (NGC2323, 5.9v, 10' dia., dist. 0.929 kpc) in Puppis. This cluster had good resolution at this apeture and light pollution. Also in Puppis is the open cluster pair M46 and M47 (M46, NGC2422, 4.4v, dia. 20', dist. 1.375 kpc; M47, NGC2437, 6.1v, dia. 25', dist. 0.49 kpc). Their alignment is optical only, as indicated by their relative distances. As can be seen in the SEDS images, the further M46 is the more interesting, but fainter detailed target. http://www.seds.org/messier/m/m046.html http://www.seds.org/messier/m/m047.html Clark's classic _Visual Astronomy of the Night Sky_ includes a detail telescopic limiting magnitude map for M46. But a TLM map for M46 can also be quickly pulled up online from the Webda cluster database: http://www.univie.ac.at/webda/cgi-bin/ocl_page.cgi?dirname=ngc2422 http://www.univie.ac.at/webda/cgi-bin/chart_frame.cgi?ngc2422 (Use the Chart Form to set the limiting magnitude to 9 or 10.) Next, I wrapped up with two classic wide-field open clusters M44 (NGC2632, 3.1v, dia. 80', dist. 0.19 kpc, age: 562 million years) in Cancer and M48 in Hydra (NGC2548, 5.8v, dia. 40', dist. 0.77 kpc, age 794 million years). This clusters are located sidereal eastward of the prior targets and are "off" the main galactic disk. The galactic latitude of both is higher as compared to the earlier targets (M44 +15.4 b; M48 +32.5 b). M44 is close-in to Sol but is running high above the galactic plane. This accounts for its relatively old age and the prevalence of yellow stars in this cluster. Most clusters do not survive one galactic rotation (~220 million years), because they form in the galatic plane and are torn apart by gravity interactions and gravity density waves. The galactic year, the time it takes the Sun to complete one revolution around the Milky Way's core, is approx. 220 million years or 8.34 log10(years). Half of all open clusters disperse in just under one galactic year (8.13 log10(years) or 218 million years). The third quartile of open clusters disperses in just under two galactic years (8.6 log10(years) or about 430 million years). Popular old clusters and moving groups that have survived more than two galactic years and into the fourth quartile include M044 (Beehive Cluster, age ~log 8.7 Myrs) and M048 (age ~log 8.9 Myrs). On finishing the open cluster tour, it was 12:30-1am, so it turned my attention to the solar system. Comet Lulin was quickly located between and south of gam and eta Vir. It could easily be seen at 40x, but no tail detail was visible from this light polluted location. Tonight, 2009-2-22 6UT (2009-2-22 12:01am), Comet Lulin will at the edge of a 1 deg telescopic TFOV of magnitude 6.3 star SAO119100 and an SLC horizon altitude of about 37 degrees. In a binocular view, pan 2 degs east and 1 degs south of bet Vir (Zavijah). Lulin is streaking towards its rendevous with Saturn on 2-23, 2-24. At 1:00am, Saturn is nearly transiting and gave good, crisp and steady views with good seeing. This may be the time for some of the best Saturn views this year with its unique edge on rings. Although the early morning hour is inconvienent, I recommend setting the alarm clock for a quick 1 or 2am setup. Finally, I tried to hunt down Ceres, which is featured page 60 of the March 2009 Sky and Telescope. (Initially I had a hard time confirming a detection. My asteriod element file in my planetarium program was outdated.) Ceres (6.0v) was seen with 8x35 binos and the 4 1/4 reflector. For binocular detection, Ceres currently (2/21) is about 4 degs northwest (PA 328) of del Leo (Zosma). The parallelogram asterism is formed by: 72 Leo East 4.6v 67 Leo North 5.7v Ceres South 7.0v 54 Leo West 4.5v Ceres should not be confused in the bino view with nearby 64 Leo (6.5v). The Flamsted referenced stars are found on most charts. Ceres is at the "bottom" or most southern vertex of the diamond shape. Also helpful for locating Ceres in binoculars is 54 Leo. 54 Leo anchors the "bottom" or south of a small, prominent triangular asterism consisting of: 54 Leo South anchor 4.5v 50 Leo Northeast corner 6.4v 48 Leo Northwest corner 6.2v Weather picture for tonight as of 3pm MST is uncertain. Fronts appear to still be approaching, but trapped on the west coast. The 3pm MST SLC sky has light leading edge altocirrus clouds. This has been the situation for the last two nights. Clear Skies - Kurt

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Thanks SLAS
by Tyler Allred 21 Feb '09

21 Feb '09

To all the wonderful SLAS members. Many thanks for being such a nice audience last night. And, thanks for the many emails I have received today, both on and off the list. I appreciate the support and the kind words. I am glad that my presentation was so well received. Feel free to contact me through my website at: www.allred-astro.com <http://www.allred-astro.com/> I am happy to help, or to answer any questions you might have about astro-imaging. Cheers, Tyler _____________________________________________

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Re: [Utah-astronomy] Abell 31
by Debbie 20 Feb '09

20 Feb '09

Patrick, Abell 31 is the largest known planetary nebula in the sky. I think the trick will be to find the parallagram of 4 stars in the field. There is a picture and a nice observing report at this website. Maybe your skies there are not dark enough. I picked up Abell 35 at Bryce Canyon a few years back and that was faint. I also viewed Jones-Emberson1 at Fort Pearce a couple of years ago. It was out of the light pollution from St George. Low surface brightness planetaries need dark skies and averted vision and lots of patience. http://www.skyhound.com/sh/archive/feb/PNG_219.1+31.2.html Debbie On Thu Feb 19 9:24 , erikhansen(a)TheBlueZone.net sent: >>It's listed at mag 12.2 spread over large area (16'). > > > Hi Debbie, >> >> We had surprisingly good weather last night so I tried to get a >> picture of Abell 31. >> >> Despite binning 3x3 and shooting a 10 minute exposure there was >> nothing there. >> >> That is one faint planetary. >> >> patrick >> >> p.s. 'Course if I sent the data to Tyler he could probably extract it. :) >> >> >> On 15 Feb 2009, at 18:56, Debbie wrote: >> >>> I'm dusting off my telescope this weekend to get it ready for some >prime winter >>> observing. I'm hoping to bag a few large planetary nebulae like Abell 31. >> >> >> _______________________________________________ >> 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://gallery.utahastronomy.com >> Visit the Wiki: http://www.utahastronomy.com >> > > > > > >_______________________________________________ >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://gallery.utahastronomy.com >Visit the Wiki: http://www.utahastronomy.com

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And while we are making our calendars - April 22 6_15am MDT
by Canopus56 19 Feb '09

19 Feb '09

- A nearly new Moon occults mag -1.6 Venus a few minutes before civil sunrise. Moon sallows Venus for about 50 minutes but Venus is so bright that when it appears around 7am, it may be telescopically visible. - Kurt

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Re: [Utah-astronomy] Four of Saturn moon's to transit Saturn's face 2-24
by Canopus56 19 Feb '09

19 Feb '09

Whoops. Got that one wrong. Mimas is on the disk along with Titan by 11 UT and it is Dione and Enceladus skirting over the rings. So the count is at 11UT (4AM): 2 moons on the disk, two skirting the rings, and one really bright nearby comet! Not quite sure if the minor Moon other than Titan would be visible. Any experienced based estimates from the historical SLAS brains trust? My apologies. Clear Skies - Kurt

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