July 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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Re: [Utah-astronomy] Parallax experiment with (3833) Calingasta
by Canopus56 31 Jul '10

31 Jul '10

Patrick, Thanks for the notes. The method I outlined only applies to targets at opposition - which for asteroids can be determined in real time using Warner's MPO Canopus Lightcurve group. http://www.minorplanetobserver.com/Misc/EphemerisGenerator.htm But I forgot to ask the obvious first question: Is the asteroid in the photo at opposition? If it was not, then the method discussed upthread is not directly applicable. I have not run the specific computation to find the distance limit for a diurnal parallax measurement. It probably would reach the inner asteroid belt using amateur equipment, but not 1 A.U. Warner's Asteroid Ephemeris Generator lists the following asteroid as coming to opposition on July 30 - 1004 Belopolskya, mag 14.4, but it is at a distance 3.8 A.U. - Clear Skies - Kurt

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Calling Rich Tenney...
by Kim 31 Jul '10

31 Jul '10

Is Rich Tenney still on this list? Kim

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Re: [Utah-astronomy] Parallax experiment with (3833) Calingasta
by Canopus56 31 Jul '10

31 Jul '10

Patrick, Not that you need my help on the math, but below are three posts with background info on the analogous problem of computing the distance to Mars based on diurnal parallax. I will have to dig out the stored parallax construction that I did from the 2005 Mars opposition and put it back on the Utah Astro Gallery. The Yerkes Hands-On-Universe 2003 Mars opposition project to replicate measuring the distance to Mars by the diurnal parallax method, referenced in my post, is now at this location: http://www.handsonuniverse.org/activities/Explorations/MarsParallax/ but they seem to have deprecated the path rights to the math construction documentation. Here is Pete Lawrence's page from his 2005 attempt at the analogous problem of diurnal parallax: http://www.digitalsky.org.uk/Marsnight/marsnight-2005-10-23.html Some where in my archives I have Gill's 1878 paper on measuring the parallax of Mars - which I recall was useful - but it can probably be retrieved out of NASA-ADS with "Gill Acsension report 1878". My apologies in advance if this post is in the category of "too much information." Clear Skies - Kurt ================ From: "canopus56" <canopu...(a)yahoo.com> Newsgroups: sci.astro.amateur Subject: Historical astronomy - finding Mars parallax and distance Date: 19 Oct 2005 21:21:06 -0700 I just finished reading Arthur Berry's _A Short History of Astronomy_ (1898, 3d 1961). Berry reviews the major astronomical accomplishments through the end of the 19th century. Berry mentioned that in addition to the transit of Venus, the parallax of Mars at opposition was also used in the 1870s to establish an Earth-Mars distance and by Kepler's Third Law, the Earth-Sun distance. Berry at Chap. XIII, Sec. 281. Earlier measurements were made in the 1670s. Berry at Chap. VII, Sec. 161. This suggests that modern amateurs equipped with CCDs and web cams could replicate the experiment and measure the parallax of Mars using an Earth baseline during the Oct 30, 2005 greatest size and/or Nov. 7, 2005 opposition of Mars. Pete Lawrence restaged a similar historical experiment to find the parallax and distance of the Moon using the Nov. 8, 2003 and Oct. 28, 2004 lunar eclipses. Lunar Parallax Demonstration Project http://www.digitalsky.org.uk/lunar_parallax.html Two techniques have been used to measure the parallax of Mars. The first involves an Earth baseline and two observers. This method was first used by Cassini, Picard and John Richer during 1671-1673. Richer traveled to Cayenne (lat 5 deg) while Picard and Cassini observed from a newly completed observatory in Paris. Chap. VII, Sec. 161. This provided a north-south baseline on which the observers could make a position observation at the same time - opposition. The second technique, called the diurnal method, involves one observing station measuring Mars' position on the night of opposition at different times. The changed position of the OP over time resulting from the Earth's rotation provide the baseline. This technique was invented by Flamsteed (1646-1720) and was revived by Sir George Airy (of the Airy Disk) in 1857. In 1877, a Dr. "Gill" working at Ascension used the diurnal method to measure the parallax of Mars at opposition. Berry at Chap. XIII, Sec. 281. The current Mars opposition occurs on Nov. 7, 2005. At that time, Mars will be about 69,415,600 km (43,132,800 miles) from the Earth. Using the half-angle formula, those distances suggest a parallax at opposition on a 6,000 kilometer baseline of 2.8 arcsecs, or on a 12,000 km baseline of 5.6 arcsecs. A similar educatonal project was undertaken by the Univ. of Chicago Yerkes Observatory Hand-On-Universe outreach program for the 2003 Mars opposition. That project used the diurnal method. The project documentation is here - http://sunra.lbl.gov/~vhoette/Explorations/MarsParallax/ including a useful spreadsheet on computing the size of the baseline for the diurnal method. http://sunra.lbl.gov/~vhoette/Explorations/MarsParallax/docs/ ============================= From: "canopus56" <canopu...(a)yahoo.com> Newsgroups: uk.sci.astronomy,sci.astro.amateur Subject: Re: MARS PARALLAX NIGHT Date: 23 Oct 2005 13:02:38 -0700 canopus56 wrote: > For the diurnal method, the total parallax is computed from a > baseline of - > 1) the apparent motion generated by the relative distance > traveled by Earth and Mars during the measurement period; > 2) _less_ Mars's parallax along the baseline between the > two diurnal measuring points. After thinking on it some more, looks like I got it wrong in the last post. This post contains what I feel is the right construction and estimation for Mars parallax within apparent diurnal motion. Attached is a geometric construction for the diurnal motion of Mars at opposition on 11/7/2005 at 8:30 UTC as seen from 43 deg N latitude using two astrophotos taken about 3 1/2 hours before and after opposition: http://members.csolutions.net/fisherka/astronote/observed/20051107Mars/2005… The apparent diurnal motion in this example - 418" across 7 hours - is predicated to be the sum of: 1) the astrometric change in position of 396". 2) Mars's parallax of 37.5", adjusted to 21.74" when the parallax is measured from 43 deg North. The astrometric position change is caused by the Earth's revolution around the Sun and a baseline from the Earth's 7 hour motion at its orbital velocity of 20358 km/hour, or a total baseline of 142506km. The half-angle forumla result on this baseline is 396" which is similar to the 393" arcsec astrometric position change per the MPC epheremis generator. At first glance, apparent diurnal motion of Mars would simply be based on the distance travelled by the Earth because of its rotation between taking the photographs plus the observer's Earth baseline movement as a result of the Earth's rotation during that same period. See diagram. However, part of the rotation distance travelled duplicates the revolution baseline distance travelled. For example in the geometric construction, the observing point moves as a result of the Earth's orbit over 7 hours by 142506km. The observing point also moves as a result of the Earth's rotation a total of 7410km. However, 1/2 the total baseline movement caused by the Earth's rotation is duplicated by the motion caused the Earth's revolution. So, in the geometric construction, the observer does not move 149916 km. The observer moves 149916km minus 1/2 the Earth's rotation baseline movement of 7410km, or 3705km. This gives a baseline perpendicular to Mars over the 7 hours of 146211km. On a 146211km baseline, a 43 deg North observer should see 418" of apparent movement of Mars across a 7 hour period centered on the opposition at 11/7/2005 8:30UTC. This post, data in prior posts in this thread, and the above geometric construction schematic illustrates how astrophotographers can prepare geometric constructions to confirm if Martian apparent motion seen in their astrophotos measured by the diurnal method (two photos taken at the same latitude at differing times) is consistent with a Mars parallax of 37.5". - Canopus56 ============================== From: "canopus56" <canopu...(a)yahoo.com> Newsgroups: uk.sci.astronomy,sci.astro.amateur Subject: Re: MARS PARALLAX NIGHT Date: 21 Oct 2005 19:43:43 -0700 Brian Tung wrote: > Err, sure--if you can measure those 12,000 km to an accuracy of a few > cm, and the time to an accuracy of a millisecond or so. Here's the predicted values I get for three dates and times using data from the Minor Planet Center Ephemeris generator, the half-angle forumla and Duffet-Smith's simplified equation for parallax. The MPC ephemeris generator gives the one-way-light distance to Mars. The half-arcsecond variance on 38" is much less than what can measured with a typical amateur's CCD setup, but still it's almost two Mars angular diameters, or even using a 6,000 km baseline, it's about one-Mars diameter. Half-angle formula: Parallax= 2 * arctangent ( ( Earth baseline distance / 2 ) / Mars distance ) Duffett-Smith's simplified parallax equation (Practical Astronomny with Your Calculator, 3ed at Sec. 39, p. 70), for the Sun, planets and comets (other than the Moon): Parallax = 8.794 arcsecs / r where r is the ratio of the distance to the object divided by one astronomical unit. Constants - The speed of light is 17987547.48 kilometers per second. Earth equatorial diameter baseline: 12756.27 kilometers ================= 10/23/2005 6:00 UTC Approx. date of Parallax of Mars Project Light-speed distance: 3.8922 minutes Distance kilometers: 70011132.3 km Half-angle formula parallax Earth diameter baseline: 37.58215967 arcsec Duffett-Smith method parallax: 37.58155686 arcsec Half-angle formula parallax 6,000 km baseline: 17.6770293 arcsec ================= 10/30/2005 7:30 UTC Maximum angular size; Minimum light speed distance Light-speed distance: 3.859126 minutes Distance kilometers: 69416212.16 km Half-angle formula parallax Earth diameter baseline: 37.90425134 arcsec Duffett-Smith method parallax: 37.90364337 arcsec Half-angle formula parallax 6,000 km baseline: 17.82852735 arcsec ================= 11/7/2005 8:30 UTC Opposition - Sun-Earth-Angle = 180 deg Light-speed distance: 3.909013 minutes Distance kilometers: 70313556.94 km Half-angle formula parallax Earth diameter baseline: 37.42051558 arcsec Duffett-Smith method parallax: 37.41991537 arcsec Half-angle formula parallax 6,000 km baseline: 17.60099888 arcsec To find the parallax for any Earth baseline, take the value for the "Half-angle formula parallax Earth diameter baseline" and multiply by the ratio of your baseline in kilometers to the Earth diameter of 12756.27 kilometers. - Canopus56 P.S. - Other minor variations include using the Earth's polar diameter (12713.5 km) or mean diameter (12745.59 km).

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More telescope mount questions
by Kim 30 Jul '10

30 Jul '10

Assuming I can't repair or otherwise would have to replace my LXD 650 mount, what would anyone recommend? The OTA with finder, diagonal and larger eyepieces probably would weigh 20 to 25 pounds. As long as I have to put out the $$$ anyway, I would probably also want to eventually be able to do some imaging unless the cost gets prohibitive. I've not been shopping for scopes and such for some time, so I was interested to come across this piece of equipment for a relatively modest price: http://www.telescope.com/control/product/~category_id=bargainsgalore/~produc t_id=09160. ;-) I do like the minimalist design of this series of scopes. Kim

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Re: [Utah-astronomy] Parallax experiment with (3833) Calingasta
by Canopus56 30 Jul '10

30 Jul '10

Kim wrote: > No, not too much. Very interesting. Does Mars' apparent > size create problems for using the diurnal parallax method > to determine distance? Yep. That's part of the uncertainty factor. But here again, modern CCD astrophotography and astrophoto software like AIP4WIN makes short work of getting an estimate of the apparent position of bright Mars. Think of Mars as a bright Poisson distributed object that you can use a built-in reduction tool on to extract a near exact set of plate coordinates. Having reread this stuff after a few years, the short-cut reduction method is: 1) use JPL Horizons to extract the heliocentric x,y,z coordinates of your topocentric position at the start and end times of your photos. 2) Use the 3D distance formula between two 3D points to find the length of your Earth travel distance baseline. Take one-half the Earth-traveled distance. 3) Measure the small diurnal parallax angle from your photo. This will probably be on the order of less than 80 arcsecs for an asteroid belt object. Take one-half the measured diurnal parallax angle. 4) You now have a right-angle triangle to solve: y = sin ordinate = 1/2 Earth traveled distance in kilometers x = cos ordinate = distance to object in kilometers theta opposite angle = 1/2 the measured diurnal parallax in degrees tan(theta) = y/x x=y/tan(theta) Clear Skies - Kurt

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Current south delta-Aqr meteor shower peak
by Canopus56 30 Jul '10

30 Jul '10

The south delta-Aqr minor meteor stream is currently in its peak and is giving a strong ZHR flux this year. For ham operators who want to try at radio meteor communications, tonight between 8 and 11 UT (2am to 5am MDT) might be a good reflection window. For visual observers, the waxing gibbous Moon is near the radiant and is washing out the sky. Local radio meteor count chart for July 1 through this morning: http://www.slas.us/gallery2/main.php?g2_itemId=3605 Radiant est. position is RA22.6 Dec-16 near the bright star delta Aqr transit alt 33 deg. - Clear Skies Kurt See also: July 28, 2010 Spaceweather News - High delta Aquarid returns http://spaceweather.com/archive.php?view=1&day=28&month=07&year=2010 cross post to Utah astro and Utah ham radio lists Live int'l amateur radio meteor stations http://217.169.242.217/rmob/pages/liveradiometeorpage.php

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Great Basin National Park Astronomy Festival
by Patrick Wiggins 30 Jul '10

30 Jul '10

From: Kelly_Carroll(a)nps.gov Date: 30 July 2010 10:16:17 MDT To: utah-astronomy(a)mailman.xmission.com Subject: Great Basin National Park Astronomy Festival Hello again! I just wanted to remind everyone of our first annual Great Basin National Park Astronomy festival scheduled for August 6 through August 8. Again, we will be having a free astronomer's camp. This will be an area located close to the Lehman Caves Visitor Center where all participating astronomers can set up a tent or small trailer. The area will be secured from regular park visitors during the day and most of the night so equipment can be set up and left up. The area will be opened to park visitors for approximately 2-3 hours per night to give people (and for most their first) view of the night sky through a telescope. It would be great if you could open up for scope to allow people to gaze through. The area will have bathrooms, a paved area for equipment, picnic tables, however, there will not be electrical power available. Saturday evening will feature our keynote speaker, William Fox, as well as an astronomer's dinner provided by us. There is time in the schedule if you'd like to give a presentation (hint) or outdoor activity. You can contact me at kelly_carroll(a)nps.gov or call 775-234-7331. Our schedule will be posted at http://www.nps.gov/grba/planyourvisit/2010-astronomy-festival.htm Please let me know if you have any questions and we would love to see you here and have your support for our growing night sky program. Thanks! Best, Kelly

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Re: [Utah-astronomy] Another fried electronics story and powered USB buffers
by Canopus56 30 Jul '10

30 Jul '10

Joe wrote: > Very interesting, Kurt. Does the mini-hub have a separate power > supply? Thanks, Joe Yes. I not near my gear right now, so I cannot look up the specific brand and model that I bought. I just went to the Best Buy and Office Max on 21st and 300 West and looked on the shelves until I found a mini-hub that also had an AC-to-DC power adapter in the box. It was about $15. Must USB mini hubs are port - not external powered. Just look at the packing closely. - Kurt

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Benefits of owning a Large Dob . . .
by Jay Eads 30 Jul '10

30 Jul '10

This came from CloudyNights and I know not all will see it so I re- post it here: http://stellafane.org/images/2002_conv/gallery/photo065.jpg Enjoy.

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