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

Dark sky piece in New Yorker
by Patrick Wiggins 04 Sep '07

04 Sep '07

Cristine Jennings posted this link to the OAS group earlier today (Thanks, Christine!). It'll be in News but that wont be until Friday so I thought I'd post it here now: http://www.newyorker.com/reporting/2007/08/20/070820fa_fact_owen patrick

1 0

RE: [Utah-astronomy] Aurigid report
by daniel turner 03 Sep '07

03 Sep '07

Kim asked: > Is there a specific technique for estimating meteor brightness? I've heard serious amateurs who report a bolide as "brighter than Mars, but dimmer than Jupiter." It's then easy to find in S&T the approximate magnitude of those planets that night. Right now Mars is zero mag, Jupiter about -2 and Venus is -4. For the really bright ones, the half moon is -10 and the full moon is -12. I have seen a Leonid that bright and I heard it too. Listen for this phenomenon: http://science.nasa.gov/headlines/y2001/ast26nov_1.htm DT ____________________________________________________________________________________ Park yourself in front of a world of choices in alternative vehicles. Visit the Yahoo! Auto Green Center. http://autos.yahoo.com/green_center/

4 5

Sunbeam
by Boyd McNeil 03 Sep '07

03 Sep '07

I hate to disappoint every one but my Tiger shrank to an Alpine. I can only wish it was a Tiger, however it still runs well and looks good. Boyd

2 1

Re: [Utah-astronomy] OT: Sports cars
by Ann House 03 Sep '07

03 Sep '07

Once had a Lotus Elan and a Sunbeam Tiger (like Maxwell Smart). Still own the 1970 Porsche 914-6, very rare and built for racing. It leaks oil. Always has. -A

5 8

RE: [Utah-astronomy] Aurigid report
by Kurt Fisher 03 Sep '07

03 Sep '07

Kim wrote: > What about when instrumentation or photographs are > available? Does meteor brightness have any scientific > value in that case? I don't know the answer to the photgraphic or the scientific value of magnitude question. This is an area that I'm just getting into. For that shower, I had put together and was doing an initial test run on a meteor camera with an 18 deg TFOV but was not lucky enough to get any streamers. I decided that I need to do another run at remachining a C-to-T lens connector to get the camera to work properly. As Chuck pointed out, the gold standard amateur meteor imaging project is to capture a low-res spectrograph to see what kind of emission lines can be seen. A sample photo from Saturday mornings shower can be seen on the NASA Ames site. Once I get the camera really working, I intend to try a grating in front of it to see what can be captured. The camera no's biggee. It's just a Meade DSI-1 or a DSI-Pro that that has an SLR fish-eye lens attached through a Pentax(bayonet)-to-C(male) adapter and a C(female)-to-T(male) connector. The Edmund Optics C-to-T adapter had to be modified by machining in order to get the camera to focus. The camera tracked the radiant by mounting on a GEM. The real way to do this would probably be to just put a fish-eye lens (about $200) on a digital SLR like a Canon Rebel D20 to get a full 120 degree TFOV. Then pull the images in real time out of the camera through a USB2 wire to a laptop for astronomical image processing. Since I don't own a Canon Rebel that's another $800, so I decided to try a poor man's kludge. Chris Peterson has a video camera design posted on his website previously referenced. The key to his video design appears to be special order lens listed on his plans - a Rainbow L163VDC4P 1.6-3.4mm lens - which means nothing to me. - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

1 0

RE: [Utah-astronomy] Aurigid report
by Kurt Fisher 02 Sep '07

02 Sep '07

Kim asked: > Is there a specific technique for estimating meteor brightness? To answer to your narrow question, there is no formal method for estimating meteor brightness that I know of. Informally, I usually mentally review UMi stars in the North Polar sequence, a constellation near the radiant and the major bright stars that are up that night. I only feel good above quoting brightnesses in two mag bins, e.g. - v0-1, v2-3, v3-4, etc. - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

1 0

SPOC Eclipse Watch page now includes Joe's pix
by Patrick Wiggins 02 Sep '07

02 Sep '07

Joe's pictures of the eclipse have been added to the evolving SPOC Eclipse Watch web page that will eventually move to the SLAS site. http://users.wirelessbeehive.com/~paw/temp/ECLIPSE.HTML pw

1 0

RE: [Utah-astronomy] Aurigid report
by Kurt Fisher 02 Sep '07

02 Sep '07

Kim asked: > Is there a specific technique for estimating meteor brightness? Kim, As a general rule because estimating meteor brightness is so subjective and imprecise, the official IMO counting method does not use meteor brightness as a parameter. The IMO limiting magnitude charts are used to estimate sky brightness (NELM or naked-eye limiting magnitude) in the observing FOV. Since you see fewer meteors in a brighter sky, the NELM information is used to normalize the raw real-time meteor flux to a ZHR under an ideal sky at about mag 6.2. The IMO has the 30 charts of their limiting magnitude areas well hidden on their website: http://www.imo.net/visual/major/observation/lm These charts, in an easier to use format, can also be found at: http://obs.nineplanets.org/lm/rjm.html Before the invention of the Sky Quality Meter ( http://www.unihedron.com/projects/darksky/ ) I used the IMO limiting magnitude charts to estimate ZLM during general observing. I still ocassionally use them for NELM (naked-eye limiting magnitude) estimates for off zenith fields. Tke Sky Quality Meter only works on the zenith. The IMO limiting magnitude method is a star counting game. How many stars can you count in the defined region - usually about 5 x 8 degrees? Count the stars and then look up the limiting magnitude in the table. The fields were charted carefully to yield 0.1 magnitude intervals. The system was created by professional astronomer Alistar McBeath. (If you want a humbling reminder of how age dims visions, do a count-off with your 9 or 10 year old children or grandchildren.) As you can see on the IMO Live Count page, the observers look at and count in the region of their 35-40 deg diameter for normal vision around a constellation - AUR in this case. ("SPO" on the reporting form means sporadics seen in the FOV.) For ZHR counting purposes, anything you can see counts as a hit without regarding to magnitude. IMO observers provide supplemental notes on the magnitudes seen, but these are not used for modeling purposes. Estimating meteor magnitudes is too subjective and imprecise. The limiting magnitude charts are used to determine the NELM in the observing field. As a practical matter you pick an LM field about 20 degrees off the radiant and center your observing for a 20 deg radius (40 deg diameter) around that LM field. But you can also use the LM reference stars to estimate the brightness of a particular meteor. The IMO Meteor Live Count ( http://www.imo.net/live/alpha-aurigids2007/ ) normalized the observed rate at 112 ZHR - basically close to Vaubaillon's prediction but way lower than Jenniskens's 200 p/h prediction. The NASA Ames Aurigids Mac page has a number of good photographs ( http://aurigid.seti.org/ ) as does Chris Peterson's (a retired professional) meteor cam website ( http://www.cloudbait.com/science/aurigid2007.html ). On Cloudy Nights, Chad Moore - the Park Service light pollution guy - reported a max real-time flux rate of 60 p/h with an peak report time of at 5:15 AM UTC from Bryce Canyon. This is similar to the ~42 peak flux rate and same peak time reported by the NASA Ames Aurigid Mac project. Other amateurs in internet reports (including myself) saw a different peak near 5:45am. Chris Peterson's meteor count records two peaks - one at 11:20 UTC and a second at 11:40 UTC (5:20am and 5:45am) at around a real time flux rate of 70 p/h each. I saw a max rate of 50 p/h from the Moon washed out 3.5 ZLM sky at Little Mountain centered 2 minutes off the predicted peak of 11:37 UTC (5:37 am MDT). Total count was 17 between 5:15am to 6:00am - capped by a nice v0-1.0 mag fragmented three part bolide at 11:39 UTC. The 11:39 UTC bolide was very similar to the 1998 image shown in your September copy of Sky and Telescope at page 56. Really a very pretty but short shower, a nice night, and a good 3rd quarter Moon - followed by an really impressive sunrise featuring a bright Venus. All in all a great night out. I'm still typing up my notes on this one and will have a further report in a separate webpage in a few days. The shower has the usual diminished expectations quiping associated with it - which is intended as a general observation and not as a negative comment directed at this listserv. The RV and lawn chair types at Little Mtn griped that "That's all it was. I got up at *@$# 4:00am for that! What a disappointment!" Instead of living in the here and now and taking life's events for what they have to teach, many continue to measure things against a some distant once-in-a-lifetime event - that "Leonid shower that I saw a few years ago. Now that was a shower!" - Kurt _______________________________________________ Sent via CSolutions - http://www.csolutions.net

3 4

Re: [Utah-astronomy] OT: Sports cars
by Ann House 02 Sep '07

02 Sep '07

Rob, What ever happened to your uncle's 914-6? Porsche only produced a couple thousand of those cars. Speaking of driving in Hawaii, we need to renew our conversations about our SLAS-Hawaii visit. There are quite a few people interested in going. -A

4 5

How do I respond to a posting?
by Randall Peterson 02 Sep '07

02 Sep '07

I can't figure out how to do this and I can't seem to log on to utahastronomy.com - any instructions? thx, R ____________________________________________________________________________________Ready for the edge of your seat? Check out tonight's top picks on Yahoo! TV. http://tv.yahoo.com/

2 1