Artist’s impression of the asteroid (234) Barbara. Thanks to a unique method that uses ESO’s Very Large Telescope Interferometer, astronomers have been able to measure sizes of small asteroids in the main belt for the first time. Their observations also suggest that Barbara has a complex concave shape, best modeled as two bodies that may possibly be in contact.
Credit: ESO/L. Calçada
This announcement of a new measuring technique was distributed on the IOTA Occultation Yahoo Discussion Group first by Dave Herald on February 4th, 2009. It announces a new interferometric technique that allows the VLT-MIDI team to measure asteroids at greater distances with higher precision than adaptive optics observing. One asteroid they measured, (234) Barbara, was newly discovered with this technique to potentially be a binary asteroid. Upon reading the Press Release from the ESO I became intrigued about the possibility of finding an occultation of a star by (234) Barbara. Occultation timing provides the highest resolution currently available to man. By using video recordings of such occultation events we have 0.017 second time resolution, and at the average speed of an asteroid’s shadow on the ground we can then resolve 10s to 100s of meters of spatial resolution of the asteroid (versus kilometers for adaptive and interferometric measurements).
A quick search identified several upcoming asteroidal occultations by (234) Barbara. I sent out a notice that very day of a list of three potentially viewable occultations, with a highlight of the November 21st, 2009 involving an exceptionally bright star passing over many highly populated areas. With a visual magnitude of 7.5, this target star is easily monitored with nothing more than a steady pair of binoculars! Thus a large number of amateur astronomers, and even the general public would have the ability to use a tape recorder and a shortwave radio to provide timing data. The most valuable data for measuring the utmost accurate size and shape of Barbara will be derived from video timings. With this advanced notice of this Press Release, those interested in pursuing simple video equipment have time to prepare. The significance though of this event is it gives amateurs the chance to validate a newly emerging technology: interferometric measurements of asteroids by the VLT-MIDI method. The brightness of the target star opens up the opportunity for David Dunham, Paul Maley, I, and other occultation video observers to deploy a very large array of 30 or more Mighty Mini observing stations in Central Florida, meaning a very high resolution profile will result (providing weather cooperates). This event will culminate with a planned LIVE broadcast from one of my remotely deployed stations via Scotty’s Sky, so immediate results of whether a shadow was captured will be known around the world instantaneously.
After some discussions within the group about the importance of this event, IOTA then rearranged the planned annual meeting to occur in Orlando, Florida so that a higher number of occultationlists would be in the path of the shadow. Also, Frank Gutowski of the Central Florida Astronomical Society immediately responded to our initial email offering to provide local support for both the November 21st occultation and the IOTA annual meeting. Terry Redding, Tom Campbell, and Hal Povenmire of Central Florida have been our eyes and ears on the ground there locally and have provided immense amount of information on potential observing sites already.
Marco Delbo of ESO’s VLT-MIDI team has responded saying he is very interested in observing the November 21st, 2009 event as well since the shaodw passes through Europe. He and his team are keenly interested in any results that can be obtained to help verify their observations.
Please make plans if you are in or near any of the places the shadow(s) of (234) Barbara pass on the morning of November 21, 2009 to accurately time the eclipsing of the starlight of 7.5 magnitude HIP 34106. More information follows, feel free to ask if you need more information. Richard Nugent has a great resource he has published entitled “Chasing the Shadow”, which will give you great information on “How To” get started. The IOTA Yahoo Discussion Group is your best resource for daily information on occultations.
Good luck and CLEAR SKIES!
“Some discussions have been ongoing with the French group who successfully timed the recent Oct 5 occultation of Barbara from the Canary Islands showing only a very small shift from the predictions, meaning the ephemeris is pretty good for her. There is the main body of Barbara that is represented by the shadow path on OW. But the satellite that is the main goal of this observation (for me) may be up to 100km or so from the main body and is not represented in the prediction path. David Dunham has calculated our best odds to image the main body and the (potential) satellite is to cover ± 70km from centerline. Those who wish to venture that far from centerline must do it with the understanding that you are statistically likely to have a miss. But that miss will be valuable constraint data. You also may get one or two of the only chords through the companion! Those of us who deploy more than 1 station with unattended remotes are encouraged to set some of the remotes in this outer region, which is really only a little past the 1 sigma zone anyway. But I wanted everyone to be aware of this when making your plans. If you want to do the main body only stick to the current path on OccultWatcher and Derek's site. If you want to go for the satellite you will be guessing, but an educated guess at least.”
USA: (Central Florida) Tampa, St. Petersburg, Lakeland, Orlando, Cape Canaveral, Florida
Atlantic: Saint George’s Island, Bermuda
Europe: London, England
The Island chain cities of Borkum, Memmert, Juist, Norderney, Langeoog, Wangerooge, Mellum, Scharhorn, and Trischen, Germany
Drej, Svenborg, Stryn, and Langland, Denmark
Southern tip of Sweden
Western part of Central, Russia.
Live broadcast of the (234) Barbara Asteroidal occultation effort in Central Florida will begin around 2PM EST (19h UT) Friday Nov 20th (NOTE: some areas I will be traveling in have limited cellular coverage, so there may be times my signal drops out. Keep watching, as I eventually do come back online)
· 2:00 pm – 4:00 pm EST (19h – 21h UT) Friday Nov 20: Preplanning of deployment for the (234) Barbara occultation at University of Central Florida.
· 4:00 pm – 6:00 pm EST (21h – 23h UT) Driving to first deployment site.
· 6:00 pm – 10 pm EST (23h UT Fri – 3h UT Sat ) Deploy up to 20 sites.
· 10 pm EST begin transmitting live view through telescope near centerline.
· 10:18 pm EST (3h UT Sat) Dr. Eberhard Bredner will phone from Europe to announce live the results of the shadow passing there (they get Barbara’s shadow 20 minutes before we do).
· 10:38 pm EST (3:38: UT Sat) Barbara’s shadow passes through the field of view I am broadcasting. So you can watch live to see if the star blinks out or not from Barbara passing in front of it.
· Final results of everyone’s data will be posted at: http://www.asteroidoccultation.com/observations/Results/
A special group rate has been established at the Comfort Suites a few blocks from the Orlando Science Center where Saturday afternoon’s meeting will be held. The group rate is $94/night (compared to $119/night) and is a valid offer until November 13th. There are rooms with one King or two double beds available (and cots are available if you need more in a room).
Here is the hotel info:
To make your reservation call this number with a credit card:
877-228-4007 (this is direct to the hotel)
Ask for the Group Rate: IOTA
Friday Nov 20: Preplanning of deployment for the (234) Barbara occultation
University of Central Florida, Business Administration Bldg., Room 146, 2:00 pm - 5:00 pm EST
Saturday Nov 21: IOTA 2009 Annual Meeting, Day 1 ***
Orlando Science Center, Imagination Classroom, 9:00 am - 5:00 pm EST
EVO broadcast link: http://evo.caltech.edu/evoGate/koala.jnlp?meeting=MvM2Ml2D2nDaDn999vDe9v
Sunday Nov 22: IOTA 2009 Annual Meeting, Day 2 ***
University of Central Florida, Math and Physics Bldg., Room 359, 9:00 am - 5:00 pm EST
EVO broadcast link: http://evo.caltech.edu/evoGate/koala.jnlp?meeting=MeMMMu292BDIDB9D9vDv9e
*** (I have been discussing with others who will video tape this event about helping them reduce their data. If you would like me to help reduce your video data just bring your original recording with the instrument it was recorded on (i.e. your VCR, camcorder, etc.) to the Saturday or Sunday meetings and we will dub these off to one of my miniDV recorders for me to transfer via firewire in DV AVI format to my computer. I'll be more than happy to do that for those who do not have the tools or experience to reduce video to lightcurves.)
The following ZIP files contain prepoint charts for the Mighty Mini and Mighty Midi observing systems. These charts allow a person the ability to arrive at any location in Central Florida at any time after Civil Twilight on Friday evening November 20th and identify which star to point to so that at exactly the time of the occultation the target star will drift into the center of the field of view without the need for having a clock drive system. Details on these types of charts can be found at:
ZIP file with Post Script prepoint charts for printing:
ZIP files with PDF prepoint charts for printing:
Kissimmee Clear Sky Chart: http://cleardarksky.com/c/KssmFlkey.html?1
National Weather Service forecast: http://forecast.weather.gov/MapClick.php?CityName=Kissimmee&state=FL&site=MLB&textField1=28.3035&textField2=-81.4105&e=0
Realtime Florida IR satellite loop: http://adds.aviationweather.gov/satellite/displaySat.php?region=TPA&isingle=multiple&itype=ir
Intellicast National satellite loop: http://www.intellicast.com/Global/Satellite/Infrared.aspx?location=USKS0112&enlarge=true&animate=true
Site selection and declaration:
OccultWatcher is the preferred method of declaring your observing site. It is used to prevent two people from observing on the same chord.
OccultWatcher by Hristo Pavlov: http://www.hristopavlov.net/OccultWatcher/OccultWatcher.html
If you cannot use OccultWatcher, please locate you longitude and latitude with the Google Maps below and send these to firstname.lastname@example.org
Scotty’s NOTE on sites: If you need a site assigned to you I have 152 sites and their GPS coordinates for the Orlando, Florida USA area. Contact me at email@example.com and I will be glad to give you a few options.
Google Earth KML file of path: http://www.poyntsource.com/New/Google/20091121_18170.KML
Steve Preston’s page: http://www.asteroidoccultation.com/2009_11/1121_234_18170.htm
Derek Breit’s main asteroid occultation page: http://www.poyntsource.com/New/Global.htm
Derek Breit’s Google Maps: http://www.poyntsource.com/New/Google/20091121_18170.HTM
Distance (Occult) Prob. Station info Event Time (UT)
113.8 km 0.1% == Right limit plus 3-Sigma ==
85.9 km 2.3% == Right limit plus 2-Sigma ==
72.9 km @349° 6.3% (6) Barb Harris Home : video + gps 03:38:12 UT
70.3 km @346° 7.5% (47) Dunham 01 : video + gps 03:38:19 UT
65.7 km @349° 10.1% (48) Dunham 5 : video + gps 03:38:19 UT
60.0 km @348° 14.2% (49) Dunham 10 : video + gps 03:38:20 UT
58.1 km 15.8% == Right limit plus 1-Sigma ==
57.9 km @347° 15.9% (23) One : video + gps 03:38:21 UT
52.5 km @345° 21.0% (24) Four : video + gps 03:38:22 UT
46.7 km @349° 27.5% (25) Three : video + gps 03:38:23 UT
46.3 km @350° 27.9% (50) Dunham 16 : video + gps 03:38:21 UT
43.1 km @351° 31.9% (51) Dunham 20 : video + gps 03:38:22 UT
40.3 km @351° 35.4% (14) Paul Maley 23 : video + gps 03:38:22 UT
36.9 km @341° 39.8% (46) Eddie Mac : visual + radio 03:35:34 UT
35.4 km @346° 41.7% (22) Four : video + gps 03:38:24 UT
33.5 km @334° 44.3% (44) Talbot J Home : video + other 03:20:13 UT
33.4 km @349° 44.4% (15) Paul Maley 30 : video + gps 03:38:23 UT
30.3 km 48.5% === Right limit ===
29.3 km @350° 49.7% (52) Dunham 33 : video + gps 03:38:23 UT
28.6 km @348° 50.6% (8) Campbell T Mobile #1 : video + gps 03:38:26 UT
26.6 km @349° 53.2% (16) Paul Maley 38 : video + gps 03:38:24 UT
25.5 km @348° 54.5% (57) Dunham 39 : video + gps 03:38:24 UT
18.7 km @342° 62.1% (17) Paul Maley 41 : video + gps 03:38:25 UT
15.6 km @341° 65.1% (58) Dunham 45 : video + gps 03:38:25 UT
15.2 km @348° 65.4% (19) Campbell T Mobile #2 : video + gps 03:38:28 UT
13.8 km @336° 66.6% (43) Mánek J mobile (unsure) : video + gps 03:18:00 UT
11.0 km @0° 68.6% (18) Paul Maley 5 : video + gps 03:38:26 UT
6.6 km @333° 71.0% (42) Scotty TX 109 : video + gps 03:38:20 UT
3.3 km @315° 72.0% (12) Redding T Mobile 3 : video + gps 03:38:20 UT
0.6 km @278° 72.3% (53) Dunham 157 : video + gps 03:38:27 UT
0.0 km 72.3% ==== Centre Line ====
-0.5 km @236° 72.3% (21) Paul Maley 47 : video + gps 03:38:27 UT
-0.9 km @100° 72.3% (41) Scotty 116 : video + gps 03:38:21 UT
-4.2 km @148° 71.8% (54) Mike Hoskinson 118 : video + gps 03:38:21 UT
-4.3 km @182° 71.7% (13) Frank Gutowski : visual + other 03:38:23 UT
-4.6 km @185° 71.6% (1) Campbell T #3 Home : video + gps 03:38:32 UT
-6.4 km @161° 71.0% (9) Eberhard Bredner : video + gps 03:18:08 UT
-7.3 km @157° 70.7% (40) Scotty 120 : video + gps 03:38:21 UT
-10.8 km @157° 68.7% (39) Scotty 122 : video + gps 03:38:22 UT
-13.6 km @162° 66.8% (55) Mike Hoskinson 124 : video + gps 03:38:22 UT
-14.0 km @162° 66.4% (36) Scotty 125 : video + gps 03:38:22 UT
-15.8 km @163° 64.9% (11) Redding T Mobile 2 : video + gps 03:38:22 UT
-16.4 km @164° 64.4% (56) Mike Hoskinson 128 : video + gps 03:38:22 UT
-17.4 km @165° 63.5% (35) Scotty 130 : video + gps 03:38:23 UT
-19.1 km @166° 61.8% (34) Scotty 133 : video + gps 03:38:23 UT
-21.5 km @172° 59.2% (33) Scotty 134 : video + gps 03:38:24 UT
-22.8 km @166° 57.8% (10) Redding T mobile 1 : video + gps 03:38:23 UT
-26.3 km @168° 53.5% (37) Scotty Mobile : video + gps 03:38:25 UT
-28.5 km @167° 50.7% (32) Scotty 135 : video + gps 03:38:25 UT
-30.3 km 48.5% === Left limit ===
-31.0 km @166° 47.6% (38) Scotty 136 : video + gps 03:38:25 UT
-33.3 km @165° 44.5% (31) Scotty 137 : video + gps 03:38:25 UT
-37.1 km @166° 39.5% (30) Scotty 138 : video + gps 03:38:26 UT
-41.7 km @167° 33.6% (29) Scotty 143 : video + gps 03:38:26 UT
-46.3 km @166° 27.9% (28) Scotty 145 : video + gps 03:38:27 UT
-50.1 km @158° 23.6% (4) Bulder H Home : visual + other 03:18:36 UT
-52.2 km @169° 21.4% (27) Scotty 147 : video + gps 03:38:27 UT
-57.6 km @167° 16.2% (5) Scotty 149 : video + gps 03:38:28 UT
-58.1 km 15.8% == Left limit plus 1-Sigma ==
-63.7 km @168° 11.5% (26) Scotty Mobile : video + gps 03:38:28 UT
-71.2 km @166° 7.1% (20) Scotty Mobile : video + gps 03:38:29 UT
-85.9 km 2.3% == Left limit plus 2-Sigma ==
-113.8 km 0.1% == Left limit plus 3-Sigma ==
-264.2 km @159° - (59) Rothe W. Home : video + gps 03:17:22 UT
-715.6 km @161° - (45) Dangl G Home : video + gps 03:17:00 UT
(click on 2009 locations to view the predicted path with Google Earth KML file)
November 30, 2009 22:52 UT: Northern United Kingdom, Southern Norway and Sweden, Estonia, Central Russia. Combined brightness 10.8 magnitude.
January 10, 2010 04:41 UT: Crosses the entire USA. Combined brightness of star and asteroid about 11.2 magnitude.
January 17, 2010 12:11 UT: Mongolia, Northeast China, Japan. Combined brightness 11.6 magnitude.
888-687-5444 toll free to cell
http://www.ustream.tv/channel/scottys-sky LIVE broadcast at event time from the shadow path!
Derek Breit firstname.lastname@example.org
Tom Campbell email@example.com
Barbara Harris firstname.lastname@example.org (yes, Barbara will observe Barbara!)
Hal Povenmire email@example.com
Europe Event Coordinator for IOTA: Dr. Eberhard Bredner Eberhard@Bredner.eu
Observatoire de la Côte d'Azur, Nice, France
Phone: +33 (0)4 9200 1944
Sebastiano Ligori firstname.lastname@example.org
INAF- Osservatorio Astronomico di Torino, Italy
Phone: +39 011 8101 964