The International Occultation Timing Association's 27th Annual Meeting at the Orlando Science Center and the University of Central Florida
November 20-22, 2009
Tom Campbell and Paul Maley
Dr. Barbara Harris and Hal Povenmire
David Dunham opens the meeting
Video Conference, Dave Herald on right
Chuck Herold and Hal Povenmire
Dr. Terry Redding
Scotty Deganhardt's programmable remote
Tom Campbell's Cool Vest
Richard Nugent wearing the Cool Vest
Highlights of the 27th IOTA Annual Meeting
November 20-22, 2009
Orlando Science Center, University of Central Florida
by Richard Nugent, Executive Secretary
Steve Preston, recipient of the IOTA's 2009 Homer F. DaBoll Award for his unique and sustained contributions in accurate prediction of asteroid occultations. Thanks for your hard dedicated work !!
The 27th annual meeting of the International Occultation Timing Association was held Saturday-Sunday November 21-22, 2009 at the Orlando Science Center and the University of Central Florida in Orlando, Florida. This location was chosen to coincide with the asteroid occultation 234 Barbara Friday evening November 20. The Barbara event was a favorable event for North America in 2009 as it occurred at 10:38 PM EST on November 20th (3:38 UT Sep 21). Numerous positive chords were obtained and the results are posted at the asteroid occultation results page:
234 Barbara is suspected of having a binary nature. The profile for 234 Barbara obtained taken from Brad Timerson’s Results page are shown:
“D” and “R” points only Chords only
The meeting location was kindly hosted by the Orlando Science Center on Saturday and the University of Central Florida on Sunday. A planning meeting for the 234 Barbara event was held at the University of Central Florida on Friday September 20 from 2-5 PM. The final meeting schedule, and most of the presentation files, are located as a link from Brad Timerson’s North American Observations web site:
A total of 34 persons participated in the meeting:
At Orlando, Florida:
President Dr. David Dunham from Maryland,
Vice-President Paul Maley from Texas,
Executive Secretary Richard Nugent from Texas,
Dr. Terrence Redding from Florida,
Scott Degenhardt from Tennessee,
Chuck Herold from Texas,
Dr. Ken Coles, from Pennsylvania,
Dr. Barbara Harris from Florida,
Dr. Roger Venable and Anna Venable from Georgia,
Hal Povenmire from Florida.
Tom and Marsha Campbell from Florida.
Mike Hoskinson from Canada,
Ernie Iverson from Texas.
Video Internet Conference Attendees: Peter Eachman, IOTA webmaster Rob Robinson, Jan Manek, Hans Heynan, Bob Sandy, Pedro Sada, Gerhard Dangl, Steve Conrad, Dave Herald, John Grismore, Dave Gault, Brad Timerson, Aart Olsen, Frank Suits, Sander Pool, Derek Breit, Chad Ellington, (IOTA Secretary/Treasurer), Dave Clark, Steve Messner and Randy Peterson.
Technical Session – Saturday morning
President Dr. David Dunham opened the meeting at 9:30 AM and welcomed everyone. Dunham then asked the attendees to introduce themselves. He thanked the Orlando Science Center and the University of Central Florida for allowing us to host the meeting at their facilities (even though no one from these organizations showed up). A few minutes was spent by the Florida attendees summarizing results from their 234 Barbara stations. Among those with multiple stations were Scotty Degenhardt – 8 stations, Paul Maley – 5 stations, Roger Venable – 4 stations, David Dunham – 4 stations, Terry Redding – 3 stations, Richard Nugent – 3 stations, Tom Campbell – 2 stations.
Vice President Paul Maley described his international outreach efforts involving bright star asteroid occultation events in foreign countries. Maley has traveled to different countries where these events occur pursuing IOTA’s objectives – to recruit, inform, educate and expand occultation knowledge with hands on experience to amateur astronomers. He showed photos and described two recent expeditions. Maley traveled to HerceGovina in Bosnia for the 1041 Asta occultation on June 6, 2008. He showed photos of the Sarajevo Observatory’s 8-meter dome which originally housed a 40-cm Cassegrain reflector. These were destroyed the recent war conflict. They have since replaced it with a 10" Meade LX-200. For the Asta event 3 sites were set up with Physics teachers and some of their students. There was a 100% forecast for thunderstorms, and luckily the sky cleared, but due to the high humidity, the cameras at all 3 stations failed.
The 2nd event was 96 Aegle across Europe on September 8, 2009 again with 3 teams of observers set up. Unfortunately overcast skies foiled the event. Maley then described IOTA’s upcoming effort for the annular solar eclipse on January 15, 2010 in Uganda, Africa. As part of IOTA’s long term study to measure possible solar radius variations, plans call to have 2 stations set up at the north eclipse limit collaborating with IOTA-ES with 2 stations at the southern limit.
The next total solar eclipse occurs on July 11, 2010, however the entire path crosses the southern Pacific Ocean with no landfall at either north or south eclipse limits. Maley’s planned expedition is to Tahiti to observe near the center line. In 2011 there are 4 partial solar eclipses, thus no IOTA research can be done with these. The next favorable annular eclipse occurs on May 20, 2012 with the path going over China, Japan, the Pacific Ocean and ending up over the western and central United States.
Dave Herald mentioned that the Japanese satellite Kaguya’s high resolution topographic data of the Moon was recently released and has been incorporated into the Occult program. This ten-fold improvement over the outdated Watts data will allow refinement of the existing lunar limb profile dataset for IOTA’s solar eclipse research and will be used for future eclipses.
The Kaguya-Selene satellite was launched by the Japanese Aerospace Exploration Agency (JAXA) on September 14, 2007 from Japan’s Tanegashima Space Center. Among it various instruments on board was a laser altimeter to measure the topography of the Moon from a 100 km circular 90° inclined orbit. Two other sub-satellites of Kaguya were at highly elliptical orbits; the Relay satellite at 100 x 2400 km orbit and the VRAD satellite at 100 x 800 km orbit.
Maley described plans for the bright star asteroid event for 148 Gallia over the Philippines on September 30, 2010. The target star is Epsilon Hya, m = 3.1. At event time, the altitude of the star will be 29° and it occurs in the early morning hours allowing plenty of time to set up remote video stations. Maley is working with the Philippine Astronomical Society in preparation for this event. Dave Herald mentioned that there are slightly different positions for this star from the Tycho and Hipparcos catalogues due to different proper motions used. And this will be true of many bright stars compared from these two catalogues.
A problem with bright star occultation events is the position of the star determined from the Hipparcos and Tycho catalogues. Very bright stars saturated the satellite’s scanning sensors making it difficult to determine the centroid of the star for determining an accurate positional solution. This was also the case back in the era when photographic glass plates were used for astrometry. Large overexposed images caused problems in locating the centroid of the image on the plate’s emulsion. It was mentioned that new images of the star and asteroid might be obtained with the United States Naval Observatory’s (USNO) 61-inch astrometric reflector within a month prior to the event.
Maley next discussed funding issues with IOTA. This has been a long standing problem for IOTA and its research. Although IOTA Officers and members have requested funding from numerous sources over the years only rarely in IOTA’s history has there been funding for any expeditions and/or equipment. He is currently communicating with Bill Merline of the Southwest Research Institute (SWRI) in Colorado. Merline is currently researching asteroid satellites and understands that multiple remote stations seem to be one of the best methods of catching an asteroid satellite. This could lead to possible funding of IOTA’s asteroid occultation events through SWRI. This promising potential funding source was largely due to Scotty Degenhardt’s revolution in multiple “Mighty-Mini” stations and success with the 135 Hertha event on December 11, 2008. Merline also recognized the spectacular occultation observation of an asteroidal satellite made by Japanese observers on November 7, 2007 of the M-Class main belt asteroid 22 Kalliope. This result was published in Sky and Telescope magazine in the February 2007 issue. Degenhardt’s success with 135 Hertha was on December 11, 2008 in which he obtained 14 of the 23 chords. This asteroid profile was published in Sky and Telescope in the November 2009 issue.
Maley proposes that IOTA identify high probability asteroidal satellite targets over the USA only. If funded, IOTA’s status would be as an independent contractor meaning money would only be dished out per event. We would need good path coverage and RESULTS ! Plain and simple: No results = no more funding. He suggested IOTA pick 3 events for SWRI that we can produce good results. Possible 2010 candidate events are: 96 Aegle October 29 (target star m = 9.7) and 375 Ursula December 4 (target star m = 10.0). As mentioned previously 148 Gallia is outside the USA, but is certainly a bright star event that cannot be ignored even if not funded.
Dunham mentioned that funding was available in the 1970’s for the University of Arizona and Lowell Observatory. They used Celestron 14’s and other large telescopes plus expensive photometric equipment. There was a lack of results and hence a lack of interest with funding.
Next, Paul Maley presented an overview of the tax benefits of occultation expeditions for United States observers. This presentation was to inform USA observers of new tax reporting requirements associated with work done for non profit 501c corporations such as IOTA. As an example, if one makes an international trip for a solar eclipse to do IOTA research and stays for 1 week, the entire week’s expenses cannot be deducted. Only those expenses related to the eclipse research are allowed. Sightseeing expenses on other days is not allowed to be deducted. Airfare, taxi and travel costs surrounding the eclipse event which means hotel and meals the day before and the day of the eclipse only would be allowed because these are vital for making the observations.
There are expenses in the “maybe” category which are possibly allowed deductions. Examples would be equipment costs as long as it was vital to the observations being made, batteries, cables video camera, phone (for collaborating with other team members), internet access (for checking weather) and copies (charts, maps, etc.).
A new IRS record keeping rule went into effect August 17, 2006 regarding contributions to non profit organizations. It requires the donor to obtain and keep a bank record or a written communication from the recipient as a record of the contribution. Written records prepared by the donor (such as check registers or personal notations) are no longer sufficient to support charitable contributions.
Also for donations of $250 or more to IOTA, the donor must have proof (cancelled check, money order, wire transfer, etc. or appraisal for equipment donations greater than $5,000) and the recipient must send acknowledgement to you. For claimed non-cash contributions over $5,000, generally a qualified appraisal prepared by a qualified appraiser must be obtained. For appraisals prepared in connection with returns or submissions filed after August 17, 2006, see IRS Notice 2006-96.
It is important that persons take note that IOTA is not in the business of providing legal or other professional advice in regard to tax expenses applied to occultation activities. When in doubt about allowed expenses consult a competent accountant or CPA. Each person is responsible for their tax reporting and its accuracy. The IOTA Manual Section 2.2.1 (page 25) has a brief summary of expenses involved with occultation activities.
Maley’s presentation (along with the others at the meeting) is on Brad Timerson’s IOTA 2009 Presentation website link stated above. If you are planning to make a contribution to IOTA North America, contact one of IOTA’s Officers and they will assist you.
Dave Herald then called for a panel discussion in reference to publication of results. Although IOTA and it’s sister organizations maintain webpages with up to date results, the information about occultation activities and discoveries does not seem to reach the community of professional astronomers such as the USNO. In regard to double star results, such as new discoveries, or confirmation of suspected double stars, Herald suggested that we publish the results quickly. Currently IOTA has a poor record for delivery of double star information and discovery. A recent publication was a paper co-authored by Dave Herald and Bob Sandy in the October 2009 issue in the Journal for Double Star Observations (JDSO). In this paper Sandy and Herald reported the discovery of a new double star made and confirmed by video. Such double star papers will obviously require light curves to prove the discovery as visual observations don’t carry much weight these days. Another recent publication example is Brad Timerson’s paper in the Minor Planet Bulletin (MPB) in from the July-August 2009 issue along with 15 co-authors of 3 important recent asteroid profiles from occultations. MPB would like to see consolidated results of occultation observations with 5-6 or more chords. These two papers create a template (agreed format) for future papers.
Scott Degenhardt presented his method of broadcasting occultation observations from his laptop from his car. Degenhardt uses a Supercircuits camera mounted in his car to monitor his activities prior to the occultation event. This include the assembly of Mighty Mini’s and other components for setting up a station. The transmission is done via a broadband connection through his laptop which is also mounted in his front seat. During the 234 Barbara occultation he had a viewer from Athens, Greece. The maximum # of viewers he has had is 70. This important method advertises IOTA and its real time activities worldwide for free.
Lunch break 12 - 1 PM
Business Meeting 1 PM
IOTA Secretary/Treasurer Chad Ellington presented the income and expense report. A summary of the year’s bank balances are:
Starting Balance: $6,648.48 2008, August 19
Ending Balance: $6,753.66 2009, November 20
Net Increase in Balance: $105.18
The net increase in balance is due to the lack of publishing the Occultation Newsletter (ON) which accounts for the bulk of printing costs. In the past few years the publication rate of ON is way behind, sometimes only 1 issue is published per year. This represents an embarrassment for IOTA, as some Library subscribers has asked where are the 4 issues/year that they pay for. The question is does IOTA really need to continue with ON ? Most of IOTA information including articles, discussions (IOTA listserver) and results are now on the Internet. Dunham raised the fact that ON has IOTA’s history. It was agreed that ON needs to continue, possibly with a new format. The other issue is that if ON had a steady stream of articles it would be in competition with MPB which has a larger readership and has 50-100 pages per issue. All members need to consider contributing articles on any aspect of occultation science as the ON Editor has a lack of material for publishing.
Ellington went on to explain that he Occult program was used for the first time this year for graze predictions. Dave Herald has now incorporated the Kaguya data into Occult’s limb profile database.
This year’s presentation of the annual Homer F. Daboll Award was made by the Award Committee Chair Dr. Terrence Redding. The Homer Daboll award is given annually to an individual in recognition of significant contributions to Occultation Science. “Occultation Science” is limited to actual IOTA research: total and grazing occultations, asteroid occultations and solar eclipses.
Homer F. DaBoll had a long history with IOTA until his death on March 10, 1990. DaBoll was born on May 22, 1920. He led numerous grazing occultation expeditions in the Chicago area spanning 3 decades, from the 1960’s to 1990. He was the first ever editor of Occultation Newsletter for 16 years from its first issue in 1974 thru early 1990 when health reasons forced him to pass on the Editorial duties to Joan Dunham. DaBoll was the person who came up with the acronym IOTA, International Occultation Timing Association. Members of IOTA have always held Homer DaBoll in the highest regard for his numerous contributions to occultation observations, expeditions, ON, and his many other volunteer efforts.
This year’s committee received nominations from nine persons for the award, six of the nominations were the same person. The Committee’s main objective in selecting an award recipient was to reach a consensus and not choosing someone by a majority vote. The rules allow any person to be considered for the award except for current IOTA Officers and Committee members.
The 2009 Homer F. Daboll award recipient was Steve Preston from Seattle, Washington for his dedicated contributions in the prediction of asteroid occultations worldwide. Preston’s webpage, www.asteroidoccultation.com is the standard source for prediction of asteroid occultations used by nearly all occultation observers worldwide. Dunham called Steve on his cell phone at the time of the announcement and Steve offered a hearty “Thanks You” for the award.
2010 Elections – Dunham mentioned that in regard to next year’s elections, IOTA could use some new blood, and possibly a Board of Directors that can oversee a variety of IOTA activities. Terry Redding mentioned that we could amend IOTA’s by-laws to create a Board of Directors. The only problem is finding the by-laws. Paul Maley said he thinks he has a copy but it’s been since 1983 when IOTA was incorporated in Texas that he last saw them. Roger Venable mentioned that IOTA officers could rotate their respective positions as does the Association of Lunar and Planetary Observers (ALPO).
With no further business Executive Secretary Richard Nugent Motioned that he business meeting be closed. Terry Redding seconded the Motion, and the Business Meeting ended at 3 PM.
Technical Session – Saturday afternoon
Several double star discoveries were made during asteroid occultation observations. Recent ones mentioned were 336 Lacadiera and 790 Pretoria. Dr. Roger Venable believes the Pretoria results might indicate a double-double (quadruple) star system. Scotty Degenhardt suggested that any double star discovery should be reviewed by a 3rd party prior to any type of publication. This review would include review of the video(s) and the light curves. This would be in addition to the regular referee process journals use.
David Dunham presented a brief review of remote station observing. The first ever successful remote video station event was that of 9 Metis on September 7, 2001. Twenty-six (26) additional remote video station asteroid events were done through February 10, 2008, most of these involving just 2-4 stations set up by a single observer. Several IOTA members have improved on and polished the technique including Dr. Roger Venable, David Dunham, Dave Gault, Steve Preston and Scotty Degenhardt. Scotty Degenhardt showed a graph of observed remote stations from the years 2000-2009.
Following a short break David Dunham listed some favorable remaining grazes and asteroid events for the year 2009. They are:
Graze Events 2009
December 7, 2009, 14 Leo, m = +3.5, 69% Moon
December 31, 2009 – during this total lunar eclipse – there are no grazes
Asteroid Events 2009
706 Hirundo 11-30-09, m = +11.2
120 Elektra 12- 1-09, m = +9.4, 182 km path width over Canada
423 Diotima 12- 6-09, m = +11.4
234 Barbara 12-14-09, m = +11.7
216 Kleopatra 12-24-09, m = +11.7 (m = +10.2 red light)
324 Bamberga 12-24-09, m = +11.9
81 Terpsichore 12-25-09, m = +8.5
From the Royal Astronomical Society of Canada’s Handbook a few notable events occur in 2010:
Antares - graze is on January 11 by the 13% early morning crescent Moon. Graze line is northern Canada and Greenland. This is the last graze of Antares in the current series. The next graze of Antares will be in 2023.
Merope – March 21, 2010. This is the last graze of this Pleiades star until 2023.
Dr. Terrence Redding presented a talk on “How Amateur Astronomers Learn”. This was a study Dr. Redding did based on a survey of 213 amateur astronomers. In deciding why to do such a survey, Dr. Redding knew that amateur astronomers have unique characteristics not associated with any other group of unpaid scientists:
1. They are members of the oldest science
2. As a group they demonstrate high persistent learning across a lifetime
3. As amateurs, they love learning, are not paid for their learning efforts
4. As a group they are recognized for their ability to contribute new knowledge, skills, and discoveries in their field of study
He mentioned that most astronomers got started from some unique event they either experienced first hand or heard about, such as first view through a telescope, first solar/ lunar eclipse, first visit to a planetarium, etc. He showed charts from his survey showing various statistics of amateur astronomers:
1. Ethnic background: 91.8% were Caucasian, the remaining 8.2% were Black, Hispanic and Asian
2. Males (91.6%) outnumber the females (8.4%)
3. Highest level of education: 60% had 4-year college degrees including 22.8% with graduate degrees and 12.9% with Ph.D’s. Only 3.5% never attended or didn’t finish high school.
4. 89.4% were self learners compared to 11.6% learned in a group
5. Encouragement to study astronomy: 83.1% through oneself and 40.2% through magazines. Other sources of encouragement were; 25.4% - family, 22.8% - clubs, 18% - libraries, 12.7% school and 7.4% - Museums
6. Place where you engage in the hobby: Outdoors 47.9%, Personal observatory 28.7%, home office 17.6%, family room and kitchen 2.1% and garage 1.6%
The numbers clearly show that amateur astronomers are largely a self taught group of highly educated individuals. Redding gave two examples of famous self taught scientists. Sir William Gilbert was born in 1544. He studied magnetism and his research and findings stood for 200 years. He devised the modern scientific method and the textbook. Galileo Galilie was born in 1564. His father was a musician and Galileo was home schooled. He studied to be a priest and failed to graduate. He became a professor of mathematics by age 26. He struggled with money and saw the telescope as a way to gain financial success. His discoveries were tempered by the Church. Galileo was a highly self-directed individual.
Scotty Degenhardt demonstrated his method of using programmable remotes for his unattended video stations. One of the main problems with multi station setup for an event is the amount of tape (or capacity on SD memory cards) available to record on a particular digital video recorder (DVR). For example, with 2-hours of recording time (even with a 5-hour battery) you are limited to starting the tape just under 2 hours prior to the event time. So the question is how many additional stations can you set up during this 2-hour window prior to the event? Station setup can be complicated - setting up the tripod and video camera, pre-pointing to the target area of the sky, GPS time stamping the video, etc.
Scotty solves the problem of DVR’s limited recording capacity by using the “Sony Integrated Remote Commander RM-AV3000” programmable remote. He uses one remote per video station. These remotes are connected to the DVR. These units are programmed to signal the start time and the end time to the DVR. Thus only 5-10 minutes of tape are used. With a 5-hour battery, many more remote stations can be setup by a single observer increasing coverage. Scotty also recommended the use of an exercise mat when setting up stations. Since much time is spent on your knees setting up the tripod, video camera, DVR, GPS time stamping etc., increased comfort allows you to move quickly at each station.
Frank Suits presented the talk, “USB Video Cameras” in which he promoted the use of current USB cameras for occultation timings. By USB camera, he meant any digital camera that records directly to a personal computer. In order it to be video it must autonomously generate a series of frames at a steady pace driven by its own clock – i.e. no handshaking with or waiting on the receiving device. This is crucial for occultation timings.
The emergence of low cost USB cameras on the market provides a means of recording video directly into a computer’s hard disk. This has the advantages of digital readout, control over exposure/gain, arbitrary frame rates, binning, cropping, more than 8-bit output and no analog transmission or raster conversion. A few problems exist with them for occultation timings: They are harder to timestamp and the recordings can sometimes suffer from dropped frames depending on the PC/hard drive speed. Suits has devised a method to time stamp video with a small device that projects an LED illuminated spot onto the camera. The spot follows a ramped triangle wave pattern precisely synchronized to the GPS 1 pulse-per-second (1pps) signal using a microcontroller circuit Suits designed and built himself with materials costing less than $60.
Another issue with the ramped LED spot is identifying, “Which second is it ?” The video capture software records the PC time for each video frame, giving the nearest second, which is then combined with the light spot signal to give the full time at the millisecond level. He suggested also manually blinking the light at the 59 second marker to identify the minute. Simpler approaches to optical time stamping are possible just by placing a flashing LED at the front of the telescope, but that illuminates the entire camera field. Suits’s presentation is located on Brad Timerson’s website.
The meeting adjourned at 5:00 PM and several attendees met for dinner later that evening at a local restaurant.
Sunday, November 22, 9:50 AM. Technical Sessions continue
Dave Herald discussed recent developments in the lunar occultation database and reporting. In 2008 IOTA took over the task of collecting lunar occultation observations from Japan’s ILOC (after 27 years of service to the occultation community) which closed due to lack of funding. This conversion has gone fairly smoothly, as there are now 7 Regional Coordinators (see the IOTA Manual Appendix F.1). The meeting attendees held the regional coordinators and others who made this smooth transition possible in the highest regards or their hardworking and dedicated efforts. He reported there are now some 3190 grazing occultation observations in the database and these will be submitted to the Astrophysical Data System (ADS) when the format revision is complete. This will place the 45+ years of grazing occultation data online with all other astronomy databases.
Herald then re-emphasized the situation with regard to double stars. Discovery claims by occultation persons rarely reaches the professional double star community. He stressed the need for the occultation community to publish results rapidly. The double star report cycle is as follows:
From asteroid discoveries – to your regional coordinator
From Lunar occultations – to Brian Loader (New Zealand)
Publish papers – to the JDSO with authorship
USNO – picks up information from the JDSO
Occult program – data is periodically updated from USNO
The two recent papers published in 2009 by Brad Timerson in MPB (three recent asteroid occultations) and by Bob Sandy and Dave Herald in JDSO (confirmation of an existing double star using video) as mentioned earlier set the templates for future publications. He again stated that publication of results is crucial while the “irons are hot” and not to delay. Double star papers need to have the light curves published for credibility.
Herald has also updated the Occult program to include an alert message for double stars with separations < 2². And it will include double star details in graze predictions.
Herald has taken the Kaguya’s lunar altimeter data and converted it into limb profiles in the Occult program’s database. This high accuracy data now supercedes the older outdated Watts data. Its fit with past grazes is excellent, only occasionally do the grazes have inconsistencies. He showed an example of a recent graze plotted with the Kaguya data. The graze was on March 22, 2009 with lunar libration angles of l=-2.87° , b = +1.19°. The graze observations were in excellent agreement with the Kaguya data as shown on the Occult profile plot:
Lunar limb profile using new Kaguya laser altimeter data
Roger Venable asked if the Kaguya data would help with the solar eclipse reductions, Dunham answered that it probably will, the Europeans are now working with this data with their eclipse observations.
One of the principle investigators (PI) for the Kaguya mission was Dr. Mitsuro Soma of Japan. This allowed IOTA access of the catalog of laser altimeter measurements prior to their being released. The Kaguya satellite was in a 90° inclined polar orbit around the Moon thus there are numerous more passes at the lunar poles that at the equatorial regions. This provided coverage not only of altitudes of lunar mountains and terrain but also along their slopes. This huge dataset is visible in the Occult programs plots showing the 3-dimensionsal profile of the lunar limb.
David Dunham briefly discussed the current status of IOTA’s solar eclipse research. A research grant he had obtained a few years ago jointly with Drs. Sabatino Sofia (Yale University) and Wayne Warren was extended. Dunham and Sofia had recruited high school students to assist with the Baily’s Beads data reduction. The data reduction of Baily’s Beads timings is difficult to do visually since the “D and “R” of the Beads are not instantaneous as in stellar occultations, rather they are gradual. In 2008, Richard Nugent proposed and demonstrated a new method to reduce the Bead timings using LiMovie. The appearance and disappearance of a bead can now be determined to within 1 or 2 video frames allowing for high precision timings. Dunham remarked that a paper was published this year in the journal Solar Physics on the August 1, 2008 eclipse over China summarizing the Baily’s Beads effort by IOTA and IOTA-ES observing teams. The paper had 27 authors in Europe and the USA, including IOTA’s North American astronomers D. Dunham, R. Nugent, C. Herold, W. Warren, M. Patel and D. Schwartz. In that paper, 598 data points were obtained by 23 observers at 28 stations at both the north and south eclipse umbral limits. Dunham is currently working on analyzing the recent 2006-2008 eclipses and hopes to have a summary paper on the results published shortly.
David Dunham showed a power point presentation given by Detlef Kochny of the European Space Agency’s (ESA) Solar System Mission Division. The original presentation was made at ESA’a Malta Symposium on Hazardous Near Earth Asteroids October 12-16, 2009. The presentation was on the relevance of asteroid occultation measurements and their possible use for the study of NEO’s (Near Earth Objects) and KBO’s (Kuiper Belt Objects). The presentation covered many of the facts and aspects already known to IOTA about the prediction, observation and data reduction of asteroid occultations. A main point in the presentation was that successful occultations can produce astrometric position of asteroids accuracies of 0.001²- 0.002² relative to the target star. With the upcoming launch of ESA’a Gaia astrometry mission (currently scheduled for 2011), stellar positions are expected to be improved down to the 20 μas (20 micro-arc seconds, 0.000020²) range for some 1 billion objects. This represents approximately 1% of the Milky Way’s population.
At 12:20, a 1 hour lunch break was taken.
Dr. Ken Coles/Dave Gault authored a presentation updating the status of archiving and extracting data from older graze reports from the 1960’s and 1970’s. They volunteered to scan these older reports and to place the data into a useable format for Occult and other programs. One such report examined by Dave Gault was a graze done using the USNO’s 12² refractor. In plotting the graze observations it showed poor correlation with the Watts Data. In an email to Dave Gault, Dunham had mentioned that the 12² telescope was moved since 1964 when the original observation was made. In researching the position of the telescope, and then re-plotting the graze data using the new Kaguya limb profile showed excellent agreement. There are still many missing older graze reports from the 1960’s and 1970’s. Gault and Dave Herald had made a request recently on the IOTA listserver requesting that observers check the current graze database for the inclusion of their reports. If any occultation observer has a record of an observation that is not in the database, they are requested to forward the reports to Dr. Ken Coles and Dave Gault.
David Dunham presented some history of IOTA members that have made valuable contributions to Occultation Science over the years that passed away in 2009.
Dr. Tom Van Flandern 1940-2009 worked at the USNO for 21 years and was Chief of the Celestial Mechanics Branch of the Nautical Almanac Office. He published several dozen papers in the fields of analyzing graze data, improving the lunar ephemeris using occultation observations, celestial mechanics and edge observation from solar eclipses. His obtained his PhD in 1969 from Yale University, with a dissertation involving lunar occultation of stars by the Moon. Van Flandern helped establish the basic infrastructure of IOTA, he helped with predictions, and solar eclipse edge observations. His last eclipse was December 4, 2002. Van Flandern had started the controversial Meta Research organization in the 1980’s. He had some drastic new ideas (some have called these ideas radical) about the nature of gravity, light bending, the origin of the Moon, planets, planetary satellites, comets and a host of other celestial phenomena. He published many of his ideas the 1993 book “Dark Matter, Missing Planets & New Comets, Paradoxes Resolved, Origins Illuminated”. It was also Van Flandern that introduced David Dunham to Dr. Joan Bixby whom he married in 1970.
Emil Volcheck 1930-2009. Dr. Volcheck earned his PhD in Organic Chemistry from the University of California at Berkeley in 1955. He actively pursued astronomy and computers as hobbies. His interest in astronomy began in high school when he made his first telescope. He was active in the Delaware Astronomical Society (DAS) starting in 1958 and served in several Offices including its President. It was at a DAS star party that he met and married his wife Diana. While he was in the Richmond, VA area in the late 1970’s and early 1980’s he led several grazing occultation expeditions in the DC area. He was the director of Mt. Cuba Observatory in Delaware, and helped arranged the IOTA meeting which was held there in September 2006.
Clifford Bader 1934-2009. Cliff helped organize graze expeditions in the Philadelphia area and was a graze computor for the Mid-Atlantic region. Cliff attended the IOTA meeting at Mt. Cuba Observatory in 2006.
Dunham next listed some of the important asteroid occultation events over the USA for 2010:
139 Juewa Jan 8, 2010 m = 10.0
1248 Jugurtha Feb 3, 2010 m = 5.9
88 Thisbee Mar 2, 2010 m = 9.6
598 Octavia Mar 9, 2010 m = 9.3
824 Anastasia Apr 6, 2010 m = 2.5 (Southern California – British Columbia)
995 Sternberga Apr 11, 2010 m = 6.1
16 Psyche Aug 21, 2010 m = 8.3
1736 Floriac Nov 26, 2010 m = 6.1
The event of 824 Anastasia involves the m = 2.5 star Zeta (13) Oph. This is the brightest asteroid event in the USA/Canada in many years. Although not specifically mentioned by Dunham at the meeting, this star is a spectral type O9.5 main sequence star with an estimated diameter of 24 R¤ thus diffraction effects plus the star’s diameter could lead to gradual “D” and “R” observations.
Dr. Roger Venable presented a talk “Calibrating a Video File”. Occultation events made with smaller aperture telescopes and faint stars will lead to low signal to noise ratios (S/N). He started off with an example of an asteroid occultation observation that would normally not be detectable by the unaided eye. The event chosen was 360 Carlova that occurred on June 3, 2009. Venable recorded this occultation. This event had a m = 13.7 star, m = 13.7 asteroid, a magnitude drop Δm = 0.7, max. duration was 8.8 sec and star altitude = 37°. Watching the tape on a video monitor visually he could not detect an event. After using a 7 frame stack with the program Registax, he was able to see the event. After taking a dark frame, he then plotted the video and noticed a 1-sec periodicity in the data. Venable’s analysis of this 1-sec effect seems to indicate it’s caused by a combination of dark field read noise and dark current. He also mentioned that many false events are caused by dust particles and pollen grains and other artifacts on the acrylic cover of the CCD chip.
For the occultation of 1258 Sicilia on January 14, 2008, Venable had 3 stations set up and recorded 2 positive events. He analyzed the videos with LiMovie (confirmed by Dave Herald) and it shows the discovery of a new double star.
Venable has determined from his findings in regards to false positives is that they are caused by a number of factors:
1) Dirty optics
2) Low S/N
3) Faint star
4) Low magnitude drop Δm
5) Noisy, high gain video camera
6) Small telescope
8) Light pollution
By utilizing a dark frame subtraction in the data, Venable can reduce the unavoidable random noise level in a video. This reduces the incident of false positives. He listed several freeware programs to aid in this: Virtual Dub 1.6, AVI Synth 2.5, Registax 4.0 and LiMovie 9.20.
Tom Campbell demonstrated his home made “Cool Vest” that he uses when observing during the hot humid summer months in Florida. This vest is worn by the observer along with a back pack. The net patterned vest has plastic tubing wrapped uniformly around it that carries cold water circulated via a battery powered pump stored in the backpack. The water is chilled with ice which is also stored in a small ice chest in the backpack. A pair of polypropylene non leak quick disconnect hose couplers are connected on the front of the vest start the cold water circulating. The backpack and vest weigh in at 25 lbs. Richard Nugent tried the vest on and immediately felt the cold effect of the water circulating through the tubing. Campbell designed and made the vest with $100 in materials. Compare this to commercial cooling vests that run $400 or more. His design is the result of a year’s worth of experimenting with two different designs and swears it keeps him cooler during long observing sessions. He also finds it very useful when mowing his lawn. Campbell has detailed plans on constructing the vest with photos posted on the website: http://www.poyntsource.com/New/Cool_Vest.htm
Richard Nugent presented a talk “A Non-Motorized 10' Domed Observatory”. This talk had nothing to do with occultations hence it was saved for the end of the meeting when extra time allowed its presentation. Nugent built a personal observatory in Ft. Davis, Texas, just 8 miles down the road from McDonald Observatory. The observatory is situated in the Davis Mountains at an altitude of 5,200 ft. The all metal construction consists of a 10' dome, and 3 foot hallway connecting a 10' x 10' control room. This design was utilized to allow the domed portion to have circular walls eliminating water leaks which are problematic with square observatory buildings. After installing the dome, he found that the supplied motors would not rotate the dome nor open/close the shutter. The dome was one of only two made by a company that eventually went out of business. After spending over $1,000 and experimenting with various motors and hardware, Nugent finally decided to use the theory of Occam’s Razor, that is use the simplest method for the dome’s rotation and shutter opening. He then purchased two $25 winches and 50 feet of garage door cable and now the dome and shutter open up easily by turning the cranks on the winches. The observatory houses a Meade 14² LX-200. Nugent plans to do asteroid astrometry with this observatory as soon as a CCD camera is acquired.
The meeting attendees then summarized their efforts for the 234 Barbara occultation which held a record for the most remote stations attempted.
Dunham 4 stations
Maley 5 stations
Scotty D. 8 stations
Nugent 3 stations (one remote station was stolen before he retrieved it)
Redding 3 stations
Povenmire 1 station
B. Harris 1 station
Campbell 2 stations
Venable 4 stations
Iverson 1 station (two videos on two telescopes)
Coles 1 station
The meeting adjourned at 5:07 PM as several attendees had to catch flights back home. Informal discussions continued afterwards.
IOTA's Annual Meetings
The International Occultation Timing Association is the primary scientific organization that predicts, observes and analyses lunar and asteroid occultations and solar eclipses. IOTA astronomers have organized teams of observers worldwide to travel to observe grazing occultations of stars by the Moon, eclipses of stars by asteroids and solar eclipses since 1962.