The International Occultation Timing Association  23rd Annual Meeting at Stillwater, Oklahoma

Oklahoma State University Campus

October 29-30, 2005



IOTA's parking attendants at the Physics Building.


IOTA Vice President Paul Maley with his portable telescope system


IOTA President Dr. David Dunham showing the Lunar graze profile obtained from the July 18, 2005 Antares graze  over Texas


David Dunham and Danny Falla


Secretary/Treasurer Dr. Art Lucas, who arranged this years meeting


Sandy Bumgarner and Dr. Roger Venable discussing video techniques


This year marked the first meeting broadcast over the web. Thirty-two members and attendees were present. This  included fifteen persons present at the Oklahoma State University Physics building and up to seventeen persons watching via a Webcast. The minutes of the meeting are below:



Saturday, October 29

            Art Lucas Receives Honorary Doctorate

            Business Meeting

            Technical Sessions

                    New Google Earth Maps for Occultations

                    GPS and WWV Video Time Insertion

                    Pre-Pointing Method for Telescope systems


                    Solar Radius Research from Solar Eclipses

                    87 Sylvia has two confirmed asteroidal moons

Sunday, October 30

            Technical Sessions

                    71 Noibe's possible large Satellite

                    Asteroid Satellite Searches

                    2006 events           


                                         Highlights of the 23rd IOTA Annual Meeting, 2005

                                         Oklahoma State University, Stillwater, Oklahoma

by Richard Nugent, Executive Secretary

The 23rd annual meeting of the International Occultation Timing Association was held Saturday and Sunday October 29-30, 2005 at Room 110 of the Physics building at the Oklahoma State University (OSU) in Stillwater, Oklahoma. This location was chosen to coincide with the favorable asteroid occultation of 790 Pretoria in the pre-dawn hours of October 29, The meeting location was arranged and hosted by IOTA’s Secretary/Treasurer Art Lucas who lives in Stillwater, Oklahoma.

Thirty-two members and attendees were present. This included fifteen persons actually at the Physics building and up to seventeen persons watching via a webcast:

President David Dunham from Maryland,

Vice President Paul Maley from Texas

Executive Secretary Richard Nugent from Texas,

Secretary Treasurer Art Lucas from Oklahoma,

Barb Lucas from Oklahoma,

Roger Venable from Georgia,

Rick Frankenberger from Texas,

Derald Nye from Arizona,

Bob Sandy from Missouri,

Derek C. Breit, Daniel Falla, Sandy Bumgarner from California.

Chad Ellington, Rob Walker, Byron Labadie, Peter Shull from Oklahoma,

Webcast members present:

Dave Gault, Australia; Ed Morana and Charles Poplinger, California; Pedro Valdez Sada, Mexico; John Graves (editor Occultation Newsletter, ON), Tennessee; Willem Van Leewen, Netherlands; Walt Robinson (IOTA’s Webmaster), Kansas; Jim Stamm (Vice President Planetary Occultations), Arizona; Rocky Harper and Dave Clark, Texas; Tony George, Oregon; Suresh Singh, India; Vincenzo Flourincio, Italy; and Warren Grider, Oklahoma.

Saturday, October 29

Art Lucas opened by introducing Dr. McKeever, Vice President of Research at OSU. Dr. McKeever immediately mentioned the long history of contributions to the University by Art and Barbara Lucas, including the starting of the first observatory at OSU. For this and his many other contributions to OSU’s Physics Department over the years, Art received the highest honor an individual can receive: an honorary Doctorate in May 2004. A round of applause followed this announcement. Congratulations to Art Lucas for this outstanding achievement!

President David Dunham opened the meeting and asked the attendees to introduce themselves. Following the introductions of the local attendees, the webcast meeting began with an inappropriately timed (for us) maintenance power outage at the host location at the California Institute of Technology. The webcast was delayed by approximately 2 hours, including all of the business session.

Business Meeting, Saturday, October 29

President David Dunham motioned the floor to open the business meeting and was seconded by Roger Venable. Secretary/Treasurer Art Lucas gave a report of IOTA’s financial status. IOTA is in good financial shape and has shown a positive cash flow from 2004 to 2005. 

Lucas reminded everyone to check their mailing labels for their own dues expiration date. Lucas explains this in the page that he encloses with each ON, but many don’t read it far enough and just assume that they need to renew when they see the "renewal" page. Some members are way ahead on their dues, and the credits will not be refunded. Lucas remarked that every mailing of ON results in a flurry of membership dues payments.

Lucas also mentioned that Occultation Newsletter (ON) editor John Graves has a lack of material for publishing and encouraged IOTA members to submit their articles and observations, since this is the medium where IOTA maintains a permanent record of its continuing activities. Overall, IOTA seems to be in good financial shape. And since the bulk of IOTA’s expenses is the ON, the membership should take advantage of it and submit material to John Graves, whether it be observations, techniques, etc.

There was no opposition to the financial report, and it was accepted by the members. An original copy of the Annual Financial Statement is on file with the Executive Secretary.

Executive Secretary Richard Nugent noted that the 2004 meeting minutes were published in ON. In 2004, it was considered that IOTA seek publication of a "Proceedings" similar to other specialized astronomical groups, and Nugent had received some quotes from the Astronomical Society of the Pacific. They were interested in publishing such a volume and were also seeking a minimum of approximately $4,000 in sales. This would have come to about $55/volume. At that time ON was very short on submission so it was decided to drop the idea of an outside source for a Proceedings publication.

Art Lucas has asked the members to seriously consider taking over his job as Secretary/Treasurer due to his age/health reasons. The main duties of the Treasurer are:

1.     Mail the ON from the printer,

2.     Deposit member dues checks into the bank,

3.     Make a year end financial statement (2 pages),

4.     Make a membership list,

     5. Prepare lists for distribution, mainly, annual predictions.

Chad Ellington volunteered to do the secretarial work, but not the treasurer’s work. Art said this would be very helpful, and Chad, who also lives in Oklahoma, has started to work with Art to learn the system.

Dunham told the group that the yearly Sky and Telescope (S & T) asteroid occultation articles would probably be much shorter and published several times per year. This being due to the initial large uncertainties in the paths of these events. A world map of the better 2005 events is now on the S & T website.

Richard Nugent presented the status of the IOTA Observer’s Manual. He brought a paper copy (256 pages) of the completed chapters and appendices to pass around. Remaining chapters needed to complete the manual are solar eclipses (limited to IOTA solar radius research and lunar polar diameter measurements), grazes and IOTA history. The results of IOTA’s long term solar radius experiment just recently became available in September 2005 so Nugent now has the needed results to proceed with the eclipse chapter. Nugent gave a current copy of the manual (electronic form) to Sandy Bumgarner and David Dunham. Due to the large size of the manual, a new website will be used to show the chapters. It is located at

With no further business, at 10:55 it was motioned to close the business portion of the meeting, Bob Sandy seconded the motion and the business meeting was closed.

Technical Sessions

President David Dunham began the technical sessions asking for preliminary results of the asteroid event by 790 Pretoria earlier in the morning. Results were:

Bob Sandy: 45 km north of predicted center, 6.6 second occultation,

Derald Nye: Dew and clouds, 30 km north,

Paul Maley, 8 second occultation 11 km north,

Richard Nugent: 7 second occultation, 40 km south of predicted center,

Chad Ellington: 5 second occultation, 25 km north,

Rick Frankenberger: Clouds,

Roger Venable/Derek Breit: Clouds/dew.

11:20 AM 12:00 Noon --- Break

David Dunham mentioned that Steve Preston now has predictions for all asteroid occultations for 2005 and 2006 on his website. Full updates are given for events about a month in advance, with preliminary updates for the rest. He also mentioned that valuable accurate asteroid astrometric observations comes from the Jet Propulsion Laboratory’s Table Mountain Observatory since they have a telescope that is not restricted to meridian observations, but the bulk of the observations are still provided by the FASTT Meridian Transit telescope of the U. S. Naval Observatory in Flagstaff, Arizona. Hugh Harris is now providing most of those observations after the unfortunate recent death of Ron Stone, who established the FASTT program with the important linkage to the accurate Hipparcos/Tycho catalogs that became available from ESA in 1997.

A brief discussion began about the possible use of automated telescopes to capture asteroid occultations (and occultations by asteroidal satellites). IOTA Vice President Paul Maley and others agreed that it is very difficult to recruit general observers for asteroid events unless the observation is very convenient (i.e., done from their backyard, a bright target star, Saturday night, before 12 midnight, etc.). Such occultation telescopes might be controlled from the internet. Internet telescopes exist to do this, however few, if any, are portable; they must be reserved long in advance; and many have fees associated with their use. More discussions on this continued during the breaks.

Chad Ellington showed the use of Google Maps for plotting and viewing asteroid event paths. The program Google Earth can take Steve Preston’s detailed Info files to overlay the asteroid ground track on a map with just a few mouse clicks. "Kiwi" Geoff Hitchcox wrote the software to accomplish this. These maps are clickable to show terrain to extraordinary detail, and can calculate the distance of a line (using mouse dragging) from the center of limit of the path. Charlie Ridgway in New York City has a web page for North American asteroid events showing the capability of these maps at 

12:30 – 1 PM- Lunch down the hall hosted by Art and Barbara Lucas.

Dr. Peter Shull showed slides of the OSU’s HS Mendenhall Observatory located 6 miles southwest of Stillwater. Dedicated in 2003, it currently has a Celestron-14 under a 16 foot Home dome. A new 24-inch telescope to be built by Optical Guidance Systems, out of Pennsylvania has been recently funded by an Air Force Grant.

Video Time Insertion

Several GPS time/WWV video time inserters are in use for occultation work. The current status of some of the available units was discussed by the attendees:

Manly WWV Time inserter: This is the oldest time inserter, developed by Peter Manly in Arizona about 20 years ago. Derald Nye built his unit using the Manly time inserter circuitry plus other components. Derald has boards for sale for $25 including instructions and a parts list. Nye said he cannot give construction advice therefore a good knowledge of electronics is essential to build one of the units. He reduces his video tapes after the events due to the increased number of wires needed to use the unit in real time. The main advantage of this time inserter is that time insertion can be done after the observation is made, so that anyone who has recorded WWV, WWVH, or CHU time signals on a video tape can later obtain a time-inserted copy from an IOTA member who has one of these units. Rick Frankenberger in San Antonio provides this service for most IOTA observers.

KIWI OSD: "Kiwi" Geoff Hitchcox designed a GPS time inserter that displays LAT/LONG, Altitude and GPS time. It has a backup time to keep the time display going in case the GPS signal is lost (built in quartz clock), allows NTSC/PAL formats, displays satellite info, and is accurate to 1 ms of UTC. These units are now manufactured and sold by PFD Systems, LLC in Bethesda, Maryland, Web site for details:

The price of this unit ready to go and assembled is $150. It requires a Garmin 18 LVC GPS receiver for an additional $85 plus shipping/handling.

McAfee VTI: Don McAfee (e-mail designed a box unit fully assembled which displays GPS time to 0.001 second, plus LAT/LONG, ALT and date info all for about $285 ready to go. Like the Kiwi OSD, it uses the Garmin 18 LVC GPS receiver which has a built in magnet to attach to a convenient location. This VTI also has a toggle switch to go back and forth from position info to time. The time displays a single time to 0.001 sec unlike the Kiwi OSD which has half frame times displayed. The McAfee unit also uses a built in quartz clock to keep the time displayed in case of loss of signal. McAfee has made only a few of these units, not having the larger manufacturing capacity of PFD Systems for the Kiwi unit.

ViTi and GHS Clock: This unit is designed and sold in Japan. More info is available from . This device can display a variety of GPS/time/satellite information and has been used by Japanese observers for a few years now, it being the first GPS video time inserter designed for occultation work.

Hans-Hellmuth Cuno gave a talk at the European Symposium on Occultation Projects (ESOP) about a GPS time inserter he built. Details can be found at

Derek Breit suggested setting up a GPS unit early for an occultation to allow almanac data to download to your particular receiver. This helps prevent time errors which have been known to deviate from WWV by as much as 10 seconds, either when satellite geometry is poor due to local obstructions or during the early acquisition before the GPS solution has had time to stabilize; this usually takes 5 minutes or more.

David Dunham showed some slides for the pre-pointing method. The basic concept of this method is to have telescope stations already set up and pointed in the direction that the target star will be at the predicted time, allowing a non-specialist to record the occultation since the pointing can be done hours in advance. The pre-pointing is made to a star field at the same declination as the target star, with a right ascension difference equal to the time difference to the event, taking into account the 10-seconds/hour difference between sidereal and mean solar rates. The non-specialist will have to do only a few simple tasks to get the system operational for the occultation, such as: a) setting an alarm to wake up, b) taking the cover off the end of the telescope tube, c) reconnect any batteries, d) turn on the timing device (WWV shortwave), e) press the "record" button on the VCR/camcorder. f) stop the recording after the event. With the non-specialist working the pre-pointed telescope system, the specialist drives to another location to set up another station. If time permits, two or more telescopes at different locations can be pre-pointed. The basic idea was developed for remote (unattended) stations, but it has other applications, helping those who can’t find target stars to obtain observations. The pre-pointing should be timed to an accuracy of about 10 seconds, which can easily be obtained with inexpensive self-setting "atomic" clocks that use WWVB or DCF long-wave time signals. The technique can be used for visual as well as video observations. Dunham first used the technique in 1965 for a visual observation of a daytime partial occultation of Jupiter by the Moon when both objects were too close to the Sun to see without telescopic aid.

Vice President Paul Maley talked about his rating method for advertising asteroid occultations in the Houston, Texas area. Steve Preston’s "rank" for asteroid events is a bit confusing for the general observer so Maley came up with his own ranking method to make it easier to recruit these observers. It is based on a variety of factors including the star magnitude, magnitude drop, day of week, time of day, elevation, azimuth, Moon phase, Moon distance, Sun distance, and prediction accuracy, He assigns a numerical weighting scheme for these factors to come up with a rating as to whether or not the general observer should try the occultation.

Maley’s ratings are:

X = eXtra special/don’t miss it =5

PG = Pretty Good =4

G = Give it a shot =3

M = Maybe worth trying =2

R = Ridiculous but not impossible =1

An "X" rated example event for this system for the Texas is the December 3, 2005 occultation by 52 Europa. This is an 8.9 mag. star with a maximum predicted occultation of 7.8 seconds, with a very large asteroid with wide path with high certainty.


Kazuhisa Miyashita in Japan developed a new software program to produce light curve plots of occultation events; its basic operations are in English. LiMovie converts a video to a light curve for a qualitative analysis of occultations events including those difficult ones with very small magnitude drops. The high detail of the light curve plots can allow the user to detect possible asteroidal satellite events by analyzing the magnitude drops. LiMovie is useful for occultations involving close double stars, allowing measuring the component magnitudes. LiMovie is a free program obtainable at: 

David Dunham gave a few tips on finding the target star for asteroid events using a GO TO telescope based originally on Walt Morgan’s on-line article. The preferred finderscope is a straight thru type, except for stars near the zenith when a right angle finder is easier to use. When the GOTO scope is moving toward the target star check carefully that you have the correct field. This might involve moving/inverting/flipping your star chart to identify the field. Some GOTO scopes allow the user to jump to bright stars when moving toward a target area. A synchronization key can be used to minimize errors in pointing as the telescope moves closer to the target star. This reduces the propagation of errors as the telescope slews across the sky. Morgan prefers the Starry Night Pro to create finder charts, Dunham prefers the Millennium and/or Herald-Bobroff Atlases. The various planetarium programs such The Sky, MegaStar, SkyMap, etc. have a rectangle that can be overlaid onto the FOV simplifying the identification of video fields.

Problems can occur with a GOTO telescope system. Don’t assume that just because you push a few buttons that you are dead on the target star. Alignment star errors, the amount of slewing distance, and other factors can affect your GOTO accuracy. Bob Sandy commented that a dry run is useful 2 or 3 days before the event. A practice session can help identify unforeseen problems. The lesson here is to learn your own system.

David Dunham discussed how to use predictions and profiles to find observing sites for grazing occultations. The Tan Z correction and limit correction were plotted on the 1:125,000 scale Delorme’s Street Atlas USA Version 8. Dunham mentioned some important considerations about using graze predictions: The Tan Z correction can usually be ignored for elevations less than 750 feet above mean sea level since it is so small, and graze profiles change when stations are more than 100-200km along the limit line. Unlike asteroid events, in which the asteroids are relatively small and far away, the Moon’s profile changes slightly due to its proximity to Earth.

Dunham spoke about the southern-limit graze he attempted last December 17, 2004 of m = 7.5 ZC 3434 at Valley Lee, Maryland from 3 stations. He set up 2 remote stations and one attended station. With these optimally placed stations, he recorded 3 lines of the lunar profile. The attended station recorded a 1.5 minute occultation, the middle station had 8 events, and the southern most station 6 brief events at mountain tops. Dunham made a 92-mile trip to the sites from his office through rush hour traffic. He would have been able to set up a 4th station, however a property owner had called his cell phone and asked him to remove his equipment. One station Dunham had set up in the most shaded part of the local Post Office’s parking lot, but he didn’t realize until after setting it up that it was only about 30 feet from the entrance.  Despite several persons walking in and out to get mail from their P.O. boxes, no one bothered the equipment.

Wayne Warren had attempted to observe this graze with Dunham, however he didn’t make it through the rush hour traffic in time and wasn’t able to start observing until just after the graze ended! David Dunham has made the record book again: this event marked the first graze profile entirely determined by a single observer operating 3 stations. He actually did even better during the graze of tau Aquarii on December 21, 2001 at Kitty Hawk, NC when he recorded that graze from 4 widely-separated stations (3 remote video stations), but 9 other observers also timed the multiple events during that graze.

On the topic of grazing occultations for 2005, several videos of the more favorable ones were shown: Kerry Coughlin’s video of Antares from Baja California on March 3, and Ed Morana’s and Derek Breit’s videos of Upsilon Gem on April 18 (m = 4.1 star). This event had 9 stations and 15 observers. Dunham recorded a graze of Tau Ari (m = 5.0) on March 15 with a 30% Moon from 3 stations in clear cold skies in Pennsylvania. Ken Smith, a local homeowner, made the mistake of offering to help Dunham. Ken quickly obtained permission from his neighbors to set up the scopes at nearby locations, helping with the setups, and then running one of them at his home!

The best graze of the year was of the 1st magnitude star Antares on July 18. Dunham showed graze profiles obtained from expeditions from Washington State/Utah, Texas and Georgia, and Bob Sandy showed a video Dave Clark took of the Antares graze in Texas..

Bob Sandy then showed the reduction profile of the Aldebaran graze from September 12, 1998 from Tennessee. This unique graze occurred at extreme Cassini region libration angles and was the the 3rd graze observed that night making it an IOTA "second": The second triple graze observed in one night. Exactly 19 years before, on September 12, 1979, a Meton cycle earlier, Richard Nolthenius first accomplished this feat with the SAME three stars with similar geometry in California. The 1998 Aldebaran graze had 10 stations and 18 observers, coinciding with the 16th annual IOTA meeting at Dyer Observatory in Nashville.

Following a short break Bob Sandy showed some color slides; the first one of the planet Venus after it reappeared from behind the 33% sunlit Moon on 26 December, 1978.  This is the same shot as the picture at the heading of his web site.  Then he showed a slide sequence of Jupiter, and its four brighter moons being occulted by the Moon. The Moon/Venus occultation slide is the one used on the IOTA baseball cap.

David Dunham continued the meeting with a status report on his (and Wayne Warren’s) long-term effort in IOTA’s solar radius experiment and research. Dunham had presented the results of his research at the 2005 SORCE (SOlar Radiation and Climate Experiment, a NASA satellite launched in 2003) Science Meeting September 14-15, in Durango, Colorado. A 3-year grant proposal was submitted in April 2003 and accepted in December 2003, and finally funded by NASA in June 2004. The principal investigator is David Dunham, with co-investigators: Wayne Warren, Jr., Alan Fiala, Harry Bates, Sabatino Sofia, David Herald, and help from many IOTA observers. The main focus of the research was to analyze Baily’s Beads timing data from solar eclipses to search for solar radius variations. Previous eclipse data analyzed and published in 1994 included eclipses from 1715 to 1987 giving small changes of the solar radius relative to the 959.63² standard value for each of the eight eclipses.

Videos of Baily’s Beads obtained during the eclipses of 1991, 1994, 1995, 1998, 1999 and 2002 were analyzed in part with David Herald’s Baily’s Bead module of the program OCCULT. James Thompson, a NASA summer mentor student, performed most of the work under Dunham’s supervision. The results indicate solar radius changes varying from 0.06¢ ¢ ± 0.06¢ ¢ (Aug 11, 1999 eclipse) to -0.27¢ ¢ ± 0.02¢ ¢ (May 1994 eclipse). A plot of the solar radius changes didn’t show any obvious trend, however this doesn’t prove that there isn’t a cycle of small scale solar radius changes occurring with the Sun.

One of the nagging issues in this research is the criticism of the lack of standardization of equipment used for the Baily’s Bead’s videos. Different telescope systems and different solar filters were used at each of the eclipses studied and this may be partly responsible for the inconsistent results. Different filters allow different maximum wavelength transmissions of the Sun’s light to be analyzed possibly affecting the Bead timings. Dunham suggested that Richard Nugent’s compact 4-inch telescope system with Thousand Oaks solar filter would be useful to use as a standard system.

Roger Venable suggested testing all equipment and combinations side by side at the next solar eclipse. The videos/bead timings can be analyzed for any type of variation or systematic errors. Along these lines, Sandy Bumgarner suggested using remote stations for testing/comparing the equipment. Maley cautioned that although in principle this sounds simple enough, there are unstable conditions beyond the observer’s control such as dust storms, wind, tampering/theft of equipment, etc. More study is needed and the funding of this research has an additional year to go; a final paper is planned for publication.

Paul Maley discussed his proposed Project Blind Squirrel, a concept for intercepting asteroid occultations and asteroid companions. The concept is to provide a deployable portable system of 8-inch telescopes for asteroid occultation intercepts. Several telescope systems were discussed, that have been nicknamed TOTO=totable occultation tracking optics. Maley commended Dunham and Venable who have used multiple stations to achieve success but believes that to get better results the adage "more is better" should be applied.

The portable systems (approximately 10-15) would be deployed at intervals along a road for an asteroid event, the actual locations to be defined by the occultation. The systems would be required to have a simple quick setup (15 minutes) and be automated to record the occultation event. Control of the telescope systems could be automated/robotic, done via the internet or some other wireless method. One possible lower cost (~$500) system would consist of an Orion portable table top mount, 50 mm telephoto lens suitable only for 7th mag or brighter stars, and a Supercircuits PC164 camera.

The advantages of this method are to increase the probability to intercept occultations and increase the chances to detect and confirm an asteroid satellite. Funding is needed to implement such a system; so far, IOTA has received no support for this work.

David Dunham briefed the attendees about an ESOP 2005 (European Symposium on Occultation Projects) presentation by Wofgang Beisker on The Dual Wavelength Occultation Camera. This camera shoots the occultation simultaneously at two wavelengths using dichroic mirrors, making it is possible to record images in two or even more different wavelengths from a single telescope without wasting light. This method was developed mainly for occultations involving planets with atmospheres, but it could also be used to measure the colors of components of binary stars occulted by the Moon or by asteroids.

Prior to the close of the meeting, Danny Falla mentioned a Science News article for August 13, 2005 that the asteroid 87 Sylvia now has confirmed 2 satellites. See the Science News web announcement: 

The meeting was adjourned for the day at 6:15PM. The attendees proceeded to Art and Barbara Lucas’s house for a BBQ dinner.

Sunday October 30, 9:20 AM

David Dunham began the meeting with a plan to update all observed asteroid occultation events into the OCCULT program historical observations database. There are over 700 observed asteroid occultation observations with just 413 listed in version 3.0 of OCCULT. New observed events are being made at the rate of about 2-3 per week. Sandy Bumgarner asked if the reporting of asteroid events could be standardized into a unique format so that the information could be loaded directly into the OCCULT program database (by creating the .obs file). There is a web page maintained by Jan Manek that allows observers to report asteroid events online.

2005 did not any have any spectacular asteroid events observed with dozens of observers, but a few are worth mentioning:

71 Niobe may have a large satellite when it occulted an 8th magnitude star on February 10, 2005. The occultation was observed photoelectrically by Bob Cadmus at Grinnell College Observatory, Grinnell, Iowa. Doug Kniffen, south of Warrenton, MO, timed a 1.0-second occultation using a 16-inch telescope. Both observations were definite and accurately timed, but an analysis of them shows a 35-second mismatch that is most easily explained as occultations by two separate objects. A short Niobe occultation timed in Japan in November 2004 might also have been caused by the satellite. The next occultation by Niobe will occur on 2006 Feb. 16.

54 Alexandra was timed by 15 stations on May 17, 2005 in Mexico, Texas, and Oklahoma. Dunham traveled to Baja California to view the event. He brought 4 camcorders, which the Mexican customs officer saw and pointed out that tourists are only allowed one. After an explanation of the purpose, and that this was a private effort, the officer let him pass. The officer said that next time he should write a letter to the Mexican Consulate to get permission. The size of Alexandra from the observations is an ellipse 160.1 ± 1.3 km x 135.1 ± 1.2 km. This high precision fit is due largely to the long duration of the occultation chords - several over 60 seconds, and good distribution of observers across the actual path, in spite of a substantial south shift. Dunham also noted that a rotation period could be computed with 3 good occultation profiles combined with a light curve data.

89 Julia was observed by 7 stations on August 13, 2005. The resulting size came to 174.4 ± 5.8km x 135.6 ± 2.6km.

166 Rhodope by the 1st magnitude star Regulus on October 19, 2005 (10 days before the IOTA meeting) over Europe/Asia. This was a daylight event except for southern Europe; Iberia had the darkest skies. Dunham traveled to Spain and was assisted by Arturo Montesinos from Madrid. The preliminary reduction profile by the European Asteroid Occultation Network (EAON) showed that Dunham’s remote station had an occultation near the southern limit. His manned station further south had a miss. Regulus is a fast 15 hour rotating elongated (2:3 size) star as measured by interferometry.

Costantino Sigismondi led an expedition for the Regulus event to Vibo Valentia, Italy. They had a 1.96sec occultation. With their data and combining the observations of other observers he and David Troise derived the projected distances from the centerline for each observer. They derived a circular shape (in one quadrant) of Rhodope with a radius of 29.8km. This size/shape is not conclusive as 2 visual observations on the north side of the path were not used in deriving the profile. If these visual observations were reliable, then Rhodope’s shape would be irregular. Their paper and research is available upon request from   

Another chance to see Regulus occulted is in 2014 March 20 by 163 Erigone over the northeast US. Mark your calendars !

Dunham mentioned a good tip for airline travelers. He places a note in his suitcase with his equipment so that when the TSA security officials randomly inspect his checked baggage, they can contact him about the strange equipment on his cell phone. The note in the suitcase idea is an excellent method to avoid a delay which could possibly cause his baggage to be removed from the flight.

Paul Maley discussed his efforts on random asteroid satellite searches. Tom Van Flandern has calculated that an asteroidal satellite can have a stable orbit at least up to 10 asteroid diameters from the parent asteroid. Fueled by Maley’s own visual observation of a blink during the asteroid occultation event of (6) Hebe in March 1977 while he was far outside the occultation path, and other observations/photographs of asteroid satellites, Maley has attempted to observe all occultations where he was within 1,000 miles of the path from 1977 to the present. In all he has attempted over 800 such appulses, 80 of them alone in the first 6 months of 2003, with 43 successes overall. Maley has a supporting database of observers in Houston which consists of their lat/long position and telescope size. He discussed his concentration on the deployment of large urban groups to intercept asteroid occultation paths, the most successful of which has been the 1983 Pallas expedition.

A brief discussion continued on the possible methods of detecting asteroidal satellites and the theory of their origin, including the impacts and the approximate distance from the parent asteroid. In order to confirm an asteroid moon, IOTA needs observers separated by no more than 2-3 km, since these objects are typically expected to be relatively small compared to the primary.

Possible solutions to help IOTA confirm an asteroidal satellite are:

1) Need more remote stations

2) Two (or more) nearly co-located sites less than 5 km apart to confirm the short

occultations caused by satellites

Maley believes that for a single person attempting to provide confirmatory evidence of an asteroid satellite one approach is to place one video/and one visual < 5km to 5 meters apart. In this way it is easier for one person to control and support two stations and maintain their integrity.

Along this discussion, Sandy Bumgarner said that the popular Collins I3 image intensifier may not be available for sale to individuals due to large government orders of the basic tube for the Iraq war and homeland security.

Following a short break Dunham recapped the observations made earlier on Saturday morning by 790 Pretoria. At the time of the meeting, there were 7 positive chords which included Dunham’s remote station which recorded a 3 second occultation.

Dunham mentioned there are a few good grazes left in 2005:

25 November 2005: σ Leo from North Carolina to Tennessee.

23 December 2005: β Vir ( m = 5.0) from Florida to San Francisco

25 December 2005: 1st magnitude Spica from El Paso to Seattle

26 December 2005: Eta Vir, San Antonio to Oregon

In 2006 no observable 1st magnitude star grazes occur over the USA, however several Pleaides grazes will occur.

With some occultations at or near daylight conditions, Roger Venable suggested using an infrared filter to increase the contrast to aid in observing the event.

Remaining good asteroid events for 2005:

15 November: 345 Tercidina, m = 8.9 star California to Kansas. The station details for this one are on Derek Breit’s web site.

2 December: 52 Europa, California to El Paso

2006 Events:

3 January 2006: 598 Octavia, m = 10.0 star in Gemini

28 January 2006: 490 Veritas, m = 10.0 star in Orion

16 February 2006: 71 Niobe, South Florida to Spain. Niobe has a possible satellite

from occultation observations as mentioned earlier. This is a good one to watch.

21 February 2006: The Mars moon Deimos will occult a m = 9.0 star

24 February 2006: 530 Turandot, m = 7.9 star, northeast USA.

12 April 2006: 305 Gordonia (50km size) occults λ Vir, a m = 4.6 star over southern Africa

and Madagascar.

5 May 2006: 7 Iris, occults HIP 116495, m = 5.8 over the northeast USA. This is a low altitude event near morning twilight.

6 May 2006: 762 Pulcova, m = 11.9 star in a north south path from Houston to Canada. Pulcova is a known binary asteroid with a separation of about 500km.

David Dunham said Adirondak Video now markets an occultation video package which consists of a Supercircuits PC-164 camera and adapters for about $170.

From the web, ON editor John Graves wrote in that possibly several times per year, we could have a webcast to pursue online discussions. This would be a useful way to prepare for important occultation events and other IOTA matters. Needless to say, verbal communications are often more effective at getting things done than the usual emails.

Following this a few videos were shown of the Pretoria event and other recent occultations.

The meeting adjourned at 12:53 PM and the attendees continued their informal discussions.

Most of the presentation files for this meeting are at



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.