The International Occultation Timing Association's 28th Annual Meeting
AAVSO Headquarters, Cambridge, Massachusetts
Clay Science Center, Brookline, Massachusetts
December 3-5, 2010
Bruce Berger explains the S.C.O.R.E. system
Dr. Terry Redding and Doc Kinne operate EVO system
Clay Science Center's 25" (0.6 meter) telescope
Dr. Terry Redding
Roger Sinnott signs autographs on some of his many books
Dr. David Dunham
2010 Homer Daboll Award given to Hristo Pavlov
Attendees discussing important scientific results
David Dunham packs his Mighty Minis
Some of the EVO Participants
Bruce Berger's portable occultation system
Frank Suit's AllTimer system
Richard Nugent's new video method to measure double stars
Frank Suits and Marco Minozzo
Clay Science Center
Journal of Occultation Astronomy replaces Occultation Newsletter
New IOTA Middle East section
IOTA's Annual Meetings
Hristo Pavlov, 2010 Homer F. Daboll award recipient
Highlights of IOTA's 28th Annual Meeting, December 3-5, 2010
AAVSO Headquarters, Clay Science Center, Massachusetts
by Richard Nugent, Executive Secretary
The 28th annual meeting of the International Occultation Timing Association was held on Saturday December 4, 2010 at the American Association of Variable Star Observers (AAVSO) Headquarters in Cambridge Massachusetts and at the Clay Science Center on Sunday December 5, 2010 in Brookline. Massachusetts. This location was chosen to coincide with 3 asteroid occultations: 628 Christine, Dec 4 and 212 Medea/10 Hygiea Dec 5. Nearly all observers who tried these were clouded out except for a handful.
Positive chords were obtained and the results are posted at the asteroid occultation results page:
The meeting location was kindly hosted by the AAVSO on Saturday and the Clay Science Center on Sunday. 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 50 persons participated in the meeting:
President Dr. David Dunham from Maryland,
Executive Secretary Richard Nugent from Texas,
Dr. Terrence Redding from Florida,
Marco Auerelio Minozzo, San Paulo Brazil,
Steve Conard from Maryland,
Frank Suits, New York,
Ted Blank, New Hampshire,
Bruce Berger, Ron Dantowitz, Arne Henden, Gary Jacobson, Marek Kozubal, Doc Kinne, Glen Meurer, Mario Motta, Don Price, Roger Sinnott, Alan Sliski, Paul Valleli from Massachusetts
Video Internet Conference (EVO) Attendees: IOTA webmaster Rob Robinson, Jan Manek, Hans Heynan, Bob Sandy, Dave Clark, Wolfgang Rothe, Scott Degenhardt, Pedro Sada, Gerhard Dangl, Dave Herald, Roger Venable, John Grismore, Dave Gault, Brad Timerson, Aart Olsen, Derek Breit, Chad Ellington, (IOTA Secretary/Treasurer), Steve Messner, Gene Mroz, Lawrence Garrett, Tony George, Eberherd Bredner, Wofgang Biesker, Tim Haymes, Rick Hunter, Wayne Warren, Ryc Rienks, Ned Smith, Ernie Iverson, Kerry Coughlin and Randy Peterson.
President Dr. David Dunham opened the meeting at 8:40 AM and welcomed everyone. Dunham then asked the attendees to introduce themselves. Following the introductions, it turned out no one was able to obtain chords for the Christine occultation the night before due to overcast skies in the area. Dunham had made a last minute dash to Rhode Island however with the setup time needed for his equipment he wasn’t able to acquire the target star until 2 minutes after the occultation.
Business meeting 9 AM
IOTA Secretary/Treasurer Chad Ellington presented the income and expense report. A summary of the year’s bank balances are:
Starting Balance: $6,753.66 2009, November 20
Ending Balance: $7,089.65 2010, December 4
Net Increase in Balance: $ 335.99
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 has represented an embarrassment for IOTA, as some Library subscribers have asked where are the 4 issues/year that they pay for. All members need to consider contributing articles on any aspect of occultation science as the ON Editor has a lack of material for publishing. Along this line, ON has undergone a name change, (Journal for Occultation Astronomy, JOA) format changes and has new Editor. More about this from Richard Nugent’s talk later on.
New Server: Currently a new web site is being used for membership in IOTA, http://www.asteroidoccultation.com/iota/ . This page also allows payment for subscriptions to ON/JOA. The old site, www.occultations.org was being paid for by Art Lucas and maintained by John Graves. Chad had difficulty uploading files to it and the usernames/passwords for access to issues of ON were very archaic to remember and use. (For example, Nugent’s username was KV8247, password 522948). Occultations.org will be lost unless we continue to pay for it. Dave Herald mentioned that all of our websites need to be cross-correlated to avoid scattering of information on the Internet.
A google group website is currently up and running to be used for accessing past ON issues and IOTA business. The URL is http://groups.google.com/group/iota_us. All users and access would be approved by Chad, as he would maintain the site. In this scenario, users would be able to customize their access page such as having links to the asteroid predictions, lunar graze events, software programs, IOTA-ES, RASNZ, Euraster, weather forecasts, etc.
Derek Breit asked if such a page would increase IOTA’s exposure. The consensus of the attendees is that it would probably will. This means the web access needs to be good looking and user friendly with links to all IOTA activities: asteroids, grazes, JOA, Manual, member pages, etc. The discussion continued about making JOA visible to non members.
David Dunham then announced the creation of a new IOTA section in the Middle East. The website is http://www.iota-me.com/. The web page has the left half in English and the right half in Arabic. Uses may contact the group via a general email address: email@example.com. The new section had their first meeting on November 17-19, 2010 in Gonbad, Iran. Seventy-four (74) persons attended (mostly women as seen from the conference videos) making this perhaps the most attended Occultation meeting to date. Dunham had recorded an introductory video in English for the group that was played at the meeting. Richard Nugent has been corresponding with the organization’s webmaster about the IOTA Manual and it’s possible translation into their language.
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 the 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 nine nominations from eight persons for the award. All were excellent candidates. The Committee’s main objective in selecting an award recipient was to reach a consensus and not choosing someone by a simple majority vote. The rules allow any person to be considered for the award except for current IOTA Officers and Committee members.
The 2010 Homer F. Daboll award recipient was Hristo Pavlov from Australia for his dedicated contributions in “writing software that coordinate observations, keeps occultation astronomers informed and aids in analysis of their data.” Hristo’s OccultWatcher program located here: http://www.hristopavlov.net/OccultWatcher/OccultWatcher.html. It allows observers to post their proposed asteroid occultation sites to avoid duplication of chord efforts along with many other useful features.
Hristo also wrote and released Tangra, (http://www.hristopavlov.net/Tangra/Tangra.html) photometry software for analyzing asteroid occultation events. Tangra also has an astrometry feature for determining precise positions of slow and fast moving targets from videos.
There was no method of contacting Hristo at the time of the award’s announcement (Hristo was not logged onto the EVO) so an email was sent to him. The next day Hristo sent out the following email to the IOTA Yahoo discussion group accepting the 2010 Homer Daboll award:
From: Hristo Pavlov To: firstname.lastname@example.org 12/6/2010
Subject: [IOTAoccultations] Homer Daboll 2010
I would like to sincerely thank you for the honor of presenting me with this
year's Homer DaBoll award!
I would also like to apologize. A combination of technical issues, the late time
of the session and my demanding family (3 months old daughter and 23 months old
son) prevented me from preparing and responding more adequatly during the online
EVO session of the IOTA meeting. Thanks to Dave Herald who recorded and sent me
Terry's presenation I finally watched it yesterday.
Someone on the record said that I should probably prepare and present a speech
before I am allowed to have the award :) Well, fair enough. Let's start with a
bit of a history.
After I moved to Australia and renewed my astronomical activity in 2006 I met
many people in IOTA and in Australia in particular that inspired me to observe
occultations, helped me to learn and threated me as a good friend. I have to say
that it really takes a special person to drive to a dark road in the middle of
nothing, setup a telescope, wait to record a few seconds event, not observe
anything interesting most of the time and still feel happy and fulfilled. These
are people like you, that have the desire to help the science with their efforts
and actually do science without being a scientist. This is what inspired me most
to start observing occultations and not for example to start taking more
pictures of M-42.
Occultations however are a team work and team work needs coordination. In 2007 I
met David Dunham in Auckland, New Zealand and we discused some aspects of an
automated global occultation coordination software. I have had just presented
the very first version of OccultWatcher at the First Trans Tasman Symposium on
Occultations and back then OW couldn't do more than grabbing Steve Preston's
events and showing you very basic details of what is close to you and showing
you when Steve has updated some of his predictions.
With time I kept adding new bits to OccultWatcher to become what it currently
is. Some people have told me that with OccultWatcher I have revolutionalized the
way occultation observers plan and coordinate their observations but to be
honest from my point of view I have just made my life easier which also turned
out to make other people's life easier as well. But I have to admit that I am
glad that observers use OccultWatcher and It makes me happy to see events in
U.S. and Europe with more than 10 stations in OccultWatcher. It is really good
to see when people go out, coordinate and most importantly observe.
I guess the other part of this story is also about analisys of video
observations. I have to say that Kazuhisa Miyashita's LiMovie was also something
that impressed me along the way and I always thought it should be very difficult
and complicated to write something like it. Now that have done it with Tangra I
can tell you that I was not wrong. Writing video light measurement tool with
automatic tracking is not an easy job. And I think you can also tell this from
your experience with LiMovie and Tangra's tracking which doesn't aways work the
way you want it.
When I started writing Tangra I wasn't absolutely sure that having a second
light measurement tool was a very good idea. I still don't know but I hope that
what I have added as 'improvements' will really be seen as improvements one day.
And if you ask me what is the bigest advantage of Tangra I will say that this is
the ability to see how the measuring apertures have been positioned for every
single measured datapoint in every measured frame. And not only this but also
the ability to send a much smaller .lc file to someone else to evaluate your
light curve. That's right, I may not be able to guarantee that Tangra will do
better tracking and better measurements than other tools but I can really
guarantee that if there is a bogus measurement you can defenitely identify it
after the measurement looking at the .lc file in Tangra.
Some people have also asked me why the name "Tangra" and others have even
suggested I have named it after my favorite rock band. I thought it may be
curious to say where the name comes from. It is in fact the name of the supreme
god of the ancient Bulgarian tribes and this also reveals my background - I was
born in Bulgaria. Oh yes, and Tangra was the god of the sky, of course.
And finally I should also say that I was a little surprised that the award was
given to me this year when I think that there are other more experienced people
that have been contributing for IOTA for a much longer period of time than me. I
hope in future years to see people being presented with the Homer DaBoll award
for observing, organizing observers and also doing scientific research using
occultations with the observations provided by you - the observer, because in my
opinion it is those people that have helped most to advance the occultation
One more time, Thank You so much for giving me this honor, I appreciate it very
Now, can I have my award please?
Elections – Executive Secretary Richard Nugent presented the results of this years elections (Officer elections are every 3 years). Nugent presented the results of the 2010 IOTA election of Officers and Directors. As of the meeting, email votes were received with no additional nominations for any positions. All attendees were in favor of the straight slate of Officer and Director positions. The elected positions are for a 3-year term and they are:
President David Dunham
Vice President Paul Maley
Executive Secretary Richard Nugent
Secretary/Treasurer Chad Ellington
V.P. Grazing Occultation Services Mitsuru Sôma
V.P. Planetary Occultation Services Jan Manek
V.P. for Lunar Occultation Services Walt “Rob” Robinson
Editor Journal of Occultation Astronomy Michael Busse ………
(formerly Occultation Newsletter)
Michael Busse (IOTA-ES) has volunteered to edit the renamed ON (Journal of Occultation Astronomy). This position taken over from John Graves.
Richard Nugent presented the new format of the Journal of Occultation Astronomy. Occultation Newsletter, ON has not been published for some time now and at this years ESOP meeting, it was proposed that IOTA-ES would take over the responsibilities of editing and publishing ON. At the same time, it was suggested that the name be changed to reflect occultation astronomy for what it has evolved to be – an accepted scientific field of astronomy that produces new discoveries, new methods, and new techniques. Nugent showed a few screen shots of the new JOA format. Articles would be submitted to the Editor as specified on the inside cover page. This page also has article submission requirements. The first new issue (covering the time period December 2010-March 2011) has already been proofread and should be online within the next month (December 2010).
Dunham then presented a talk on behalf of Vice President Paul Maley. Maley has been actively involved in international outreach to assist and educate occultation observers in several different countries. He travels to places where high ranking asteroid occultation events occur and recruits new and experienced observers to do the observations. To date he has traveled to 19 countries and had positive chords on three events.
On the subject of occultation expedition funding there are funding discussions with the Southwest Research Institute (SWRI) which started in 2009. To date, 3 proposals were submitted by SWRI to NASA and NSF. These proposals are for research into asteroid sizes/shapes and asteroid satellites for Main Belt and Trojan asteroids (Bill Merline, PI) and regarding occultations of Pluto and/or KBOs, (Marc Buie, PI) for which he has solicited IOTA help. Funding is potentially available for travel only and the following events are being considered for 2011 with priority given to multi-station deployment to maximize chances of acquiring data.
Potential Major Expedition List
Asteroid UT Date Star magnitude
Parthenope Jan 26 10.6
Aurelia Feb 2 8.8
Feronia Mar 9 8.2
Iris Apr 30 9.9
Europa Jul 4 10.0
Antiope Jul 19 6.7
Prokne Aug 6 8.9
Another proposal does not entail any funding for new occultation data. Instead it seeks to combine existing photometric data with existing asteroid occultation data to get better sizes/shapes of asteroids, using the KOALA method. IOTA help is sought in finding and interpreting existing occultation data and, what’s more, the occultation data will contribute to key new science results, leading to better understanding of asteroid sizes, shapes, densities and compositions.
On eclipse planning, Maley has planned for the next two solar eclipses: An expedition to Australia for the November 14, 2012 total solar eclipse (the southern edge site was scouted in 2010) and an expedition to centerline in Utah for the annular eclipse of May 20, 2012.
2011 IOTA Meeting. Dunhan/Maley have proposed that IOTA’s 2011 meeting be held in Rocklin, California (near San Francisco) at Sierra College to coincide with the asteroid event of the 120km size 90 Antiope (m = 6.7 star) on July 19, 2010. The target star is in the ZC catalog, ZC 3339 and Antiope is a known binary asteroid. Dave Herald said the HIP position is good and upcoming lunar occultations can confirm this. Steve Preston’s current prediction shows a low error ellipse size 0.025" x 0.016".
Good weather is almost a sure thing and the event is just before sunrise allowing ample time for multi-station deployments. This would be a repeat location as the 2003 IOTA meeting was held at Sierra College.
With no further business the business meeting was closed. The Business Meeting ended at 11:08 AM.
Technical Session – Saturday
Dave Herald told about the status of the Occult program. The current version is 188.8.131.52. It is stable and reliable with only minor issues arising from time to time usually from new users. The next major revision will be associated with an update of the main star catalogue used for asteroidal predictions. He will also be keeping an eye out for useful downloads that will enhance data availability. Dave asked if anyone comes across a useful dataset for IOTA activities to contact him for possible inclusion in Occult’s data base.
Occult’s data base consists of updates of asteroidal observations, lunar observations, and binary asteroid discoveries. Dave also monitors the IAU announcements for binary asteroids. Occult’s periodic updates of the XZ catalogue for doubles and variables is almost ‘routine’. The main issue is coordinating these updates with Brian Loader (New Zealand). A new compilation star catalog consisting of the UCAC3 & CMC14 has been withheld from release for 12 months. This may include the UCAC4. This subset will likely be the basis for future Occult star catalogues.
On the lunar occultation/graze archive effort – the main achievement is completion of all past observations. This is a huge task, but now all past observations are considered ‘safe’.
Double star discoveries and measurements represent an important ‘new’ area of lunar occultations. Occult Watcher has the capability to ‘announce’ lunar occultations of interesting doubles – but this will need someone to generate a feed for the region (North America for example).
If new double found, follow-up observations can usually be made the following month in Europe, Australia or Japan – however this needs global coordination.
On asteroid events the subject of reliable observations was brought up – visual vs. video. A GPS time inserted video can be analyzed carefully for events, blinks, flashes, etc. A visual event (even with a tape recorder) will always be subject to known or unknown personal errors, reaction times or whether the event was real. Visual observations are fine but they must have WWV or similar radio standard to be considered reliable.
To illustrate this concept, if a visual observer has a 0.5 reaction time it would produce a more accurate data point with a 20-second event vs. a 2-second event. For the 20-second event, the error would be on the order of 2.5%, and the 2-second event’s error would be 25%.
On the subject of which star catalog produces the best asteroid prediction, this is an ongoing judgment call. The star catalog comparison option in Occult only produces predictions based on estimated star position errors. As we have seen, sometimes the catalog with the highest error gives the best prediction and vice-versa.
On the asteroid occultation results database to date the total number of events recorded = 1810. In 2010 to date, 167 events have been observed compared to 2009 when 211 events were observed.
David Dunham presented the best (remaining) occultation events for 2010 and 2011.
1115 Sabouda Dec 11, m = 10.8 star, Dunham will use a soon to expire free plane ticket to do this one
1409 Isko Dec 16 m = 10.2 star, Florida
Grazes – Dec 21 – Total lunar eclipse. There are no good grazes during totality in the USA
Dunham showed a list of 31 grazes for 2011 from the Observer’s Handbook for 2011. The star magnitudes range from +2.3 to +8.0 with most stars in the m= 4-5 range.
2011 Asteroid events:
1424 Sundmania Jan 12, m = 8.3, Washington state to Georgia
66 Maja Jan 16, m = 8.7, British Columbia to Long Island (NY)
150 Nuwa Jan 18, m = 6.8, Canada, Europe, China
635 Vundtia Jan 22, m = 10.4, Washington state to Georgia
11 Parthenope Jan 26, m = 10.6, Southern California, Texas, Florida
419 Aurelia Feb 2, m = 8.8, British Columbia to Maryland
72 Feronia Mar 9, m = 8.4, Washington State to Louisiana
7 Iris Apr 30, m = 10.3, Washington State to Maryland
194 Prokne Jun 1, m = 7.4, Australia
52 Europa Jul 4, m = 10.1, East central USA, SE USA
90 Antiope Jul 19, m = 6.8, California to western Canada (2011 IOTA meeting)
194 Prokne Aug 6, m = 9.2, Baja Mexico to Ontario (Canada)
704 Interamnia Nov 5, m = 10.3 California, Mexico to cenrtal USA
Grazes – Dec 11 – Total lunar eclipse. There are no good grazes during totality in the USA
Frank Suits presented his continuing research/development into the low cost AllTimer video system. This recording system uses a USB camera that is GPS time based. Digital video cameras, e.g. USB are preferred but his system can also handle analog input. The system will accurately set a PC clock in the field using USB and GPS and includes an “occultation” LED for self-checks for timing accuracy. The time on USB cameras comes from a projected spot that ramps up and down each second. All power for the system is supplied directly from the computer from the USB port, however there is a battery backup.
On his circuit board (about 6-7 inches size) is the PIC18F4550 m-controller, the Venus 634 GPS module, MAX 7456 Text insertion, a PIC Ready1 board, GPS Antenna and LCD display. Frank showed sample screens showing the display format. The text shows standard items such as
time and field count. The display cycles through items such as: No. of satellites, Lat/Long, elevations plus more. The displayed character set is designed to be read by software for each field.
One of the advantages of this system can be the use of high speed recording rates - 245 frames/sec. As the AllTimer system is PC based, it applications go beyond occultations.
Richard Nugent presented two new video methods to measure double stars. Using the same equipment as for an occultation observation, the observer will video record a double star drift completely across the DVR/camcorder screen with the telescope motor drive turned off along with GPS time insertion. The drift should be fairly close to the east-west direction, but need not be perfect. The offset from a true east-west drift will compensated for in the reduction.
Using an overlooked feature in the program LiMovie, (x,y) data points for each aperture ring (star) for each video frame is stored in the output CSV file. This is all one needs to compute position angle and distance of the double star after correcting for a scale factor.
For a 60 second video and a 30 frame/sec video recording rate, this means that LiMovie will generate (60 sec) x (30 frame/sec) = 1,800 (x,y) data pairs for analysis. This amount of data pairs for analysis is unprecedented compared to any other visual, video or CCD method to measure double stars. Typical scale factors for an optical systems will be in the range of 0.6 – 2.0 arc-seconds/pixel. Nugent and Ernie Iverson have been making test video to test out this technique. They have used several telescopes so far: 3.5" Questar, Meade 14" ACF LX-200, and a Meade 14-inch f/10. Iverson has used several focal reducers, f6.3, f3.3 and f10 and the best results seem to come from the f10 system. In positional astronomy, the less glass between the star and the video/camera chip, the better.
Richard showed a table of double star measures as compared to the Washington Double Star Catalog (WDS). Most separations were within 0.0 – 1.0" of the WDS values and position angles were either right on or within 3-4 degrees. The source of the larger than expected differences in position angle will be investigated. Communications with Brain Mason of the USNO indicate that the WDS values are not necessarily accurate as many of the entries come from amateurs that publish their results in the Journal for Double Star Observations, Webb Society Double Star Section and other places. His research into this area is described here: http://weblore.com/richard/double_stars_video.htm .
Russ Genet and Bruce Holenstein presented their design for a portable 1-meter class telescope that can be used for occultations. Named the “Alt-Az Initiative” their goal was to reduce the cost of 1-meter size telescopes to that of a currently equipped Celestron 14 (C-14). With such a medium cost portable telescope system several of the faint KBO occultations would be within reach of the occultation observer. They compared the cost of a typical 1-meter telescope and it’s features to their proposed design. A commercially available 1-meter telescope can cost upwards to 1.8 million US dollars. Their prototype version would be in the range of $20,000. Their telescope is an f/4 system and weigh in at 300 pounds. Their “BanichBylaw” is for this telescope is 1) to be enjoyable 2) repeatedly used, 3) must be happily set up by no more than two people of ordinary strength and dexterity, 4) setup time - 30 minutes or less. They showed slides showing the setup. Setup time averaged 30-45 minutes with two persons. The weight of the largest component (the mirror) as 200 lbs.
The design of such a telescope involves new mirror technologies all to reduce the weight and cost: slumped meniscus design, foam glass, sandwiched glass, spin-cast epoxy and multiple spherical mirrors. They discussed and showed prototypes of the foam glass design by Andrew Aurigema, the sandwich design by Tong Liu (similar to the Hubble Optics) and spin-cast epoxy methods. The website method by Lisa Broadhacker from Lander University, is the multiple –spherical mirror design as modeled after the MMT on Mt. Hopkins, AZ and the Giant Magellan mirror in Hawaii. A non-vacuum coating method was shown from the work of Sagar Venkateswaran at Peacock Labs. This method would place a silvered coating on the glass followed by a “permaloc” coating. They also showed new designed of their mounts and compute controlled deformable mirror cell. Russ and Bruce will be presenting their 1-meter telescope system designs at the “Light Bucket Astronomy Conference” at the Canada France Hawaii Telescope Headquarters in Hawaii this coming December 3, 2010-January 2, 2011.
Bruce Holenstein continued with the efforts to improve signal to noise ratio of occultation sources. This research follows from the Alt-Az research initiative. Applications of a high S/N ratio include 1) detection of stellar companions, 2) stellar sizes, 3) limb darkening effects, 4) presence of spots on stars and possibly 4) detection of hot Jupiters. To increase the S/N, one would need a larger telescope aperture which requires new mirror technologies, mounts and controllers. These aims could possibly be achieved with the 1-meter class telescope used along with a visible bandwidth photometer, high gain low noise amplifiers, and off the shelf CMOS fast CCD camera.
The web site for the Alz-Az initiative is http://www.altazinitiative.org and their discussion group is http://groups.yahoo.com/group/AltAzInitiative.
Dave Gault showed a short video from the November 17-19, 2010 meeting of the new IOTA Middle East Group from Gonbad, Iran. He then presented Tony Barry’s talk about a low cost GPS-VTI. This newly designed GPS time inserter was made with commercially available parts. It required that the user solder 30 wires which could be done in an afternoon by someone with experience with small circuit boards. Dave showed the circuit diagram and some screen shots of the setup screen and timing screen. The display screens were easy to read and included No. of satellites, lat/long, altitude, UTC CPU statistics, etc. The software is free for the microcontroller. The estimated cost for these units is the range of $100-$140 and they should be available in 2011.
Dave G. then presented the current status of the archiving of lunar grazing occultations, a huge project he has been involved along with Dave Herald. A few years ago there was a huge dataset of non-computerized grazes and the plan was to merge them with the existing file into a single collection to be part of the Occult program. Dr. Ken Coles has been assisting in this effort and has scanned a large number of paper graze reports and sent them to Dave G. Dave G. has reported that approximately 85% of the pre-1970 grazes have been reviewed and restored and this includes 49 new ones found. Six months into the project, the Kaguya data was released replacing the outdated Watts profiles.
The graze dataset includes the 1st successful graze in which a team traveled to record the event: The Sep 8, 1963 graze of the star ZC 464 in Davis, California. Also restored was a graze Dunham had been using is many of his talks: 1981 May 9-10, delta Cancri. A preliminary finding from the Kaguya data is that several grazes show a possible error in the proper motions.. Dave G. is investigating this and is working on a paper on this topic.
Thus far 3,618 grazes have bee reviewed and considered. 193 new grazes have been found that were previously unreported. Dave mentioned that if anyone knows of a graze that is not included in the dataset (the Occult program) to please contact him. The attendees both in person at the meeting and on the EVO held Dave G. in the highest regard for his dedicated work in logging and computerizing the huge amount of grazed observations.
Steve Conard proposed an idea to create an Astronomical League (AL) observing award for occultations. The AL has 240 member astronomy clubs/societies in the US and Canada. They have a yearly convention and publish a quarterly newsletter. There is currently 34 observing club awards including the Messier certificates, observations of double stars, clusters and nebula, etc. An occultation award certificate would encourage occultation visibility (especially among younger people) and help gain new observers.
Steve said Aaron Clevenson (Houston) is one of two national AL coordinators that would approve of an occultation observing certificate. Steve mentioned AL’s procedure to create such an award. It would involve submitting to AL a proposal, develop a manual to instruct observers on how to make and report their observations. The proposal would be considered at the next AL convention in the Spring 2011. To be considered the proposal must be submitted to the AL coordinators at least 1 month before their convention. There was a brief discussion on whether IOTA should pursue an AL observing occultation award. Most agreed that it not only satisfies IOTA outreach and educational objectives, but the recruiting of new observers is crucial to bring new blood into IOTA (also many of the membership is advancing in age). Steve will be working on this new observing award and will keep the rest of the group posted.
Bruce Berger brought his highly portable occultation system (named SCORE, Self Contained Occultation Recording Equipment) and demonstrated it use. Bruce is a newcomer to occultations and his first experience was the Antares graze on January 11, 2010 event time 7:39 PM. The temperature of the event was +2 F (-16C) and Bruce had major difficulty setting up his equipment, connecting cables, positioning and reviewing the small camcorder screen, etc. (Bruce succeeded in collecting data for this graze). He thus came up with the idea to place all components of the recording system (except the telescope) in an aluminum briefcase for easy access and operation.
The requirements for this compact box was that it had to have all hardware in a single easily transportable case, have all components connected and ready to go by turning on only power switches, operate in New England winters, and be able to fit in a airplane overhead bin as carry on luggage. It has a 7-inch (18-cm) flat screen monitor, video amplifier, GPS VTI, 25-ft (8-meter) cable, camcorder, Supercircuits camera and all components are powered by a 12volt motorcycle battery. The motorcycle battery has the advantage over typical AA sized (and rechargeable) batteries in that it can last and operate in extremely cold conditions. A photo of the SCORE system is shown below along with a diagram identifying the components:
Bruce had his S.C.O.R.E. setup featured in the July 2010 Sky and Telescope issue. Bruce’s website is http://scopemaker.com
The meeting adjourned at 5:30 PM. The attendees made plans for tonight’s Medea and Hygiea occultations.
Sunday December 5, Clay Center, Brookline, MA. 11:30 AM, technical sessions continue.
David Dunham opened the meeting summarizing the expeditions of the French for the July 11, 2010 total eclipse over the islands in the French Polynesia at a post eclipse meeting he attended on September 30,, 2010. The previous month before the eclipse in June saw the launch of the long awaited French satellite, PICARD which is designed to measure the Sun’s physical quanities, seismology, shape and diameter. The radius measurements will compliment and help calibrate the ground based radii obtained during eclipses. The French set up several stations at several islands including some stations near to the edge of the Moon’s shadow. They used multiple photometers on different atolls including the island of Hao where Richard Nugent and Chuck Herald made their observations.
Their experiments were to measure the flash spectrum at 2nd and 3rd contact. Their recording camera at Hao had a high frame rate and the goal was to pin down the spectral line change at the moment totality started and ended. This method was first tried by the Japanese in the 1970’s-1990’s. Isao Sato also attempted this technique at the February 26, 1998 eclipse on the island of Curacao. A comparison was made of the flash spectral lines vs. the lunar limb profile with estimated contact times from inflection points.
At this same meeting, Costantino Sigismondi’s presented a talk on his efforts into the possible changing solar radius changes. Dunham described Sigismondi summary of the various techniques that have been used to measure the solar diameter: the drift scan method, angular direct measurements, Mercury and Venus Transits and eclipses. These methods suffer from unavoidable seeing effects and timing issues. The IOTA manual describes these methods in detail along with their results in Chapter 11.
Richard Nugent presented the results of IOTA’s expedition to the Hao atoll for the July 11, eclipse. Paul Maley, Richard Nugent and Chuck Herold traveled to 2 Atolls in the South Pacific in the French Polynesia and set up two stations - Hikueru and Hao. Unfortunately the Hikueru station where Maley was had cloud/rain problems immediately after 2nd contact. IOTA's method of planning eclipse stations normally places them at the north and south eclipse limits, however the path of this eclipse was just about entirely over water so Nugent/Herold and Maley set up on complementary sides of the center line: Maley at Hikueru just 10km north of the eclipse center line and Nugent/Herold at Hao 70 km south of the center line.
Maley obtained video of Baily’s Beads at 2nd contact just before a cloud moved in. Unfortunately he was unable to get his KIWI time inserter to work. The clouds obscured the Sun during the entire duration of totality. At Nugent/Herold’s site it was clear skies for totality plus 2nd and 3rd contact. Nugent obtained high resolution GPS time inserted video of Baily’s Beads at 2nd and 3rd contact. Following 2nd contact, Nugent removed the solar filter and panned around the Sun’s corona during totality still maintaining GPS time insertion. At the meeting he mentioned the important point, “we do not know what data astronomers of the future will need, but we do know they will need this data more accurately.” Nugent postulated that future astronomers might have a need for time inserted video of the Sun’s coronal structure.
Although not at the eclipse limits, independent inner chords of the Sun’s shape could be obtained from the Baily’s Beads data. This effect is illustrated in the diagram on Nugent’s webpage http://www.poyntsource.com/Richard/Jul_11_2010_Eclipse.htm along with a summary of the expedition.
---Lunch break 12:40, Pizzas were delivered and were consumed by the members after the technical session resumed.—
1:35 PM Technical session continued.
Ron Dantowitz, Clay Science Center’s Director presented a talk titled “Dynamic Astronomy”. He began by explaining that the Clay Science Center is geared mainly toward education/research activities for younger students in the local Boston metro area. The Center houses a 25-inch (0.6 meter) telescope in a domed observatory on the roof of the 5-story building. The Center also has 30 other telescopes ranging in size from 3 to 16 inches (8 cm to 40 cm).
Ron is one of the top innovators of high resolution imagery using video/CCD camera techniques and has had numerous images published in Sky and Telescope and other publications. He utilized his techniques and the 60-inch (1.5 meter) telescope at Mt. Wilson to obtain high resolution photos of the lunar crater Tycho that rival those taken by Ranger spacecraft. One particular photo was taken 60 seconds before Ranger impacted the lunar surface. The ground based photo from the Mt. Wilson 60-inch telescope looked identical to this Ranger spacecraft image and had a 140 meter/pixel resolution.
One of the Clay Center’s students has collaborated with NASA and Google to image meteors from an aircraft (Google loaned the use of a plane). He showed high resolution video of the Virgo area of the galaxy on one such flight that was 20 km altitude. In 2005 a laser was pointed at the Space Station and when Ron imaged the Station it had spread to a diameter of 5-6 feet. Ron showed more high resolution images of the Shuttle docked to the Space Station. Details on the solar panels and the Shuttle were easily seen. Next year Ron mentioned that the Clay Center would try and get more involved with IOTA activities, as his techniques have a wide application to IOTA’s video recording and data reduction.
David Dunham presented a brief review of remote station observing. The first ever successful remote video station asteroid event was that of 9 Metis on September 7, 2001. Over 35 successful additional remote video station asteroid events were made since then, 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. Terry Redding asked if the asteroid size /shape data IOTA obtains is catalogued anywhere. Dunham said it was, it’s located on the NASA/Small Bodies Node-Planetary data System website, http://sbn.psi.edu/pds/resource/occ.html
David Dunham continued the meeting with a status report on IOTA’s long-term effort in the solar radius experiment and research. Dunham had previously 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, 2005 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 (deceased), Harry Bates, Sabatino Sofia, David Herald, Patricia Rosenzweig 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 eight eclipses from 1715 to 1987 indicated small changes of the solar radius relative to the 959.63 arc-second standard value for each of the eclipses.
Cosantino Sigismondi from Italy had joined the effort in IOTA’s solar radius research. He has analyzed the Baily’s Beads videos from the eclipses of eclipses of 2006 and 2008. His plots of the solar radius changes didn’t show any obvious trend, however this doesn’t indicate that there isn’t a cycle of small scale solar radius changes occurring with the Sun.
Dunham said a few words about the passing of Tom Van Flandern (2009) and of Alan Fiala (2010). Both worked at the US Naval Observatory and both were experts in celestial mechanics and solar eclipses.
Scotty Deganhardt presented his exciting new research entitled: “Io and Europa’s Atmosphere ad Io Torus Detection through Occultations and Conjunctions” . On August 7, 2009 Scotty video recorded Io eclipsing Europa and 23 minutes later Io occulting Europa. The entire event was 46 minutes long. An unknown dimming and brightening trend occurred before and after the occultation. He postulated causes for the effect: Camera response, the recording method, the reduction method and or extinction via Io’s atmosphere. Scotty investigated all of these possible causes and concluded that the cause was a Torus or extended atmosphere around Io. Thus he launched the IAEP project: Io Atmospheric Extinction Project and a global plea for observations was made. The results included 11 observers from 4 countries that acquired 53 data sets from 28 individual events.
He also presented the results in early 2010, Degenhardt, S. et. al, Io and Europa Atmosphere Detection through Jovian Mutual Events, at The Society for Astronomical Sciences:
Proceedings for the 29th Annual Symposium on Telescope Science. Web page:
http://scottysmightymini.com/IAEP/SAS2010_Io_Europa_Degenhardt.doc. Scotty also has four (4) YouTube videos describing the event and results.
One of the primary conclusions Scotty reached (and are obvious by looking at the light curves) is that occultations on Io’s Jupiter facing limb have longer extinction slopes. These longer extinctions indicate more extinction material. And with more extinction material on Io’s Jupiter facing limb, this implies that a stream of material exists from Io towards Jupiter. This comes as no surprise given that Jupiter is called the “vacuum cleaner” of our solar system. What is the source of the extinction material ? It is well known that Io has a geologically active surface with extensive volcanic activity. During the Voyager II flyby in 1979, ash from an erupting volcano was photographed being ejected into space. Much of this material is in orbit around Io and is replenished constantly, although it has been shown that it dissipates after a few days. Scotty provided some slides showing the more favorable occultation events by Io for 2011 and 2012. He issued a challenge to observers to obtain spectrums of Io to detect spectral line changes during extinction events.
Persons who have contributed datasets to the research effort included Salvador Aguirre (Sonora, Mexico), Dave Clark (Texas), Scotty Deganhardt (Principal Investigator, Tennessee), Terry Redding and Don Parker (Florida), Tony George (Oregon), Andy Scheck (Maryland), John Talbot (New Zealand), Brad Timerson, (New York), Wayne Green (Colorado), Mike Hoskinson (Alberta, Canada), John Menke (Maryland) and Roger Venable (Georgia).
The meeting adjourned at 4:50 PM.
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.