The International Occultation Timing Association's 31st Annual Meeting
David Dunlap Observatory, Richmond Hill, Ontario, Canada
October 4-6, 2013
by Richard Nugent, Executive Secretary
Scotty’s Maxi mount to hold a 120mm short tube refractor
Lifetime Achievement Award to David W. Dunham
Homer F. Daboll Award to Graham L. Blow
David E. Laird Award to Harold R. Povenmire
Paul Maley setup for 41 Daphne occultation in Indonesia
David Dunlap Observatory
IOTA at NEAF conference
David Dunham given IOTA's Lifetime Achievement Award
Io's torus and light curve
The minutes of all IOTA annual meetings are at:
Graham L. Blow, 2013 Homer F. Daboll Award Recipient (photo coming soon)
Harold R. Povenmire, 2013 David E. Laird Award Recipient
David W. Dunham, Lifetime Achievement Award Recipient
The 31st annual meeting of the International Occultation Timing
Association was held Friday,
Saturday and Sunday October 4-6, 2013 at the David Dunlap Observatory at
The meeting location was kindly hosted by the David Dunlap
Observatory. The final meeting schedule, and most of the presentation files, are
located as links from Brad Timerson’s North American Observations web site:
Forty-eight (48) persons participating in the meeting in
person and via internet conference:
site attendees: President
Dr. David Dunham from
Internet Conference Attendees:
Steve Messner, Brad Timerson, Ted Blank, Steve Conard, IOTA Treasurer Chad
IOTA Executive Secretary Richard Nugent, Bob Anderson, Tony George, Bob
Dunford, Ted Swift, Derek Breit, Roger Venable, Bruce Holenstein, Ernie Iverson,
Jan Manek, Bob Sandy, Brian Loader, Dave Gault, Dave Herald, Graham Blow,
Hristo Pavlov, John Broughton, Marjan Zakerin, Rob Robinson, Jacquie Milner,
Scott Degenhardt, Wayne Warren, Breno Giacchini
– Meeting start – Introductions
Dr. David Dunham opened
the meeting and welcomed everyone to
the David Dunlap observatory which was built in 1934.
He then asked the attendees to introduce themselves. All present at the
Observatory introduced themselves.
Chad Ellington presented
IOTA’s membership status. Currently there are 43
report: A summary of the year’s bank balances are:
$5,997.29 2012, Oct 19
$6,038.02 2013, Oct3
in Balance: $ 40.73
breakdown of this past year’s budget is:
$ Not determined
of registered agent $5
Secretary Richard Nugent presented
election results as 2013 is an election year. After 30 years as President and
Vice President David Dunham and Paul Maley decided to step down and let new
blood run the organization. Dunham and
Maley are not leaving IOTA, they will remain on its Board of Directors. Expect
to hear from them with their observations, wide range of expertise and input as
before. Jan Manek retired
after 15 years as VP for Planetary Occultations. Jan’s volunteer work for IOTA
has been held in the highest regard by the occultation community.
new slate of candidates that were voted on were:
Vice President: Roger Venable
Executive Secretary: Richard Nugent
Secretary & Treasurer:
V.P. for Grazing Occultation Services: Mitsuru Soma
V.P. for Planetary Occultation Services: Brad Timerson
V.P. for Lunar Occultation Services: Walt "Rob" Robinson
total of 29 votes were received by email, none were received by Post Office
mail. No nominations were received and Richard certified the election, and the
candidates were officially installed into their respective positions.
elected Vice President for Planetary Occultations Brad Timerson gave the status of publications. He listed some
articles from the Minor Planet Bulletin from 2009-present, and one article in
press submitted to Planetary and Space Science Journal regarding Steve Conard’s
discovery of a possible satellite of 911 Agamemnon from a video he made. Joan
Dunham’s had nominated the
name “Kephalos” as a name for the Agamemnon satellite.
showed the binary asteroid 90 Antiope occultation profile from July 2011 which
an article is currently pending. He asked for help in someone to write these
papers and showed a list of asteroid events since Jan 2011 that are candidates
for future articles. Paul Maley said in order to maintain IOTA’s credibility
and status we need to keep publishing these articles.
Maley showed Steve Conard’s
presentation on insurance and liability for IOTA activities. The major question
is: does IOTA need liability insurance? IOTA has no property and virtually no
assets. Several types of insurance options were shown to protect people on IOTA
expeditions. They are General
Liability and Director and Officers (D&O) Liability. Even without liability,
this won’t prevent a lawsuit. The D&O coverage would pay for legal
has been doing expeditions since 1975 and formerly incorporated in 1983. Paul
got a quote from State Farm (quote for
Povenmire mentioned an
upcoming bright star occultation of ZC 2629
and ZC 2826 as these are suspected binary stars. These occultations are
visible from the eastern
Blank (for Walt Morgan)
presented the IOTA-VTI Status Report. IOTA has the rights to the IOTA-video time
inserter. It’s manufactured by Video Timers and technical details are handled
by Walt Morgan and Sandy Bumgarner. The basic unit has a built in GPS receiver
and an external GPS is available.
George presented the
double star report. Four papers were published in the Journal of Double Star
Observations (JDSO) since October 2012 showing new double stars discovered. New
double star discoveries are:
by asteroid 336 Lacadiera,
event date 2009 April 6
Orionis, (TYC 126-0781-1) by
asteroid 57 Mnemosyne, event date 2012 March 11
6223-00442-1 by asteroid
52 Europa, event date 2012 August 12
42913552 by asteroid 388 Charybdis, event date 2012 December 3.
Tony next discussed R-OTE,
the Occultation Timing Extractor. R-OTE is a signal analysis tool that he and
Bob Anderson have developed. It’s a more advanced estimator than OCCULAR to
extract D and R occultation timings. A major difference from OCCULAR is that R-OTE
independently determines D and R events, whereas with OCCULAR they were linked
by the duration of the event. Other advances are the ability to estimate stellar
diameters and occultation limb angles, limb darkening models, and extract
difficult to see events from low SNR light curves with high confidence. He
showed some light curves and how R-OTE used the maximum likelihood estimator (MLE)
and Akaike Information Criterion (AIC) for light curve fit and model selection.
Examples were also shown on how R-OTE uses advanced methods to deal with
noise and SNR issues.
Maley asked if R-OTE could be used to reexamine previous videos made at the
limits of the occultation where no event was initially seen in the hope of
extracting a real event. Tony responded yes and that it would be limited by the
amount of noise in the data.
next talk was about Near Earth Asteroids (NEA’a) and IOTA’s possible future
involvement. New proposed research (not yet funded) by the Cascade Airless body
Research Institute (CARI)
is to characterize the properties of observed NEA’s including IR measurements,
thermophysical properties, effects of space weathering, sample return technology
and physical measurements using occultations/light curve data. Equipment
currently available for this project is
Maley discussed the
status of funding from the Southwest Research Institute (SwRI) for asteroid
occultation events. Thus far 387
how to observe asteroid occultations from multiple stations. This same talk was
presented at the European Symposium on Occultation Projects (ESOP-32) in
attendees then discussed plans for the 306 Nike event Saturday night with a
+10.6 magnitude star and went to dinner.
meeting adjourned at 5:35 PM EDT.
October 6, 9:10 AM meeting continues
Pavlov discussed OccuRec – A new
video Recording software for windows. A main issue with windows recording of
occultations is the delay in getting the time stamps in synch with the video.
Hristo came up with a program that solves these issues. He demonstrated how to
run this program with on his desktop for all to see. Terry Redding asked which
captre cards will work with the software and Hristo said all capture cards that
work with direct Show will work.
next talked about the new Watec camera WAT 910-BD. It will have a sensor that is
2 times more powerful than the WAT-910HX camera. He acquired a WAT 910-BD camera
and did some tests compared to WAT 120N, the WAT 910 HX. Many more stars were
Holenstein presented a talk entitled
on “Application of EMCCDs to Faint Occultations”. A “faint” occultation
is considered one that is out of the reach of typical IOTA equipment, where the
target star is in the range of magnitude +14 or fainter. A “emCCD” is a
camera with an extra set of registers to multiply electrons before readout.
Bruce showed slides on how emCCDs work and their noise characteristics and how
noise is significantly reduced. These emCCD cameras are much larger than our
conventional video cameras and Bruce showed some photos of how he mounts them on
his telescope. In tests on a 14”
f/10 SCT, he observed stars to m =
+17 with a Photometrics 512B emCCD camera.
The camera had much improved signal to
noise (SNR) over the Stellacam EX camera and reached stars 2 or 3 magnitudes
emCCD cameras are capable of very fast recording rates. An example occultation
of mu GEM from March 2013 was shown with a phenomenal 333 frame/sec recording
rate. The light curve graph clearly
showed effects of the large 16 mas angular size of the star.
minute break, resumed 10:35 AM EDT
Marjan Zakerin of IOTA-ME
presented the Scientific Achievements of IOTA-Middle East Section and some of
their recent activities. IOTA-ME was formed just 3 years ago in 2010.
IOTA_ME has two departments: Occultations/ TNO’s (12 members) and Variable
stars/Exoplanets (50 members). She
showed slides on several projects they are currently working on. IOTA-ME has
published 34 monthly newsletters since their creation. The newsletters have
articles presenting original research by its members. They are currently
translating a book on exoplanets for use by its members and writing a book on
analysis of light curves from IOTA-ME experiences/observations. IOTA-ME has
participated in several workshops concentrating on hands on training for its
members – how to make observations, writing papers, analyzing results, etc.
They participated in the 3rd international Conference of Occultation
and Eclipses in October 2012 and will participate in the 4th
conference scheduled starting October 24, 2013. With 62 members, they are one
of the largest IOTA organizations in the world.
year’s presentation of the annual Homer F. DaBoll award and David
E. Laird award was made by the Award Committee Chair Dr. Terry Redding.
The Homer F. 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. The David E. Laird award (this being the first
award year) is given to people who have made significant contributions to
occultation science prior to 15 years ago. Laird (1931-1968) was an organizer of
grazing occultations in the early 1960’s. The Laird award was conceived to
help “catch up” on awards to some older IOTA members.
Homer F. Daboll awardees: 2007: Dave Herald (
year’s Award Committee consisted of all past recipients (above) and Dr. Terry
2013 Homer F. DaBoll award recipient was Graham L. Blow from
2013 David E. Laird went to Harold. R. Povenmire of
then presented a Lifetime Achievement
Award to David
W. Dunham. The award inscription reads, “For His Leadership, Commitment And Tireless Efforts Toward The Promotion
Of All Aspects Of Occultation
Science. IOTA Looks Forward To His Ongoing Contributions”. David Dunham is the
father of the modern occultation program having started his interest when
he was 15 years old in 1957 and
making numerous milestones since then. A YouTube video of this award
presentation is here:
Break, resumed 1:30PM EDT
presented a summary of IOTA’s participation in the North East Astronomy forum
(NEAF). Joining Ted at that event was Dr. Ken Coles, Steve Conard, Bruce
Holenstein, Bruce Berger and Al Carcich. Over 4,000 people attended this event
which lasted 2 days. IOTA offered a class both days, “Introduction to
Occultations”. For NEAF attendees Walt Morgan offered a $15 discount on the
IOTA-VTI time inserter. A sign up sheet had 33 people sign up and a few of these
people are in contact with current IOTA members. Brochures were passed out, the
IOTA-VTI was displayed the ten-inch travel scope was set up and shown and sample
graze profiles and asteroid profiles were displayed. The cost of IOTA attending
was $450 of which IOTA paid $300 and the balance came from other
members/companies. Feedback from NEAF included Elizabeth Warner’s offer to
consolidate all of IOTA‘s myriad of websites into a single front-end website.
updated the results of the Astronomical League’s Occultation Program status.
Three years in the making, the Astronomical League (AL) finally accepted IOTA’s
occultation observing program at their 2013 meeting. Initially the
the results of the 196 Philomela and 41 Daphne international occultation events
earlier in 2013 as part of his outreach efforts to foster interest in these
events. Both these paths had bright stars good path statistics. Paul observed
the Daphne occulted HIP 93026 on March 31, 2013 on the small
September 11, 2013 he observed 196 Philomela occult an m
= 7.1 star HIP 2038 from
his Maxi Mount for use with the Orion 120mm short tube refractor. His mount is
all sky accessible, has slow motion control for pre-pointing, stands 24” tall,
all parts costs $100 and has a magnitude limit with the PC164-EC of
about +12.5. The tripod is made from
a Sears sprinkler tripod and Orion mini EQ Tabletop equatorial mount. He showed
the parts list and photos of the assembly procedure of the mount.
next presented his continuing
research of Jovian extinction events (JEE) and how he is able to model the
Jovian dust field, moon atmospheres, flux tubes and Io’s Torus. This exciting
new research begun when Scotty saw evidence for an atmosphere (dimming effects)
for Io and Europa during an eclipse/occultation event August 9, 2007.
Since then he has been collaborating with Arne Henden (AAVSO) who
correctly estimated the observations would reach a 0.015 mag standard deviation.
observations seemed to show that Europa seems to show a 18-radii extinction
with a 0.25 magnitude drop as evidence. For Io they found an 8 Io radii
extinction detection with an 0.18 magnitude drop. He showed slides illustrating
how the extinction event is viewed from Earth to detect Io’s torus. Scotty
even took the Hubble challenge from a professional planetary astronomer –
could he detect Io’s torus as it transits Jupiter?
He was able to do it despite the non-uniform brightness of the disk of
Jupiter in the background.
showed numerous light curves from extinction videos. The precision of the
magnitude data showed standard deviations of 0.009-0.019 with S/N ratios ranging
from 8.7-12.2, hence the detection of the “wings” on the light curves was
quite simplified. The light curve fits to JPL ephemeris data was also very good.
In 2014 Jupiter’s orbital plane reaches edge on hence a new series of
transit/eclipse events begins. One of the goals now is to add spectral data to
add multi-color date to the observations.
Nike occultation event was scrubbed due to cloud cover so David Dunham
finished his presentation of multi-station deployment that he started yesterday.
Brad Timerson presented a summary of asteroid occultation statistics for late 2012 and
2013. He showed histogram charts of the total number of observed events and no.
of chords obtained for these events. A possible new satellite was observed for
2258 Viipuri on August 3, 2013. Inversion
models were shown for several asteroid events along with their corresponding
occultation chords. The agreement was excellent in most cases except for 45
Eugenia on May 20, 2013 in which one southerly chord didn’t match the
David Dunham continued with a list of future asteroid/planetary occultations for 2013 and 2014 and showed a list of “best” events in the RASC Observer’s Handbook. He showed some Occult maps of some of the major events involving brighter stars. A fantastic opportunity exists for the occultation mag +1.4 Regulus by 163 Erigone on March 20, 2014 over New York/Canada.
Richard Nugent's YouTube page has an animation of the Regulus event as seen over the New York/Canada:
Another bright star event is by 3 Juno
occulting the mag +7.4 star SAO 117176 will occur on November 20, 2014.
David completed his talk on the RASC handbook
lunar occultation and graze events for remaining 2013 and 2014. He showed the
RASC table of grazing events for the rest of 2013 and the list for 2014. Graze
maps were also shown for the same time periods for the USA/Canada.
Herald presented his annual presentation of “Occultations
from Around the World” from July 2012 through September 2013. Part 1 – lunar
occultations observed by region: Japan led with 4,158 observations, North
America had only 458 observations. Brian Loader reports that 254 double stars
were observed which included 22 new discoveries. Part 2 – best asteroid
events. 2012 and 2013 has seen a drop in the total no.of observations. Dave
believes the drop is not due to people attempting events but rather the
decreasing accuracy of predictions due to the declining precision of star
positions and proper motion effects from catalog errors. Two possible satellite
discovery profiles were shown -
from Jan 19, 2013
and Aug 3, 2013 by 2258 Viipuri.
Since June 2012,
7 new double stars were discovered. An interesting double discovered was on Aug
15, 2013 in Australia of the 611 Valeria occultation in which the time
differential was 66 seconds. This wide double was estimated have a separation of
380mas. He then showed several
asteroid profiles obtained from the best observed events including 87 Sylvia in
which one of its 2 known satellites was picked up by 2 chords.
next presented a self narrating talk “Asteroid Dimensions from Occultations”. This
talk is intended for all observers and John started by listing the main factors
necessary to make an asteroid occultation observation including having a
telescope properly pointed, a recorder going, problems with weather, path
errors, etc. He showed how chords are “weighted” to determine asteroid
sizes. John showed how timings were converted to chords, then event diameters,
then mean diameters and finally converted to ellipsoids. John listed some of the
most well determined profiles/mean diameters. ESA’a GAIA satellite offers
promising new highly accurate star positions to offer highly improved path
predictions. And with future large survey telescopes this will expand
observations to Kuiper belt objects and TNO’s expanding occultation
12:10 PM EDT Lunch break
Dudley Observatory in Schnectady, NY talked about “Hands on Astronomy”. Her
background and graduate work was in asteroid spectrometry, now she leads the
educational/public outreach with students at the observatory. She started
with a short video about 3-D modeling and printing. NASA’s Night Sky Network
actually suggested her starting students to learn about asteroids by making them
out of clay. She showed a better way by
using 3-D shape models and printing them using 3-D printing
methods. A 3-D printed model of an asteroid would rise above the plane of
the paper (like mountains on a globe). She showed the example of 135 Hertha,
from observations to light curves to shape models to printed models. She
continued to explain how a digital model is converted to printable form using
texture, density to various cross sections of the asteroid using various 3-D
printing technologies. 3-D printing machines range in cost of $500-$20,000+.
Some companies offer 3-D printing services priced based upon volume and material
the user wants.
Blank showed an animation of D and R’s for the
asteroid occultation of the 90 Antiope double asteroid event from July 13, 2011.
He used a program (After Effects ) to do these D and R animations. First he used
a Google Map of the path area for the background, then plotted the positions of
the observers (from their lat/long). He then choose a shape of the asteroid
(oval, circle, ellipse) and made it move at real time rates across the map.Hits
have observer’s points disappear with misses keeping their points at full
brightness. Ted’s son was also involved in developing this project.
discussed “Trying to Hit the Flat Areas of Grazing Occultation Profiles Using
Kaguya Data”. He started by showing the basic geometry of grazes along with
several profiles. Then he showed slides of the multiple station technique used
on a few grazes starting with the Dec 21, 2001 tau2 Aqr graze. On April 10, 2011
he has a good success with mag +3.5 Eta Gem using Mighty Minis/Maxis. He then
described the May 13, 2013 graze of an +8.9 mag star with a 8% sunlit waxing
Moon just 17 degrees above the horizon in his home state of
next graze was on June 2, 2013 near Mozhayskoye in
then summarized the ESOP 2013 meeting presentations.
David talked about the long history of double star discoveries from occultations
and IOTA’s efforts to catalog probable and possible events from lunar
occultations. IOTA’s recent double star efforts call for observers with video
cameras with wide separations to help confirm these doubles. Several papers have
been published in the Journal of Double Star Observations (JDSO) identifying new
double star discoveries from both lunar and asteroid occultations.
He showed some slides on how professionals using larger telescopes and
high speed photometric capability have discovered some double and triple star
systems from lunar occultations.
video was showed of a Spica graze from November 30, 1994 with WWV audio that was
later converted to digital with time insertion. This conversion uses the WWV
tones to trigger an internal quartz
sub-second timer which is overlaid on the screen.
He then showed Steve Conard’s time inserted video showing a possible
satellite of 911 Agamemnon from Jan 19,
2013. Next was a video of a double star discovery from an asteroid event from
George then presented “Integrating Video Cameras
Operating Guidelines”. Many IOTA members have integrating video cameras to
help reach fainter stars. Most common ones used by members are the WAT-120N+,
PC165DNR, Minitron and the Mallincam. Tony stressed that it is the user’s
responsibility to know your camera’s settings and how to use them – shutter
control, gain settings, gamma functions, etc. Tony showed how to set the WAT
120N camera and showed screen shots of the PC165DNR settings. He recommended
that you use the fastest possible shutter speed for best time resolution.
Regarding gain control, he recommended a fixed max gain setting that would not
saturate the star images. For color cameras, set them to B/W mode. Tony
recommends if you are in doubt ask an expert on how to set your camera’s
settings for maximum results.
Tony provided a list of resource people for questions on the various integrating cameras:
WAT 120N --- Tony George
Stellacam EX --- Steve Conard, Ernie Iverson
PC165DNR --- Ted Swift
Mallincam --- Tony George (tentative)
Minitron --- John Meneke
Samsung SCB 2000 --- Terry Redding (tentative)
Timerson presented “Timing analysis spreadsheet for
Pre/Post Time Stamped Videos”. The technique was pioneered by Scotty
Deganhardt for his multi-station technique using Canon digital (DV) camcorders.
Digital camcorders have internal clocks that are not in sych with UTC and this
error propagates. With help from John Talbot, Tony George and Brad came up with
a Excel Spreadsheet and Word document describing the proceedure to compensate
for this. This spreadsheet computes the actual UTC time of an event by
converting the internal times/frame
#’s from an digital camcorder with a time stamp before and after the event.
With the frame(s) of the event identified in Limovie, the spreadsheet
will calculate the UTC time of the event. Brad has a zip file which inclusdes a
Word Document with examples on the North American Asteroidal webpage.
Door Prizes were given. Richard Nugent, David Dunham and Jan Manek are the lucky
Terry Redding talked about “Seeing More with Less”.
Terry described how he educates students on how faint they can see events and
how to plan for events. He tells students about the history of occultations,
types of discoveries made (close doubles, asteorid sizes/shapes). He tells
people what the plan is – have a telescope, record (preferably) with video,
importance of timing techniques, preparing to travel and weather forecasts. He
showed some of the cameras they could use – over the counter digital cameras
such as Canon Powershot down to the PC164C and Mighty Minis. He
showed a few slides of some of his early occultation atempts, failures and what
he learned, how Occult Watcher is used, using star charts, filing
reports, etc. In summary, Terry does not discourage anyone from attempting
events regardless of their
experience, and/or availabilty of equipment.
The meeting ended at 5:15 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.