The
International Occultation Timing Association's 34th Annual
Meeting
July 29-31, 2016
Jean Meeus -David Laird Award recipient |
Derek Breit - Homer Daboll recipient |
Joan Dunham shows IOTA VideoRecorder |
Art Lucas and Byron Labadie |
|
Dr. Roger Venable IOTA's Vice President |
Dr. David Dunham |
Art and Barbara Lucas, Paul Maley |
John Broughton's Paver mount |
Ted Blank |
The
minutes of all IOTA annual meetings are at:
http://www.poyntsource.com/Richard/IOTA_Annual_Meetings.htm
Derek
Breit, 2016 Homer F. Daboll Award Recipient
Jean Meeus - 2016 David E. Laird Award Recipient
The
34th annual meeting of the International Occultation Timing Association was held
Friday, Saturday and Sunday July 29-31 2016 at the
The
meeting location was kindly hosted by Art Lucas. The final meeting schedule, and
most of the presentation files, are located on the IOTA web site presentation
page:
http://occultations.org/community/meetingsconferences/na/2016-annual-meeting/
Persons
participating in the meeting in person and via internet conference:
On site attendees:
President Steve Preston, Vice President Dr. Roger Venable, Executive
Secretary Richard Nugent, Ted Blank, Bob Sandy, Steve Conard, Paul Maley, Chuck
Herold, Drs. David and Joan Dunham, Eric Benton, Byron Labadie, Don Stockbauer, John Grismore, Russ McCormick, Bill Hanna, Oliver Causey, Art and Barbara Lucas,
Hal and Katie Povenmire.
Internet Conference
Attendees: Derek Breit, Brad
Timerson, Ted Swift, Chad Ellington, Tony George, Steve Messner, David Herald,
Aart Olsen, Bob Anderson, Gerhard Dangl, John Broughton, Bob Dunford, Denis
Hopper, Wojciech Burzyriski, Bart Billard, Chris Douglas, Jerry Berdecker,
Oliver Kloes, John Newman,
1:00PM – Meeting
start – Introductions
Vice President Dr.
Roger Venable opened the meeting and
welcomed everyone to the meeting. A brief summary of the early morning Aldebaran graze
was talked about by the attendees.
Business meeting:
Treasurer
This trend could be explained
by the fact that IOTA predictions, methods/techniques and results are all online
free. IOTA's Journal of Occultation
Astronomy (JOA) is only available to paid members.
Expense report: A summary of the year’s bank balances are:
Starting
Balance:
$9,608.45 2015, Oct 14
Ending
Balance: $10,416.06 2016,
Jul 21 (Includes funds donated for a
special
asteroid satellite award)
Net Increase in Balance:
$807.61
The
breakdown of this past year’s budget is:
Membership Income:
$600
IOTA-VTI Royalties:
$496
down $192 from last year
PayPal Balance:
$1714.76
Expenses:
-Printing/Mailing JOA
consistent from last year
-Web Service:
Still Donated
-Awards:
$
Not paid for yet
The JOA it is getting further behind on schedule now 2 issues behind
from 2015. More articles are needed. The new password access for downloading it
is working, however many folks have trouble remembering passwords.
This year’s presentation of
the annual Homer F. DaBoll award and David E. Laird award was made by the Award Committee Chair Ted
Blank. 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 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. Laird confirmed the existence of a giant impact on the Lunar far
side, The Laird award was conceived to help “catch up” on awards to some
older IOTA members.
Previous Homer F. Daboll
awardees: 2007: Dave Herald (
Previous David E. Laird
awardees: 2013: Hal Povenmire (
This year’s Award Committee
consisted of all past recipients (above), Ted Blank (Chairman-Massachusetts) Dr.
Terry Redding (
Nominations were received
from multiple countries and all nominees were excellent candidates. To gain more
nominations a new web site will be available to all members to submit nominees
all throughout the year.
This year a Special
Achievement Award went to Art Lucas for his outstanding support for IOTA,
arranging the 2005 and 2016 meetings plus his many observations of asteroid
occultations.
The 2016 Homer F. DaBoll award recipient was Derek C. Breit. Derek has made numerous contributions to the
occultation community with his numerous web pages and detailed maps for 1000’s
of asteroid events, solar eclipses, etc. Derek is also a contributor to the
RASC’s Observer’s Handbook, a regional coordinator since 2007 for lunar
occultations, created the "Why Occultations Flyer" which has been
passed out to all IOTA meetings/conventions.
He has participated in at least 20 grazing expeditions, 74 individual
lunar occultations events and 53 asteroid occultations. His enthusiasm has been
an inspiration to us all.
Derek
was notified of the award a few days before the meeting and sent a response for
the Daboll award to Ted Blank. Ted read it at the meeting.
The 2016 David E. Laird went
to Jean Meeus,
for his 60+
years of sustained eclipse, occultation and positional astronomy calculations.
Jean is a Belgian astronomer specializing in celestial mechanics. Jean was the first person ever to calculate a graze and observe
it in 1959. His
books are classics such as "Astronomical Formulae for Calculators",
"Astronomical Tables of the Sun and Moon.", Cannon of Solar
eclipses (co-author), plus about a dozen othe books.
Executive
Secretary Richard Nugent presented
the IOTA’s election results. Officer elections are held every 3 years as per
the by-laws. All current Officers agreed to continue and the election was
announced on the IOTA list server with voting open from July 3-29, 2016. The
voting was unanimous and the Officers re-elected are:
President:
Steve Preston
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
Directors: David Dunham and Paul Maley
Roger
Venable gave
a brief eulogy for Sandy Bumgarner who passed away this year at age 75.
He was an active observer of occultations since the 1980's and always was
full of energy when it came to occultations, electronics and IOTA activities. It
was Sandy who designed and built the variable gain control ("Bumgarnering")
for our occultation video cameras, an extremely useful feature.
Sandy
also originally designed the IOTA-VTI which is the standard time recording
method for all occultation observations. As a child
Art
Lucas made a few comments about
Ted
Blank
presented an update on the IOTA-VTI version 3. The VTI was originally designed
by Sandy Bumgarner and sold and distributed by
The key features of the IOTA
VTI version 3 are:
Powered by 8 to 28v DC (centre positive)
CCIR (PAL) or EIA (NTSC) compatible
Will work without a camera connected
LED to confirm that a camera is connected.
Internal sensitive GPS is standard
External GPS antenna available
Characters have a drop-shadow – viewable against say, the lunar bright
limb
Comprehensive Data Quality Assurance system
Lithium battery give the unit a non-volatile memory
Licensed to IOTA to prevent untimely withdrawal
Price US$249 + shipping
Can be purchased now at
http://www.videotimers.com
The
units were modified by Dave Gault and Tony Barry of
Since
2011 when the unit was introduced over 400 units have been sold. Most all of the
units have been bought by IOTA and "occultationists", including Marc
Buie's RECON team.
Technical Sessions
Steve
Conard presented early data from
hardware tests - ONAG system. This
is a high speed data collection system. He used a ZWO 224 color camera in the
near infrared. He showed the results using Aldebaran occultation from January
2016 at his observatory in
Steve
Conard next presented test results
from several Mini DVR video recorders. The Canon ZR video recorders have been
popular choices for occultation observers, however they are no longer made and
have lots of problems as they have been aging. The smaller DVRs are mainly used
by motorcycle riders, dirt bike racers, and the included button cameras can be
used for surveillance video.
He bought some low cost DVR's.
The cost depends if you buy them directly from the Chinese manufacturers or a
USA Seller. They have 2.5"
screens, many skip every other field at 30 Hz, and the batteries last a long
time. They do not however have a
programmable start timer which would be EXTREMELY useful for remote stations for
asteroid events. A "Readymade
RC RMRC Pro-1200 Steve acquired has a 5" screen, can also record wireless
video and records in high resolution color. Cost: $150.
Steve showed a comparison chart of
the 4 units he tested.
Steve found a method to make programmable start time recordings using some of the unit's "automobile mode" with a low cost delayed timer from ebay. Steve also estimated the approximate S/N ratio and found that recording to a laptop directly vs. to the DVR, about 0.5-1 magnitude was lost in brightness with the DVRs. Steve's overall comments was that the units make a good backup, they have nice features and are compact.
Steve
Conard next presented a new EXTA (Exposure Time Analyzer) invented
by Gerhard Dangl and built by Bob Auburger from design instructions from
kuriwobservatory.com. The system allows for finding a timing errors
in our video cameras. The
primary driver for fabricating this device was to determine time accuracy of the
less typical cameras used for specialized observations.
He showed videos of test results for the StellaCam at various
integrations. The unit can analyze at 2 millisecond intervals. Near term plans
include testing of ZWO 224 cameras, and Joan Dunham's ZWO and QHY cameras.
The unit is available for loan to any
Atila
Poro from IOTA-Middle East (ME)
presented their experiences and goals via a pre-recorded You Tube video. IOTA-ME
got started 6 years ago in 2010 and has had over 70 active members, more than
any other IOTA region. IOTA-ME has participated in many conferences, members
have observed over 300 lunar occultations, 4 successful asteroid occultations,
several members are working with professionals on NEAR objects plus members have
been doing research on binary stars and exo-planets. Atila has been recruiting
and teaching younger people occultations to foster more interest. The average
age of their members is 24, and he has even done outreach to high school level
students.
Bob
Anderson presented ArtStar/ArtStar
Lite: a new testing system for
video cameras used in occultations. It's a system that runs on a laptop for
testing cameras and frame grabbers. Bob showed the hardware components and some
tests using a Watec 120N integrating camera. A nice feature of ArtStar is the
ability to show an occultation in a frame by frame mode.
ArtStar Lite uses small PVC
parts compared to the longer optical tube for the ArtStar system. The few kinks/surprises he found in his analysis affect the
photometry of the recordings, not the timing.
Bill
Hanna presented his ambitious idea for
autonomous observatory stations - a development in progress. There is no doubt -
setting up multiple video stations has many issues to deal with and the
procedure is complicated. Bill is investigating a self contained unit with an easy
fast alignment plus the unit would operate automatically from there. Initially
there would be a manual coarse alignment, using the Sun, Moon, bright star or
for daytime alignments - a terrestrial target such a tower or mountain peak. The
units would have a "on board" computer for comparison alignment. Fine
alignment would involve pan/tilt mirror control, (x,y)
mirror control and possibly tripod leg servos to change the lengths. Using a
mirror mounted just above the objective of a telescope, to Bill was able to get
within 16 arc-minutes on multiple slews using widely available servo motors.
He hopes to use digital servos on the next round of tests. They have
drawbacks: they use more power, have possible overheating issues and are more
expensive. One suggestion was
to point the telescope down on a ground mounted mirror that moves to orient the
FOV. As a example, the 10-meter Hobby-Eberly (
Paul
Maley and Tony George presented their observational
results of a 13th magnitude star occulted close (3 degrees) to the
full Moon. The m = +13.2 star and m = +12.7 asteroid 712 Boliviana would result in a Δm= 0.5. A seemingly impossible
observation, Paul tried it anyway. He used a Celestron 11 and a Watec 120N
integrating camera at his place in the Phoenix
area. With the star so close to the full Moon, he began setup 1.5 hours before
with pre-point charts provided by Ernie Iverson. To bring out the stars, Tony
used Registax to stack frames. Unfortunately a pointing error resulted in Paul
recording the wrong field. However Paul did get the Pallas event on July 7, 2016
with a 0.8 mag drop and Tony was able to bring out the occultation.
Richard
Nugent presented an analysis of an
unusual 1960 occultation made by a father and son in
5:30
PM - Adjurn
-
-9:00 AM Saturday, Technical Sessions continue - -
After
some technical problems getting logged on Dave
Herald presented the impact of
GAIA on asteroid occultations. A
number to remember is that 1 mas uncertainty for main belt asteroids corresponds
to about 2km on the Earth's surface. Right now, typical star position
uncertainties = 50 mas, and for asteroids 150 mas. Path shift errors are the
result of both uncertainties. GAIA is expected to produce positions to m-arcsec
(0.000001", one thousand times better than the Tycho-2 positions), proper motions and parallaxes of 1
billion stars to m = +20.
Asteroid positions will not be released until 2019, thus realistically
assuming the star position is known, all uncertainty will be with the asteroid
position. With accurate asteroid positions known to the expected certainty, path
predictions should be accurate to within a few km vs. the dozens of km they are
now. This will be a tremendous advantage
to recruit new and old observers who have though of the chasing asteroids was a
wasted effort.
GAIA will impact variable stars - photometry will be done on 5,000,000 classic Cepheids, 3,000,000 eclipsing binaries, 300,000 binaries with rotationally induced variability, 250,000 Miras and SR variables, 60,000 - 240,000 delta Scuti variables, 70,000 RR Lyrae variables and 20,000 supernova. Compare this to the AAVSo index catalogue of 342,000 variables !!
GAIA
will also impact double stars. Expected data are 700,000 radial velocity orbits,
800,000 radial velocity and astrometric orbits, 2,000,000 astrometric orbits,
4,000,000 non linear proper motion systems, 40,000,000 resolved binaries.
All binaries could be resolved with separations less than 20 mas. Compare
this to he current Washington Double Star Catalog: 135,000 doubles, and the USNO 6th Astrometric
Catalogue: 83,000 pairs. ( WOW !!)
Dave
Herald presented how to report light
curves with Occult.
Dave has uploaded over 2,060 light curves to the VizieR database.
Why do this ? At video
recording rates of 30 fps, an angular resolution of 0.01" can be obtained.
Light curves contain important information of occultation reductions and having
them available can assist current and future investigators. Light curves can
show the presence of a double star either by discovering or confirming them. Dave showed how to use Occult to report light curves. Tangra has this capability to
transfer light curves to Occult, Limovie now has it.
Light curves can also be viewed in Occult.
Brad
Timerson presented his yearly asteroid
events statistics since the 2015 meeting. For 695 Bella, light curve analysis showed a new double star. Brad showed
individual events and their excellent agreement to inversion models, including
an observation in January 2016 by Ned Smith which was originally thought to be
an asteroid moon observation, but following detailed analysis it turned out to be a graze of the asteroid.
Dr.
David Dunham presented
the best observed lunar grazing events he made recently including the Aldebaran
graze coinciding with this meeting. He and wife Joan set up 7 stations, in which
2 of
them they attended. He made most of his observations on the very sturdy John
Broughton paver mounts.
David
Dunham showed how to use last minute
weather forecasts for mobile station positioning. For long range cloud cover
forecast he uses weather.gov and watch the cloud probabilities. He also uses
"Skippy Sky", the Canadian Weather forecasts for astronomy,
Weatherbell
(pricey at $25/month), the European weather site ECMWF and Meteoblue. Its always
a guess when trying to predict cloud cover more than 1- 2 days out.
Bob
Anderson talked about Correlated Noise
as a factor in error estimates of timings. He discussed correlated noise,
temporal noise and the various characteristics of each. He set up various
Tony
George presented an update for R-OTE
v4.5.1. (R-code Occultation Timing Extractor). R-OTE runs on a variety of
platforms, Windows 7 - 10, Safari (Mac), Google Chrome, Internet Explorer, etc.
R-OTE identifies the concept of noise asymmetry in light curves between event
noise and baseline noise. It uses the Akaike information Criteria (AIC) to
determine whether an event really occurred or if it was result of noise
fluctuations and other random effects. It can also allow
analysis of gradual transitions of larger stars and stellar limb darkening.
- 12:15
Lunch Break -
Ted
Blank next talked about a comparison
of three video time inserters. Terry Redding, Ted Blank and
David
and Joan Dunham talked about their
previous night's pre-pointing using John Broughton's paver mount for the
Aldebaran graze. The paver mounts are alt/az mounts attached to a patio paver
stone. The paver stones sit on the ground are heavy and are not subject to
movement from wind and other atmospheric effects. David brought his telescope
setup with Broughton's paver mount that attaches to the patio stones and demonstrated how it's setup and works.
Steve
Preston talked about using star
catalog comparisons with thoughts about GAIA data. Its well known that different
catalogues have different reference frames (different telescopes used to
photograph fields, different/combined catalogs used to reduce the data, etc.) In
comparing catalogues, UCAC becomes unreliable for stars brighter than m
= +8, URAT1 proper motions are generally not reliable. Normally Steve will
combine the UCAC4 proper motion with the URAT1 mean position to derive a star
position for an occultation. As mentioned earlier by Dave Herald, GAIA will help
in the short term with relative astrometry as "last minute astrometry"
won't be needed. Only the asteroid position will be needed to be updated as the
GAIA star position will be excellent. As GAIA improves asteroid positions, the
orbits will be greatly improved and thus the path predictions will also improve.
David
Dunham talked about 4 bright asteroid
occultations to occur within a month of this meeting.
They are:
71
Niobe - Aug 15 2016 - north south path
85
Io - Aug 26/27 2016 m = +7.5 star SAO 126327,
51
Nemausa - Sep 3, 2016, m
= +7.6 star,
224
Oceana - Sep 8, 2016, m = +6.9 star HIP 86404,
David
Dunham next presented
Regulus occultations
he attempted. David showed slides of Regulus occultations beginning with the
2005 event over
David
Dunham showed the best grazing events for the coming year. The best one is
Aldebaran on Oct 19, 2016, southern
Roger
Venable showed how he'll plan his
summer vacation: plans for the Sep 1, 2016 annular eclipse in
Dunham
talked about a half a year "down under", recorder timing tests, NACAA
& TTSOO conferences. Dunham presented results of some asteroid events from
2015 he and Joan observed from
Dunham
next
presented his identical talk at the TTSO10 meeting on the Venus Ashen light from
last October's occultation by the Moon. He briefly talked about the historical
observations of the ashen light going back to 1643 by Giovanni Battista. He
described attempts to observe the ashen light in the 20th century which all had
inconclusive results. For the Oct 8, 2015 occultation, Dunham got a good video
and it was analyzed by Tony George, Scotty Deganhardt and Roger Venable. Dunham
showed several frames enhanced of Venus reappearing from behind the dark side. A
hint that some ashen light was detected was speculated by Scotty from his
analysis. Tony George did a Limovie analysis of Dunham's video and it didn't
corroborate Scotty's findings. Roger Venable's analysis
- he stacked images to eliminate Venus's movement. Roger's results were
similar to Scotty's analysis. A paper is being prepared by the Dunham' on this
event and analysis. The next Venus occultations are in 2019, 2022 and 2028.
- 6:20P Meeting adjourned and attendees went to dinner at a local
restaurant-
9:00
AM Sunday – Technical sessions continue
Dave
Herald talked about determining
asteroid diameters and the role of occultations.
A recent New York Times article appeared a few months ago in which the
author claimed asteroid diameters were significantly off due to inferior
mathematical/statistical methods. Asteroid diameters are found from visiting
satellites, radar imaging, direct imaging (adaptive optics) and occultations.
The occultation methods are relatively accurate (1km or better) however
it is only a line of sight size/shape at the time of the event. And asteroids are irregular
in shape - they are not all perfect basketballs. An issue is defining what the
mean diameter is of an asteroid.
227 +/- 4km (equivalent surface area)
Europe 61 events (50 sites
"
)
Japan 25 events (17 sites
"
)
Dave
Herald next
talked about his record
breaking graze from November 17, 2015. Previously the maximum number of events
observed was in the low 20's. And many of these observations had issues of
spurious events, so the real number is probably closer to 15 events.
With the LOR/LOLA lunar
profile data, Occult can now predict the ideal locations to maximum the # of
events an observer can observe/record. Using
Occults graze prediction, he set up 4.7 km away from the nominal graze path.
https://www.youtube.com/watch?v=ucAP5FAx9uA
Dr.
Joan Dunham (co-authors Steve Conard, Steve Preston, Russ McCormick)
presented Occultation Observations with the IOTA Video Recorder. IOTA
VideoCapture 1.0 software was written by Russ McCormick. IOTA VideoCapture allows
recording directly on laptops, thus its a computer based recording system. The
Dunham's observed 107 Camila with this system. Joan listed the components needed
for this setup, (see the 2016 presentation page for the Power Point talk for the list), the most expensive component was $99. The total cost for 2 systems
came to $560. Steve Conard
was able to purchase the system using ebay and Amazon for a reduced total cost
of $115. A drawback of the IOTA
VideoRecorder is that it's a Window based system, currently there is no
Apple/Mac version. Joan mentioned a few of the lessons learned with the system,
a few are : minimizing the number of
external communications, keep the system awake (no sleep mode) and limit the #
of USB ports used during an observation to avoid dropped frames.
David
Dunham summaries of occultations by
216 Kleopatra. It has a large 1.4 mag light curve amplitude. He showed results
and profiles of several occultations:
August
10, 2003 - all visual observations from
David showed a chart of all
he eclipses he analyzed (1715-2006) from a NASA grant. All relative diameter
changes were made with respect to the 959.63" standard value at 1 A.U.
The Feb 26,1998 eclipse over
Curacao/Aruba had estimated radius correction of 0.04" to 0.22". This
eclipse had 2 video recordings at both north and south limits. Video observers
were Dunham, Dr. Patricia Rozenweig,
Dr. Wayne
Warren and Richard Nugent.
Another method to determine
the instant of totality start/end is to record the flash spectrum as previously done by the
Japanese. David suggested comparing the absorption vs. emission lines to
effectuate this method. He
summarized the remaining work needed including re-analyzing the
Just 2
days after the eclipse
is a rank 78 asteroid occultation of a m =
+9.1 star path from