The International Occultation Timing Association's 35th Annual Meeting

Western Nevada College/Jack Davis Observatory

Carson City , Nevada, September 9-10, 2017

 

                                                                      

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Dr. Marc Buie and Red Sumner

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Ted Blank

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Walt Morgan - David Laird award recipient 

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  Brad Timerson - Homer Daboll award recipient

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Eric Frappa - Homer Daboll award recipient

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John Talbot - Homer Daboll award recipient

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Steve Kerr - Homer Daboll award recipient

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Tsutomu Hayamizu - Homer Daboll award recipient

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Meeting attendees

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The minutes of IOTA's annual meetings are at:

http://www.poyntsource.com/Richard/IOTA_Annual_Meetings.htm

The 35th annual meeting of the International Occultation Timing Association was held Saturday and Sunday September 9-10, 2017 at the Western Nevada College’s Jack Davis Observatory. The meeting was kindly hosted by Observatory director Dr. Tom Herring. This location coincided with 2 asteroid events, 357 Ninina 10 Sep 2017 and 241 Germania 12 Sep 2017 both paths across northern Nevada.

The final meeting schedule, links to presentation files and You Tube videos of the talks are located on the IOTA web site presentation page:

                      http://occultations.org/community/meetingsconferences/na/na2017/

Persons participating in the meeting on site and via internet conference:

On site attendees: President Steve Preston, Vice President Dr. Roger Venable, Executive Secretary Richard Nugent, Aart Olsen, Ted Blank, Dr. Ted Swift, Eleanor Swift, John Moore, Walt Morgan , Jerry Bardecker, Derek Breit, Dr. Rick Nolthenius, Dr. Marc Buie, Red Sumner, Bill Hanna. Observatory Director Dr. Tom Herring, Chris and Loreli Patrick, Danny Falla.

Internet Conference Attendees:  Gerhard Dangl, Brad Timerson, Secretary Treasurer Chad Ellington, Drs. David and Joan Dunham, Tony George, Atila Poro, Steve Messner, Bob Dunford, David Herald, Ernie Iverson, Oliver Kloes, Bob Sandy, Chris Erickson, Barton Billard, Darrel Irwin, Esdert Edens, Bruce Krobusek, Art Lucas, John Newman, Lloyd Franklin, Mark Smith, Walt Robinson. 

NOTE: If you were an online attendee and your name isn't here contact  RNugent@wt.net to be included.

9:00AM – Meeting start

Vice President Dr. Roger Venable opened the meeting and welcomed everyone to the meeting. The onsite attendees introduced themselves and described their backgrounds and current research.

Business meeting:

Treasurer Chad Ellington presented IOTA’s membership status. Currently there are 18 USA print subscribers plus 1 outside USA, 48 online subscribers, total subscribers is 67 this represents a net decrease of 37 members since last year. Except for the small member increase in 2016, membership trend has decreased in the past 10 years. The IOTA list sever has over 600 members.

This low no. of paid members 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:                   $10,416.06   2016 Jul 21 (Includes funds donated for a special asteroid satellite award)

          Ending Balance                     $10,496.81  2017 Sep 7

          Net Increase in Balance:        $80.75 

 The breakdown of this past year’s budget is:

          IOTA-VTI Royalties:         $392 (down $104 from last year)

          PayPal Balance:                  $2,764.04 Up 1,049.28 from last year but layout/printing costs have not been paid for several issues  

          Expenses:

                   -JOA  print cost     consistent from last year                                        

                   -Web Service:        still donated

                   -Awards:               paid for last meeting

The JOA it is getting further behind on schedule now 2 issues behind from 2015, 1 issue for 2016 and currently 1 behind in 2017. More articles are needed. The new password access for downloading the JOA  is working, however many folks have trouble remembering passwords.

Walt Morgan  presented the IOTA-VTI status report. IOTA receives a royalty for every unit sold. It was originally designed by Dave Gaul and Tony Barry. Walt was the proprietor, with the late Sandy Bumgarner the engineer. Last year (July 2017) Walt transferred the operation to the new licensee Bob Aubuger in Owings Mills, Maryland. The website name is unchanged and Auburger's website name is now on very unit sold. 

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-$292 (depends if you want an external antenna/serial dongle)+ shipping

Can be purchased at http://www.videotimers.com

Walt mentioned that the Li-ion battery in the unit has a useful life of about 3 years. Users are encouraged to check the bottom of the start up screen for battery warning message. If the battery fails, the units memory/ almanac will be lost. Walt then showed a few error notification screens. The total IOTA-VTI sales through June 2017 was 484 units. Most all of the units have been bought by IOTA and "occultationists", including Marc Buie's RECON team. Total royalties paid to IOTA through June 2017 $3,535. Rick Nolthenius asked how long the unit updates following a leap second. Walt said it’s done almost immediately. The best advice for using the IOTA-VTI is to run it for 15 minutes to clear all potential errors and update the almanac.    

Dr. Joan Dunham (talk given by Ted Blank) presented some of the posters IOTA uses at the NEAF meeting and other venues. Several posters on boards designed by Ted were shown. Since boards are difficult to transport, Joan and David designed high quality material posters that could be rolled up and easily transported. These posters are used at NEAF, Alcon, St. Louis Eclipse Expo and the American Astronomical Society (AAS) eclipse meeting. Shortly the posters will be available for download for individual use at other venues.

Dr. Terry Redding (talk given by Steve Preston) presented the annual Homer F. DaBoll award and David E. Laird awards. The Homer F. DaBoll (1920-1990) 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 Midwest USA in the early 1960’s. Laird confirmed the existence of a giant impact on the Lunar far side. Unfortunately Laird suffered from Leukemia and died in 1968 at age 37. The Laird award was conceived to help “catch up” on awards to some older IOTA members.

Previous Homer F. Daboll awardees: 2007: Dave Herald ( Australia ), 2008: Edwin Goffin (Europe), 2009: Steve Preston (USA), 2010: Hristo Pavlov (Australia), 2011: Scotty Degenhardt (USA), 2012: Kazuhisa Miyashita (Japan), 2013: Graham L. Blow (New Zealand), 2014: Brian Loader (New Zealand), 2015: Gerhard Dangl (Austria), 2016: Derek Breit (USA).

Previous David E. Laird awardees: 2013: Hal Povenmire (Florida), 2014: Gordon Taylor (England), 2015: Bob Sandy (Missouri), Jean Meeus (Belgium).

This year nominations were received for both the Daboll award and the Laird award. The Committee’s main objective in selecting an award recipient was to reach a consensus and not choosing someone by a majority vote. Eligibility for the award is for anyone who has made significant contribution to occultation science or for the work of IOTA and its goals. Persons not eligible are current IOTA Officers & the award committee. Candidates nominated are not required to have IOTA membership.

This year’s Award Committee elected to give multiple Daboll awards to the IOTA regional coordinators in the USA, Europe, Japan, and Australia/New Zealand that maintain the IOTA regional asteroid websites. These dedicated people have worked tirelessly in maintaining the occultation sites in their region over many years. They are given recognition as the asteroidal occultation program would collapse without their involvement and hard work.

The recipients of the 2017 Daboll awards are:

Brad Timerson – USA, Eric Frappa – Europe, Tsutomu Hayamizu – Japan, John Talbot and Steve Kerr  – Australia/ New Zealand.

The 2017 David E. Laird went to Walter Morgan, for his for his over 60 Years of Active occultation work, leading, lunar graze expeditions, technical development for occultations and manufacturing the IOTA-VTI. Walt described his history with IOTA since the 1968 when he made is first occultation observation. He later became a "computor" making predictions for observers over 6 regions. Back in the early days Walt had to mail the predictions via the US Post Office and this typically cost $60 in postage per quarter!! Walt's dedicated work with occultation science over many decades was held in the highest regard by the IOTA community.

 10:00am... End of Business meeting. Technical Sessions begin.

Dr. Marc Buie  of the South West Research Institute (SWRI)  talked about 3 recent TNO occultations:

MU20170603 - 2017 June 3, 12 systems deployed to Argentina near Mendoza and 13 systems deployed to South Africa near Cape Town,

MU20170710 - July 10, 2017 a faint m=+15.6  star across the Pacific (not attempted on the ground but done by SOFIA )

MU20170717 - July 17, 2017 across South America , m= +12.6 star. 25 systems deployed in Argentina near Comodoro Rivadavia.

Marc showed the ground track uncertainties computed by Hubble's observations and data from the recently released Gaia catalog. This resulted in ground path uncertainties ranging from 0.25 - 1.5 mas, where 1 mas ~ corresponds to 34 km on the ground.

For the June 3rd event, 22 portable 40-cm telescopes were deployed with CMOS detectors and GPS timestamps. 3 systems were deployed by UVa. The maximum occultation was 2sec and all observers got usable data. Preliminary analysis showed no diffuse material in the neighborhood of the object.   

For the July 10th event observed by SOFIA, the goals were to search for diffuse or ring material +/- 30,000  km for stability region with a 45 minutes recording time window. The goal was to detect a solid body which meant being in a 1-2km zone. Preliminary results were 1) No diffuse material or rings seen, 2) no obvious solid body signature.        

For the July 17th event detecting a solid body was a top priority. Marc set up the stations over a 4.5σ range. Telescopes were spaced out 4.5km from each other. Five chords were obtained with the longest duration = 1 sec, shortest 0.3 sec. The preliminary shape profile looked like this:  

                                               

                                        Preliminary shape profile of MU20170717. Blue dots represent the positive chords.

The shape interpretation could be:

-Single object 34x20 km irregular shape

-Contact Binary 34x19km

-Close Binary 20km and 16km sizes respectively.

The shape profile estimates above are line of sight profiles only at the time of the event. The next major event is the occultation of MU20180814 by 2014MU69 SBP-170825 over South America and northern Africa. Planning is underway.

Marc next talked about the RECON (Research and Education Collaborative Occultation Network) team which was set up in 2013 to measure TNO objects > 100km. RECON covers the western USA with ~50 telescope systems setup over a 2,000 km north-south "fence" from Canada to San Diego. Each system consists of a Celestron C-11 SCT, a Mallincam video camera, IOTA-VTI and a laptop computer. RECON telescope systems are setup at schools and community colleges. Students (grades 4-12) setup the telescopes and make the measurements guided by adult team members. Typically 6-8 occultation observations are made each year. The first TNO occultation result, (229762) 2007 UK had a measured radius of 340 ± 10km was published in the Astronomical Journal (AJ) in 2015. Marc has periodic video conferencing for annual team meetings. RECON (www.tnorecon.net) has an email listsever, plus it's on Twitter @tno_recon and Facebook: TNORECON. Recon predictions are on the SWRI website:

http://www.boulder.swri.edu/~buie/recon/reconlist.html   

RECON Team members - in larger communities, there are always plenty of replacements when someone leaves, however this is not usually the case in smaller communities. When new people take over, re-training has to be done again. 

Tony George presented the R-OTE Volunteer Group. Members are Tony George (Coordinator), Ted Blank, Darrel Irwin, Ernie Iverson, Greg Lyzenga, Chris Patrick, Ted Swift and Brad Timerson. The group goal is to support IOTA North America observer's observation reports of occultations using the R-OTE and PYOTE light curve analysis programs. Volunteers review observer csv files and reports and generate updated D and R times and error bars using R-OTE and PYOTE.

Tony next introduced a new light curve analysis program, PYOTE, Python Occultation Timing Extractor written by Bob Anderson. It's a stand alone program for analysis of occultation light curves. It can be installed in any operating system that supports PYTHON code. It uses the same mathematical algorithms as R-OTE and it has been tested for both Mac and Windows operating systems. PYOTE has a maximum likelihood estimator to determine the best fit model light curves to the actual data. Sub-frame timing is included in the calculation of D and R times. A PDF file to guide users through the installation of the program (available on Brad Timerson's website):

MAC

http://www.asteroidoccultation.com/observations/NA/pyote-mac-revised-installation.pdf

Windows

http://www.asteroidoccultation.com/observations/NA/pyote-windows-revised-installation.pdf

PYOTE supports both Tangra and Limovie csv files. A nice feature is the "Start Over" button which allows bringing up all analysis scenarios the user has tried for comparison......which are recorded. Also, a new excel program AstReport will account for camera delay corrections.

Tony next did a demonstration of how PYOTE works. The program is quite simple to use and stores the analysis, error bars, and D/R times for use in the report form. PYOTE is a work in progress and Bob Anderson will provide future developments. Future developments will include the uploading of light curve to the IOTA/VisieR database. 

Aart Olsen presented "Timing in the Optical Domain". Aart's goal was to insert the time of the event right into the same image as the object being recorded. This method could work with any camera, including video cameras. The goals he set for this research: time displayed in every field, DIY capable and cheap enough to assemble for multiple deployments. The system is based on a Arduino microcontroller board. Cost is approximately $35 USD. Aart showed photos of the various components he uses. 

A few demo frames showed the optical times right on the image. Aart needed to utilize a pattern of LED lights to get sub-second timing to match the GPS inserted time precisely. Another feature of the system is that one can interpolate between frames to extract times.

 12:30-1:55 PM -  Lunch break

Ted Blank presented how to use portable GPS units to determine the centerline of the field for occultation events. Finding your position from the center line for your assigned chord is not necessarily easy without the Google internet maps. It turns out older (and newer) GPS units have an "Off Course" feature which was originally designed for use by ships at sea to tell them how far "off course" they were in their voyages. Ted showed how to get path coordinates from Occult or Steve Preston's prediction site and create a route file to be sent to your GPS device. The GPS units then display the centerline and output the "off course" perpendicular distance feature from the center line. On older GPS units, one can manually enter at least 2 lat/long waypoints to create a “center line track” of which the off course distance is computed and displayed.  

Ted next presented his portable "stick-computer" occultation recording kit designed for the new RunCam cameras to be used for his multiple deployments. The "stick" computer system was originally researched by Joan Dunham in 2016. The computer that records the video is the Lenovo Ideacentre Stick 300, which has no monitor. It uses Windows 10, 2 GB RAM, has a 32GB internal drive, and is powered by just 5v (not 12v). One of the reasons for using this 5v powered computer is that the RunCam Eagle camera also uses 5v and thus can be tied to the same power source. Ted showed images of the components connected. The only issue is focusing of the camera since the Leonova has no monitor. Ted uses a 7" LCD monitor (any monitor can be used) to check the camera's focus and then reconnects the camera back into the system.  

Dr. David Dunham  presented John Broughton's updated portable telescope design.  John's old design was a 10" "suitcase" telescope. David showed pictures of the new 2016 design:

                                            

                                             

Note the video camera at the position where a secondary mirror would normally go. This provides a faster f ratio. One of the nice features is the altitude/azimuth adjustment system. The total weight 43.8 lbs, is within airline limits for air travel. A few minor changes were made for the 2017 design. The 2017 design is quite steady and compact. David offered some thoughts on manufacturing options. Perhaps with 100 pre-orders, a telescope manufacturer could offer a commercial design. The telescope also works as a general purpose visual telescope. 

Offline Roger Venable worked with the attendees to assign sites for the 357 Ninina asteroid event later in the evening. Roger had previously checked out over a dozen sites to aid in the planning. 

David Dunham next presented the occultation of Regulus by 268 Adorea 2016 October 13. He and Joan observed the event from the northern New Ireland of Papua New Guinea where they recorded the event with a 10-inch suitcase telescope. With this setup they were able record Regulus's faint companion. Earlier on 2015 May 24, Paul Maley had made an expedition in Saudi Arabia to observe the Regulus occultation by 1669 Dagmar obtaining 1 chord. David and Joan Dunham along with Wira Hadiputrawan attempted this Dagmar event from separate locations in southeast Sumatra with only a 4-deg altitude of Regulus. David and Joan were clouded out. At Wira's location, Tony George was able to follow the star (faint in the haze) to determine times that could be used with Paul Maley's timings to approximate the shape of Dagmar.  David described a few other Regulus events observed since 2005 including the totally clouded out event from March 2014 over New York and the Northeastern US States.

Brad Timerson   presented a summary of 2016-2017  (through 8/31/2017) asteroid occultations.  Brad showed a graph of yearly observations going back to 2006. There seems to be a trend this year (2017) of events with 3,4 and 5 or more chords which is a good thing. Individual events were shown with the 3-D models and as expected occultation chords fit very well with these models.

One event was 113 Amalthea on March 14, 2017 with the possible discovery of an asteroidal satellite companion. An announcement was made on the Central Bureau for Astronomical Telegrams (CBAT 4413). Two observers Eisfeldt and Campbell made positive events outside the region of the other 5 positive chords indicating a possible asteroidal companion. IOTA North America offers an asteroid satellite discovery award, upon confirmation of the observation by independent means.    

Dave Herald presented Global asteroid occultation results 2015-2017. IOTA is now averaging 250 events/year, however 2016 had 280 events, likely due to the Gaia catalog release.

The No. of events by region for 2016 is:

Australasia         53

  Europe              91

USA               107

Japan                 27

Other                   7

Late additions    15

Total                300

Double stars - 4 discovered in 2016, separations ranging from 10mas - 211mas. One double star, 2U31329020, (from the occultation by 695 Bella on 2016 Mar 19) had a separation of 10mas and PA = 57.0° which is below the resolution of Gaia.

He then showed 17 profile plots, many compared to 3D shape models. Most, not all profile plots had excellent matches with the 3D shape models.

Dave next presented "Volumes and Bulk Densities of 40 asteroids from ADAM shape modeling" as published in a paper in Astronomy and Astrophysics 2016 Oct 25.  One question, why diameters are important? They're needed for occultation path limit predictions and spacing of observers. Densities can tell us much about composition and their origin. Densities come from mass and volume of the asteroid and thus occultation data helps out greatly with their sizes. 

Masses are estimated from orbit deflections/pertubations and for contact binary systems by their orbital dynamics. Volumes of asteroids can come from size estimates from the chords from (hopefully) several occultations. He then discussed how complex the volume and mean diameter estimates can be to derive. Asteroid shapes can come from space craft imaging, direct imaging with large telescopes (poor resolution though), radar imaging (mainly NEO's), multiple occultations, and light curve inversions.  Light curve inversions can only be possible when there is a significant variation in its inclination of its axis of rotation as seen from Earth. The method is quite complicated but does provide a volume-equivalent and surface diameters of the model.

He then described some of the limitations with light curve inversions. As an example, he showed volume, surface equivalent of 135 Hertha from 2008 compared to IRAS and Wise satellites plus the Asteroid catalogue using AKARI - (AcuA). Dave stressed the importance of such comparisons and that they should be done from multiple occultation observations. On average IRAS is the best at determining these parameters but in reality they are all equally reliable to within ±8% as compared to occultation and shape model.  

Sunday 9AM...Meeting continues

Aniruddha Deshpande presented (with co-investigators Suhas Gurjar,  Deepak Joshee, Sameer Godbole) from India presented "Occultation Activities in Jyotirvidya Parisanstha , India " (JVP). Their goal for occultation observations was to put together 10 sets of instruments and train observers for occultation observations for the 22 Kalliope event 24/25 Dec 2016.  Paul Maley assisted with 8 video setups, pointing techniques and analysis of the data obtained. The path went over western and southern India . The team JVP had 16 stations planned out to observe the event and 8 stations had video. He then showed slides of several instrument setups. He showed the resultant profile which included 8 hits and 3 misses. Their shape profile matched well with the 3D shape profile. Their successful observation made the local newspapers in the area:  

                                             

Atilo Poro and Zeinab Lesani  presented a new mobile application of timing via a pre-recorded video. Unfortunately the audio was not discernable form the video. They began by describing the current timing methods and their problems. The goal was to have a timing method that was accurate, standalone, eliminated the problems of manual methods, was temperature independent and freed the observer's hand for other duties and the observer could add comments instantly.  The time base for the method was the GPS ABC unit made by Dave Gault from Australia. Several screenshots were shown to demonstrate how the timing method works. The method works on a computer and has options for storing start/stop times, and sending a report form with the times. Dave Gault assisted them with the development of this system.

Dr. David Dunham  next presented the results of two recent grazes of Aldebaran. One graze was 29 Jul 2016 during the 2016 IOTA meeting near Stillwater, OK. On 2017 Jul 29 a graze path in the USA went from El Paso, TX to the Great Lakes. For this graze David and Joan Dunham drove to Childress, TX.  He set up 7 stations on sites predicted by Ernie Iverson. He showed the resultant limb profile with his observations. Next he showed the  2017 Feb 18  m=+3.9 gamma Librae graze and one of the light curve recordings. This graze was chosen due to the fact that the lunar profile would offer many D and R events. The observations (4 unattended stations and 2 attended stations) matched very well with the lunar limb profile:

 

                        

 Observations and limb profile of Gamma Librae graze Feb 18, 2017 by Joan and David Dunham, during last quarter Moon. Vertical scale is 30X exaggerated relative to the horizontal scale.

The next Aldebaran graze was March 4, 2017 with the path going across the northern USA. This was the best graze in the current series as the next series will be in 15 years.  He had successful recordings at 3 stations. Being the coldest night of the year, the other stations failed. Another team led by Andreas Gada set up 10 stations and 5 video systems. Their spectacular combined synchronized video is here:

                     https://vimeo.com/209854850   

                 

Dr. Roger Venable  went over the 357 Ninina event from the previous night. There were 6 preliminary positives and a one unsure event from Nugent which was later confirmed as a positive event.

David Dunham next presented preliminary results from the Aug 21, 2017 total solar eclipse. This eclipse was the most recent in the series of  IOTA's continuing study on measuring possible solar radius observations. One issue is that an accurate disappearance of a Baily's bead is not as easy as it looks. With LRO lunar profile data, central path timings are useful in addition to edge observations. With the widespread advertising of this eclipse, the Citizen Science Edge Determination project was started but not enough observers were interested as compared to the Jan 1925 eclipse that went over New York City. At the St. Louis Eclipse Expo on June 17, 2017, Aart Olsen had a booth to help recruit observers.

A method used in the past to estimate the moment of totality start/end is the flash spectrum technique. This technique shows the spectrum of the corona when totality starts/ends. It has been used by Japanese observers in the past with limited success. David next showed observers who made observations at the northern and southern limits and described a few of the equipment setups, some of their sky conditions and results. A few timed observations were made at the center of the path by Ernie Iverson in Nebraska, Eberhard Bredner, Chris Anderson in eastern Idaho, Carles Schnabel at Nampa, Idaho and Derek Breit in Oregon. Derek was able to get time inserted timings of 2nd contact but had cloud problems for 3rd contact. David showed 6 eclipses that  occur through 2024 including an annular (Oct 14, 2023) and total eclipse (Apr 8, 2024) whose paths cross the continental USA intersecting near Austin, Texas.

Bill Hanna and Roger Venable then described their Aug 21, 2017 eclipse experience and equipment issues. 

David Dunham next presented "Upcoming Grazing Occultations":  

Regulus 2017 Oct 15,  Oregon to Quebec. Low altitude in Oregon, Idaho (11deg), David showed some Google maps of some of the areas. This northern limit graze will be spectacular in Minnesota with Regulus on the dark side of the 20% sunlit Moon. David plans to organize an expedition to Bemidji, Minnesota where the Moons altitude will be 22.5 deg.       

Aldebaran, 2017 Dec 30, across central Florida, the Moon will be 93% sunlit

Aldebaran, 2018 Jul 10, 11% sunlit Moon, near twilight

David showed a page of other North America grazes from the Observer's Handbook for 2018 published by the Royal Astronomical Society of Canada. David then showed a high resolution video of the Baily's beads from the Aug 21 eclipse near one of the limits showing the mesosphere.     

Steve Preston presented the best North America asteroid events remaining for 2017.

Roger Venable then went over site assignments for the 241 Germania event.    

 12:15 - 1:35PM  - Lunch break

Tony George presented the discovery of a double star  from the occultation by 834 Burnhamia of  the m = +9.2 star TYC 5780-308-1 from by observers Ted Blank, John Moore, Paul Maley and Steve Messner.  The event occurred on 2017 Aug 23 and each observer had double dips in the light curves.

                                  

The separation came to  0.0143″ ± 0.0004  and PA = 73.8° ± 2.6°. The results will be submitted to the Journal of Double Star Observations (JDSO).

Tony then spoke about the RunCam Night Eagle Astro Edition camera. Its a low cost (under $100), high sensitivity camera for observers. Its horizontal resolution is 800 TVL lines, min lux of 0.00005 lux, small, lightweight, 14.5gm and power requirements 5-17 v.   The camera also has three built in integration times. Tony has extensively analyzed the camera and had earlier in the year had uploaded his test reports.  The camera has on-screen-display (OSD) for adjusting settings such as NTSC/PAL, integration times, shutter speed, image enhance, gain, mirror image, brightness and zoom. Tony has reached (with integration) stars to m = +14.2 using his 12" SCT with no hot pixels! He then showed slides of the various settings and how to use them to maximize the quality/contrast of the videos. The RunCam camera also has a FOV just about 1 arc minute smaller than the Watec 902 camera series, as the chip size is slightly smaller than the Watec chips.

The camera had a slight problem with light leaks, and Tony showed how to fix them by opening the back of the unit (by adding a piece of foam around the boards) or sealing the edges with tape. The RunCam camera is no longer on the company website however they will sell to IOTA (through Ted Blank) in bulk orders of 10 cameras. Ted put together a package consisting of the camera, adapters and a focal reducer for $185USD (meeting price $170USD). Persons wanting to own this camera should get with Ted Blank. Several papers on the RunCam Night Eagle's performance and features for occultation use are given below:

ArtStar test results for:  RunCam Owl Plus, by Bob Anderson September 22 2016, IOTAoccultations:

https://groups.yahoo.com/neo/groups/IOTAoccultations/files/Light-curve-analysis-papers/RunCamOwlPlus-report.pdf

Test report: RunCam Night Eagle Astro (prototype) by Bob Anderson, 20 April 2017:

http://occultations.org/documents/RunCam-Night-Eagle-Astro-test-report.pdf

Testing RunCam Night Eagle by Tony George, December 2016, The RunCam Night Eagle CCD Video Camera is tested against three other cameras:  WAT910HX, PC164C-EX2, and RunCam OWL Plus:

http://www.occultations.org/documents/NightEagle-Comparison.pdf

Steve Conard  next presented his talk about the QHY174M-GPS camera. Steve and Bruce Holenstein bought them when they came out earlier this year and even with limited testing, SWRI chose to use them for the MU69 event this past summer. Steve showed a comparison of the camera to the Watec 910-HX camera. The QHY has smaller pixels, larger chip size (and thus larger FOV) and outputs via USB3.  Regarding cost, the QHY setup cost about $360USD  more than the Watec 910-HX but it does have GPS timing built in.  Steve mentioned that due to the large chip size the only focal reducer that comes close to fitting is the Antares 0.5x from ScopeStuff for $52USD.  

Steve next talked about the Triton occultation on 2017 Oct 5. Details star magnitude m = +12.4, Triton m = +13.5, the separation from Neptune is 11.4" with a max duration 161sec. SWRI is making an effort to observe from the centerline in northern Florida being led by Eliot Young. MIT has a very organized effort: https://hubble.mit.edu/.  They currently list 8 fixed observatories in the US. Per the IOTA agreement with Bruno Sicardy, we (IOTA) are obligated to share our data with his group.

SWRI plans to have 24” and 20” portable telescopes on the centerline with one visible and one SWRI camera. (2) UVa C-14’s with Hyperstars, 3 fixed observatories in mid-Atlantic/New England. Additionally, they will send ~6 Skywatcher 16” telescope systems to the area around the centerline.

Dave Herald next spoke about Gaia's impact on asteroid occultations. A number to remember is that 1 mas (0.001") uncertainty for main belt asteroids corresponds to about 2km on the Earth's surface. In the pre-Gaia era, typical star position uncertainties wewre 50 mas, and for asteroids 150 mas. Gaia's sensitivity is down to m = +20 and the detectors are saturates at m = +12,  however they can measure down to m = +3, its hoped they can measure the 243 stars brighter than m = +3.

Gaia will provide the following:

         μ-arcsec (0.000001")positions, proper motions & parallaxes down to m =+20 (~1 billion stars) – meaning distances to the center of the galaxy can be achieved to ±10%. precision 

         Radial velocities and spectral types – stars down to m ≈+16 (~150 million stars), Gaia has a spectroscope

         Element abundances for stars brighter than m = +11

         Positions and orbits of asteroids and TNOs, to m =+20

For variable stars:

         5,000,000  ‘classic’ Cepheids

         3,000,000  eclipsing binaries, with precise physical and orbital parameters for 10,000

         300,000  with rotationally induced variability

         250,000  Miras and SR variables

         60,000 - 240,000  δ Scuti variables.

         70,000  RR Lyrae

         20,000  supernovae

AAVSO Index catalogue has a mere 342,000 entries

 

For double stars, expected results:

         700,000  radial velocity orbits

         800,000  radial velocity + astrometry orbits

         2,000,000  astrometry orbits

         4,000,000  non-linear-proper-motion systems

         40,000,000  resolved binaries

         Resolve all binaries with separations >20mas which have a moderate magnitude difference.

The current Washington Double Star catalogue has 135,000 pairs. USNO 6th Interferometric catalogue: 83,000 pairs  

Gaia data will be used to combine proper motion data from previous catalogues:

         Gaia14 – Tycho-Gaia, plus all Gaia stars to mag 14.0, with proper motions derived using UCAC4 mean epoch positions

         HSOY -  Hot Stuff for One Year ( Univ. of Heidelberg ) - Proper motions derived from PPMXL positions

         UCAC5 – Proper motions derived from a re-reduction of UCAC images using Tycho-Gaia to derive early epoch positions

For asteroids in the May 2018 release, 100,000 asteroid positions (not orbits) are expected. Dave said that (obviously) asteroid positions are fully dependant of Gaia's spacecraft position in its orbit in the solar system. Dedicated telescopes are being used to image Gaia against the stellar background to get its accurate position. 

Gaia's final release is planned for 2022. The astronomical community will enjoy a full set of astrometric, photometric, and radial-velocity catalogues. All available variable-star and non-single-star solutions will have been completed. Multiple astrophysical parameters (derived from BP/RP, RVS, and astrometry) for stars, unresolved binaries, galaxies, and quasars will be included. In addition, there will be: 

 

• An exo-planet list.

• All epoch and transit data for all sources.

• All ground-based observations made for data-processing purposes.

With high accuracy asteroid occultation predictions, he suggested we identify and give preference to observations of binary asteroids, asteroids with shape models, asteroids having some other characteristic of importance. (eg. member of certain classes of asteroids – whether that be based on composition, orbit type, or some other consideration) and events with smaller, fainter asteroids can be predicted more often.

Dave Herald presented screen shots on how to report light curves with Occult. Dave has uploaded over 3,000 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, thus they should be retained. Light curves can show the presence of a double star either by discovering or confirming them. A new feature of Occult is the ability to view existing light curves, if they exist for a particular event. Occult now has the feature to get light curves from Limovie. Tangra has this capability to transfer light curves to Occult. Light curves can also be viewed in Occult. Occult will remind you in 30 days if you've not uploaded your light curves.

Light curves are available for viewing/download on VisieR under B/occ. After the talk ended, Dave answered a few questions from online attendees.

 The meeting ended at 4:30 PM.

      

 

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.