With Red Sumner, Patty Bean, and Carson High Students. Unfortunately we had a miss.

Just wanted to wish everyone in RECON a happy Spring Equinox, which occurs at 9:30PM PDT tonight (20 March @ 4:30 UT)!

We also wanted to take this moment thank the RECON network for a great year.  Our Southern RECON teams met in Kingman, Arizona, one year ago today!

RECON Southern Training Workshop, March 19-22, 2015

While entering RECON site coordinates into my IOTA (Occult4) site database I noticed several little known (to me) facts. I thought I would share these with the rest of the RECON community:

1.  Chiloquin, OR is the westernmost site at Longitude 121 degrees 52 minutes West
2.  Kingman/Dolan Springs, AZ is the easternmost site at Longitude 114 degrees 08 minutes West
3.  Oroville, WA is the northernmost site at Latitude 48 degrees 56 minutes
4.  Yuma, AZ is the southernmost site at Latitude 32 degrees 42 minutes
5.  Lee Vining, CA is the highest site at elevation 2060 meters (6759 feet)
6.  Calipatria, CA is the lowest site at elevation -56 meters (-184 feet)

The RECON team network is a very widely spaced community of observation sites, spanning:

1. an elevation difference of 2116 meters (6943 feet)
2. a latitude difference of 16 degrees 14 minutes (or approximately 1118 miles [4/100th the distance around the Earth])
3. a longitude difference of 7 degrees 44 minutes

Way to go RECON!

Snatching a positive from the jaws of a negative.

Many occultation observations never make it to the analysis stage, as it is clear that the observation is either a negative (miss) or impossible to analyze due to outside effects such as clouds or technical problems.  However, when there are difficulties it often pays to perform an analysis anyway, to make sure that something is not present in the video.  The (268) Adorea observation by Chris Patrick is a perfect example.

(268) Adorea was advertized to the IOTA and RECON observers in Arizona, Nevada, and California.  Three observers were able to observe the event and report results.  The path map is shown here:

Chris Patrick near Kingman, AZ was the only person to get a positive video observation.  Initially, he was not sure if there was anything on the video, due to the thin clouds that obscured the observation.  Never-the-less, he submitted the video for analysis.

Tony George was able to review the video using both Limovie and R-OTE.  Limovie produced a light curve as shown below:

The blue light curve is the target star.  The yellow light curve is a very nearby, slightly brighter, secondary star.  Thin clouds obscured the occultation, causing both light curves to drop over the course of the observation.  The blue light curve looks like ‘maybe’ there is an occultation, but it is hard to tell.

Because the secondary star was not occulted, it can be used as a ‘reference’ star by which the brightness of the target star an be normalized.  The only variation of the brightness of the secondary star is due to dimming caused by passing clouds.  If this dimming is normalized out of the target star light curve we can see if there was an occultation.

R-OTE was used to normalize the target star light curve.  The resulting light curve is shown here:

Now, there is a clear occultation event.  Analysis showed the event to be nearly 8.9 seconds long, even longer than the maximum duration predicted for the event.  This event, coupled with the two other chords — one positive and one miss — resulted in an estimate of the size and shape of Adorea as follows:

The key to the above result is the hard won observation obtained by Chris Patrick of the RECON team.  Congratulations to Chris for this great observation.

There are many more good events occurring with paths crossing RECON teams in the month of March.  Good luck to all who try these events.

Our first RECON manuscript has been published in The Astronomical Journal and featured in AAS Nova.

The paper describes the design and development of the RECON Project and will serve as an important technical reference for future results papers.

Thank you again to all of our RECON students, teachers, and community members for your continued contributions to this citizen science research effort!!!

Below are details for an optional RECON Main Belt Asteroid this Thursday evening.  Team members in Parker, Havasu, Mohave Valley, Bullhead/Laughlin, Kingman, and Searchlight are well situated for this event.  Feel free to sign up on OccultWatcher and/or let us know if you plan to observe.  Again, this is an optional event, but great practice and a targeted opportunity for the above teams to get a positive occultation measurement and create object profile!

Starcharts and Sense-Up

Date: 2016 March 4 UT
Recording Window: 05:27:00 – 05:28:00 UT
RA: 04:41:43 (of date)
DEC: 20:54:20 (of date)
Sense-Up: x4

Below is a starchart for the event:

Star chart for Adorea

This was the last event for February posted by Tony George.  The event ocurred early evening on Feb 25 at around 7:38 PM (PST).  Predicted event time was 03:38:34 UT February 26th.  The target star (11.6 mag.) for the occultation was low in the west at 27 deg altitude and in the constellation Pisces.  The predicted maximum duration was 1.6 seconds at the predicted centerline.  On the Occult Watcher prediction map my location was just outside (2 km) on the south side of the shadow path in the 1 sigma zone.  I had previously contacted Red Sumner at the Jack C. Davis Observatory to see if he could possibly observe.  The observatory was only a few kilometers off the predicted centerline.  Although partly cloudy most of the afternoon, the clouds started to clear by early evening and there appeared to be a good chance for an observations.  Scope setup went quickly, but just before event time a small patch of cirrus moved over the field stars.  I set the camera integration to 8X and the VirtualDub timer program to record for 5 minutes centered around the predicted time. Then it was just to hope for the best.  Sure enough, the clouds cleared and almost exactly at the predicted time I observed a short ‘wink’ of the target star.  A follow-up analysis by LiMovie confirmed an approx. 1.7 second occultaion event.  Tony George was gracious enough to provide a formal R-OTE analysis as seen below.

The actual camera and VTI corrected duration was 1.670320 seconds.  This event turned out to be one that could have been observed by as many as three RECON sites (Gardnerville, Yerington, and perhaps Hawthorne).  It appears though that, as of this writing, I was the only positive observer.  A formal report was filed with the IOTA using the OW IOTA Reporting plug-in which uses a simple Excel spreadsheet format.

Reported IOTA occultation results for all of North America can be viewed at : http://www.asteroidoccultation.com/observations/Results/

This Blog is contains advance alerts for main belt asteroid events that may be of interest to select RECON teams where the path crosses their specific observing locations.  Teams in the Pacific Northwest will be pleased to see that the majority of the events are favorable to the Oregon and Washington Teams.

Alerts are Not Mandatory

These alerts are not part of the RECON campaign. I have permission to send out these alerts, but they are not mandatory. Should any individual or team in RECON chose to observe these events, it is entirely voluntary. Observing these events will contribute to understanding the main belt asteroids, but it will also provide opportunities for RECON teams to practice their skills and keep interest in observing occultations. Nothing inspires an occultation astronomer more than seeing a star on the video screen wink out as predicted and then suddenly reappear.

Format of Alerts

For events occurring in March, each alert is listed below. For each alert, the path map can be used by observing teams to decide if they should attempt to participate in the event. If your team is not near or within the path, then there is no need to respond to the alert.

For each alert, the following information is listed:

Asteroid (number) and name
Catalog number of star occulted
m = combined magnitude of star and asteroid occulted (this will help to establish the sense-up to use for each event)
altitude @ azimuth of the target star at occultation time
Universal Date and Time of event (may be a day later than calendar Date shown in each title listing)
maximum duration of event in seconds (if you see an event, it will likely be shorter than this)
predicted magnitude drop of event (values < 1 may be difficult to see ‘on-screen’ and may require post-video processing to be detected; values between 1-2 will be visible as a dimming on-screen but the star will not disappear; and values >3 will likely be easy to see as a total disappearance of the star)

Sense up recommendation range

A recommended observing time is provided for each alert.  Record video for two minutes before the recommended time and two minutes after the recommended time.  Dark and flat recordings are not required for these events.

A path map is shown for each alert.

Teams or individuals who plan to participate in the event should sign up for the event on OccultWatcher.  Also, you can send me an email directly at triastro@oregontrail.net and I can communicate directly with team members to provide guidance on camera settings, finder charts, recording times and where to post your videos. In special cases, if there is enough interest, I might post a specific blog highlighting a specific event.

Summary of March Main Belt Asteroid Occultation Events

(527)      Euryanthe occults TYC 0863-00353-1;       m= 11.9 (combined); 60° @ 233°; 03 Mar; 10:07:49 UT; 4 sec; drop: 2.9; 4x-16x

http://www.asteroidoccultation.com/2016_03/0303_527_36450.htm

(147)      Protogeneia occults TYC 1223-01956-1;   m= 10.3 (combined); 36° @ 265°; 04 Mar; 03:10:58 UT; 3 sec; drop: 4.4; 4x-8x

http://www.asteroidoccultation.com/2016_03/0304_147_36453.htm

(268)      Adorea occults TYC 1279-02052-1;             m= 10.8 (combined); 35° @ 273°; 04 Mar; 05:27:39 UT; 9 sec; drop: 3.3; 4x-8x

http://www.asteroidoccultation.com/2016_03/0304_268_36454.htm

(63)        Ausonia occults TYC 1873-00163-1;           m= 10.8 (combined); 49° @ 275°; 11 Mar; 05:01:56 UT; 7 sec; drop: 1.8

http://www.asteroidoccultation.com/2016_03/0311_63_36479.htm

(1261)   Legia occults TYC 1884-00657-1;                 m= 10.4 (combined); 30° @ 282°; 12 Mar; 07:23:51 UT; 4 sec; drop: 5.8; 4x-8x

http://www.asteroidoccultation.com/2016_03/0312_1261_37578.htm

(257)      Silesia occults TYC 1241-00454-1;               m=   9.5 (combined); 37° @ 271°; 18 Mar; 03:02:04 UT; 2 sec; drop: 5.6; 2x

http://www.asteroidoccultation.com/2016_03/0318_257_37473.htm

(363)      Padua occults 2UCAC 37184759;                m= 11.8 (combined); 65° @ 227°; 18 Mar; 08:06:39 UT; 8 sec; drop: 1.5; 8x-16x

http://www.asteroidoccultation.com/2016_03/0320_61_37474.htm

(61)        Danae occults TYC 1778-01059-1;               m= 10.1 (combined); 12° @ 298°; 20 Mar; 04:27:18 UT; 2 sec; drop: 3.3; 4x-8x

http://www.asteroidoccultation.com/2016_03/0320_61_37474.htm

(119)      Althaea occults 4UC 537-015602;               m= 12.4 (combined); 38° @ 266°; 20 Mar; 04:54:27 UT; 3 sec; drop: 1.1; 8x-16x

http://www.asteroidoccultation.com/2016_03/0320_119_38018.htm

(1271)   Isergina occults TYC 1341-01471-1;            m= 11.3 (combined); 57° @ 258°; 25 Mar; 04:15:35 UT; 4 sec; drop: 4.6; 8x

http://www.asteroidoccultation.com/2016_03/0325_1271_36518.htm

(394)      Arduina occults TYC 0859-00398-1;            m= 10.2 (combined); 46° @ 251°; 29 Mar; 09:20:35 UT; 2 sec; drop: 4.5; 4x-8x

http://www.asteroidoccultation.com/2016_03/0329_394_37478.htm

(675)      Ludmilla occults TYC 0220-00072-1;           m= 10.8 (combined); 23° @ 260°; 01 Apr; 08:05:23 UT; 18 sec; drop: 1.8; 4x-8x

http://www.asteroidoccultation.com/2016_04/0401_675_36544.htm