Lassen Dark Sky Festival

This past summer 12 RECON team members participated in the 4th annual Lassen Dark Sky Festival in August of 2015. Members helped conduct stargazing and discussions about astronomy with over 4,500 visitors.  Since 2012, thousands of spectators visit Lassen national park every year to celebrate special astronomical events including the annular eclipse, the transit of Venus and the Lassen Dark Sky Festival.

Visitors can participate in various activities throughout the festival:

Lassen National Park is a sanctuary of natural darkness and offers spectacular views of the night sky.

Check out our RECON Team members at the Lassen Festival.

Check out more pictures of the Lassen Dark Sky Festival here.

Here are future events dates at Lassen National Park:
August 12-14, 2016 -100th Anniversary of National Park Service and Lassen Festival
August 11-13, 2017  One week before the total solar eclipse
August 3-5, 2018  James Webb Space Telescope launches in October

Alerts for Main Belt Asteroid Occultation Events in February 2016

Hello RECON members. I’ll be busy with family visits this month, so I will keep my February alert list short and sweet. Here is the list of events that cross RECON member site locations in February:

Monthly List for February

These are all high probability events.  That is, if you are in the path or near the path, you have a very good chance of observing an occultation.  If we can get three or more RECON teams to observe each event, we can derive a good estimate of the size and shape of the asteroid, like was done for the Aegle event last year.  Also, all these events will be observed by IOTA observers in addition to RECON teams, so there is potential for several chords on each event.

All these events can be found on the OccultWatcher website.  For each event, if you click on the ‘View Details on Web’ menu button along the bottom of the screen, you can find a link to Steve Preston’s website for the event.  This website has links to path maps, and star charts.  On the path map is the ‘of date’ coordinates needed for pointing to the target star.

Here is the above list by date showing the RECON teams that are within or near the occultation path, along with recommended Mallincam settings:

Team List February 2016

For all these events, except the February 16 event, the occultation should be clearly visible on-screen as a star disappearance.  For February 16, the event will appear as a slight fading of the target star.  All observations will require video processing to derive the Disappearance and Reappearance times.

For all events, I suggest you upload your videos to the IOTA RECON Dropbox site.  If you have not already signed up to share this site and plan to observe one of these events, let me know and I’ll send you a link to the website for sharing/uploading the video files.

Once the videos are analyzed, I’ll work with each team to produce an IOTA report for submission to IOTA.

Good luck if you try any of these events in February 2016!



Alerts for Main Belt Asteroid Events in January 2016

Why These Alerts

By way of introduction, my name is Tony George.  I am a RECON collaborator.  In the winter I observe from Scottsdale, AZ, and in the summer I observe from Umatilla, OR.  I have been a member of IOTA (International Occultation Timing Association) for more than 25 years.  In the last 10 years or so, I have helped IOTA to coordinate focused observing campaigns in the Pacific Northwest and more recently, when spending winters in Scottsdale, in the Southwest.  What I have done is find promising main belt asteroid events with high certainty that pass over known IOTA observers and send out alerts to these observers so they may coordinate their efforts and get multiple positive observations of the asteroid.  Because RECON teams are spread uniformly across the Pacific Northwest and Southwest, many team sites are also near IOTA member sites, and it makes sense to solicit RECON participation in these events when this occurs.  This Blog is my first attempt at preparing advance alerts for main belt asteroid events that may be of interest to select RECON teams where the path crosses their specific observing locations.

Alerts are Not Mandatory

First and foremost, 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.  In my past occupation as an astronomy instructor, many of my classes were elated when they could watch an occultation on-screen in real time.  I still am excited each time I see an occultation occur in real time.

Format of Alerts

So, now for the alerts occurring in the remainder of January.  Each alert is listed below.  For each alert, the RECON observing teams targeted for observing the event are listed.  If your team is not mentioned then there is no need to respond to the alert.

For each alert, the following information is listed:

  1. Asteroid (number) and name
  2. Catalog number of star occulted
  3. m = combined magnitude of star and asteroid occulted (this will help to establish the sense-up to use for each event)
  4. altitude @ azimuth of the target star at occultation time
  5. Universal Date and Time of event (may be a day later than calendar Date shown in each title listing)
  6. maximum duration of event in seconds (if you see an event, it will likely be shorter than this)
  7. 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)

A recommended observing time is provided for each alert.

A path map is shown for each alert.

Teams or individuals who plan to participate in the event can send me an email directly at 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.

(393) Lampetia January 21

RECON Teams: Indian Springs, Henderson, Searchlight/Boulder City, Kingman/Dolan Springs, Laughlin/Bullhead City, Mohave Valley, Lake Havasu, Parker

(393) Lampetia occults 4UC 479-013479; m= 13.0 (combined); 40° @113°; 22 Jan; 02:11:45 UT; 11 sec; drop: 0.9 [Note: this is a low mag drop and may not be visible on screen — all videos should be submitted]

Observation Time:  02:11-02:13 UT

(866) Fatme

RECON Teams: Fall River/Burney, Susanville, Greenville, Quincy, Portola

(866) Fatme occults TYC 1904-00739-1; m= 9.5 (combined); 53° @89°; 24 Jan; 03:35:12 UT; 7 sec; drop: 4.7

Observation Time:  03:34:30-03:37:00 UT

(791) Ani

RECON Teams:   Laughlin/Bullhead City, Kingman/Dolan Springs, Searchlight/Boulder City, Henderson, Indian Springs, Beaty, Lone Pine, Bishop

(791) Ani occults UCAC4-515-020156; m= 11.3 (combined); 44° @105°; 30 Jan; 01:57:08 UT; 9 sec; drop: 3.4

Observation Time:  01:56:30-01:58:30 [Note: event at end of twilight may be hard to find until just before event time]

(795) Fini

RECON Teams:  Madras/Culver, Sisters, Redmond, Bend, Oregon Observatory 

(795) Fini Occultation of 2UCAC 42354740 on Feb 2 8:21 PST 9:21 MST (03 Feb; 04:21:39 UT)(795) Fini occults ; m= 12.0 (combined); 47° @279°; ; 6 sec; drop: 3.5

Observation Time:  04:19:30-04:21:30

Moon occults Aldebaran just before this week’s event

As RECON teams are setting up for our next campaign event involving Centaur 03WL7 this Tuesday evening, which begins around 7:30PM Pacific (2016 January 20 03:28 UT), they will be treated to an added bonus as the Moon passes in front of the bright red star Aldebaran around 6:20 Pacific (02:20 UT). This will definitely worth checking out if you have clear skies!

For a better look at sky forecasts, check out our Sky Conditions Page. While things look pretty socked in throughout Washington, there is a chance for clearing just in time for the event throughout the remainder of the network!

We recommend all teams print and go through the event page for Centaur 03WL7. Some teams have had difficulty with resetting the Capture Pin as described in Step 4 of the Camera Settings Guide. If you end up with a green screen, you can go back to using default screen size for this event until we’ve had a chance to provide a workaround.

Good luck to all!


Documentation of occultation of 2UCAC 39956822 by (86) Aegle

The last positive occultation captured in North America in 2015 was the occultation of the star 2UCAC 39956822 by the asteroid (96) Aegle.  Overall, there were 8 observers who observed the event.  There were 7 positive observations and one miss observation.  Three of the positives were recorded by RECON team members, Chris Patrick, Steve Bock, and Tony George.  This blog will document the data contributed by the RECON members.

Here is the path map for the event.  You can see the path crosses through central Arizona and southern Nevada, where three RECON members are located.  Other observers in Arizona and central California were also able to observe the event.

Light Curve Analysis

All videos were uploaded via DropBox to an IOTA repository.  DropBox is a tool used by IOTA for capturing and exchanging video files.  Each of the video files were then analyzed by Tony George using Limovie.  Limovie is a tool for commonly used by IOTA for video light curve analysis.  Here are the three light curves that were captured by RECON members:

Chris Patrick

(96) Aegle 2015-12-30 Chris Patrick.ROTE.sqWave

Steve Bock

Aegle 20151229 Mt Potosi PSF TG.ROTE.blockint.detrended.sqWave

Tony George

(96) Aegle 2015-12-30.ROTE.detrended.sqWave

These three light curves have some interesting characteristics that should be noted.

The Chris Patrick light curve is very erratic and during the event, a very flat and uniform bottom.  These are characteristics of the camera settings, which did not match the standard RECON guidelines.  Whenever observing asteroidal occultations, RECON guidelines should be used for camera settings unless otherwise directed by the campaign organizer.

The Steve Bock light curve looks very ‘skimpy’.  Again, this is the result of camera settings, most significantly, the degree of sense-up that was set.  Steve used a sense-up of 64x.  This integrates 32 frames which means that each block of 32 video frames looks essentially the same.  Integration also cuts down on the amount of variation between individual frames and blocks of integrated frames. A sense-up of 64x is a common RECON guideline for TNO occultation observations, however it may be too much integration for use in brighter asteroid occultations.

When compared to Tony George’s light curve, you can see the degree to which a high sense-up can affect the look of the light curve.  Tony used a sense-up of 2x.  This integrates two video fields into one frame, so there are 30 frames per second that are all independent of adjacent frames.

While Tony’s light curve might not look good, it actually is the best of the three light curves for determining the correct D (disappearance) and R (reappearance) times from the video.  That is because integration (sense-up) averages the video data and the D or R might occur somewhere within the integration block and the actual time must be estimated from the brightness value of the block of frames.  With Tony’s video, the times can be derived to times less than 1-frame accuracy.

Occultation Disappearance and Reapperance Analysis

Once each video file was analyzed in Limovie, a data file is created in a comma separated variable format (csv).  That csv file can be analyzed by different software applications to search for hard-to-find occultations, however this occultation was easy to see.  The software programs can also be used on easy-to-see occultations, particularly those with video integration, so that more accurate estimates of the D and R times can be derived.  Tony George used the program R-OTE (R-code Occultation Timing Extractor) to analyze all three light curves.  The D and R times were determined and provided to the observers so they could send in their reports on a standard Excel spreadsheet provided by IOTA.  For those that have OccultWatcher on their computers, the Excel form is easily available through a reporting app in OccultWatcher.

Asteroid Profile Analysis

Once the various observation D and R times are sent to IOTA  for analysis, a powerful program called Occult4 is used to combine the times and geographic coordinates to determine the size and shape of the asteroid.  For each observer, a chord across the earth is developed indicating where and when the star was visible.  Where the star disappears, there is a gap in the chord equivalent to the length of time of the disappearance.  When multiple chords are combined, the gaps in the chords trace out the size and shape of the asteroid.  Here is the profile developed for the (96) Aegle event:


Note:  Click on the above image to get a high-resolution view of the plot

The chords of observations by the various observers are shown in different colors.  The chords of the three RECON observers are Chord 1: Chris Patrick; Chord 2: Steve Bock; and, Chord 5: Tony George.  You can see from this plot the rough outline of the size and shape of the asteroid.  Superimposed on the plot of the chords is the ellipse of best fit to the openings in the chords.  The size of the asteroid as determined by this analysis is and ellipse with major axis of 169.6 km and minor axis of 163.0 km.  This is one of the best observations ever obtained of the asteroid (96) Aegle.  While this is only one snapshot of the asteroid on the date of the observation, future observations can determine the size and shape from other perspectives and hence the volume and density of the asteroid can also be determined from amateur astronomer observations.  This type of data is very helpful to astronomers and space scientists as they continue to characterize the main belt asteroids and try and made decisions on asteroids to visit on future space flights.

RECON Observations Were Critical to Getting Size and Shape of (96) Aegle

The determination of the size and shape of an asteroid by occultations requires a good spread of observers across the path.  In the case of the (96) Aegle event, the two Chords collected by RECON members Chris Patrick and Steve Bock were critical in setting the northern limb of the asteroid.  Without those two chords, the true size and shape of (96) Aegle could not be determined from the other chords.  This shows that occultation astronomy is a team sport.  It takes a variety of observations to get the size and shape of an asteroid.

Opportunity to Participate in Future Main Belt Asteroid Events

While not a focus of the RECON project, RECON members can participate in the observation of main belt asteroids to sharpen their skill in doing occultations.  The probability of getting a positive with a main belt asteroid event is higher for those within the path, since the orbits of main belt asteroids are better known than TNO’s.  In the future, Tony George will be sending out alerts for main belt asteroid occultations predicted to cross the observing sites of RECON members.  Typically, for a large main belt asteroid, the path may go over 3 or 4 RECON observers in the network.  Watch for postings of favorable main belt asteroid events on the tnorecon email list.  With luck, we will see your groups chord on a future profile plot.


Prepping for 03WL7

Below is a calendar of events as RECON preps for our first campaign event of 2016!

Monday 1/11, 3-4PM PST / 4-5PM MST:
Optional videoconference for Southern RECON Teams (and any other teams)

Tuesday 1/12, 4-5PM PST / 5-6PM MST:
Optional videoconference for Central RECON Teams (and any other teams)

Wednesday 1/13, 4-5PM PST / 5-6PM MST:
Optional videoconference for Northern RECON Teams (and any other teams)

By Friday 1/15:
Complete Pre-Event Confirmation Form and upload Video of Camera Settings. This includes an important change to the VirtualDub configuration for all sites.

Sunday 1/17, 4-8PM PST:
John will be at the Oregon Observatory RECON Meetup with team members from Gilchrist, Sunriver, Bend, Sisters, Redmond, and Madras/Culver.

Monday 1/18, 4-8PM PST:
John will be at Paisley School RECON Meetup with team members from North Lake, Paisley, Lakeview, and Cedarville.

EVENING OF TUESDAY 1/19: 03WL7 Campaign Event 
Centaur 03WL7 will be occulting on Tuesday evening January 19 (2016 January 20 around 03:36 UT).  Check out the 03WL7 Event Page with pre-event checklist and a new procedure for taking science, flat field, and dark field videos. Below is the current prediction for 03WL7, which has a 1-sigma cross-track uncertainty of 810 km.

03WL7 Shadow Prediction with 810 km cross-track uncertainty

03WL7 Shadow Prediction with 810 km cross-track uncertainty

Happy New Year RECON!

Welcome to 2016!!!

Wanted to share a recent asteroid occultation that occurred just before the New Year. On 2015 December 30 UT, main belt asteroid (96) Aegle occulted an 11.6 magnitude star. RECON team members Chris Patrick from Kingman Arizona, Steve Bock and John Heller from Indian Springs, and Tony George from Scottsdale recorded positive observations of the occultation.  Below is the light for this event from Kingman:

Light curve for Aegle collected in Kingman Arizona

Light curve for Aegle collected in Kingman Arizona

Below is a preliminary object profile for Aegle generated using data from Chris, Steve, Tony, and 5 additional IOTA observers.  You can view this and other 2015 IOTA results at Asteroid Occultation Results Page for North America.

20151230_AegleProfileUpdatedGreat job Chris, Steve, John, Tony, and other IOTA members!  Hope all enjoy the New Year Weekend!!!

Happy Winter Solstice!

We wanted to take this Winter Solstice opportunity to thank all of our teams for their exceptional involvement in RECON over the past year. It has been a truly exciting and productive year!

Looking forward to January, our next RECON campaign involving Centaur 03WL7 will occur on 20 January 2016 at 03:36 UTC. This event is earlier in the evening than our previous events, occurring on Tuesday, January 19 around 7:36PM Pacific / 8:36PM Mountain.

Wishing all a happy and health holiday season!!!  Marc, John, Jeralyn, and Ilianna

Daytime Occultation of Venus by the Moon!

This Monday morning, December 7, the waning crescent Moon will occult the planet Venus!  This event should be visible to the naked eye and will occur around 8:00 AM Pacific Time (7:53 AM in Seattle, 8:03 AM in Los Angeles).  Venus is visible to the naked eye during the daytime as long as you know where to look, and tomorrow the Moon will guide you to this point. Look for Venus just to the east of the moon about a half hour before the occultation, and then watch as the Moon approaches and blocks the planet from the west.

For more information, check out articles by and Sky & Telescope.