Turnkey System for Occultations

Finally, a turnkey system is available for recording stellar occultations by asteroids and trans-Neptunian objects (TNOs)! All you need besides the kit is a telescope and a PC. A big thank you to Ted Blank and IOTA for putting this together!

Occultation Recording Kit

  • Highly sensitive RunCam Night Eagle Astro Edition video camera
  • 0.5x focal reducer & adapters to attach camera to 1¼-inch eyepiece holder
  • IOTA VTI (Video Time Inserter) V3
  • StarTech SVID2USB23 USB video capture device
  • Instruction manual
  • Cost: $518

http://occultations.org/observing/recommended-equipment/iota-vti/

We need more observers in the Midwest (everywhere, really) to give us more chords across the asteroids and TNOs, thus increasing the scientific value of the observations. Right now, we are desperately in need of observers in Iowa (where I lived for many years and will always be home to me), and we have precious few active observers in Wisconsin (yours truly), Minnesota (Steve Messner), and Illinois (Bob Dunford, Aart Olsen, Randy Trank).

If you have an interest in pursuing this interesting and rewarding speciality that gives you the opportunity to make a valuable scientific contribution, feel free to post a comment here and I’ll be happy to help!

To Catch a Shadow

Many times each week, all manner of asteroids and trans-Neptunian objects pass in front of stars, casting shadows a few miles wide all over the Earth.  There are several potential events each week at any particular location.  I use the word “potential” because there is still significant uncertainty in the paths for many of these events.  The orbits of most small solar system objects are not yet precisely known, and, to a lesser extent, there is some uncertainty in the position of the occulted (obscured) star.

On Sunday evening, November 20, I got lucky.  Not only did I record a 1.02 second occultation event, but I was lucky to see it at all as I was significantly south of the predicted path.

The star affected was Tycho 5182-758-1 (also known as BD -3° 5037) in Aquarius and the object that moved in front of it was the asteroid 430 Hybris, a space rock about 20 miles across that orbits once around the Sun every 4.8 years.  Many asteroids have interesting names, and Hybris is no exception.  In Greek mythology, Hybris is a spirit of insolence, violence, and outrageous behavior.  It is also an alternative form of the word hubris.  All quite appropriate given the outcome of the U.S. presidential election less than two weeks earlier.

Here is the video I recorded of the event:

Occultation of the star Tycho 5182-758-1 in Aquarius by the asteroid 430 Hybris

And here is the light curve I derived from the video which clearly shows the event:

Steve Messner (near Northfield, Minnesota) and I were the only ones to observe this event.  It was a miss for Steve, and he was much closer to the predicted path!

Why do we do it? Even a single positive observation can greatly improve our knowledge of the orbit of the asteroid or trans-Neptunian object.  More than one positive observation gives us valuable information about its size and shape.  We can discover asteroid/TNO satellites and even rings!  But that’s not all.  These occultation events can also give us valuable information about the star.  Its size, position, and the separation and position angle of new or known companion stars.  Someday, we may even be able to use these events to discover exoplanets!

If you love observational astronomy and would like to contribute scientifically valuable observations by observing occultation events, contact me and I will help you get started.  The more observers we have, the more valuable our scientific contribution will be.