Tag: asteroids

Voyager 4.5 by Carina Software

My all-time favorite planetarium software program is Voyager 4.5 from Carina Software.  Hardly a day goes by when I am not using it, and my use of Voyager goes all the way back to 1993.  The current version for Mac OS X (and Windows) is 4.5.7.  Sadly, the last update was in 2010.  I wish there was something we could do to ensure that Voyager will be maintained and enhanced in the future.

Speaking of maintenance, in 2015 Voyager ceased being able to import comet and asteroid orbital elements through its automatic Updates process.  This happened because the URL changed for both.  Seems like a pretty easy fix to me.  If Carina won’t fix it, then maybe someone can edit the executable and change the two URLs?

Fortunately, you can still manually import these orbital elements by following these instructions.

Adding Comets
  1. Navigate your web browser to https://www.minorplanetcenter.net/iau/Ephemerides/Comets/Soft00Cmt.txt and save this page to a file, which will automatically be called Soft00cmt.txt.  You can save it anywhere, but I’d suggest you save it in the Import Files folder in the Voyager 4.5 main directory within your Applications folder.
  2. In Voyager, go to File : Import : Comet Orbit File…
  3. Navigate to Applications : Voyager 4.5 : Import Files : Soft00Cmt.txt and click Open.  You will get a message box asking “Before importing new data, do you want to delete all current asteroid/comet/satellite data?”  Click Yes.  Next you will see an Import results box showing you the number of comets added to Voyager’s database.  Click OK.
Adding Asteroids
  1. Navigate your web browser to https://www.minorplanetcenter.net/iau/MPCORB.html and under Available Files right click on MPCORB.DAT (uncompressed) and Save Link As… to your Voyager 4.5 Import Files folder.  Do not open this file in your web browser as it is over 147 Mb in size!  The file saved is called MPCORB.DAT.
  2. Navigate to Applications : Voyager 4.5 : Import Files : MPCORB.DAT and edit the MPCORB.DAT file with the editor of your choice.  Remove the header lines at the top of the file right down through the line of dashes, and save the file.
  3. In Voyager, go to File : Import : Asteroid Orbit File…
  4. Navigate to Applications : Voyager 4.5 : Import Files : MPCORB.DAT and click Open.  You will get a message box asking “Before importing new data, do you want to delete all current asteroid/comet/satellite data?”  Click Yes.  It will take a while to import all the asteroids, and then you will see an Import results box showing you the number of asteroids (and transNeptunian objects, by the way) added to Voyager’s database.  Click OK.

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.