Saturday, February 4, 2012

Asteroids Eros and Tyche

Yes a two for!

I was attempting to catch Eros, which is a Mars-crosser asteroid, and the first known to come within the orbit of Mars.  Eros was also the first asteroid to be orbited by a probe, NEAR Shoemaker. (

Fighting rain, clouds and bad seeing I missed closest approach by a few days. I also found I didn't know how to find the proper ephemeris.  This did cause me to miss imaging Eros the 1st time out.  That ended up ok, as I learned a lot about asteroid hunting and found a 2nd named asteroid, Tyche lurking right nearby!  Pleasant surprise!

So, the good stuff.   The following 17 sub-exposures of 2minutes each are taken on February 2nd, 2012 from 0528 to 0602 UT.

*WARNING* I didn't get perfect darks and there are some hot pixels drifting, but they're pixel sized, whereas the stars and asteroids are not.  The stars are bloated and oversized due to slag in focus over the capture period, bad seeing, surface winds knocking the mount, overexposure and some coma in the optics of my Newt.

Look for two 'streaks' in this 34minute stack.

Labeled view with Eros near the large arrow on the left and Tyche in the lower right. (Click for larger view 40% original sized)

Click here for the mouse over finder chart

Close up of Eros' motion

And Tyche, which is a mere 13.2mag and 40km in size.

Here's a link to the larger, 67% size version 

Some things I learned:

 - How to use edit Stellarium database with new objects

 - How to lookup information in the MPC ( by object, date and time

 - How to lookup a random area of the sky to find out what known objects are there in the MPC database (

 - I also found some discrepancies between the MINOR PLANET CENTER ORBIT DATABASE (MPCORB) orbital elements for #Eros located here ( Don't seem to agree with the +MPC listing here: 

 - A program called Astrometrica can perform field plots for Asteroid ephermis discovery and measurements.   Thanks Dr. Pamela Gay!

Things I want to learn more about:

 - How to use Astrometrica to do what it's supposed to do.

 - Contribute my own observations to the community.

 - My 14" F/4.5 Newtonian scope has fairly noticeable coma that I'd like to understand more.

 - I may have  a budding asteroid hunting fever and may want to learn more about search strategies!



1 comment:

  1. Thanks for sharing. Best of luck with your asteroid hunting.:)


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