Saturday, February 25, 2012

Mars Limb Removal Techniques in Gimp

I made a tutorial on how to remove the limb artifacts on your Mars images. You'll see in this video tools in Gimp like layers, opacity and selection tools. I hope this is useful. It's 8 minutes long, but be sure to full screen and set to 720 to see all the little things going on in it.

Others here:

Friday, February 10, 2012

Mars 20120208

I think this is my 1st post of Mars this apparation that I'm proud of! Only my 3rd of the season. Weather was avg to just above avg, I ranked it 3+ of 5. Right now I'll take what I can get, but Mars peaks at such a late / funny hour I loose soooo much sleep....

anyway, TIA and enjoy!


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!



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