October 17, 2017

25.05.10- Ad-Hoc Imaging and the Tale of Copland Crater.

Copland Crater as imaged by Messenger. (Credit: NASA/JPL/Messenger).

Copland Crater as imaged by Messenger. (Credit: NASA/JPL/Messenger).

 

   Oh, how far we’ve come… time was when the family portrait of the solar system included blurry images snapped from world class observatories. Fast forward to the 21st century, and amateur astronomers now routinely delete pristine images from memory cards for tiny flaws that would have been the envy of astronomy text books a decade ago. Professional and amateur astronomers have always run a technological arms race of sorts, and the tale of the planet Mercury over the past decade is a good case in point.

Right up until the recent series of Messenger space probe flybys, most of the surface of Mercury stood unmapped. The tiny world stubbornly refuses resolving into much more than a blurry dot in even the largest ground-based telescopes; it never strays far from the turbulent horizon during dusk and dawn apparitions, and spotting it near the Sun during the daytime can be a risky proposition, at best. Most of our knowledge of the surface of Mercury came from the brief flyby of Mariner 10 in 1974 which only mapped 40% of the surface.

Enter a team led by Ron Dantowitz. Using off the shelf hardware, Dantowitz managed to obtain a packet of 40,000 video images during a favorable 1998 elongation of the tiny world, such as the one to occur this Wednesday morning. This was done with the time procured on Mt. Wilson’s 60-inch reflector. Imaging was done during the daytime, when the innermost planet is high in the sky and thus out of the murk of the lower atmosphere. An infrared filter was also incorporated to cut down glare and increase contrast, and precise pointing-software was utilized to keep the scope pointed away from the Sun while the dome shielded the optics. This was semi-reassuring to the directors at the Wilson observatory, as most astronomers do not even like the thought of opening up their optics when the Sun is above the horizon! The results were astonishing; the 37%-lit crescent shape of Mercury revealed details never before seen. Today, amateurs are familiar with the process of image stacking; by sampling a series of frames, a computer program can average out and determine the best quality. If you own a laptop (you’re reading this, right?) a webcam, and a telescope, you could be out imaging the planets tonight, as we realized when we first got wind of this emerging technique back in 2003. Back in 1998, however, Dantowitz and colleagues had to manually sort through 40,000 images for the best 40, and then clean up the resulting image in a process known as selective image reconstruction.

The images displayed several intriguing bright patches yet to be named. Realizing in 2008 that Messenger was about to reveal these patches for what they were, Dantowitz petitioned the International Astronomical Union to name the most prominent after composer Aaron Copeland. Features on Mercury are named after authors, artists, and musicians, and Copeland, who wrote Fanfare for the Common Man seemed fitting, for as Dantowitz notes, “The feature was discovered by common, off-the shelf equipment!”   

Messenger’s resolution was to bear testimony to Dantowitz’s images. Copeland was given a 129 mile wide impact basin, and astronomers are still sifting over the images from Messenger’s subsequent flybys. Messenger is due for permanent orbital insertion on March 18th, 2011. And the moral of the tale? You can go out (or online) tonight and make a significant astronomical contribution, and you don’t need a personal space probe to do it. Of course, the keys to the Mt Wilson observatory might come in handy…

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  2. [...] This post was mentioned on Twitter by Matthew Balan, David Dickinson. David Dickinson said: http://bit.ly/aM1AYR 25.05.10: Ad-Hoc Imaging and the Tale of Copland Crater. How off the shelf tech beat Messenger to the punch! [...]

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