September 28, 2012
Amateur Astronomer Creates Map Of Jupiter Moon’s Reflectivity
Lee Rannals for redOrbit.com - Your Universe Online
This map shows off the higher areas of reflectivity on an object's surface, recording where material is bright or darker in areas.
The map developed by the astronomers closely aligns with professional images of Ganymede's surface, showing off features like Phrygia Sulcus and the Nicholson region.
“Ganymede has a tiny disk as seen from Earth so was a good test for my techniques," said Emmanuel I. Kardasis of the Hellenic Amateur Astronomy Association. "If the same methods were applied to other worlds, perhaps the volcanic moon Io, we could capture surface fluctuations. Professional observatories may create better images but they cannot monitor our rapidly and ever-changing Universe.”
In order to produce the images, Kardasis attached a camera to his telescope and recorded a video of the moon.
By selecting only the sharpest frames of the video, he was able to obtain a series of images when the atmospheric conditions were most favorable.
The images were then stacked and aligned, before being enhanced through photo-editing software.
“Creating useful images of planets requires a telescope with a diameter of at least eight inches. For tiny discs, such as the moons of Jupiter, bigger is definitely better," Kardasis said. "My Ganymede images were made using an 11-inch telescope. You also need a good motor drive on your tripod, a sensitive camera, some freely-available software, and lots of patience!”
Future amateur programs could help monitor both surface and atmospheric changes on worlds like Uranus, Neptune and Titan.
“I hope my work will inspire anyone interested in astronomy to use whatever equipment they have to make useful observations," Kardasis said.
Image 2 (below): The original observations (top) and interpretations (bottom) of the first ever amateur albedo map of Ganymede. Credit: Manos Kardasis
Image 3 (below): Albedo maps of Ganymede (left) and how they relate to known surface features (right). Credit: Manos Kardasis