Mars rotation movie for 2/3 of a Martian day (which is 24 hours 37 minutes long). Since the "atmospheric seeing" varies from day to day, and hour to hour, some of the frames in this movie sequence are sharper than others. Also, it is difficult to achieve the same color balance, and contrast, for the various frames, and this too compromises the smoothness of the movie. The main feature, Syrtis Major, come in at the end, and I need more frames for that longitude region. The Martain longitudes included in this sequence are: 36, 49, 94, 106, 123, 130, 145, 152, 179, 196, 207, 224, 232, 246, 254, 266 and 270 degrees. The opportunities for catching Syrtis major occur at intervals of approximately 40 days, and in mid-July I'll have another chance to fill-in this part of the sequence. Stay tuned! [This movie sequence was acquired during the period 2001.06.16 to 2001.07.07. Each frame is created from a review of approximately 1000 images acquired over a half-hour interval. Typically, a frame is the average of 6 images, each of which is processed for color balance, range of brightness, contrast, and color plane offset. The processed image is then adjusted to a standard size, and is centered in a standard frame size before it is combined with other frames in the animation program.]
Rotation sequence for first part of movie, using full-resolution frames. Martian longitudes are 36, 49, 94, 130 and 145 degrees. The rotation direction is from right to left since the north pole is at the bottom (and rotated to the 5 o'clock position), which is a traditional presentation favored by visual telescope observers.
Rotation sequence for last half of the above rotation movie. Syrtis Major is the large dark region that can be seen in the last 3 images, moving in from the right limb. The central meridian longitudes are 207, 232, 246, 254 and 270 degrees. This corresponds to 4.5 hours of rotation. The Mars disk was 20.8 arc seconds across on the evening of June 19, 2001, when these pictures were taken. A declination of -26 degrees makes this opposition difficult for north hemisphere observers since Mars' elevation angle never exceeds 29.6 degrees at my latitude. The last image is fuzzy due to the poorer atmospheric seeing of lower elevation angles. A total of 2100 images were taken June 19, and only 1% of them were useful for combining to produce these pictures. All images have been contrast enhanced to show subtle details that are seen visually. [June 19/20, 2001, LX-200, 10-inch Schmidt-Cassegrain, 1/2-inch FL eyepiece projection to Nikon Coolpix 990 digital camera, 1/125-second exposure when using full aperture, 1/15-second when aperture was stopped to 4 inches due to seeing conditions. The red, green and blue sub-images were split and recombined with proper offsets to copensate for the greater atmospheric refraction of blue light compared to red that is important at low elevation angles.]
Repeat of the 2001.06.29 image, longitude 094, without the size rescaling degradation required by the first group figure. Notice the clouds surrounding the south polar cap (top), and a faint north polar cap (bottom). There are no significant dark features at this longitude, which is unfortunate because the seeing was unusually good, and the dust storm of 2001 had not spread widely to obscure surface markings, when the picture was taken.
Major Dust Storm Beginning June 27, 2001
It has become difficult to photograph Mars during July because of a
major dust storm that has enveloped the entire planet. According
to an instrument aboard the Mars Global Surveyor, the Thermal Emission
Spectrometer (TES), the storm originated in Hellas (south of Syrtis Major,
"above" Syrtis Major in the images on this web page) on approximately mid-June,
and "exploded" June 27 to cover most of Mars by July 10, 2001 (see TES
Storm movie). For Californians, there were opportunities to observe
the Syrtis Major region in early June and late July, so the latter images
will be very obscured. Here's an example of an obscured iamge of
Syrtis Major is barely visible left of center in the left image, taken July 19, 2001, and not visible at all in the right image, taken July 20, 2001. The same processing procedures were used for these and the earlier images. The North polar cap appears clearly (at the 5:00 o'clock position), but that's about all that can be seen. The central meridian longitude is 307 and 280 degrees. The Martian "dust storm of 2001" has put a stop to my endeavor to fill a gap in my rotation movie. Wait til next opposition, in 2003, which will be a little more favorable to northern hemisphere observers.
Hubble Space Telscope Pictures
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You may click on any of the above 4 photos to see a larger version. Central meridian longitudes are 0, 25, 200 and 280 degrees.
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This site opened: August 26, 1998. Last Update: September 11, 2001