Dust Devils In Jezero Crater, single-point repository of imagery |
Dust Devils In Jezero Crater, single-point repository of imagery |
Dec 25 2021, 05:53 PM
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#136
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Member Group: Members Posts: 808 Joined: 10-October 06 From: Maynard Mass USA Member No.: 1241 |
-------------------- CLA CLL
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Dec 26 2021, 07:45 PM
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#137
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Member Group: Members Posts: 808 Joined: 10-October 06 From: Maynard Mass USA Member No.: 1241 |
-------------------- CLA CLL
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Jan 5 2022, 10:17 AM
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#138
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Member Group: Members Posts: 692 Joined: 9-May 21 From: Germany Member No.: 9017 |
A "storyboard" an an animation of a dust devil on sol 308 during a Mastcam-Z multispectral photo series.
The Mastcam-Z filter number and the time in seconds after start of the series are annotated in the storyboard. The difference-to-average method does not work here because of the spectral filters, therefore contrast enhancement was used. |
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Jan 5 2022, 02:19 PM
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#139
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Member Group: Members Posts: 692 Joined: 9-May 21 From: Germany Member No.: 9017 |
The dust devil on sol 308 continues into the infrared region of the spectrum with Mastcam-Z right eye filters 1 to 5.
The Mastcam-Z filter number and the time in seconds after start of the series in the previous post are annotated. Contrast enhancement did not work here. Instead the difference-to-average method with manual adjustments to each image was used. Overexposed and/or clipped highlights (link to the first raw image) in the bright landscape around the dust devil resulted in featureless patches of medium gray, which are masked here with red color. A second dust devil appears in this series. Starting with filter ZR5, the dust devils merge with the bright infrared background. |
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Jan 8 2022, 04:35 PM
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#140
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Member Group: Members Posts: 692 Joined: 9-May 21 From: Germany Member No.: 9017 |
Mastcam-Z images, an orthorectified HiRISE image, and a HiRISE digital terrain model were used to determine the route of the sol 308 dust devil on the ground.
Twenty control points of corresponding features were set in the Mastcam Z image and the HiRISE image. With some measurements and calculations, pixel coordinates in the Mastcam-Z image could be transformed into map coordinates of the HiRISE image. The length of the visible part of the dust devil's route is about 820 m. The average horizontal ground speed was about 30 km/h, and even 36 km/h on average between second 0 and 57. To verify the calculations, it would be interesting to see if the dust devil left a visible track. Edit: corrected typo km/s to km/h (thanks to Floyd) |
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Jan 8 2022, 05:38 PM
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#141
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Member Group: Members Posts: 913 Joined: 4-September 06 From: Boston Member No.: 1102 |
Was the horizontal ground speed actually m/s not km/s?
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Jan 8 2022, 05:50 PM
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#142
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Martian Photographer Group: Members Posts: 352 Joined: 3-March 05 Member No.: 183 |
8.2 m/s, 30 km/hr.
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Jan 8 2022, 06:04 PM
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#143
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Member Group: Members Posts: 692 Joined: 9-May 21 From: Germany Member No.: 9017 |
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Jan 9 2022, 09:45 PM
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#144
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Member Group: Members Posts: 611 Joined: 23-February 07 From: Occasionally in Columbia, MD Member No.: 1764 |
Mastcam-Z images...... The average horizontal ground speed was about 30 km/h, and even 36 km/h on average between second 0 and 57. What is the diameter of the devil. Some years ago I identified an empirical law for the longevity of dust devils on Earth and Mars : Duration (s) = 40 * d^0.66 with d in m. Apropos of this topic Anyone interested in dust devils on Earth and Mars might enjoy my Physics Today webinar to be held 2pm EST January 12, 2022 (I guess you can view it online thereafter) https://event.on24.com/wcc/r/3543264/A422D6...BBA18667191242C |
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Jan 10 2022, 02:35 AM
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#145
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Senior Member Group: Members Posts: 2998 Joined: 30-October 04 Member No.: 105 |
Mastcam-Z images, an orthorectified HiRISE image, and a HiRISE digital terrain model were used to determine the route of the sol 308 dust devil on the ground. snip I wondered about the possibility of transferring the DDs we see to a groundtrack on a map and seeing if a track was left. --Bill -------------------- |
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Jan 10 2022, 10:09 AM
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#146
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Member Group: Members Posts: 692 Joined: 9-May 21 From: Germany Member No.: 9017 |
What is the diameter of the devil. . . . Here is a very rough estimate of the diameter of the dust devil using a scaled image. The last three subimages where the dust devil begins to dissipate were not taken into account. 1 pixel corresponds to 0.76 m in nature. Diameter of the brightes part where it touches the ground: 25 to 40 m Diameter of the shadow: 60 to 70 m (local mean solar time was 11:09) It was a nice coincidence that the dust devil entered the field of view exactly at the moment when the image series started. |
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Jan 10 2022, 10:57 AM
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#147
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Member Group: Members Posts: 692 Joined: 9-May 21 From: Germany Member No.: 9017 |
I wondered about the possibility of transferring the DDs we see to a groundtrack on a map and seeing if a track was left. --Bill Groundtracks on a map can be reconstructed only if we see in the photos the point where the dust devil touches the ground. In most cases this point is hidden behind local elevations. For example, in this image a second dust devil emerges to the left from the existing one. However, its distance from the rover can be anywhere between 50 m behind the nearest ridge and 7000 m on the inner slope of the crater wall. |
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Jan 10 2022, 02:18 PM
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#148
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Member Group: Members Posts: 692 Joined: 9-May 21 From: Germany Member No.: 9017 |
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Mar 19 2022, 04:29 PM
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#149
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Member Group: Members Posts: 808 Joined: 10-October 06 From: Maynard Mass USA Member No.: 1241 |
Sol 372 DD watch
21 images - 11:40 AM (I have a backlog of DDs -- broke my wrist -- sold my house - moved to a new one -- crashed PC -- but all set now....) -------------------- CLA CLL
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Mar 20 2022, 06:12 AM
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#150
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Senior Member Group: Members Posts: 2998 Joined: 30-October 04 Member No.: 105 |
Be well!!
Looking forward to the Backlog. --Bill -------------------- |
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