MSL - Astronomical Observations, Phobos/Deimos, planetary/celestial observations and more |
MSL - Astronomical Observations, Phobos/Deimos, planetary/celestial observations and more |
Jun 26 2023, 11:19 PM
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#406
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Senior Member Group: Members Posts: 1089 Joined: 19-February 05 From: Close to Meudon Observatory in France Member No.: 172 |
A nice meteor seen Sol 3868!
(link : https://mars.nasa.gov/msl-raw-images/proj/m...NCAM00598M_.JPG ) |
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Jun 27 2023, 01:09 AM
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#407
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Senior Member Group: Members Posts: 4259 Joined: 17-January 05 Member No.: 152 |
Considering the low sensitivity of navcam I'm thinking it was more likely a glancing cosmic ray hit.
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Jun 27 2023, 01:53 PM
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#408
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Senior Member Group: Members Posts: 1089 Joined: 19-February 05 From: Close to Meudon Observatory in France Member No.: 172 |
Considering the low sensitivity of navcam I'm thinking it was more likely a glancing cosmic ray hit. Thank you for your nice explanation. What hinted for me as being a meteor, is that when you transform the image, the incoming trail becomes more apparent (see here below) |
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Jun 27 2023, 04:24 PM
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#409
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Founder Group: Chairman Posts: 14444 Joined: 8-February 04 Member No.: 1 |
A nice meteor seen Sol 3868!..... (link : https://mars.nasa.gov/msl-raw-images/proj/m...NCAM00598M_.JPG ) Your link isn't to the same image you posted - but both have CR hits. The aliasing of the streak strongly suggests a grazing CR hit rather than a real optical phenomenon. Your version where you have vertically compressed the image doesn't show a contiguous streak - one could draw many such lines based on hot pixels elsewhere in the image, many of which would go below the local horizon. |
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Jun 27 2023, 06:36 PM
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#410
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Member Group: Members Posts: 149 Joined: 18-June 08 Member No.: 4216 |
Thank you for your nice explanation. What hinted for me as being a meteor, is that when you transform the image, the incoming trail becomes more apparent (see here below) Most likely a CR, though one cannot dismiss the meteor hypothesis entirely. If there were an object in the foreground like a boom or mast that could interrupt the trail, it would help distinguish between a CR and a bona fide meteor. |
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Jun 29 2023, 02:01 PM
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#411
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Martian Photographer Group: Members Posts: 353 Joined: 3-March 05 Member No.: 183 |
Based on the morphology, the image has a CR that entered the CCD on the anti-readout side of the detector near the image's horizon (thus the high diffusion) and was near the readout side by the time it exited the imaging part of the CCD (hence the low diffusion). The pointiness of the streak is pretty diagnostic of a CR, with the tip being sharper than the optical point-spread function (giving djellison's aliasing). Well, that and fredk's observation about sensitivity and (from a statistical point of view that may support the wrong conclusion once every many thousand times) the many 1000s of CRs vs. no meteors yet identified.
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Mar 3 2024, 05:55 AM
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#412
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Senior Member Group: Members Posts: 1089 Joined: 19-February 05 From: Close to Meudon Observatory in France Member No.: 172 |
Sol 4106: the Curiosity rover took a series of pictures showing the Martian sky.
At the top of all the images it looks like the same stars. Or maybe that they are bad pixels? An opinion? Link: https://mars.nasa.gov/raw_images/1301343/?site=msl |
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Mar 3 2024, 05:14 PM
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#413
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Senior Member Group: Members Posts: 4259 Joined: 17-January 05 Member No.: 152 |
That sequence was shot at around 11:00 local time, so broad daylight. The bright pixels are hot pixels.
You can also tell by zooming into the image because these bright spots are basically just single pixels. Any real point source would always be imaged as at least a few pixels (the "point spread function"). You can see the local time (LMST) of those MSL pics here: http://lcdm.ca/msl/4106/index.2.html (And latest images here: http://lcdm.ca/msl/) |
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Mar 4 2024, 08:46 AM
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#414
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Senior Member Group: Members Posts: 1089 Joined: 19-February 05 From: Close to Meudon Observatory in France Member No.: 172 |
That sequence was shot at around 11:00 local time, so broad daylight. The bright pixels are hot pixels. You can also tell by zooming into the image because these bright spots are basically just single pixels. Any real point source would always be imaged as at least a few pixels (the "point spread function"). You can see the local time (LMST) of those MSL pics here: http://lcdm.ca/msl/4106/index.2.html (And latest images here: http://lcdm.ca/msl/) Thanks Fredk (and also for the links) |
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Sep 16 2024, 06:01 PM
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#415
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Senior Member Group: Members Posts: 2113 Joined: 13-February 10 From: Ontario Member No.: 5221 |
Conjunction of Earth and Phobos
QUOTE NASA's Curiosity Mars rover used its Mast Camera, or Mastcam, to capture this view of Earth setting while Phobos, one of Mars' two moons, is rising. It's the first time an image of the two celestial bodies have been captured together from the surface of Mars. The image is a composite of five short exposures and 12 long exposures all taken on Sept. 5, 2024, the 4,295th Martian day, or sol, of Curiosity's mission. An inset in the image shows Phobos on the left and Earth on the right. From the rover's perspective, the inset area would be about half the width of a thumb held at arm's length. Wonderful image, faint Mars shine on the night side.... I wonder how often it actually occults Earth? |
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Sep 16 2024, 07:16 PM
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#416
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Martian Photographer Group: Members Posts: 353 Joined: 3-March 05 Member No.: 183 |
I did not verify this with the ephemeris, but I did consider the question when looking at the night-to-night motion of Phobos' track. I estimated that an occultation should happen around once or twice each Mars year (so around every year) -- but it would only happen when they were visible in the morning or evening twilight about every 3-6 years. This depends on dust and exactly how 'visible' is defined, but I think it is about the right scale.
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