IPB

Welcome Guest ( Log In | Register )

28 Pages V  « < 26 27 28  
Reply to this topicStart new topic
MSL - Astronomical Observations, Phobos/Deimos, planetary/celestial observations and more
vikingmars
post Jun 26 2023, 11:19 PM
Post #406


Senior Member
****

Group: Members
Posts: 1073
Joined: 19-February 05
From: Close to Meudon Observatory in France
Member No.: 172



A nice meteor seen Sol 3868!
Attached Image


(link : https://mars.nasa.gov/msl-raw-images/proj/m...NCAM00598M_.JPG )
Go to the top of the page
 
+Quote Post
fredk
post Jun 27 2023, 01:09 AM
Post #407


Senior Member
****

Group: Members
Posts: 4245
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.
Go to the top of the page
 
+Quote Post
vikingmars
post Jun 27 2023, 01:53 PM
Post #408


Senior Member
****

Group: Members
Posts: 1073
Joined: 19-February 05
From: Close to Meudon Observatory in France
Member No.: 172



QUOTE (fredk @ Jun 27 2023, 03:09 AM) *
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)


Attached Image
Go to the top of the page
 
+Quote Post
djellison
post Jun 27 2023, 04:24 PM
Post #409


Founder
****

Group: Chairman
Posts: 14431
Joined: 8-February 04
Member No.: 1



QUOTE (vikingmars @ Jun 26 2023, 03:19 PM) *
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.
Go to the top of the page
 
+Quote Post
tolis
post Jun 27 2023, 06:36 PM
Post #410


Member
***

Group: Members
Posts: 149
Joined: 18-June 08
Member No.: 4216



QUOTE (vikingmars @ Jun 27 2023, 02:53 PM) *
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)


Attached Image


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.
Go to the top of the page
 
+Quote Post
Deimos
post Jun 29 2023, 02:01 PM
Post #411


Martian Photographer
***

Group: Members
Posts: 352
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.
Go to the top of the page
 
+Quote Post
vikingmars
post Mar 3 2024, 05:55 AM
Post #412


Senior Member
****

Group: Members
Posts: 1073
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?

Attached Image


Link: https://mars.nasa.gov/raw_images/1301343/?site=msl

Go to the top of the page
 
+Quote Post
fredk
post Mar 3 2024, 05:14 PM
Post #413


Senior Member
****

Group: Members
Posts: 4245
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/)
Go to the top of the page
 
+Quote Post
vikingmars
post Mar 4 2024, 08:46 AM
Post #414


Senior Member
****

Group: Members
Posts: 1073
Joined: 19-February 05
From: Close to Meudon Observatory in France
Member No.: 172



QUOTE (fredk @ Mar 3 2024, 06:14 PM) *
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) smile.gif
Go to the top of the page
 
+Quote Post

28 Pages V  « < 26 27 28
Reply to this topicStart new topic

 



RSS Lo-Fi Version Time is now: 19th March 2024 - 09:14 AM
RULES AND GUIDELINES
Please read the Forum Rules and Guidelines before posting.

IMAGE COPYRIGHT
Images posted on UnmannedSpaceflight.com may be copyrighted. Do not reproduce without permission. Read here for further information on space images and copyright.

OPINIONS AND MODERATION
Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators.
SUPPORT THE FORUM
Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member.