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Unmanned Spaceflight.com _ Spirit _ New Meteor ?

Posted by: vikingmars Oct 25 2005, 02:44 PM

smile.gif Here is a picture just downloaded from Pancam sol 643 at 22:03 LLT
Does anyone knows is Mars is going now throu

gh a swarm of meteors ?

Posted by: Tesheiner Oct 25 2005, 02:52 PM

I would say yes because this meteor search is intentional.
I correlated that image to the following planned sequence:

643 p2734.03 18 0 0 18 2 38 pancam_meteor_search_L1R2

And there is another one planned for sol 644:

644 p2737.03 18 0 0 18 2 38 pancam_meteor_search_L1R2

Posted by: Richard Trigaux Oct 25 2005, 02:56 PM

Eventually meteors on Mars may be more numerous and brighter, as the layer where they appear is closer to the ground. This of course is independent of the real number of objects which disintegrate in the atmosphere, which may be roughly the same than on Earth.

Posted by: fredk Oct 25 2005, 06:36 PM

I'm sceptical these are meteors, as I explained in the http://www.unmannedspaceflight.com/index.php?showtopic=1534. Even this latest long streak would've been an incredibly bright fireball. Even though they call them "meteor searches" in the planning sequences, at the very bottom of http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20051021a.html it says

"Bright streaks in some parts of the images aren't stars or meteors or unidentified flying objects, but are caused by solar and galactic cosmic rays striking the camera's detector."

And earlier

"Scientists use the images to assess the cameras' sensitivity and to search for evidence of nighttime clouds or haze."

But on the evening of sol 643, Spirit took an extremely interesting http://marsrovers.jpl.nasa.gov/gallery/all/spirit_p643.html, eerily reminiscent of my "suggestion" in the first post of the http://www.unmannedspaceflight.com/index.php?showtopic=1534. There are five sequential images of the same region of sky. In the attached image I tried to sum these images, but I'm sure the experts could do a better job. The result clearly shows the trails as arcs around what must be the south Martian celestial pole off to the left, though I haven't ID'd the stars yet. It's a spectacular shot!

 

Posted by: akuo Oct 25 2005, 07:13 PM

This sure does look like a meteor (some of the ones in earlier night time pics did too), though there are a lot of cosmic rays too. I think it would be pretty unlikely for a cosmic ray to make such a long mark without being deflected.

About the brightness: you have to remember that the pancam is a pretty long telephoto lens and with that sort of magnification you see quite dim objects. Also CCDs are quite sensitive instruments. The field of view of the pancam is also quite small and you see a lot of stars there, meaning that the dimmest are quite dim (longer exposures don't help that much, as the stars aren't tracked). They probably are dimmer that we would see with naked eye, maybe 7-8 mag. Therefore that meteor doesn't really need to be that bright, probably dimmer than 0 mag, so not in the fireball range.

antti

Posted by: Tman Oct 26 2005, 06:52 AM

Wow that's a great sequence from Spirit. And only ten shots to capture a meteor in such small field smile.gif

I think too that's a typical meteor track. Maybe they tried it because there's a.t.m. a well-known stream near Mars.

Fred's image was first a secret to me how he's processed it blink.gif but then it works too. Tried to get more darkness in the lower part: http://www.greuti.ch/spirit/Spirit_pancamL1_M1.jpg

Posted by: vikingmars Oct 26 2005, 08:03 AM

biggrin.gif CONGRATULATIONS, Fredk !
So far, this is the 1st astronomical sky rotation picture ever seen from Mars !


QUOTE (fredk @ Oct 25 2005, 06:36 PM)
I'm sceptical these are meteors, as I explained in the http://www.unmannedspaceflight.com/index.php?showtopic=1534.  Even this latest long streak would've been an incredibly bright fireball.  Even though they call them "meteor searches" in the planning sequences, at the very bottom of http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20051021a.html it says

"Bright streaks in some parts of the images aren't stars or meteors or unidentified flying objects, but are caused by solar and galactic cosmic rays striking the camera's detector."

And earlier

"Scientists use the images to assess the cameras' sensitivity and to search for evidence of nighttime clouds or haze."

But on the evening of sol 643, Spirit took an extremely interesting http://marsrovers.jpl.nasa.gov/gallery/all/spirit_p643.html, eerily reminiscent of my "suggestion" in the first post of the http://www.unmannedspaceflight.com/index.php?showtopic=1534.  There are five sequential images of the same region of sky.  In the attached image I tried to sum these images, but I'm sure the experts could do a better job.  The result clearly shows the trails as arcs around what  must be the south Martian celestial pole off to the left, though I haven't ID'd the stars yet.  It's a spectacular shot!
*

Posted by: AndyG Oct 26 2005, 09:35 AM

QUOTE (fredk @ Oct 25 2005, 06:36 PM)
...The result clearly shows the trails as arcs around what  must be the south Martian celestial pole off to the left, though I haven't ID'd the stars yet.  It's a spectacular shot!
*

It's lovely!

I've made a stab at placing the Mars' South Pole location relative to the map, but I'm away from any useful starcharts at the moment. Anyone like to hazard a guess of where we are, from the annotated http://personal.strath.ac.uk/cjis28/trails.jpg?

Regards,

Andy G

Posted by: Joffan Oct 26 2005, 12:16 PM

I agree, what great images! biggrin.gif

QUOTE (AndyG @ Oct 26 2005, 03:35 AM)
Anyone like to hazard a guess of where we are, from the annotated http://personal.strath.ac.uk/cjis28/trails.jpg?
*

We also need camera angle to horizontal (not to rover) at least I think. Given that we have vertical trails centred in the view and that the horizon brightening looks square to the picture (=no camera tilt), the camera elevation will be a close approximation of the S latitude.

Actually I look at the image again and the vertical trails are 1/3 down the frame, so camera elevation will underestimate latitude by a few degrees. Anyone know the angular FoV for this shot?

Posted by: Tman Oct 26 2005, 12:32 PM

The field of view of these Pancam shots is a square of 16,8 x 16,8 degrees.

Posted by: SigurRosFan Oct 26 2005, 12:53 PM

Is the bright star Achernar? Exactly separation of 56°.

http://xs52.xs.to/pics/05433/Spirit_Meteor.jpg (178 KB)

Posted by: Bill Harris Oct 26 2005, 01:34 PM

QUOTE
so camera elevation will underestimate latitude by a few degrees.


The latitude of the site is known: 14.6* S. Using that and other info the altitude, azimuth, etc can be calculated and the approximate RA and DEC of the photo can be determined, which would narrow down the search.

Or wait a couple of weeks and they'll tell us at the JPL/MER site... biggrin.gif

--Bill

Posted by: Tman Oct 26 2005, 04:26 PM

smile.gif still more frames came down: http://www.greuti.ch/spirit/Spirit_pancamL1_M2.jpg

One of the R1 captured another one (I guess): http://marsrovers.jpl.nasa.gov/gallery/all/2/p/643/2P183485217EFFAI38P2734R2M1.HTML

Posted by: fredk Oct 26 2005, 06:16 PM

I was too slow with the nine frame image - as soon as I finished compiling it I see Tman's!

Nice job darkening the bottom part, Tman! My "secret" was to apply 1 pixel gaussian blur, followed by a simple levels adjust to remove most of the faint noise before summing the frames. I knew you experts could improve it!

Posted by: Tman Oct 26 2005, 06:50 PM

Hi Fred, first I thought to doing some work with the eraser between the star tracks in the second image, but too much to tinker with it.

The method I found was to copy all white structures in a new image (layer) with the "magic wand", of course first with a lot of noises too (the "white" color still to boost helps, also some "auto color changing" on small noises). Then soft-focus effects too. The background got a simulated black.

I guess there are still smarter methods.

Posted by: Edward Schmitz Oct 28 2005, 02:34 PM

Why is it assumed that this is the southern sky? Spirit can see very far into the northern sky, as well. 56 deg N would still be at about 42 deg elevation. In fact, I think that the camera platform cannot look up very far. I'll look it up, if nobody knows that off the top of their head.

I just want to point out that it could be the northern sky...

ed

Posted by: jamescanvin Oct 30 2005, 12:48 AM

QUOTE (Edward Schmitz @ Oct 29 2005, 12:34 AM)
In fact, I think that the camera platform cannot look up very far.  I'll look it up, if nobody knows that off the top of their head. 
*


No, the pancam can look vertically up, (more than) vertically down and anywhere inbetween. smile.gif

Posted by: ilbasso Oct 30 2005, 02:57 AM

QUOTE (vikingmars @ Oct 26 2005, 08:03 AM)
biggrin.gif CONGRATULATIONS, Fredk !
So far, this is the 1st astronomical sky rotation picture ever seen from Mars !
*

Well, technically, the sunset pictures/movies we have made from Viking, Pathfinder, and MERs are also sky rotation pictures - we just can't see any other stars than the Sun.

Posted by: Edward Schmitz Oct 30 2005, 08:16 PM

QUOTE (jamescanvin @ Oct 29 2005, 05:48 PM)
No, the pancam can look vertically up, (more than) vertically down and anywhere inbetween.  smile.gif
*

You're right. It can look straight up. Spec for elevation is +/- 90 deg in elevation. Per Dec 2003 JGR.

That still doesn't mean that those are southern stars.

ed

Posted by: jamescanvin Oct 31 2005, 12:17 AM

QUOTE (Edward Schmitz @ Oct 31 2005, 06:16 AM)
You're right.  It can look straight up.  Spec for elevation is +/- 90 deg in elevation.  Per Dec 2003 JGR.
*


Actually it's -104 to +90 in elevation (and for completeness 0 to 370 in azimuth)

QUOTE (Edward Schmitz @ Oct 31 2005, 06:16 AM)
That still doesn't mean that those are southern stars.
*


No of course not, I deliberately didn't quote that bit of your post as I wasn't making any reference to that.

However the image fredk posted is made of several pancam frames stacked together, so the direction of rotation can be deduced. I just had a quick look and the stars are moving clockwise (down the image, with the centre of rotation to the left) which makes that the south pole they are rotating around and hence this is the southen sky.

James

Posted by: SigurRosFan Dec 5 2005, 09:48 PM

Tman's Sol 643 Meteor: http://www.greuti.ch/spirit/Spirit_pancamL1_M2.jpg

JPL press image: http://photojournal.jpl.nasa.gov/catalog/PIA03613

--- The views shown here are a composite of nine 60-second exposures taken with the panoramic camera on Spirit during night hours of sol 643 (Oct. 25, 2005), during a week when Mars was predicted to pass through a meteor stream associated with comet P/2001R1 LONEOS. ---

Posted by: ilbasso Dec 6 2005, 12:21 AM

...and note that the press release says these are stars in Octans and Pavo, which are most decidedly constellations of the Southern Hemisphere.

Posted by: mars loon Dec 6 2005, 07:23 AM

QUOTE (ilbasso @ Dec 6 2005, 12:21 AM)
...and note that the press release says these are stars in Octans and Pavo, which are most decidedly constellations of the Southern Hemisphere.
*

More Meteors from Spirit and JPL

PIA03615: Meteor Search by Spirit, Sol 668

http://photojournal.jpl.nasa.gov/catalog/PIA03615

Annotated Meteor Search by Spirit, Sol 668

The panoramic cameras on NASA's Mars Exploration Rovers are about as sensitive as the human eye at night. The cameras can see the same bright stars that we can see from Earth, and the same patterns of constellations dot the night sky. Scientists on the rover team have been taking images of some of these bright stars as part of several different projects. One project is designed to try to capture "shooting stars," or meteors, in the martian night sky. "Meteoroids" are small pieces of comets and asteroids that travel through space and eventually run into a planet. On Earth, we can sometimes see meteoroids become brilliant, long "meteors" streaking across the night sky as they burn up from the friction in our atmosphere. Some of these meteors survive their fiery flight and land on the surface (or in the ocean) where, if found, they are called "meteorites." The same thing happens in the martian atmosphere, and Spirit even accidentally discovered a meteor while attempting to obtain images of Earth in the pre-dawn sky back in March, 2004 (see http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a.html, and Selsis et al. (2005) Nature, vol 435, p. 581). On Earth, some meteors come in "storms" or "showers" at predictable times of the year, like the famous Perseid meteor shower in August or the Leonid meteor shower in November. These "storms" happen when Earth passes through the same parts of space where comets sometimes pass. The meteors we see at these times are from leftover debris that was shed off of these comets.

The same kind of thing is predicted for Mars, as well. Inspired by calculations about Martian meteor storms by meteor scientists from the University of Western Ontario in Canada and the Centre de Recherche en Astrophysique de Lyon in France, and also aided by other meteor research colleagues from NASA's Marshall Space Flight Center, scientists on the rover team planned some observations to try to detect predicted meteor storms in October and November, 2005. The views shown here are a composite of nine 60-second exposures taken with the panoramic camera on Spirit during night hours of sol 668 (Nov. 18, 2005), during a week when Mars was predicted to pass through a meteor stream associated with Halley's comet. The south celestial pole is at the center of the frame. Many stars can be seen in the images, appearing as short, curved streaks forming arcs around the center point. The star trails are curved because Mars is rotating while the camera takes the images. The brightest stars in this view would be easily visible to the naked eye, but the faintest ones are slightly dimmer than the human eye can detect.

In addition to the star trails, there are several smaller linear streaks, dots and splotches that are the trails left by cosmic rays hitting the camera detectors. Cosmic rays are high-energy particles that are created in the Sun and in other stars throughout our galaxy and travel through space in all directions. Some of them strike Earth or other planets, and ones that strike a digital camera detector can leave little tracks or splotches like those seen in these images. Because they come from all directions, some strike the detector face-on, and others strike at glancing angles. Some even skip across the detector like flat rocks skipped across a pond. These are very common phenomena to astronomers used to working with sensitive digital cameras like those in the Mars rovers, the Hubble Space Telescope, or other space probes, and while they can be a nuisance when taking pictures, they generally do not cause any lasting damage to the cameras. Three of the streaks in the image, including one spanning most of the distance from the left edge of the frame to the center, might be meteor trails or could be the marks of other cosmic rays.

While hunting for meteors on Mars is fun, ultimately the team wants to use the images and results for scientific purposes. These include helping to validate the models and predictions for interplanetary meteor storms, providing information on the rate of impacts of small meteoroids with Mars for comparison with rates for the Earth and Moon, assessing the rate and intensity of cosmic ray impact events in the Martian environment, and looking at whether some bright stars are being dimmed occasionally by water ice or dust clouds occurring at night during different Martian seasons.

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