PDA

View Full Version : Solar Eclipse on Mars?



yaohua2000
2004-Feb-28, 05:06 AM
I've heard that a solar eclipse will be occured at Spirit/Opportunity's landing site next week from www.sina.com.cn, the largest website in China. Because the know-nothing reporters always publish science-related news mistakenly (The foolish reporters published an earth's photo today, in the photo, the earth is very big and clear. they say the photo was taken by Spirit from Mars, actually it was taken by Apollo 8), so I'm not sure if the news true or false. I searched the web at google, and found nothing about the possible solar eclipses. Could anyone tell me if any solar eclipses will be occured next week?

Maksutov
2004-Feb-28, 11:43 AM
I've heard that a solar eclipse will be occured at Spirit/Opportunity's landing site next week from www.sina.com.cn, the largest website in China. Because the know-nothing reporters always publish science-related news mistakenly (The foolish reporters published an earth's photo today, in the photo, the earth is very big and clear. they say the photo was taken by Spirit from Mars, actually it was taken by Apollo 8), so I'm not sure if the news true or false. I searched the web at google, and found nothing about the possible solar eclipses. Could anyone tell me if any solar eclipses will be occured next week?

Here (http://www.latimes.com/news/science/la-sci-mars27feb27,1,973876.story?coll=la-news-science) is information about that experiment. I hope it's successful. :)

A registration/subscription may be required, so here's the gist of the article:

Scientists Turn Rover's Gaze to Martian Dusk, Moons' Eclipses

...The Mars rover Opportunity shifted its gaze from the microscopic to the celestial moving from an examination of grains of soil to a dramatic Martian sunset.

Scientists on Thursday unveiled time-lapse images of the setting sun in a murky Martian dusk. These first sunset images of the mission were captured about two weeks ago by the rover's panoramic camera.

Next week, scientists at the Jet Propulsion Laboratory in Pasadena will attempt a Martian first recording an eclipse of the Martian moons Phobos and Deimos...

yaohua2000
2004-Feb-28, 12:48 PM
Next week, scientists at the Jet Propulsion Laboratory in Pasadena will attempt a Martian first recording an eclipse of the Martian moons Phobos and Deimos...

Next week, when? Sunday, Monday, Tuesday, Wednesday, Thursday, Friday or Saturday?

Phobos and Deimos..., Phobos or Deimos? or the both??

What a news report!

Phobos is only 6,000 kilometres from Martian surface, and runs around Mars once a few hours, so perhaps it has much possibility to transit over the Sun. But for Deimos, I'm not sure how seldom the transit can be occured, maybe less than the Moon transit over the Sun on the Earth.

Maksutov
2004-Feb-28, 01:06 PM
Next week, scientists at the Jet Propulsion Laboratory in Pasadena will attempt a Martian first recording an eclipse of the Martian moons Phobos and Deimos...

Next week, when? Sunday, Monday, Tuesday, Wednesday, Thursday, Friday or Saturday?

Phobos and Deimos..., Phobos or Deimos? or the both??

What a news report!

Phobos is only 6,000 kilometres from Martian surface, and runs around Mars once a few hours, so perhaps it has much possibility to transit over the Sun. But for Deimos, I'm not sure how seldom the transit can be occured, maybe less than the Moon transit over the Sun on the Earth.

Sorry, I'm not the LA Times, NASA, or JPL.

If I find more specific information I will post it.

请劳驾

eburacum45
2004-Feb-28, 02:31 PM
I've just posted a mock-up of a Phobos transit as seen from Mars
here (http://www.badastronomy.com/phpBB/viewtopic.php?p=214533#214533)

ToSeek
2004-Feb-28, 05:11 PM
I've just posted a mock-up of a Phobos transit as seen from Mars
here (http://www.badastronomy.com/phpBB/viewtopic.php?p=214533#214533)

Which is from Wednesday, March 3. The press conference gave the impression that we're into an eclipse "season," so that there will be a bunch of them rather than just one.

Glom
2004-Feb-28, 05:27 PM
So we're just talking about a transit here, not an actual eclipse. Mars's moons aren't big enough to cause anything dramatic like a solar eclipse.

George
2004-Feb-28, 06:09 PM
I've just posted a mock-up of a Phobos transit as seen from Mars
here (http://www.badastronomy.com/phpBB/viewtopic.php?p=214533#214533)

A picture's worth a thousand words. Great idea. 8)

Deimos should be about 97% smaller in area compared to Phobos due to it's much greater distance and smaller size. It will be probably look like the "fastest sunspot in the west" (or will it be east?).

EFossa
2004-Feb-29, 01:19 PM
Any idea what kind of observations they will make during these eclipses? Images of Phobos crossing the Sun are certain I would assume, but what using the pancam or navigation cameras to catch the shadow as it moves across the landscape, or changes in sky colour/brightness during the event?

eburacum45
2004-Feb-29, 01:21 PM
There will be no shadow, as the Sun will not be totally obscured; I am not sure that the rovers have a camera rigged to observe the transit of Phobos, but very little of scientific value would come from such an observation IMO.

ToSeek
2004-Feb-29, 03:29 PM
There will be no shadow, as the Sun will not be totally obscured; I am not sure that the rovers have a camera rigged to observe the transit of Phobos, but very little of scientific value would come from such an observation IMO.

But it's way cool!

EFossa
2004-Feb-29, 04:10 PM
The rovers seem to take quite a few images of the sun to find its orientation on the planet to enable it to accurately point it high gain antenna toward Earth I think. The camera has a special filter to do this.

There are also quite a few images from MGS showing the dark shadow of Phobos sweeping across the surface of the planet.

eburacum45
2004-Feb-29, 06:29 PM
We might be in luck then; although the transit seems only to last a few seconds, as Phobos moves very fast.

The shadow on the surface of Mars must be a penumbra, rather than a full shadow;
from the BBC;

http://news.bbc.co.uk/olmedia/500000/images/_503729_shadow300.jpg

russ_watters
2004-Mar-01, 08:58 PM
Wait, there are two separate things being discussed here: is this event a transit of the moons across the sun or an eclipse of the moons?

SeanF
2004-Mar-01, 09:06 PM
Wait, there are two separate things being discussed here: is this event a transit of the moons across the sun or an eclipse of the moons?

I was wondering the same thing. Maksutov's reference:


Next week, scientists at the Jet Propulsion Laboratory in Pasadena will attempt a Martian first recording an eclipse of the Martian moons Phobos and Deimos...

To me, an "eclipse of the . . . moon" would be the equivalent of our lunar eclipse, that is, the planet's shadow being cast on the moon. But I thought Spirit and Opportunity went to "sleep" during the Martian night . . .

ToSeek
2004-Mar-01, 09:26 PM
Look at eburacum45's post (http://www.badastronomy.com/phpBB/viewtopic.php?p=214533#214533) - it's a transit/solar eclipse, not a lunar eclipse. The latter are probably extremely common on Mars.

yaohua2000
2004-Mar-02, 01:21 AM
I found such a transit at Meridiani Planum this week. :) Phobos transit from the Sun on 2004-Mar-06 19:22:03 UTC. I computed the above with Horizons On-Line Ephemeris System introduced by JPL.

yaohua2000
2004-Mar-02, 12:38 PM
The transit will start at 2004-Mar-06 19:21:52 UT in SCET.
The transit will end at 2004-Mar-06 19:22:14 UT in SCET.

The angular separation between the Sun and the Phobos is 0.1999 degrees on 2004-Mar-06 at 19:22:03.

:D

ToSeek
2004-Mar-03, 01:42 AM
Starry Night shows me a transit of Deimos from Gusev crater (Spirit's landing site) on 2004-03-06 from 15:39:40 to 14:41:10 UT (approximately).

Maksutov
2004-Mar-03, 04:16 AM
Wait, there are two separate things being discussed here: is this event a transit of the moons across the sun or an eclipse of the moons?

I was wondering the same thing. Maksutov's reference:


Next week, scientists at the Jet Propulsion Laboratory in Pasadena will attempt a Martian first recording an eclipse of the Martian moons Phobos and Deimos...

To me, an "eclipse of the . . . moon" would be the equivalent of our lunar eclipse, that is, the planet's shadow being cast on the moon. But I thought Spirit and Opportunity went to "sleep" during the Martian night . . .

What I wrote was a quote from an article in the Los Angeles Times. It was also cross verified by an article I had already read in space.com (see here (http://www.space.com/businesstechnology/technology/rover_photos_031230.html)). Apparently Jim Bell of JPL, the lead scientist for the panoramic cameras, needs to brush up on his terminology. Here's what he said,


"We'll be sitting there at the Jet Propulsion Laboratory scratching our heads like everyone else," said Jim Bell, lead scientist for the panoramic camera each rover carries.

Scientists plan to focus on rocks strewn across the Martian landscape that could reveal clues about whether the planet was ever hospitable to life.

They also plan to photograph the sun as it rises and sets on Mars, as well as the Earth, which appears in the sky above the Red Planet as a morning star. A rover also may catch an eclipse of the sun by Phobos, one of Mars' two moons.

"It will be the first eclipse observed from the surface of another planet," Bell said.

Please excuse me for not triple checking something published in the mass media. Next time I will.

BTW, if Phobos' geometric center coincides with the Sun's center, it should look like one heck of an "freestyle" annular eclipse (sorry, there's that word again). 8)

yaohua2000
2004-Mar-03, 09:17 AM
Starry Night shows me a transit of Deimos from Gusev crater (Spirit's landing site) on 2004-03-06 from 15:39:40 to 14:41:10 UT (approximately).

My computing showed me no transit of Deimos from Gusev Crater (184.70 degrees west, 14.59 degrees south) on 2004-Mar-06 at 15:40 UT. At 15:37:26, the angular separation between the Sun and Deimos is 1.6482 degrees, which is a bit larger than the radius of the Sun add the radius of Deimos.

ToSeek
2004-Mar-04, 12:28 AM
Starry Night shows me a transit of Deimos from Gusev crater (Spirit's landing site) on 2004-03-06 from 15:39:40 to 14:41:10 UT (approximately).

My computing showed me no transit of Deimos from Gusev Crater (184.70 degrees west, 14.59 degrees south) on 2004-Mar-06 at 15:40 UT. At 15:37:26, the angular separation between the Sun and Deimos is 1.6482 degrees, which is a bit larger than the radius of the Sun add the radius of Deimos.

Starry Night thinks that Gusev is at 184o36' west, 14o36' south. Perhaps that's enough to make a difference - or maybe it's just not accurate enough. I didn't try putting in the exact position of the rover.

ToSeek
2004-Mar-04, 12:45 AM
The proposed plan for sol 39, which will end at 8:52 a.m. PST on Thursday, March 4, is to start the morning by taking images of a rare solar transit of the martian moon, Deimos. The solar transit of Deimos causes a solar eclipse only twice per Mars year (one Mars year equals roughly two Earth years). Later in the sol, Opportunity is scheduled to take a microscopic panorama of the layers in the "Last Chance" rock formation.

-- http://marsrovers.jpl.nasa.gov/mission/status.html

EFossa
2004-Mar-05, 12:03 PM
They dont seem to be updating the pancam images from opportunity much lately, the last update was Sol 37 and its now Sol 40. Maybe they're saving the images for todays press briefing.

ToSeek
2004-Mar-05, 06:50 PM
Some images here. (http://marsrovers.jpl.nasa.gov/gallery/all/opportunity_p039.html)

ToSeek
2004-Mar-07, 01:47 PM
Space.com has a set of the images (http://www.space.com/php/multimedia/imagedisplay/img_display.php?pic=h_deimos_transit_02,0.jpg&cap= Opportunity%20Mars%20rover%20used%20its%20Panorami c%20Camera%20to%20watch%20the%20rare%20solar%20cro ssing%20of%20the%20Sun%20by%20the%20martian%20moon %20Deimos.%20CREDIT:%20JPL/NASA) nicely lined up.

ToSeek
2004-Mar-08, 05:39 PM
Animated gif (http://www.moonglow.net/eclipse/merb_deimos.gif)

ToSeek
2004-Mar-09, 12:40 AM
Opportunity catches Phobos (http://marsrovers.nasa.gov/gallery/all/opportunity_p042.html)

ToSeek
2004-Mar-09, 12:56 AM
JPL press release:


NEWS RELEASE: 2004-081 March 8, 2004

NASA Rovers Watching Solar Eclipses by Mars Moons

NASA's Mars Exploration Rovers have become eclipse watchers.

Though the Viking landers in the 1970s observed the shadow of one of Mars' two moons, Phobos, moving across the landscape, and Mars Pathfinder in 1997 observed Phobos emerge at night from the shadow of Mars, no previous mission has ever directly observed a moon pass in front of the Sun from the surface of another world.

The current rovers began their eclipse-watching campaign this month. Opportunity's panoramic camera caught Mars' smaller moon, Deimos, as a speck crossing the disc of the Sun on March 4. The same camera then captured an image of the larger moon, Phobos, grazing the edge of the Sun's disc on March 7.

Rover controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., are planning to use the panoramic cameras on both Opportunity and Spirit for several similar events in the next six weeks. Dr. Jim Bell of Cornell University, Ithaca, N.Y., lead scientist for those cameras, expects the most dramatic images may be the one of Phobos planned for March 10.

"Scientifically, we're interested in timing these events to possibly allow refinement of the orbits and orbital evolution of these natural satellites," Bell said. "It's also exciting, historic and just plain cool to be able to observe eclipses on another planet at all."

Depending on the orientation of Phobos as it passes between the Sun and the rovers, the images might also add new information about the elongated shape of that moon.

Phobos is about 27 kilometers long by about 18 kilometers across its smallest dimension (17 miles by 11 miles). Deimos' dimensions are about half as much, but the pair's difference in size as they appear from Mars' surface is even greater, because Phobos travels in a much lower orbit.

The rovers' panoramic cameras observe the Sun nearly every martian day as a way to gain information about how Mars' atmosphere affects the sunlight. The challenge for the eclipse observations is in the timing. Deimos crosses the Sun's disc in only about 50 to 60 seconds. Phobos moves even more quickly, crossing the Sun in only 20 to 30 seconds.

Scientists use the term "transit" for an eclipse in which the intervening body covers only a fraction of the more-distant body. For example, from Earth, the planet Venus will be seen to transit the Sun on June 8, for the first time since 1882. Transits of the Sun by Mercury and transits of Jupiter by Jupiter's moons are more common observations from Earth.

From Earth, our Moon and the Sun have the appearance of almost identically sized discs in the sky, so the Moon almost exactly covers the Sun during a total solar eclipse. Because Mars is farther from the Sun than Earth is, the Sun looks only about two-thirds as wide from Mars as it does from Earth. However, Mars' moons are so small that even Phobos covers only about half of the Sun's disc during an eclipse seen from Mars.

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington, D.C.

Images of the March 4 and March 7 eclipses are available online at http://marsrovers.jpl.nasa.gov/gallery/press/opportunity/20040308a.html . Other images from the rovers and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University at http://athena.cornell.edu .

ToSeek
2004-Mar-13, 04:20 AM
Another transit by Phobos:

http://qt.exploratorium.edu/mars/opportunity/pancam/2004-03-12/1P132370911ESF05AMP2672R8M1.JPG

http://qt.exploratorium.edu/mars/opportunity/pancam/2004-03-12/1P132370921ESF05AMP2672R8M1.JPG

http://qt.exploratorium.edu/mars/opportunity/pancam/2004-03-12/1P132370931ESF05AMP2672R8M1.JPG

http://qt.exploratorium.edu/mars/opportunity/pancam/2004-03-12/1P132370941ESF05AMP2672R8M1.JPG

ToSeek
2004-Mar-14, 12:49 AM
Spirit see Deimos transit (http://marsrovers.nasa.gov/gallery/all/spirit_p068.html)

Look closely at the Sun images toward the bottom of the page.

ToSeek
2004-Mar-24, 08:29 PM
I think the images at the top of this page (http://marsrovers.jpl.nasa.gov/gallery/all/spirit_p079.html) are showing Deimos.

ToSeek
2005-Feb-25, 03:26 PM
Another Phobos eclipse:

http://qt.exploratorium.edu/mars/spirit/pancam/2005-02-20/2P162140837ESFA600P2740R8M1.JPG

http://qt.exploratorium.edu/mars/spirit/pancam/2005-02-21/2P162222796ESFA600P2741R8M1.JPG

http://qt.exploratorium.edu/mars/spirit/pancam/2005-02-21/2P162222806ESFA600P2741R8M1.JPG

frogesque
2005-Feb-25, 03:37 PM
Nice images, were they from Oppy or Spirit?

Edit: Ok, I read the 'quote' text and I see they were from the Spirit pancam.