MSL - Stopover on the Road to Glenelg - Arm Commissioning, Commissioning Activity Period 2 - Sols 30 through 37 Options

[fredk]

Where the sun's north pole is on the M100 view will depend on the azimuth of the sun, ie the local solar time, since mastcam sits on an altazimuth mount. Shouldn't be hard to work that out...

Once all the M100 frames are down, you could do a proper super-res to hopefully confirm this spot and see if anything else is visible. Usually when they do super-res with Oppy, they have to change the pointing slightly from frame to frame. But with the sun you can keep the pointing fixed and let the diurnal movement do the trick.

[Deimos]

My eyes went to that spot as soon as I heard the question. It kind of aligns, but I am unconvinced since I wouldn't have picked the area as the best spot. The sol 42 images should be pretty definitive, if even that one is real.

[Ant103]

Sol 36 Mastcam100. Long picture is loooooooooooong.



As said in this post, this is overlaping the right part of Mount Sharp, so, we should get a 50 000 pixels wide panorama ! This is yet very tempting. Hey little Macbook, can you please do me a favour :3 ?

[maschnitz]

Some notes on the sunspot Stereo B idea: I was trying to develop a basic intuition of the geometry, so I dove into Eyes (thanks, Doug! great program). I got a couple of screenshots at the time of the eclipse.

The Sun and Phobos are where the lines intersect in the second shot. The eclipse occurred in the afternoon, with the Sun in the west on Mars, over the Gale Crater rim. Stereo B was high in the sky to the west at the time, above the Sun.

Whether you turn the Stereo B images clockwise or counterclockwise depends on whether published Stereo B images are oriented with the solar north pole up, or down, respectively. (Assuming Martian north is the same as solar north, of course.) It's probably clockwise, since the Stereo team seem to pay strict attention to latitudes in their release image. Or you can turn the MastCam images counterclockwise (that is, this would mean solar north is to the right in the eclipse shots).

You can apply all this this way to any transit event. What you're really doing is figuring out where the solar north pole is. In fact, you won't turn MastCam images exactly 90 degrees CCW, you'll turn them so the solar north pole is straight up. That'll apply equally well at other times of day on Mars. I'm not sure how best to do that, though.

Side note: EPOXI was in an even better position. But naturally, they weren't making solar observations at the time.

Attached thumbnail(s)

 

[MaG]

Maybe it's not so hard, when you take a look at situation in "Eyes". Mars is now about 90 deg behind Earth, so what is about 90 deg left on the Sun from middle part visible from Earth, that is something what is on Mars in the middle. In last days I have read some info abou CME's from farside of the Sun. When you take a look on images from Stereo B, there is one very active region and also many of complicated magnetic fields. So maybe we will see in next days...

Here is one of the best Stereo B images of this part of the Sun with eruption..


ADMIN: Inline image replaced. Plesae note Forum Rules and Guidelines 3.2 and 3.3

[Pertinax]

My eyes went to that spot as soon as I heard the question. It kind of aligns, but I am unconvinced since I wouldn't have picked the area as the best spot. The sol 42 images should be pretty definitive, if even that one is real.

I've been tinkering with sunspot visibility 'climatology' for MC100, though not sure how best to summarize the data; how to make it the most meaningful. In the meantime, it hit me that a sunspot that was just resolvable (1 pixel) on mars by MSL's MC100 might well be rather comparable to a sunspot that was at the limit of unaided human vision on earth.

To check that idea I assumed the following:

MC100 (sun from Mars): about 0.00426 deg/pixel
Human Eye (sun from earth): about 0.00550 deg/pixel (http://clarkvision.com/imagedetail/eye-resolution.html)
Angular diameter of sun from earth: 0.536 deg (avg)
Angular diameter of sun from mars: 0.354 deg (avg)
angular size of a sunspot visible from mars that would be just visible to a human on earth: (0.354/0.536)*0.00550 = 0.00363 deg

Thus, a sunspot that is at the threshold of vision to a human on earth is ~= to one pixel on MSL's MC100 (0.004 deg = 0.004 deg)

That seem reasonable? I didn't notice any issues but I also have a fussing baby in background so my focus at the moment isn't 100%

Anyway, I though that was pretty neat (assuming I didn't make any mistakes) -- [also, Sunpot 1575 is just at the edge of visibility through welding glass currently]

-- Pertinax

[udolein]

Here is my take on the Sol 42 Phobos transit.

Seems to see real stars in the background regardless of the poor signal to noise of the real transit:


link to .gif sequence

Comparison with Eyes on the Solar System:


Enlarge

The bright objects above the sun are Jupiter and a background star ....

Cheers, Udo

[udolein]

My take on the Sol 42 Deimos transit indicates that there is really a sunspot visible, especially in the enlarged version:


link to enlarged .gif sequence

Regards, Udo

[fredk]

Any star or planet would be many orders of magnitude fainter than the sun, so you'd never see them in the same image. Those bright spots are probably hot pixels on the CCD.

[Joffan]

Any star or planet would be many orders of magnitude fainter than the sun, so you'd never see them in the same image. Those bright spots are probably hot pixels on the CCD.

Yes, everything except Phobos would stay in step with the Sun if they were really stars or planets - and they don't.

[udolein]

Yes, everything except Phobos would stay in step with the Sun if they were really stars or planets - and they don't.

Yes, convincing. Seems that I'm wrong. But nevertheless an impressive coincidence between theory and non-observed reality ...

Regards, Udo

[Deimos]

The coincidence gets better--on sol 37, during the Phobos grazing event, Deimos was geometrically within the M34 field of view. (...according to Starry Night--I didn't do detailed ephemeris for that.) Somewhere else in Gale crater, there might well have been a Deimos transit followed 20 minutes later by a Phobos annular eclipse.

[Nix]

Sol 36 Mastcam100. Long picture is loooooooooooong.

-IMG-

As said in this post, this is overlaping the right part of Mount Sharp, so, we should get a 50 000 pixels wide panorama ! This is yet very tempting. Hey little Macbook, can you please do me a favour :3 ?

The number of pixels is indeed growing
The following image is a merge I've been working on but I haven't figured out what sol(s) I'm going to use for an anaglyph.
I'm waiting eagerly for the sol 42&45 full images to complete and optimize. (to avoid using left camera images) Then see if my pc isn't going to choke on this...



and a preview of the big picture;