800Whrs+ Staying Up Late ideas Options

[fredk]

I believe you're right.

Animation of Phobos rising in the west on sol 1951:

[nprev]

Great animation, Fred!

It gave me another possible evening app idea. Looks like some of those streaks just might be sporadic (random non-shower) meteors. On Earth, due to a number of factors including season & time of day, the average rate at any locale is anywhere from 2 to maybe 20 per hour across the entire visible sky. I'm certain that we have no data at all about the rate of sporadic meteor occurrence anywhere else in the Solar System.

The rate of sporadics is highest just before sunrise as the piece of Earth or Mars you happen to be on faces the direction of the planet's orbital motion around the Sun. It could be well worth while to execute a predawn observation campaign for as many days as we can to get a rough meteor count. Might even get lucky & identify a Martian meteor shower or two!

[Astro0]

fredk - fantastic animation.
What I love are the clouds that are catching the evening light.

[Deimos]

The streaks are just cosmic rays. Most CRs are small splotches, but these long exposures are enough to catch several at glancing incidence. If the navcam frames had actual meteors, the pancam L1 frames would be chock full of them--and the incidence of streaks in pancam and navcam is about the same. In fact, in the whole meteor search last time we had this kind of power, streaks were just as common in "dark" filters as in the clear filter. I've heard some analysis suggests we need to repeat 2005s observations 10x to have an expected value of 1 meteor, given camera sensitivities. So we'd need >100 2005s to get statistics. So, maybe no surprise that "meteor search" hasn't been showing up at the tracking data base. (Of course, when possible, stereo exposures are used and the exposure time is slightly offset so there's a chance one will be spotted and give speed and direction info--as long as that doesn't interfere with other objectives.)

[Fran Ontanaya]

Is there any chance to bounce a radio signal on them from one of the satellites and listen it with Spirit? Since the martian atmosphere is so thin, I guess that the ionized tails would be closer to the ground.

[helvick]

IIRC despite being much thinner at the ground Earth and Mars atmospheric density are pretty close at the altitudes where the bulk of meteors burn out - Mars lower gravity means the scale height is ~11km vs 6-7km for Earth. I ran the numbers sometime back but can't find them now unfortunately but I'd be very surprised if Martian meteors were generally burning up at significantly lower altitudes than on earth. There are further complications of course, most of the source "debris" will be slower relative to Mars than similar material impacting Earth's atmosphere and that might mean that it can penetrate lower (having less energy to burn through).

[CosmicRocker]

... when possible, stereo exposures are used and the exposure time is slightly offset ...

I was about to bemoan your depiction of CRs as "small splotches,"
but then, the above comment attracted my attention.

I didn't know there was a time offset between the stereo images. Since the time stamps in the file names of all stereo pairs I've noticed have been identical for the L and R images in each pair, I assume this offset is less than one second. Can you elaborate on this a bit? Is the offset a constant? Is it the same value for each of the camera pairs? If it is a constant, can you tell us its value?

...Thanks

[Deimos]

Sometimes the science objective requires exposures that don't help--like 10 sec L1s with 60 sec R4 or other (not to mention single eye imaging). But a common strategy is to start exposures at the same time and have one eye use a 61 sec exposure and the other use 60 (or similar 1-sec offset). So, odds are (in decreasing order) no meteor is seen; one is seen only in L1; one is seen in both with no obvious staggered end point; one is seen in each, and the end points project to different points of the sky. The last, of course, would imply the meteor was in the FOV at the end of the exposure (since start time is the same), and would show motion direction and show how much motion occurred in the last second. Low odds of success-but frequently, no cost to doing. So much of the 2005 meteor campaign used this. (generally, the right eye would get the extra second, but that's not a rule or anything.)

[nprev]

Okay, longest long-shot goofball night obs idea I can conjure up: Aurora search.

IIRC, Mars' magnetic field (what there is of it) is localized & kind of fragmented as surface remnants of its primeval core source field, so there's no real N-S mag poles like Earth. Still, the upper atmosphere must fluoresce (sp?) however weakly sometimes; long horizon exposures in the dead of night (which look through the longest chord of the atmosphere possible) might reveal occasional transient glows.

Alternatively, maybe we might pick up the occasional flash of a static discharge from airborne dust? This might even be somewhat reasonable; presumably airborne dust clouds from DDs, gusts, etc. begin to descend at night once solar heating ceases, so they might zap the ground on the way down.

<waits for waves of derisive laughter, some of which he himself emits!>

[BrianL]

Okay, longest long-shot goofball night obs idea I can conjure up: Aurora search.

Oh, not even remotely in the goofball night obs game. Two words: nocturnal life forms. OK, three words.

[lyford]

Since MRO has taken a few shots of Spirit, is it even possible that she return the favor?

[Astro0]

Here's a movie of the sunset on Sols 1940 and 1954.
A little music and colourisation added for effect. Enjoy

 Mars_Sunsets.wmv ( 2.49MB ) Number of downloads: 637

[imipak]

Well now, if we're talking goofball ideas... Astro0's evocative animation of the sunset especially reminds me that I've often wondered about the outreach potential of full-motion video. Of course, there are plenty of excellent reasons why video capture's not a requirement for present or any future lander, not least the fact that if nothing much moves... what do you film?

Well, actually quite a few things move or change their appearance relatively quickly. (That's evident from the many amazing animations posted here and elsewhere composed from still sequences.) The sun moves, of course, and the shadows cast by the landscape and rover itself. Those planets which are bright enough to be visible (more slowly.) The stars, and possibly other astronomical objects. Phobos and Deimos. Possibly orbiting spacecraft. Dust devils. Atmospheric phenomena - clouds, and dust clouds; possibly aurorae as suggested by nprev above. And (one day!) the whole landscape will move past Spirit itself.

So, how about shooting some sequences at a higher than normal rate? (e.g. , an hour of one image every 30s would make 5 seconds of 25fps "video".) Candidates might include DD movies, the moving scenery once Spirit gets back on the road, and personally I'd love to see an all-night sequence of the stars revolving across the sky. (That would require staying awake all night, which I guess would be too power-intensive even with 900 Whr?)

I have a hunch that a sequence composed of stills showed at 25 fps, even if nothing interesting is going on, would produce a more visceral, "real life" feel in viewers used to seeing the world on TV. Even a sequence where nothing moves but the noise on the CCDs would, I think, communicate something more immediate and direct about the statement "we have rovers on Mars" than still images alone.

I can see two obvious problems with this, apart from the obvious ("...but that's crazy. What's the point?"): storage space, and uplink bandwidth. No doubt there are many others!

[fredk]

Here is another animation showing Earth sliding past Venus, now including sols 1946, 48, and 49 (I can't even see Venus in the 1947 series). These are all processed the same as previously - register each sol's 4 or 5 frames on Venus, then take average, followed by a contrast stretch:

[fredk]

And here's a labelled version showing Earth's position on each sol: