[X] My Assistant

[djellison]

Frames at 10s intervals instead of the 20s intervals (iirc) they used to have.

CODE

706 p2663.06 17  17  0   0   0   34   pancam_deimos_transit_R8

Duration (hhmmss)   =  00:12:45
Data Vol (Mbits)    =      0.84

Doug

Attached image(s)

 

[tacitus]

Aside from the coolness factor, is there any remaining science to be gained from photographing these eclipses? I would have thought they had nailed down all the specifics about Phobos and Deimos by now.

[djellison]

The more data sets they have on these events, the more they can bring in the limits of +/- on variables. Imaging at 10s gives another step in the level of accuracy available. It helps constrain the orbits of the moons, and mean better targeting for observations from orbit.

For total 'wow' factor, I'd very much like to see 10s sampled Navcam imagery of the terrain during a Phobos eclipse, as it gets quite dark during those. Pity there was no chance to do this from Husband hill, as the shadow might have even been visible racing across Gusev crater.

It would mean forgoing the Pancam imagery of the sun during that time, but ... it'd be cool

Doug

[djellison]

One thing I've often thought of is that we have these great anims from time to time, but they're not 'real time'

What would that eclipse have looked like in REAL time?

It lasted about 80 seconds end to end, so I mocked up something in 3ds Max, and uses Quicktime to add a few effects to it, and this is what it might have looked like, if seen in real time.

Doug

Attached File(s)

 deimos_706b.mov ( 75.25K ) Number of downloads: 439

 

[jamescanvin]

One thing I've often thought of is that we have these great anims from time to time, but they're not 'real time'

What would that eclipse have looked like in REAL time?

It lasted about 80 seconds end to end, so I mocked up something in 3ds Max, and uses Quicktime to add a few effects to it, and this is what it might have looked like, if seen in real time.

Doug

Very cool Doug, I felt like I was there!

I was just thinking something like that would be nice, then lo and behold along you come.

James

[Pertinax]

Thank you Doug. That is something that I have wished to see as well, but lacked the tools to acomplish it myself -- kind of like going to mars, only not quiet so hard .

-- Pertinax

[mars loon]

That is indeed cool Doug. Thank you.

How about Phobos, that would be even cooler, if that is included in the rover plan

ken

[djellison]

A phobos one was scheduled for a sol or two ago, but I've not seen the images come down. I intend to pull the same trick with that however.

Doug

[mars loon]

I looked too but dont see them yet. Thanks in advance. ken

[fredk]

For total 'wow' factor, I'd very much like to see 10s sampled Navcam imagery of the terrain during a Phobos eclipse, as it gets quite dark during those. Pity there was no chance to do this from Husband hill, as the shadow might have even been visible racing across Gusev crater.

It would mean forgoing the Pancam imagery of the sun during that time, but ... it'd be cool

Doug

That would be cool, but unfortunately Phobos only covers around 1/3 of the surface area of the sun, so that means you'd only be in the very diffuse penumbra. It's very hard to notice it when the sun is 1/3 covered by our moon during a solar eclipse. But in our case the sunlight dims very slowly, on a timescale of hours. For Mars, a Phobos eclipse lasts 30 seconds or so. So if you were standing there, I think you would notice a very subtle dimming if you payed close attention.

The width on the surface of Mars of the gradient part of Phobos' shadow (ie the distance from the outer edge of the penumbra to the outer edge of the region where Phobos is entirely in front of the sun) is equal to the diameter of Phobos, for an overhead eclipse. That's roughly 20km, depending on Phobos' orientation. So even from the summit of Husband, with a horizon distance on the order of 20km, you'd need a very wide view to see the extent of that gradient on the horizon (seeing it closer would be even harder). So a hazcam shot might have shown something very subtle (if there were any eclipses to see at that time!).

Actually though, I think with a pair of hazcams, one when the shadow was on the horizon and one a minute or so later or before, you could quite easily reveal the shadow using the dust devil diferencing technique. This could be doable from somewhat high ground.

That animation was nice, Doug. I've made gifs in the past with 10 second pauses each frame to achieve "real time", but the interpolation you've done between frames makes a big difference - did you do that interpolation by hand or was it some morphing app?

[ljk4-1]

One thing I've often thought of is that we have these great anims from time to time, but they're not 'real time'

What would that eclipse have looked like in REAL time?

It lasted about 80 seconds end to end, so I mocked up something in 3ds Max, and uses Quicktime to add a few effects to it, and this is what it might have looked like, if seen in real time.

Doug

Imagine future Mars colonists with various ways of racing the eclipses to keep the moons in front of Sol as long as possible, just as we do with jets on Earth.

Viking 1 had the shadow of Phobos pass right over it:

http://en.wikipedia.org/wiki/Shadow_of_Phobos_on_Mars

http://history.nasa.gov/SP-441/ch9.htm

http://history.nasa.gov/SP-425/ch38.htm

[ljk4-1]

One thing I've often thought of is that we have these great anims from time to time, but they're not 'real time'

What would that eclipse have looked like in REAL time?

It lasted about 80 seconds end to end, so I mocked up something in 3ds Max, and uses Quicktime to add a few effects to it, and this is what it might have looked like, if seen in real time.

Doug

Imagine future Mars colonists with various ways of racing the eclipses to keep the moons in front of Sol as long as possible, just as we do with jets on Earth.

Viking 1 had the shadow of Phobos pass right over it:

http://en.wikipedia.org/wiki/Shadow_of_Phobos_on_Mars

http://history.nasa.gov/SP-441/ch9.htm

http://history.nasa.gov/SP-425/ch38.htm

[djellison]

Viking 1 had the shadow of Phobos pass right over it:

I know - that's why I want to see them try a Navcam movie looking at the ground during one - because we know it makes a lot of difference to the terrain.

Doug

[djellison]

Heck - the images are down but they're totally wierd I think I can extract what it SHOULD look like, but it'll be a bit of a challenge.

Doug

(PS - something done with what I THINK is actually an internal reflected images of the sun within the images - real-time-sim to follow)

Attached image(s)

 

[djellison]

Obviously a little hard to see much in that anim gif, but I've done my best to try and replicate as close as I can what that might have looked like in real time - unlikely to be as accurate as the previous one, but I made the duration of the eclipse from 1st to last contact as about 37 seconds.

Doug

Attached File(s)

 phobos_707b.mov ( 40.68K ) Number of downloads: 319