Jim Bell Q'n'a, July 3, 2006, Your questions answered! Options

[elakdawalla]

Biggest Doug'n'Jim show ever...
Rover Audio Updates

Enjoy!

Emily

[djellison]

Special thanks to Emily, as for obvious reasons she's more than a little busy at the moment!

As you can tell from Jim's last few words, he's enjoying doing these - and I'm having a blast - add them up and we've had 2hrs 41mins of Pancam-o-rama.

Kudos to Jim for working on the Monday that most people take off for a 4 day Indep. W'end

Doug

[RNeuhaus]

Does anyone interested to transcript the Doug's interview?

Rodolfo

[mcaplinger]

I have to take exception to one thing that Jim said, about the Pancam field of view. It isn't necessarily as simple as taking the IFOV and multiplying it by the number of pixels, because most optical systems with fields of view more than a few degrees have optical distortions that cause the IFOV to vary slightly from the center to the edge of the field. I'm not sure if the Pancams have appreciable distortion, but the Navcams certainly do.

[ustrax]

Great 1/2 hour Doug! It is always a pleasure to ear you and Mr. Bell talking about what you like...

When I sent you the question my interest was mainly on the undergradute students' role, I'm glad Jim Bell followed that path, and even more for seing that he can establish a bridge between the him and Squyres and the new kids in town...
A great future in Mars exploration is guaranteed back there at Cornell.

[lyford]

Does anyone interested to transcript the Doug's interview?
Rodolfo

I can take a little bit later on but I am really busy now getting ready to move in July... more on this later

Thanks Doug, these are really special - I download them and play on iTunes in my car during the commute.

Though judging from Jim's comments about the BBQ pic I fear we may have "defamed" his art! Glad he has a sense of humor about it...

PS - ustrax - did Doug pronounce your name right on the tape? Because I always imagined it differently in my head.....

[ustrax]

PS - ustrax - did Doug pronounce your name right on the tape? Because I always imagined it differently in my head.....

The origin of 'ustrax' is in a celtic-latin word which means fire...Due to that I say it with a different pronounce, my own, nearer the latin one, it would sound something: 'u' as the 'o' in 'to', the 's' as the 'sh' in 'show', 'trax' was quite near only the 'a' should be a little bit more open as in 'potáto'.
To resume, it should sound like: oshtráx...Or something like that...Sorry if it sounds confusing...
But it was great to ear it!

[djellison]

Though judging from Jim's comments about the BBQ pic I fear we may have "defamed" his art! Glad he has a sense of humor about it...

You didn't hear us chatting about it before I hit the metaphorical record button It was hillarious"

"MY BEAUTIFUL PANORAMA....!!!"



Doug

[David]

'trax' was quite near only the 'a' should be a little bit more open as in 'potáto'.

That must be a British pohtahtoh, rather than an American pertayter.

[lyford]

Well, I hope we cleaned up after the BBQ.... hate to have littered.

[ElkGroveDan]

Maybe next time you could ask him about the longer term plans for Spirit...surely they must be discussing what they want/can do if she makes it through the winter.

[Nix]

You didn't hear us chatting about it before I hit the metaphorical record button It was hillarious"

"MY BEAUTIFUL PANORAMA....!!!"



Doug

This was a very interesting Q 'n A ! I enjoyed it very much.

Nico

[RNeuhaus]

I can take a little bit later on but I am really busy now getting ready to move in July... more on this later

No problem, there is no hurry to read it! The flavor of reading won't miss at any time

Rodolfo

[Guest_Analyst_*]

Great as always. Just listened to it on my way to work. It's a pleasure these people take time to explain their work to us. I hope there will be a MER press conference in the near future. It's been a long time since the last one. I am also looking forward to read Jim Bell's blog at the Planetary Society. And yours Doug, too.

Analyst

[djellison]

I have to take exception to one thing that Jim said, about the Pancam field of view. It isn't necessarily as simple as taking the IFOV and multiplying it by the number of pixels, because most optical systems with fields of view more than a few degrees have optical distortions that cause the IFOV to vary slightly from the center to the edge of the field. I'm not sure if the Pancams have appreciable distortion, but the Navcams certainly do.

From JB

In case anyone wants to know them, the similar IFOV numbers for the Navcam is 0.82 mrad/pixel, and for the Hazcam is 2.1 mrad/pixel.
This is ultimately the origin of statements like "Pancam has 3 times the resolution of the Navcams", etc. For reference, the MI gives 0.42 mrad/pixel, MPF IMP had 0.99 mrad/pixel and the Sojourner rover had 3.1 mrad/pixel, and the Viking Lander cameras had two modes that gave 0.70 and 2.1 mrad/pixel. These numbers are referenced and derived for the MER engineering cameras in a paper Justin Maki et al. wrote in JGR, vol 108, No. E12, pages 12-1 to 12-24, 2003.

Determining the total size of the field of view for these other cameras is not as simple as it is for Pancam, however. That's because most wider-field camera systems have appreciable geometric distortion. So you can't just take Navcam's 0.82 mrad and multiply by 1024 and convert to degrees. That will get you close, but not spot on, and the calculation is even worse for the Hazcams, which have an enormous amount of distortion. The details of those cameras' fields of view can be found in Justin's paper--which I hope is posted online somewhere for folks to access, but I am not sure. The reason that the simple "multiply 0.273 by 1024" equation works for Pancam is simply because there is *no* geometric distortion in the optical system. We tried hard to measure it so we could characterize and correct for it, if needed, but as we wrote in our 2003 JGR paper we couldn't detect *any* distortion down to a residual of 0.01% or so across the field--even in the corners. The Cooke triplet lenses, designed by optics guru Greg Smith (see Chapter 31 of Greg's book at http://www.zemax.com/kb/articles/103/1/The...r-Camera-Lenses
, http://www.mwoa.org/Ch31.pdf , and
http://bookstore.spie.org/index.cfm?fuseac...roductid=660181
for details), are just absolutely spectacular--as you can tell.

Doug