Here's the following chapter...

Well, after an "unscheduled stop" it's time to start again.
Tosol (1871) drive moved us around 50m due south.

I have a question. For most of this mission Opportunity's stereo imagery has been recorded with either the "red" filter stereo pair (L2R2) or the "blue" filter stereo pair (L7R1). A while back Opportunity started recording L6R1 stereo pairs for images where I would have expected to see L7R1 pairs. The L7R1 pair is still being used to image the color target and certain close-ups of the ground.

I understand that the difference between the L7 (440 nm. wavelength) and L6 (483 nm. wavelength) filters is minor, but I can't imagine why this change was made. Does anyone here have any thoughts about that?

By the way, I noticed this when MidnightMarsBrowser did not generate pancam anaglyphs when I could see that there were pancam stereo pairs available. I like to view anaglyph panoramas in MMB, so I thought I'd mention this simple work-around for anyone else who has been missing Opportunity's pancam anaglyphs. AFAIK, MMB versions 2.x do not allow one to specify which filters to use for generating anaglyphs, but earlier versions (i.e, ver. 1.5) do. I simply run the earlier version and instruct it to generate L6R1 anaglyphs. Once they are generated, MMB 2.x is able to use them in its panoramas.

N.B. I can hear Mike saying, "Don't forget to tell them never to run the different versions at the same time, or the image indices will be corrupted."

Nothing, I mean, nothing escapes the inquisitive eyes of UMSF! Unfortunately the terrain in Meridiani does not have much texture when you are around ripples. As a result the ground based stereo correlation algorithm has only a handful of features to latch on and therefore our pancams have very little 3D data points. As you have probably observed the blue stereo (L7R1) images are much sharper than the red (L2R2) and my hope was that using blue stereo we would be getting much better results but alas that did not happen. Red stereo instead has blurrier images but has larger contrast: you can differentiate much better between rocks and soil, and banding on the ripples. So a few weeks ago I started asking for L6R1 with the hope that this would be a good compromise between the two. It sort of gets slightly better results, the difference is not dramatic but noticeable. Since my initial request it has become the default for drive direction pancams.

Hope this helps.

Paolo

Yeah; unfortunately MMB 2.0 was never really finished, and probably never will be. In this case, though, it would only take me a few minutes to patch the program to do L6R1 anaglyphs, so I will probably do that at some point. I hadn't consciously noticed the problem yet.

This isn't the first change in imaging that has slightly 'broken' MMB. The biggest one is probably that, a few months ago, suddenly multiple versions of images with dropouts started getting pushed out; you now see multiple versions of the same image ending in "M1," "M2," "M3," etc., with the last one being the (usually) complete version. Since before a few months ago images were always replaced rather than copied, MMB was never programmed to handle this; so for panoramas it always takes the first one, which is always the one with the most dropouts. D'oh! Fortunately you can work around this manually; and maybe someday I'll have time to fix that one, too. But anyway, we noticed that one too, Paolo

> ... Fortunately you can work around this manually ...

I can easily think of an unix script to do it through the whole directory tree, but in windows... Any help?

I mean in the program itself, you can select which images are displayed in panoramas. In the images list window, just uncheck the "M1" version of the image and check the "M3" version instead, for example. Only problem is this change doesn't "stick" after the program quits or after you change the image parameters. Like I said, it's a workaround for a basic problem I don't have time to fix.

I suppose one could do some sort of script like you suggest, but automated file deletion sounds a bit dangerous to me.

Well I hadn't noticed the L6R1's myself. But I had noticed that we have started to get some R2's to go with the R1's again. So I can do some more colour drive direction mosaics:

1870



1871


James

An extract from the latest status report in the MER page: http://marsrovers.jpl.nasa.gov/mission/sta...ll.html#sol1866

The Sol 1871 drive showed a return of the increase in the amount of current drawn by drive actuator in the right-front wheel. The project is considering mitigation practices of resting the actuator and/or driving backwards for a while.

It would be interesting to hear more about current thinking regarding strategies to reduce the amperage that motor is demanding. Early in the missions, driving in reverse proved to be an effective mitigation method for one of Spirit's ailing wheel's internal friction. Recently, one of Opportunity's front wheel's was able to eliminate friction by standing still for a while.

If both of those options are equally favored, I'd choose the one that continues to make forward progress, as long as the current draw did not increase.

They've done both of those

I've been eyeing a subtle feature on the southern horizon for a few sols. This is far away, but not Endeavour-far away (plus it's in the wrong direction to be part of Endeavour). Notice the step up from the right to the left (5x vertical stretch, view from sol 1872):

It seems that unfrtunately driving backwards does not help, but rest is. I was told that rest allows the lubricant to flow back into the gears. The RF currents are back up again and in a few sols we will be resting again I think. Sigh....

Paolo

She's getting old, when did walking backwards ever help an old lady? - Just let her rest a little...

Non so se tifi per qualche squadra, ma io stavo a San Siro stasera, e mi sembra che Inter sta per vincere il campeonato...

Drive until the axles melt!

Phil