MSL - Astronomical Observations, Phobos/Deimos, planetary/celestial observations and more Options

[Gerald]

Two Sol 606 images, this and this, of Saturn, cleaned (intersect subtracted), 4x magnified, registered, summed, some dark gray subtracted, cropped:


Edit:
A Sol 606 Phobos image cleaned by the intersection used above, magnified 2x, brightness stretched a bit:

(The hot pixel artifact / black dot occurs when using the Phobos image for cleaning, too.)

Edit: A pair of Sol 606 MR Deimos Jupiter images (this and this), cleaned by darkest, magnified x4, registered, averaged, no further brightness adjustments:

Longer exposure may have caused some motion blur.

(Edit: Corrected text, after Deimos' clarifying post about the order of aims, below.)

[Deimos]

http://www.jpl.nasa.gov/news/news.php?release=2014-126

[dvandorn]

Odd -- not only will the link not load, the main JPL website won't load, either. I'm getting good page loads pretty much everywhere else on the 'net, so I don't think it's my connection, here.

-the other Doug (with my shield, not yet upon it)

[Explorer1]

It's up now. Both of Dawn's destinations, plus a couple of outer planets to boot! With all this preparation, anticipations for October just keep growing...

[wildespace]

My version of Phobos + Deimos image layering, using "difference" mode to exclude image noise:



Pixel-resized x4:



A bit unfortunate that Phobos intersected that hot pixel area the moment image was taken.

I am curious about the slightly greenish apeparance of Phobos in Mastcam images. Is it due to the atmospheric conditions, or the way camera operates?

[fredk]

I am curious about the slightly greenish apeparance of Phobos in Mastcam images.

Check out the discussion of the greenish cast of mastcam images in the MSL Images & Cameras thread.

[Gerald]

My version of Phobos + Deimos image layering, using "difference" mode to exclude image noise:
...

I'm not quite sure any more about the other object being Deimos, after the press release.
It's probably either Jupiter or Saturn, not quite sure which of the two.
Since there is a second object which easily survived the cleaning, registering, and stretching of the images, I'm pretty shure, that the two images (973, 974) actually match.
Here the combined and enhanced version of the cleaned images:

[Gerald]

This Sol 606 Mastcam Left image cleaned, combined and enhanced, using this one:

The Phobos part is cropped of the cleaned first image.

Edit:
Similarly for Deimos, from this and this ML image:

[Deimos]

Looks like Jupiter to me. The aims appear to be Phobos-->Jupiter-->Deimos and friends-->Saturn-->Regulus.

[Gerald]

Thanks a lot!

From knowing, this and this image aiming to Regulus, at least two more stars can be identified:

(The raw images have been cleaned, combined, denoised, and enhanced over a couple of steps.)

[Gerald]

An idea of the Sol 606/607 tau (by ML):

[fredk]

What do you mean by tau, Gerald? Are you saying that the glare around the sun or Phobos is an indication of tau? I'd've guessed that glare within the optical system was more important, at least for the low tau levels these days. If you compared with identical exposures at times of high tau maybe you'd see a difference in the glare?

Normally the brightness of the sun's disc is used as a measure of tau.

[Gerald]

That's the direction I've been thinking. Part of the atmospheric opacity should be caused by scattering of light, not just by absorption. I'm presuming, that this could result in different halos or glares.

[mcaplinger]

Are you saying that the glare around the sun or Phobos is an indication of tau? I'd've guessed that glare within the optical system was more important...

This recapitulates a discussion we've had within the imaging team. I tend to agree with Fred; we never characterized the Mastcams for stray light behavior at this kind of level.

I think you could do something with the sky brightness far enough away from the sun, and I believe that's part of the tau strategy. Phobos in the field, my guess is probably not.

[MarsInMyLifetime]

Just a thought on another use for Gerald's image: Accumulation of dust on the front surface of the optics will be responsible for a significant part of this glare (isn't it actually flare?). If you can use the conventional measures of tau as a coefficient to factor out aerosol scattering contribution to the flare, the remaining component should be a relative indication of the dust accumulation.