APOD: Perseverance Takes a Spin (2021 Mar 06)

[APOD Robot]

Perseverance Takes a Spin

Explanation: After arriving at Jezero Crater on Mars, Perseverance went for a spin on March 4. This sharp image from the car-sized rover's Navcam shows tracks left by its wheels in the martian soil. In preparation for operations on the surface of the Red Planet, its first drive lasted about 33 minutes. On a short and successful test drive Perseverance moved forward 4 meters, made a 150 degree turn, backed up for 2.5 meters, and now occupies a different parking space at its newly christened Octavia E. Butler Landing location. Though the total travel distance of the rover's first outing was about 6.5 meters (21 feet), regular commutes of 200 meters or more can be expected in the future.

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[neufer]

---

I was exceedingly surprised with the print of a man's naked foot on the shore, which was very plain to be seen on the sand. I stood like one thunderstruck, or as if I had seen an apparition. I listened, I looked round me, but I could hear nothing, nor see anything; I went up to a rising ground to look farther; I went up the shore and down the shore, but it was all one; I could see no other impression but that one. I went to it again to see if there were any more, and to observe if it might not be my fancy; but there was no room for that, for there was exactly the print of a foot - toes, heel, and every part of a foot. How it came thither I knew not, nor could I in the least imagine; but after innumerable fluttering thoughts, perfectly confused and out of myself, I came home not feeling, as we say, the ground I went on, but terrified to the last degree, looking behind me at every two or three steps, mistaking every bush and tree, and fancying every stump at a distance to be a man. Nor is it possible to describe how many various shapes my affrighted imagination represented things to me in, how many wild ideas were found every moment in my fancy, and what strange, unaccountable whimsies came into my thoughts by the way.

[Wadsworth]

I have a feeling of satisfaction that images like this from the surface of Mars have become 'common place' in my day-to-day viewing pleasure.

[johnnydeep]

---

I was exceedingly surprised with the print of a man's naked foot on the shore, which was very plain to be seen on the sand. I stood like one thunderstruck, or as if I had seen an apparition. I listened, I looked round me, but I could hear nothing, nor see anything; I went up to a rising ground to look farther; I went up the shore and down the shore, but it was all one; I could see no other impression but that one. I went to it again to see if there were any more, and to observe if it might not be my fancy; but there was no room for that, for there was exactly the print of a foot - toes, heel, and every part of a foot. How it came thither I knew not, nor could I in the least imagine; but after innumerable fluttering thoughts, perfectly confused and out of myself, I came home not feeling, as we say, the ground I went on, but terrified to the last degree, looking behind me at every two or three steps, mistaking every bush and tree, and fancying every stump at a distance to be a man. Nor is it possible to describe how many various shapes my affrighted imagination represented things to me in, how many wild ideas were found every moment in my fancy, and what strange, unaccountable whimsies came into my thoughts by the way.

I didn't recognize the quote, but you made me google this lucid prose, and Lo! it's from Robinson Crusoe! More context can be seen here (Not a believer myself, but I assume "BibleHub" is a resource for bible references in literature, among the many other biblical stuff I see there):

https://biblehub.com/library/defoe/robi ... ed_one.htm

[orin stepanek]

I hope JPL/NASA flood us with pictures from Perseverance!

[De58te]

I hope JPL/NASA flood us with pictures from Perseverance!

According to the first link, Perseverance has already sent back about 7,000 raw images.

https://mars.nasa.gov/mars2020/multimedia/raw-images/

[orin stepanek]

Be nice if Asterisk could show them!

[johnnydeep]

I hope JPL/NASA flood us with pictures from Perseverance!

According to the first link, Perseverance has already sent back about 7,000 raw images.

https://mars.nasa.gov/mars2020/multimedia/raw-images/

Hmm. Many or most of these raw images seem to "only" be 1648x1200 (or less) resolution. I somehow thought we'd get better than that?

[Chris Peterson]

I hope JPL/NASA flood us with pictures from Perseverance! :D

According to the first link, Perseverance has already sent back about 7,000 raw images.

https://mars.nasa.gov/mars2020/multimedia/raw-images/

Hmm. Many or most of these raw images seem to "only" be 1648x1200 (or less) resolution. I somehow thought we'd get better than that?

The camera has a 1200x1600 pixel sensor.

The number of pixels isn't really what's important (we've all been fed this bogus nonsense with the silly pixel counts of many phones and cameras these days). What matters is the resolution. Packing more pixels in if the optics can't provide the necessary resolution is pointless. The Mastcam-Z cameras are fairly narrow field. Wide fields are provided by building panoramic mosaics, which are, of course, many thousands of pixels wide.

[johnnydeep]

According to the first link, Perseverance has already sent back about 7,000 raw images.

https://mars.nasa.gov/mars2020/multimedia/raw-images/

Hmm. Many or most of these raw images seem to "only" be 1648x1200 (or less) resolution. I somehow thought we'd get better than that?

The camera has a 1200x1600 pixel sensor.

The number of pixels isn't really what's important (we've all been fed this bogus nonsense with the silly pixel counts of many phones and cameras these days). What matters is the resolution. Packing more pixels in if the optics can't provide the necessary resolution is pointless. The Mastcam-Z cameras are fairly narrow field. Wide fields are provided by building panoramic mosaics, which are, of course, many thousands of pixels wide.

I see. So, if you only had a 100x100 pixel sensor, that would still be pretty great if it had a1x1 mm area resolution?

[Chris Peterson]

Hmm. Many or most of these raw images seem to "only" be 1648x1200 (or less) resolution. I somehow thought we'd get better than that?

The camera has a 1200x1600 pixel sensor.

The number of pixels isn't really what's important (we've all been fed this bogus nonsense with the silly pixel counts of many phones and cameras these days). What matters is the resolution. Packing more pixels in if the optics can't provide the necessary resolution is pointless. The Mastcam-Z cameras are fairly narrow field. Wide fields are provided by building panoramic mosaics, which are, of course, many thousands of pixels wide.

I see. So, if you only had a 100x100 pixel sensor, that would still be pretty great if it had a1x1 mm area resolution?

Exactly. When you have more pixels than the optics can support, it's called oversampling. A small amount of oversampling can provide additional information that specialized processing can take advantage of. But beyond that, there is no benefit, and the smaller pixels may actually result in poorer images since they have less dynamic range and may introduce more readout noise. The designers of these cameras knew what they were doing. I'd be very surprised if the pixel size and count aren't intelligently matched to the optics.

It's also worth noting that while the big widefield images are impressive, they are pretty secondary to the majority of science images the cameras will be used for, which are high pixel resolution single frames of interesting objects.

[johnnydeep]

The camera has a 1200x1600 pixel sensor.

The number of pixels isn't really what's important (we've all been fed this bogus nonsense with the silly pixel counts of many phones and cameras these days). What matters is the resolution. Packing more pixels in if the optics can't provide the necessary resolution is pointless. The Mastcam-Z cameras are fairly narrow field. Wide fields are provided by building panoramic mosaics, which are, of course, many thousands of pixels wide.

I see. So, if you only had a 100x100 pixel sensor, that would still be pretty great if it had a 1x1 mm area resolution?

Exactly. When you have more pixels than the optics can support, it's called oversampling. A small amount of oversampling can provide additional information that specialized processing can take advantage of. But beyond that, there is no benefit, and the smaller pixels may actually result in poorer images since they have less dynamic range and may introduce more readout noise. The designers of these cameras knew what they were doing. I'd be very surprised if the pixel size and count aren't intelligently matched to the optics.

It's also worth noting that while the big widefield images are impressive, they are pretty secondary to the majority of science images the cameras will be used for, which are high pixel resolution single frames of interesting objects.

Thanks again! And I suppose I should have more accurately referred not to a 1x1 mm area, but say, a 1 arc second x 1 arc second field of view, correct?

[Chris Peterson]

I see. So, if you only had a 100x100 pixel sensor, that would still be pretty great if it had a 1x1 mm area resolution?

Exactly. When you have more pixels than the optics can support, it's called oversampling. A small amount of oversampling can provide additional information that specialized processing can take advantage of. But beyond that, there is no benefit, and the smaller pixels may actually result in poorer images since they have less dynamic range and may introduce more readout noise. The designers of these cameras knew what they were doing. I'd be very surprised if the pixel size and count aren't intelligently matched to the optics.

It's also worth noting that while the big widefield images are impressive, they are pretty secondary to the majority of science images the cameras will be used for, which are high pixel resolution single frames of interesting objects.

Thanks again! And I suppose I should have more accurately referred not to a 1x1 mm area, but say, a 1 arc second x 1 arc second field of view, correct?

The physical size of the imaged zone is, of course, related to the angular size. Which units you use depends upon context; either may be the better choice. Either way, the concept you expressed is correct, though.

[johnnydeep]

Exactly. When you have more pixels than the optics can support, it's called oversampling. A small amount of oversampling can provide additional information that specialized processing can take advantage of. But beyond that, there is no benefit, and the smaller pixels may actually result in poorer images since they have less dynamic range and may introduce more readout noise. The designers of these cameras knew what they were doing. I'd be very surprised if the pixel size and count aren't intelligently matched to the optics.

It's also worth noting that while the big widefield images are impressive, they are pretty secondary to the majority of science images the cameras will be used for, which are high pixel resolution single frames of interesting objects.

Thanks again! And I suppose I should have more accurately referred not to a 1x1 mm area, but say, a 1 arc second x 1 arc second field of view, correct?

The physical size of the imaged zone is, of course, related to the angular size. Which units you use depends upon context; either may be the better choice. Either way, the concept you expressed is correct, though.

Cool.