Starship Asterisk*

rstevenson wrote: ↑Mon Apr 30, 2018 8:19 pm
As it appears more or less square, that makes it roughly 15 stories high.

That's a hunk of rock!

• Mean density of Churyumov–Gerasimenko ~ 533 kg/m³
  Surface gravity ~ 0.0001 Earth's gravity
  
  'Effective weight' of boulder ~ 2 or 3 tons.

JohnD wrote: ↑Thu Apr 26, 2018 9:54 am
Extraordinary! And taken from orbit 13kms away? Doubly so, one might be walking across the surface!

What's the scale? Those rocks bottom right could be pebble, football or house sized, I presume the latter given the distance.

neufer wrote: ↑Fri Apr 27, 2018 3:51 am
:shock: My "comments" were in regard to John Glenn's actual eyeballs.

Chris Peterson wrote: ↑Fri Apr 27, 2018 2:59 am

neufer wrote: ↑Thu Apr 26, 2018 8:52 pm

kevinmcc29 wrote: ↑Thu Apr 26, 2018 7:23 pm
When John Glenn was orbiting the Earth in his Mercury capsule, he reported a similar phemomenon, a cloud of bright white snowflake-like, star-like objects around the capsule. Could that have been something like what we're seeing here?

I think that a second imaging instrument (eyeball) to provide 'binocular vision' would have been helpful. Cosmic rays will only be able to strike one of the eyeballs, thereby providing the ability to either remove them from the real image, or give the ability to visualize the 'cosmic rays' without the background image. The cost of the second other eyeball would have been inconsequential with respect to the cost of the mission, and the science value would be great.

Well, as I noted earlier, this could easily have added tens of millions of dollars to the mission cost and compromised other instruments. I'm not sure how much science value would have been added- the two cameras would be too close for stereo vision, and cosmic rays don't really compromise the data. Had there been significant science value, a second camera would have been proposed and either accepted or rejected after a long science and engineering review process (I've been in such meetings).

neufer wrote: ↑Thu Apr 26, 2018 8:52 pm

kevinmcc29 wrote: ↑Thu Apr 26, 2018 7:23 pm
When John Glenn was orbiting the Earth in his Mercury capsule, he reported a similar phemomenon, a cloud of bright white snowflake-like, star-like objects around the capsule. Could that have been something like what we're seeing here? :?:

I think that a second imaging instrument (eyeball) to provide 'binocular vision' would have been helpful. Cosmic rays will only be able to strike one of the eyeballs, thereby providing the ability to either remove them from the real image, or give the ability to visualize the 'cosmic rays' without the background image. The cost of the second other eyeball would have been inconsequential with respect to the cost of the mission, and the science value would be great.

kevinmcc29 wrote: ↑Thu Apr 26, 2018 7:23 pm
When John Glenn was orbiting the Earth in his Mercury capsule, he reported a similar phemomenon, a cloud of bright white snowflake-like, star-like objects around the capsule. Could that have been something like what we're seeing here?

neufer wrote: ↑Thu Apr 26, 2018 5:41 pm

<<Tauntauns are 2.5 m tall bipedal reptiles, indigenous to the ice planet Hoth. Tauntauns are covered with white fur and have downturned horns, four nostrils, and a foul body odor. They subsist off lichen found in hoarfrost as well as eating mushrooms and other fungi found in ice caves. They give birth to two young at a time, twice in one Hoth year, although triplet Tauntauns are considered incredibly good luck and are often born with purple fur. They are used as mounts by the Rebel Alliance, and have been exported offworld to other cold-climate regions (including Coruscant's polar caps) for use as mounts, beasts of burden, and tourist attractions. Their thick layers of fat and fur provide adequate protection from the cold during the daytime, but tauntauns cannot survive the plummeting night temperatures without shelter. Tauntauns are sometimes preyed upon by the Wampa.>>

GoshOGeeOGolly wrote: ↑Thu Apr 26, 2018 5:32 pm
https://www.google.ca/imgres?imgurl=htt ... _B0IqgIwCg

https://en.wikipedia.org/wiki/List_of_Star_Wars_creatures#Tauntaun wrote:

---

<<Tauntauns are 2.5 m tall bipedal reptiles, indigenous to the ice planet Hoth. Tauntauns are covered with white fur and have downturned horns, four nostrils, and a foul body odor. They subsist off lichen found in hoarfrost as well as eating mushrooms and other fungi found in ice caves. They give birth to two young at a time, twice in one Hoth year, although triplet Tauntauns are considered incredibly good luck and are often born with purple fur. They are used as mounts by the Rebel Alliance, and have been exported offworld to other cold-climate regions (including Coruscant's polar caps) for use as mounts, beasts of burden, and tourist attractions. Their thick layers of fat and fur provide adequate protection from the cold during the daytime, but tauntauns cannot survive the plummeting night temperatures without shelter. Tauntauns are sometimes preyed upon by the Wampa.>>

dbooksta wrote: ↑Thu Apr 26, 2018 4:43 pm

Chris Peterson wrote: ↑Thu Apr 26, 2018 1:54 pm Cosmic ray hits on sensors are rarely a serious problem, as they can be removed in almost all cases and have minimal impact on the science.

So are you saying that the prominent "snow" in these images is entirely real reflections from physical particles in the field of view, and not an artifact of noise created by interactions of stray high-energy photons or particles directly impinging the sensor?

Chris Peterson wrote: ↑Thu Apr 26, 2018 1:54 pm Cosmic ray hits on sensors are rarely a serious problem, as they can be removed in almost all cases and have minimal impact on the science.

Chris Peterson wrote: ↑Thu Apr 26, 2018 3:03 pm

neufer wrote: ↑Thu Apr 26, 2018 2:47 pm

Chris Peterson wrote: ↑Thu Apr 26, 2018 1:54 pm
In fact, adding a second camera could easily have elevated the cost of the mission by tens of millions of dollars, and would have demanded either a different power system or the loss of some other instrument. Every watt is allocated in probes like this. Cosmic ray hits on sensors are rarely a serious problem, as they can be removed in almost all cases and have minimal impact on the science.

There are 3 cameras effectively considering the images taken just before or just after.

Exactly, and that's why transient artifacts are usually not a problem.

It is only with highly transient targets that it can be problematic, but those are rare in astronomical applications.

http://bestettler.com/EBooks/eBooks/Sagan,%20Carl/Articles/sagan1.htm wrote:
The Search for Extraterrestrial Life
by Carl Sagan

<<In practice, the community of scientists concerned with finding life elsewhere in the solar system has contented itself with a chemical approach. Human beings, as well as every other organism on the earth, are based on liquid water and organic molecules. (Organic molecules are carbon-containing compounds other than carbon dioxide and carbon monoxide.) A modest search strategy--looking for necessary if not sufficient criteria--might then begin by looking for liquid water and organic molecules. Of course, such a protocol might miss forms of life about which we are wholly ignorant, but that does not mean we could not detect them by other methods.

If a silicon-based giraffe had walked by the Viking Mars landers, its portrait would have been taken.>>

Chris Peterson wrote: ↑Thu Apr 26, 2018 3:03 pm

neufer wrote: ↑Thu Apr 26, 2018 2:47 pm
Close to the western summit there is the dried and frozen carcass of a leopard. No one has explained what the leopard was seeking at that altitude.

Enlightenment?

https://www.earthtouchnews.com/discoveries/discoveries/the-amazing-story-of-the-frozen-leopard-atop-mount-kilimanjaro/ wrote:
The amazing story of the frozen leopard atop Mount Kilimanjaro
By Ethan Shaw January 26 2017 for Earth Touch News

<<Ernest Hemingway opens his 1936 short story "The Snows of Kilimanjaro" by mentioning a leopard carcass up near the summit of Mount Kilimanjaro, at 19,341 feet the tallest mountain in Africa: "Close to the western summit there is the dried and frozen carcass of a leopard. No one has explained what the leopard was seeking at that altitude."

The short story may be a piece of fiction, but Hemingway's reference isn't. In 1926, a Lutheran pastor named Richard Reusch, who made multiple climbs up Kilimanjaro, did indeed discover a "freeze-dried" leopard at roughly 18,500 feet along the crater rim of the volcano's loftiest sub-peak, Kibo. A photo of the find shows the dead animal looking about as you'd expect after chilling (so to speak) on a mountaintop snowfield for who knows how long.

Reusch suspected the leopard had died in pursuit of a goat, the remains of which he also found a few hundred feet away. Returning to the contorted mummy the next year, Reusch lopped off an ear for souvenir purposes. At some point or another, the corpse disappeared, but given the Hemingway shout-out, it's about as immortalised as a popsicled wild animal could be. (The general location of the carcass now holds the unofficial label of "Leopard Point".)>>

neufer wrote: ↑Thu Apr 26, 2018 2:47 pm

Chris Peterson wrote: ↑Thu Apr 26, 2018 1:54 pm

Guest wrote: ↑Thu Apr 26, 2018 1:44 pm
I think that a second imaging instrument (camera) to provide 'binocular vision' would be helpful. Cosmic rays will only be able to strike one of the imaging surfaces, thereby providing the ability to either remove them from the real image, or give the ability to visualize the 'cosmic rays' without the background image. The cost of the second other camera would have been inconsequential with respect to the cost of the mission, and the science value would be great. It is still a great video effort, tho some scale would have been nice to have. I wonder how cold it is?

In fact, adding a second camera could easily have elevated the cost of the mission by tens of millions of dollars, and would have demanded either a different power system or the loss of some other instrument. Every watt is allocated in probes like this. Cosmic ray hits on sensors are rarely a serious problem, as they can be removed in almost all cases and have minimal impact on the science.

There are 3 cameras effectively considering the images taken just before or just after.

Close to the western summit there is the dried and frozen carcass of a leopard. No one has explained what the leopard was seeking at that altitude.

Chris Peterson wrote: ↑Thu Apr 26, 2018 1:54 pm

Guest wrote: ↑Thu Apr 26, 2018 1:44 pm
I think that a second imaging instrument (camera) to provide 'binocular vision' would be helpful. Cosmic rays will only be able to strike one of the imaging surfaces, thereby providing the ability to either remove them from the real image, or give the ability to visualize the 'cosmic rays' without the background image. The cost of the second other camera would have been inconsequential with respect to the cost of the mission, and the science value would be great. It is still a great video effort, tho some scale would have been nice to have. I wonder how cold it is?

In fact, adding a second camera could easily have elevated the cost of the mission by tens of millions of dollars, and would have demanded either a different power system or the loss of some other instrument. Every watt is allocated in probes like this. Cosmic ray hits on sensors are rarely a serious problem, as they can be removed in almost all cases and have minimal impact on the science.

Chris Peterson wrote: ↑Thu Apr 26, 2018 1:54 pm
When 67P was at this distance from the Sun, its surface temperature was about 200 K, give or take about 20 K depending on surface location.
Say, -70° C. A cold day in Siberia or Antarctica.

• "And it ain't a fit night out for man or beast!"

Guest wrote: ↑Thu Apr 26, 2018 1:44 pm

Chris Peterson wrote: ↑Thu Apr 26, 2018 12:47 pm

RocketRon wrote: ↑Thu Apr 26, 2018 5:48 am Do the charged particles/cosmic rays only strike the camera ccd with the shutter open, or do they continue regardless. ?
(Which may not be immediately obvious, since with the shutter closed it may not be recording anything )

Always. They strike the sensor from all directions, arriving not just from the side of the lens but even behind. Depending on the sensor type, it may well be "recording" all the time, meaning that it's collecting signal. But often this will not be stored; the charge on the sensor is cleared before starting an actual exposure. However, this is not the case for a special kind of calibration image called a dark frame. It's made with the shutter closed, in order to capture certain artifacts that are inherent in the sensor so that they can be subtracted out of the final science image. However, when you have cosmic ray hits on your dark frame, your calibration process then transfers them to any frames processed with that image.

I think that a second imaging instrument (camera) to provide 'binocular vision' would be helpful. Cosmic rays will only be able to strike one of the imaging surfaces, thereby providing the ability to either remove them from the real image, or give the ability to visualize the 'cosmic rays' without the background image. The cost of the second other camera would have been inconsequential with respect to the cost of the mission, and the science value would be great. It is still a great video effort, tho some scale would have been nice to have. I wonder how cold it is?

Chris Peterson wrote: ↑Thu Apr 26, 2018 12:47 pm

RocketRon wrote: ↑Thu Apr 26, 2018 5:48 am Do the charged particles/cosmic rays only strike the camera ccd with the shutter open, or do they continue regardless. ?
(Which may not be immediately obvious, since with the shutter closed it may not be recording anything )

Always. They strike the sensor from all directions, arriving not just from the side of the lens but even behind. Depending on the sensor type, it may well be "recording" all the time, meaning that it's collecting signal. But often this will not be stored; the charge on the sensor is cleared before starting an actual exposure. However, this is not the case for a special kind of calibration image called a dark frame. It's made with the shutter closed, in order to capture certain artifacts that are inherent in the sensor so that they can be subtracted out of the final science image. However, when you have cosmic ray hits on your dark frame, your calibration process then transfers them to any frames processed with that image.

Sa Ji Tario wrote: ↑Thu Apr 26, 2018 12:49 pm
Will m-41 be the galactic cluster?

• NGC 2362