APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

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APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by APOD Robot » Mon Oct 28, 2019 4:07 am

Image The Space Station Crosses a Spotless Sun

Explanation: Typically, the International Space Station is visible only at night. Slowly drifting across the night sky as it orbits the Earth, the International Space Station (ISS) can be seen as a bright spot about once a month from many locations. The ISS is then visible only just after sunset or just before sunrise because it shines by reflected sunlight -- once the ISS enters the Earth's shadow, it will drop out of sight. The only occasion when the ISS is visible during the day is when it passes right in front of the Sun. Then, it passes so quickly that only cameras taking short exposures can visually freeze the ISS's silhouette onto the background Sun. The featured picture did exactly that -- it is actually a series of images taken a month ago from Santa Fe, Argentina with perfect timing. This image series was later combined with a separate image highlighting the texture of the spotless Sun, and an image bringing up the Sun's prominences around the edge. At an unusually low Solar Minimum, the Sun has gone without sunspots now for most of 2019.

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by shaileshs » Mon Oct 28, 2019 5:07 am

Absolutely amazing and beautiful. I don't recall ever seeing such spotless (I mean, absolutely spotless!) Sun.

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by Markus Schwarz » Mon Oct 28, 2019 10:18 am

To me, it looks like a squadron of TIE fighters from Star Wars.

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by orin stepanek » Mon Oct 28, 2019 10:50 am

IssTransit_Poupeau_960.jpg
The Giant pumpkin
comes for Halloween!
Linus knows! :lol2:
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The oranges of a witCh hunt

Post by neufer » Mon Oct 28, 2019 4:05 pm

orin stepanek wrote:
Mon Oct 28, 2019 10:50 am

The Giant pumpkin
comes for Halloween!
Linus knows! :lol2:
https://en.wikipedia.org/wiki/Linus_Pauling wrote:
Click to play embedded YouTube video.
<<Linus Pauling (February 28, 1901 – August 19, 1994) was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. New Scientist called him one of the 20 greatest scientists of all time, and as of 2000, he was rated the 16th most important scientist in history. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. He is the only person to have been awarded two unshared Nobel Prizes.

Pauling's work on vitamin C in his later years generated much controversy. He was first introduced to the concept of high-dose vitamin C by biochemist Irwin Stone in 1966. After becoming convinced of its worth, Pauling took 3 grams of vitamin C every day to prevent colds. Excited by his own perceived results, he researched the clinical literature and published Vitamin C and the Common Cold in 1970. He began a long clinical collaboration with the British cancer surgeon Ewan Cameron in 1971 on the use of intravenous and oral vitamin C as cancer therapy for terminal patients. Cameron and Pauling wrote many technical papers and a popular book, Cancer and Vitamin C, that discussed their observations. Pauling published two studies of a group of 100 allegedly terminal patients that claimed vitamin C increased survival by as much as four times compared to untreated patients. Results from most clinical trials suggest that modest vitamin C supplementation alone or with other nutrients offers no benefit in the prevention of cancer.>>
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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by ellipseshadow » Mon Oct 28, 2019 4:22 pm

"...the International Space Station (ISS) can be seen as a bright spot about once a month from many locations." I don't understand that statement. From my location in southern Manitoba it is visible every morning from October 25 to November 12. That is 19 days in a row, and often more than once each morning. What do you mean "once a month"?

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by Chris Peterson » Mon Oct 28, 2019 4:41 pm

ellipseshadow wrote:
Mon Oct 28, 2019 4:22 pm
"...the International Space Station (ISS) can be seen as a bright spot about once a month from many locations." I don't understand that statement. From my location in southern Manitoba it is visible every morning from October 25 to November 12. That is 19 days in a row, and often more than once each morning. What do you mean "once a month"?
I would take it to mean that, averaged over the entire area of Earth where the ISS orbits, a viewer at any one location might be able to see it around a dozen times a year. That seems low to me, but to know for sure would require some careful calculations. I know that from my location (38° N) there are times when it is visible for 10 days or more in a row... but also that there are times when that much time passes with no visible passes.
Chris

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by neufer » Mon Oct 28, 2019 4:55 pm

Chris Peterson wrote:
Mon Oct 28, 2019 4:41 pm
ellipseshadow wrote:
Mon Oct 28, 2019 4:22 pm

"...the International Space Station (ISS) can be seen as a bright spot about once a month from many locations." I don't understand that statement. From my location in southern Manitoba it is visible every morning from October 25 to November 12. That is 19 days in a row, and often more than once each morning. What do you mean "once a month"?
I would take it to mean that, averaged over the entire area of Earth where the ISS orbits, a viewer at any one location might be able to see it around a dozen times a year. That seems low to me, but to know for sure would require some careful calculations. I know that from my location (38° N) there are times when it is visible for 10 days or more in a row... but also that there are times when that much time passes with no visible passes.
The ISS orbital inclination of 51.64° insures that it spends a lot more of its [sinusoidal] orbital time "hovering" above 50° N/S latitude than it does over that half of the Earth's surface that lies between 30°N & 30°S.
Art Neuendorffer

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by drjhammond » Mon Oct 28, 2019 5:58 pm

It should be noted that there are many locations and times of the year when the ISS can be seen late at night and even all night long--depending on latitude. Lunar transits of the ISS occur about as often as solar transits but are not as frequently visible because there are times when the moon is new or so close to new that it cannot be photographed. While sunspots have been rare this year, in April I was able to capture a transit when there were several visible. If I knew how to do it, I would post an image.

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by Joe Stieber » Mon Oct 28, 2019 6:51 pm

Chris Peterson wrote:
Mon Oct 28, 2019 4:41 pm
ellipseshadow wrote:
Mon Oct 28, 2019 4:22 pm
"...the International Space Station (ISS) can be seen as a bright spot about once a month from many locations." I don't understand that statement. From my location in southern Manitoba it is visible every morning from October 25 to November 12. That is 19 days in a row, and often more than once each morning. What do you mean "once a month"?
I would take it to mean that, averaged over the entire area of Earth where the ISS orbits, a viewer at any one location might be able to see it around a dozen times a year. That seems low to me, but to know for sure would require some careful calculations. I know that from my location (38° N) there are times when it is visible for 10 days or more in a row... but also that there are times when that much time passes with no visible passes.
Indeed, once a month seems very nominal.

Here at 40°N latitude, it's been my experience that ISS visibility goes through cycles. It will be visible for a couple of weeks (approximately) in the morning before sunrise, then a couple of weeks of non-visibility, then a couple of weeks in the evening after sunset, and so on. However, at times, particularly before the summer solstice, it can make multiple visible passes through the night. I've seen four of five passes in a single night a number of times, and back on May 21-22, 2018, I saw six (6) ISS passes overnight. Bob King has an online article at Sky & Telescope about spotting multiple ISS passes in a single night.

I've also seen the ISS in the daytime, usually as a silhouette transiting the brilliant sun using a properly filtered telescope, but I've also seen it with binoculars transiting, or passing near the moon in a clear blue daytime sky. Of course, the illuminated ISS tends to disappear when it passes in front of the illuminated portion of the daytime moon.

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Re: APOD: The Space Station Crosses a Spotless Sun (2019 Oct 28)

Post by TheOtherBruce » Tue Oct 29, 2019 1:21 am

I've seen ISS several times from my back garden, but I'll always remember the time I happened to be outside at dawn and saw it coming over the trees in next door's garden. It was incredibly bright — the sunlight must have been bouncing straight down from all the solar panels at once, very different from an evening sighting. I think it might even have been brighter than an Iridium flare (and I've seen a few of them, too).
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