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.
[quote="Chris Peterson" post_id=296532 time=1572280865 user_id=117706]
[quote=ellipseshadow post_id=296529 time=1572279726 user_id=144117]
"...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"?
[/quote]
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.
[/quote]
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. [url=https://www.skyandtelescope.com/observing/all-night-vigil-with-the-international-space-station/]Bob King has an online article at Sky & Telescope[/url] 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.