That's no ISS

http://www.slate.com/blogs/bad_astro...cross_the.html

Nope, it's the OTHER Space Station.

The author has a good point. I had forgotten the Chinese were up there this
month.


I'd say within a decade or less we'll have ISS, a Chinese station and a
Bigelow habitat, all crewed simultaneously at some point.

Well obviously cannot see it, but it sounds an awfully short time to cross
the face of the sun, I'd have given it about twice that time, but I suppose
its all down to perspective.
Brian

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"Greg (Strider) Moore" wrote in message
m...
http://www.slate.com/blogs/bad_astro...cross_the.html

Nope, it's the OTHER Space Station.

The author has a good point. I had forgotten the Chinese were up there
this month.


I'd say within a decade or less we'll have ISS, a Chinese station and a
Bigelow habitat, all crewed simultaneously at some point.

"Brian Gaff" wrote in message ...


It is a matter of perspective. The sun really covers a very small part of
the sky. (Can't recall the number and having trouble finding it.)

But figure the station has to cover 360 degrees in 90 minutes (give or
take). It's covering 4 degrees in a minute.

Or 1 degree in 15 seconds.

Hmm, and I was betting the sun was about 1 degree of arc, so that all jives.


Well obviously cannot see it, but it sounds an awfully short time to cross
the face of the sun, I'd have given it about twice that time, but I suppose
its all down to perspective.
Brian


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Greg D. Moore http://greenmountainsoftware.wordpress.com/
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On 6/25/2013 6:33 AM, Greg (Strider) Moore wrote:
"Brian Gaff" wrote in message ...


It is a matter of perspective. The sun really covers a very small part
of the sky. (Can't recall the number and having trouble finding it.)

But figure the station has to cover 360 degrees in 90 minutes (give or
take). It's covering 4 degrees in a minute.

Or 1 degree in 15 seconds.

Hmm, and I was betting the sun was about 1 degree of arc, so that all
jives.


Well obviously cannot see it, but it sounds an awfully short time to
cross the face of the sun, I'd have given it about twice that time,
but I suppose its all down to perspective.
Brian



Yeah I was under that same impression Greg & Brian. In fact it looks to
me closer to 15 times the time stated in the article.

According to this table from Wikipedia:

https://en.wikipedia.org/wiki/Angular_diameter

As seen from the Earth's surface, the Sun is approx. .53 degrees of arc.
That puts a transit at 7.5 seconds if the 360 deg / 90 minutes figure is
correct, which is about 15x the figure stated in the article.

So it somewhat depends upon one's definition of "transit time". For the
entire surface of the Sun, for a "naked eye view", not recommended btw,
see above. However, if we're talking about the "transit time" within a
particular field-of-view, well that can be made arbitrarily small
depending upon the magnification being used.

It may have been he had only a 1/2 second window to catch an image with
enough magnification to show the details of the Chinese Space Station in
that first photo.

But the way it is worded in that article leaves it confused to say the
least!

Dave

In sci.space.station message dvSdnQvSeO5r7FTMnZ2dnUVZ_oqdnZ2d@earthlink
..com, Tue, 25 Jun 2013 06:33:26, "Greg (Strider) Moore" mooregr@ignore
thisgreenms.com posted:

"Brian Gaff" wrote in message ...


It is a matter of perspective. The sun really covers a very small part
of the sky. (Can't recall the number and having trouble finding it.)

There is a system known as Wikipedia, which is reasonably accurate on
most technical matters. http://en.wikipedia.org/wiki/Sun's general
box includes : Angular size 31.6' – 32.7' - so if you know what size 1'
is ... ; for the Moon, Angular diameter 29.3 to 34.1 arcminutes .

But figure the station has to cover 360 degrees in 90 minutes (give or
take). It's covering 4 degrees in a minute.

Or 1 degree in 15 seconds.

Hmm, and I was betting the sun was about 1 degree of arc, so that all jives.

You should know, from eclipses, that the Sun is the same angular
diameter, as seen from here, as the Moon. The Moon, in antiquated
units, is 2,000 miles across, and 240,000 miles away (approximate
means). Therefore the diameter is 2/240 radians; and since the radian
is about 57.3 degrees, the sun appears about half a degree across.


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