I just saw the coolest thing!

OK OK OK!
So I live in Los Angeles, seeing is less the ideal.
So I was out in the back yard looking at the moon at 8:10 PM
And this BLACK spear or circle move right across the face of the moon. It
was SOOO cool.
I am almost positive it was a transit of a satellite. I don't think most of
them are round.

Well I was jazzed I have never seen that before!

So how many of you guys have seen this before? Is this common?

Anyway I am going back to look at Saturn.

Mark F.

Mark,

Yes I've seen this before and I think it's one of those GeoStationary
Satellites

"P. Edward Murray" wrote in message
...
Mark,

Yes I've seen this before and I think it's one of those GeoStationary
Satellites

Geostatonary satellites wouldn't be seen to be moving - though you may have
seen the moon moving behind it (which would have taken something like an
hour for the satellite to cross the full diameter of the moon) .

On Mon, 14 Apr 2008 19:35:01 +0100, "OG"
wrote:

Geostatonary satellites wouldn't be seen to be moving - though you may have
seen the moon moving behind it (which would have taken something like an
hour for the satellite to cross the full diameter of the moon) .

A geostationary satellite stays over the same location on the Earth. As
a consequence, it is observed to move with respect to the background
stars (and approximately, the Moon as well) at 15 arcsec/sec. So a
geostationary satellite will cross the face of the Moon in about two
minutes.

However, you can only observe a geostationary satellite cross the Moon
during those rare times when the Moon's declination happens to be near
the celestial equator- which isn't very often, and wasn't the case at
the time of this report.

Furthermore, resolving a geostationary satellite against the Moon would
seem impossible. With the naked eye, a satellite would need to be about
10 km in diameter to subtend one arcmin, the nominal resolution of the
eye. Telescopically, you might (with a big scope and near perfect
observing conditions) resolve a satellite subtending 1 arcsec. That's
still an object 173 meters across, however, and I don't think there's
anything that large in a geostationary orbit. Even detecting (without
resolving) such a satellite against the Moon seems very unlikely.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

OG wrote:
"P. Edward Murray" wrote in message
...
Mark,

Yes I've seen this before and I think it's one of those GeoStationary
Satellites

Geostatonary satellites wouldn't be seen to be moving - though you may have
seen the moon moving behind it (which would have taken something like an
hour for the satellite to cross the full diameter of the moon) .

No, it would take a geostationary satellite only about two minutes to
cross the full diameter of the moon, due to the moon's diurnal motion.
To put it another way, geostationary satellites don't seem to move *if
you turn off your clock drive*.

However, what the original poster saw could not have been a
geostationary satellite. He was observing from Los Angeles on April 13.
The moon's declination was approximately +17 degrees. Geostationary
satellites appear south of the equator for northern hemisphere observers.

-- Bill Owen

On Mon, 14 Apr 2008 03:20:01 GMT, "Mark F." wrote:

OK OK OK!
So I live in Los Angeles, seeing is less the ideal.
So I was out in the back yard looking at the moon at 8:10 PM
And this BLACK spear or circle move right across the face of the moon. It
was SOOO cool.
I am almost positive it was a transit of a satellite. I don't think most of
them are round.

What magnification were you using? How long was the transit?
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

"Chris L Peterson" wrote in message
...
On Mon, 14 Apr 2008 19:35:01 +0100, "OG"
wrote:

Geostatonary satellites wouldn't be seen to be moving - though you may
have
seen the moon moving behind it (which would have taken something like an
hour for the satellite to cross the full diameter of the moon) .

A geostationary satellite stays over the same location on the Earth. As
a consequence, it is observed to move with respect to the background
stars (and approximately, the Moon as well) at 15 arcsec/sec. So a
geostationary satellite will cross the face of the Moon in about two
minutes.

D'oh - apologies

However, you can only observe a geostationary satellite cross the Moon
during those rare times when the Moon's declination happens to be near
the celestial equator- which isn't very often, and wasn't the case at
the time of this report.

Furthermore, resolving a geostationary satellite against the Moon would
seem impossible. With the naked eye, a satellite would need to be about
10 km in diameter to subtend one arcmin, the nominal resolution of the
eye. Telescopically, you might (with a big scope and near perfect
observing conditions) resolve a satellite subtending 1 arcsec. That's
still an object 173 meters across, however, and I don't think there's
anything that large in a geostationary orbit. Even detecting (without
resolving) such a satellite against the Moon seems very unlikely.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Apr 14, 5:20 am, "Mark F." wrote:

And this BLACK spear or circle move right across the face of the moon.

Wow! You saw a black triangle!

See
http://www.space.com/businesstechnol...le_040902.html

"They have become legendary in UFO circles. Huge, silent-running
'Flying Triangles' have been seen by ground observers creeping through
the sky low and slow near cities and quietly cruising over highways."

Wow! You saw a black triangle!...etc.

I can't get into this link. What is it about?
--
Curtis Croulet
Temecula, California
33°27'59"N, 117°05'53"W

On Tue, 15 Apr 2008 00:16:47 GMT, "Mark F." wrote:

You might be right. I was just looking at transits of the sun by Mercury and
Venus online, very similar.
But to me it had the speed of a satellite and moved in a straight line.
That thing was perfecly round.

Well, you need to consider the size. The biggest thing up there by far,
the ISS, is still just the size of a tiny crater on the Moon. Have a
look at http://www.astrosurf.com/legault/iss...s_transit.html for
what the ISS and the Shuttle look like crossing the Sun... tiny. Or how
about a more typical satellite, the HST?
http://www.astrosurf.com/legault/hst_transit.html . I don't think you'd
be able to tell its shape through a telescope.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com