Stars visible in daylight, or did I see flaring geostationary satellites?

Yesterday I saw what must have been two stars in broad daylight, or
else I saw two geostationary satellites flaring brightly. I'm betting
on the former, but it would sure be exciting if it were the latter!
Even seeing stars in daylight is pretty neat -- I have once before seen
in daylight what was later identified as Jupiter, but I did not know
that any stars were bright enough to share that honor, thus my
speculation that I was seeing flaring geostationary satellites.

Here's the information:

I was watching an airplane cross the sky when I saw these two points of
light. Had my eyes not already been focused on the airplane it is
doubtful I would have seen the two points.

It was broad daylight* (about 1900 local time, Sunday, September 10,
2006, Sarasota, Florida, USA, or 2300 UTC September 10, 2006), and the
only thing that might have helped improve the viewing in that part of
the generally clear sky is that a heavy layer of cirrus had blown off a
thunderstorm, and in a hole in that canopy the sky was RELATIVELY
darker than the clear sky elsewhere. (Coordinates for Sarasota: 27.34
north; 82.53 west.) (*Sunset was at 1939 local.)

What I observed: Two points of light about three or four degrees apart
and about equal brightness. The brightness was steady and did not vary,
and I observed these points for about five minutes until finally the
cirrus canopy obscured them. The points of light had no apparent
motion, and their color was bluish white. I can't estimate the
magnitude, but it had to have been pretty bright for me to have seen
these objects in full daylight?

The azimuth was approximately NNE, and the elevation was approximately
30 degrees above the horizon.

Through binoculars the points remained just that, points. If they had
been weather balloons I think that my 8X binoculars would have been
powerful enough to have resolved some kind of shape, therefore I'm
guessing that these objects were not in the atmosphere.

So, what do the members of the group think I saw? A couple of bright
stars, viewed under just the right daylight viewing conditions, or
could it have been brightly flaring geostationary satellites? I don't
even know if there are any geostationary satellites in that part of the
sky - aren't most (or all) of them parked in equatorial orbits and
would have required me to have been looking southward instead of
northward?

A puzzler, huh?

I thank the group in advance for any help that might be rendered in
helping to identify what I saw, or at least eliminate from the list of
possibilities what it probably wasn't (a couple of geostationary
satellites).

On 11 Sep 2006 11:09:49 -0700, wrote:

Yesterday I saw what must have been two stars in broad daylight, or
else I saw two geostationary satellites flaring brightly. I'm betting
on the former, but it would sure be exciting if it were the latter!
Even seeing stars in daylight is pretty neat -- I have once before seen
in daylight what was later identified as Jupiter, but I did not know
that any stars were bright enough to share that honor, thus my
speculation that I was seeing flaring geostationary satellites.

Iridium satellites can sometimes be seen during daylight.

Apart from these, only the sun, moon and venus can be seen
during the day.

Minge.

Hi,

Nice observation!

I can't for the life of me think that it was a satellite: I've observed
many Iridium flares, up to a magnitude of -7, one of them in what was
classed as 'broad daylight' but in reality was far closer to sunset
than your observation.

The key to deciphering your objects are your words: 'brightness was
steady' and 'observed these points for about five minutes'. This rules
out LEOs and Molniyas. LEOs like Iridium flash brightly for 15 seconds
or so but traverse one end of the visible sky to the other in that
time. Deep sky objects like GPS (27,000 km mean distance) or
geostationary (42,000 km) are not seen by observers with the naked eye
and even skilled observers (I've not seen one!) use binoculars or
telescopes or capture them on video with CCD and interpret the flaring
as a thicker line on the video. The flare time generally lasts a few
seconds as the object spins or tumbles or both. As you point out, the
geostationary objects are aligned equatorially, in the opposite
direction to where you were looking. Even if there was a satellite with
a period of one sidereal day but non zero inclination, it could appear
to remain above your location for 5 minutes but in that time it would
have travelled 900 km along its orbit and the chances of it putting out
a steady flare (ie no spin, no tumble, perfect sun-MMA-observer
alignment) are not high. Let alone the chances of a second object with
identical behaviour . . . and all one hour before civil twilight . . .

We can rule out a planet, as the ecliptic plane was behind you. I'm
going to guess that the thunderstorm cleared the dust / pollution from
the air, making the light appear not to twinkle while masking the sun.
I can't believe you would see a star of magnitude +2 or +3 under these
circumstances so if it was a star, I would start at close separation,
zero magnitude contenders such as Vega and Deneb. The angular
separation between the two isn't bad but the Az El is not quite the
same, but not wildly different.

Otherwise, I'd go for a pair of high altitude weather balloons or
personally, lean towards two aircraft in formation. Must have been a
few aircraft patrolling so close to September 11 and we've all seen
aircraft on a 20 to 30 degree or so approach to a city and had to check
back over several minutes to resolve exactly what it was. Just a few
weeks back I thought I'd spotted my first NOSS satellite formation and
was quite disappointed when three minutes later they separated and went
off in different directions.

Be interested to hear any alternative explanation.

Cheers,

Bill
Canberra, Australia

Oops, WhiteStarLine stupidly wrote:

snip . . . like Iridium flash brightly for 15 seconds or so but
traverse one end of the visible sky to the other in that time . . .
/snip

Poor proof reading! I didn't really mean that they whizzed across the
night sky in 15 seconds, just that a typical low orbit satellite is
visible for a few minutes and in that time tracks across a significant
part of the visible sky.