Expert: Tom Whiting - 2/3/2007

Question
Dear sir,
Is it possible to see a satellite using our naked eyes. I recently saw an object in the sky in the south direction but could not come to a conclusion of it. So i assumed it as a satellite. Do satellites have lights as we can see in a airplane. And can we view the satellite using a telescope.
Thanks in advance

Answer
Hi Mohan,
Oh Yes,  there are over 10,000 artificial satellites now, and nearly half of them are big enough to reflect sunlight so that they can be seen with the naked eye.  In fact, for nearly 20 years now, that is considered... a separate activity of amateur astronomers using just the naked-eye or binoculars.....along with double stars, variable stars, meteor watching, deep sky objects, etc. etc.

They range in brightness from the ISS (International
Space Station with humans on board), about the brightness
of Jupiter (-2nd magnitude),  to right down to the naked eye
limit of 6th magnitude, probably the most difficult naked eye
important satellites are the NOSS triplets....3 satellites that
orbit "in formation" as an isosceles triangle.
(They have often, and mistakenly, been reported as a
transparent UFO)!!
Artificial satellites (except for the ISS) have no lights on them
as there is no need for lighting....satellites shine by being up
high enough to reflect the sun's light while you are in darkness down on the Earth's surface.  Thus,  the best time to
watch for satellites is the period of 2-3 hours after sunset, and 2 to 3 hours before sunrise.....on a typical dark sky night, you can see 30-40 satellites passing over your night sky before say, 11 pm. local time. You won't see very  many from 11 pm until 4 am because they are also in the Earth's shadow overhead during the midnight hours....only the very very high ones, which are typically quite small and dim.
The key to seeing them, like any other astronomical object, is to get into a very dark sky, well away from all city (artificial) lighting out in the country skies. (Or deep desert skies, as the case may be). {Even on an ISS pass, you are still only seeing the reflected sunlight, not the interior lighting}.

Naked eye and wide field binoculars are the best to use.....
they move too fast for the very small view (typically 1/2
degree) of a telescope, so you can't track with them very easy
using a scope.  And even if you could put a telescope on them,  all you'll see is a pin-point dot (except for the ISS which does have a slight T - shape)......how big would a car look from 200 Km away (120 miles)?  A pin point, and that's all.  So most satellite observers use only naked-eye and
binoculars because all they see are pinpoints of reflected
sunlight....that's all you are seeing.
There is a great website for all satellite (including ISS)
accurate predictions for any location on Earth that we all use, for free...go to:
http://www.heavens-above.com
Sign in, select a location, and enjoy.
Hope all this helps,
Clear Skies,
Tom Whiting
Erie PA  USA

FOLLOW UP:
The key to observing artificial satellites (or any other
astronomical objects) is to get as far away as you can, from
the glow of city lighting, and into clear, very dark skies
during the dark of the moon.  (As the moon is a big light
polluter too...in fact, most of us astronomers hate the moon!
As it knocks out all the deep sky objects that we want to
observe thru our scopes!!