unidentified satellites

OK guys - here's another question. I use Heavens-Above regularly
and their listing(s) seem quite comprehensive. There are often
several satellites per hour listed for my viewing area on any given
night. They list down to visible mag. 4.5. Tonight between scheduled
satellites, I viewed two that were not listed by Heavens-Above and
they were relatively bright, easily mag. 4.0 or more. My question
is this: Is there a particular reason why these satellites are not
listed by them. Is it an oversight? Is the data not available to
them? Are these "secret" therefor "unlisted" satellites? Anyone
have an explanation for this. Also, is there possible a site that has
more listings that may include these unidentified satellites?
Thanks in advance for any suggestions.
Tony
P.S. This morning I allowed myself an hour and a half viewing window
from 0315 to 0445 PDT and tracked 8 satellites, the 2 unidentified
mentioned above plus these 6: Spot 1, Lacrosse 3, Cosmos 1975,
Cosmos 1340, Lacrosse 4, and Cosmos 1980.

"Tony Vinci" wrote in message
om...
OK guys - here's another question. I use Heavens-Above regularly
and their listing(s) seem quite comprehensive. There are often
several satellites per hour listed for my viewing area on any given
night. They list down to visible mag. 4.5. Tonight between scheduled
satellites, I viewed two that were not listed by Heavens-Above and
they were relatively bright, easily mag. 4.0 or more. My question
is this: Is there a particular reason why these satellites are not
listed by them. Is it an oversight? Is the data not available to
them?

To the best of my knowledge, Heavens-Above bases its magnitude estimates on
standard magnitude data produced by hobbyists.

The hobbyist data is of two types. For hundreds of objects, it has been
derived from many thousands of precise positional and magnitude
observations. Here are a few examples from the SeeSat-L archive:

http://satobs.org/seesat/Dec-1995/0029.html (UARS)

http://satobs.org/seesat/Dec-1995/0043.html (KeyHole)

http://satobs.org/seesat/Dec-1995/0093.html (Vostok upper stages)

http://satobs.org/seesat/Dec-1995/0101.html (Tselina-2 satellites)

For many other objects, the standard magnitude has been estimated based on
their published dimensions, or in some cases their published Radar Cross
Section.

Our standard magnitudes are accurate, but they are mean values, with
variances of 1 magnitude or more quite common. The variances are the
unavoidable consequence of our inability to know the precise surface
characteristics and orientation of most satellites. (The Iridiums are one of
few exceptions.)

Practically, this means that an object predicted to be magnitude 5.0, could
reach magnitude 4 or brighter, but would be omitted from Heavens-Above's mag
4.5 predicted list.

In a few cases, Heavens-Above does appears not to have up to date magnitude
data. For example, Japan's first spy satellites, 03009A (std mv = 5.7) and
03009B (std mv = 3.2) often are quite bright, but Heavens-Above does not yet
have their magnitude data. Several pieces of operational debris from that
launch also are bright, including some good flashers. No doubt, in time the
data for these objects will be added.

Also, is there possible a site that has more listings that
may include these unidentified satellites?

Heavens-Above mentions an All Visible Passes option for registered users,
with the ability to set your own magnitude cut-off. Perhaps that would be
worth a try.

Ted Molczan

"Tony Vinci" wrote in message
om...
OK guys - here's another question. I use Heavens-Above regularly
and their listing(s) seem quite comprehensive. There are often
several satellites per hour listed for my viewing area on any given
night. They list down to visible mag. 4.5. Tonight between scheduled
satellites, I viewed two that were not listed by Heavens-Above and
they were relatively bright, easily mag. 4.0 or more. My question
is this: Is there a particular reason why these satellites are not
listed by them. Is it an oversight? Is the data not available to
them?

To the best of my knowledge, Heavens-Above bases its magnitude estimates on
standard magnitude data produced by hobbyists.

The hobbyist data is of two types. For hundreds of objects, it has been
derived from many thousands of precise positional and magnitude
observations. Here are a few examples from the SeeSat-L archive:

http://satobs.org/seesat/Dec-1995/0029.html (UARS)

http://satobs.org/seesat/Dec-1995/0043.html (KeyHole)

http://satobs.org/seesat/Dec-1995/0093.html (Vostok upper stages)

http://satobs.org/seesat/Dec-1995/0101.html (Tselina-2 satellites)

For many other objects, the standard magnitude has been estimated based on
their published dimensions, or in some cases their published Radar Cross
Section.

Our standard magnitudes are accurate, but they are mean values, with
variances of 1 magnitude or more quite common. The variances are the
unavoidable consequence of our inability to know the precise surface
characteristics and orientation of most satellites. (The Iridiums are one of
few exceptions.)

Practically, this means that an object predicted to be magnitude 5.0, could
reach magnitude 4 or brighter, but would be omitted from Heavens-Above's mag
4.5 predicted list.

In a few cases, Heavens-Above does appears not to have up to date magnitude
data. For example, Japan's first spy satellites, 03009A (std mv = 5.7) and
03009B (std mv = 3.2) often are quite bright, but Heavens-Above does not yet
have their magnitude data. Several pieces of operational debris from that
launch also are bright, including some good flashers. No doubt, in time the
data for these objects will be added.

Also, is there possible a site that has more listings that
may include these unidentified satellites?

Heavens-Above mentions an All Visible Passes option for registered users,
with the ability to set your own magnitude cut-off. Perhaps that would be
worth a try.

Ted Molczan

Hello Tony,

There are predictionprograms you can run yourself with the
satelements you want.
Go to the seesat-l homepage at: www.satobs.org/satintro.html
here you find links to several programs and places to get satelements.

Also to Rob Matsons Skymap, which you can use to ID observed UNIDs

Greetings
Leo Barhorst

"Tony Vinci" schreef in bericht
om...
OK guys - here's another question. I use Heavens-Above regularly
and their listing(s) seem quite comprehensive. There are often
several satellites per hour listed for my viewing area on any given
night. They list down to visible mag. 4.5. Tonight between scheduled
satellites, I viewed two that were not listed by Heavens-Above and
they were relatively bright, easily mag. 4.0 or more. My question
is this: Is there a particular reason why these satellites are not
listed by them. Is it an oversight? Is the data not available to
them? Are these "secret" therefor "unlisted" satellites? Anyone
have an explanation for this. Also, is there possible a site that has
more listings that may include these unidentified satellites?
Thanks in advance for any suggestions.
Tony
P.S. This morning I allowed myself an hour and a half viewing window
from 0315 to 0445 PDT and tracked 8 satellites, the 2 unidentified
mentioned above plus these 6: Spot 1, Lacrosse 3, Cosmos 1975,
Cosmos 1340, Lacrosse 4, and Cosmos 1980.

Hello Tony,

There are predictionprograms you can run yourself with the
satelements you want.
Go to the seesat-l homepage at: www.satobs.org/satintro.html
here you find links to several programs and places to get satelements.

Also to Rob Matsons Skymap, which you can use to ID observed UNIDs

Greetings
Leo Barhorst

"Tony Vinci" schreef in bericht
om...
OK guys - here's another question. I use Heavens-Above regularly
and their listing(s) seem quite comprehensive. There are often
several satellites per hour listed for my viewing area on any given
night. They list down to visible mag. 4.5. Tonight between scheduled
satellites, I viewed two that were not listed by Heavens-Above and
they were relatively bright, easily mag. 4.0 or more. My question
is this: Is there a particular reason why these satellites are not
listed by them. Is it an oversight? Is the data not available to
them? Are these "secret" therefor "unlisted" satellites? Anyone
have an explanation for this. Also, is there possible a site that has
more listings that may include these unidentified satellites?
Thanks in advance for any suggestions.
Tony
P.S. This morning I allowed myself an hour and a half viewing window
from 0315 to 0445 PDT and tracked 8 satellites, the 2 unidentified
mentioned above plus these 6: Spot 1, Lacrosse 3, Cosmos 1975,
Cosmos 1340, Lacrosse 4, and Cosmos 1980.

Also, is there possible a site that has more listings
that may include these unidentified satellites?

Here are some other sites with online predictions that might
include other objects:

http://web2.cnam.fr/vms/equipe/bmabboux/track.html

http://www.calsky.com/

http://www.donbarry.org/sat/

Ed Cannon - - Austin, Texas, USA
(Remove "donotspam".)

Also, is there possible a site that has more listings
that may include these unidentified satellites?

Here are some other sites with online predictions that might
include other objects:

http://web2.cnam.fr/vms/equipe/bmabboux/track.html

http://www.calsky.com/

http://www.donbarry.org/sat/

Ed Cannon - - Austin, Texas, USA
(Remove "donotspam".)