SL-16 (26076)

Has anyone seen SL-16 (listed as bebris)? Catalog number 26076.
Heavens-Above has the magnitude listed as 4.4 but I have never been
able to see it using my 7x50 binoculars or with the naked eye. I have
looked for it several times using the Heavens-Above star charts to get
an accurate location to look.

J. Thomas Jeffrey wrote:

Has anyone seen SL-16 (listed as debris)? Catalog number 26076.

I've seen it. It's a chunk of the Zenit-2 upper stage which launched
Kosmos 2369; this piece of space junk is also identified as 2000-006-F

Heavens-Above has the magnitude listed as 4.4 but I have never been
able to see it using my 7x50 binoculars or with the naked eye. I have
looked for it several times using the Heavens-Above star charts to get
an accurate location to look.

Satellite debris can have highly irregular shapes and sizes. You
may just have had the bad luck to look for it when it was at an
angle that didn't catch the sun properly for your position. I don't
know how H-A calculates magnitudes, but sometimes their forecasts
are off by a magnitude or more.

--Bill Thompson

J. Thomas Jeffrey wrote:

Has anyone seen SL-16 (listed as debris)? Catalog number 26076.

I've seen it. It's a chunk of the Zenit-2 upper stage which launched
Kosmos 2369; this piece of space junk is also identified as 2000-006-F

Heavens-Above has the magnitude listed as 4.4 but I have never been
able to see it using my 7x50 binoculars or with the naked eye. I have
looked for it several times using the Heavens-Above star charts to get
an accurate location to look.

Satellite debris can have highly irregular shapes and sizes. You
may just have had the bad luck to look for it when it was at an
angle that didn't catch the sun properly for your position. I don't
know how H-A calculates magnitudes, but sometimes their forecasts
are off by a magnitude or more.

--Bill Thompson

Has anyone seen SL-16 (listed as bebris)? Catalog number 26076.
Heavens-Above has the magnitude listed as 4.4 but I have never
been able to see it using my 7x50 binoculars or with the naked
eye. I have looked for it several times using the Heavens-Above
star charts to get an accurate location to look.

Mike McCants' RCS file, which averages USSTRATCOM's measurements
of radar cross-sections of objects, lists 26076 as .1 square
meter -- a very small object. As Bill said, it could be an odd
shape that sometimes reflects much more brightly than others.

Magnitude estimates have to be well understood. They are
estimates based on available information. Some objects are
consistently observable near estimated magnitudes, but others
vary much more. Quite a few payloads can vary wildly from
estimates if flat surfaces are nicely aligned for bright
specular reflections. Some big launch vehicle stages are
badly aligned, say pointing directly at the Earth's surface,
and may be invisible when they should be +3.5 magnitude.

Here's the link to that RCS file:

http://users2.ev1.net/~mmccants/catalogs/rcs.zip

Ed Cannon - - Austin, Texas, USA

Has anyone seen SL-16 (listed as bebris)? Catalog number 26076.
Heavens-Above has the magnitude listed as 4.4 but I have never
been able to see it using my 7x50 binoculars or with the naked
eye. I have looked for it several times using the Heavens-Above
star charts to get an accurate location to look.

Mike McCants' RCS file, which averages USSTRATCOM's measurements
of radar cross-sections of objects, lists 26076 as .1 square
meter -- a very small object. As Bill said, it could be an odd
shape that sometimes reflects much more brightly than others.

Magnitude estimates have to be well understood. They are
estimates based on available information. Some objects are
consistently observable near estimated magnitudes, but others
vary much more. Quite a few payloads can vary wildly from
estimates if flat surfaces are nicely aligned for bright
specular reflections. Some big launch vehicle stages are
badly aligned, say pointing directly at the Earth's surface,
and may be invisible when they should be +3.5 magnitude.

Here's the link to that RCS file:

http://users2.ev1.net/~mmccants/catalogs/rcs.zip

Ed Cannon - - Austin, Texas, USA