Standard magnitude of 2nd generation NOSS objects

From: Ted Molczan (molczan@home.com)
Date: Wed Sep 19 2001 - 13:07:16 EDT


The original work on this was performed in 1995 by Rainer Kracht, using Russell
Eberst's observations available at that time:

http://www.satobs.org/seesat/Dec-1995/0034.html

I have updated the analysis, using Russell's observations to date:

NOSS 2-1 (C)   1990-050C   20691   309   5.82   0.0244
NOSS 2-1 (D)   1990-050D   20692   336   5.85   0.0246
NOSS 2-1 (E)   1990-050E   20642   185   5.47   0.0166
NOSS 2-2 (C)   1991-076C   21799   333   5.72   0.0254
NOSS 2-2 (D)   1991-076D   21808   333   5.75   0.0257
NOSS 2-2 (E)   1991-076E   21809   210   5.68   0.0238
NOSS 2-3 (C)   1996-029C   23908    98   5.86   0.0197
NOSS 2-3 (D)   1996-029D   23862    91   5.77   0.0173
NOSS 2-3 (E)   1996-029E   23936    80   5.69   0.0180
------------------------------------------------------
  ALL                             1975   5.74   0.0231

column 1 : name
column 2 : international designation *
column 3 : catalogue number *
column 4 : number of observations
column 5 : standard magnitude, 1000 km range, 90 deg phase angle
column 6 : phase coefficient, magnitude per degree

* note that in the absence of official information, hobbyists have agreed on a
naming convention that designates objects according to their location with each
triad, in order of leader, trailer and outlier. Those locations could change
over time.

I believe that my methodology is similar to Rainer's, in that we determined the
range of each observation and used that information to compute the equivalent
magnitude at a range of 1000 km, according to the inverse-square law. Finally,
we correlated 1000 km magnitude with phase angle.

One small difference in methodology: Rainer used pairs of observations on the
same pass to compute an approximate circular orbit, from which he computed the
range of each observation. I used the available elements, on the basis of epoch
nearest time of observation. The advantage of Rainer's method is that it does
not depend on knowledge of the elements, while maintaining high accuracy, even
with moderately eccentric orbits (like KeyHoles). The advantage of my method is
that it does not require pairs of observations, thus increasing the number of
usable observations.

Ted Molczan

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