Re: Bright sat list / software

Robert Sheaffer (
Wed, 18 Dec 1996 08:25:28 -0800 (PST)

> Do you realize that an element file has NO indication of brightness?  You can
> use it for elevation.  A separate list is required if you want some indication
> of brightness.

Ted Molczan puts brightness information in his elements set, and this
is what I am referring to.

> If what you're looking for are bright naked eye sats, use VISUAL.TLE for your
> elements list.  That's why I made the list.   It includes virtually all sats
> brighter than mag 3.8.  Even if you're not aware of some bright sat, it should
> show up when you make predictions using VISUAL.TLE.

I was using it for a while. As I recall, it did not contain certain
satellites like the "Lacrosse" series, which are quite bright. Consequently,
I tried other sets. When I started using Molczan's elements set, all
of the unidentifieds could be resolved (you sometimes had to fiddle
with the program's brightness filter, as this "magnitudes" uncertainty is
the Achilles' Heel of our hobby).

> > > > fails to rely upon that information, this is *still* a
> > > > "cart-before-the-horse" approach. It would be fine to have a
> > > > "list of favorite satellites" mode of operation, so long as
> > > > you ALSO have a "show me everything brighter than Magnitude X"
> > > > mode.
> You CAN do that.  See above.
> > > What program are you using?  
> You didn't answer that yet.

Mostly, I'm using QUICKSAT and SKYMAP. Both will do this, but both
rely on self-contained magnitudes files, and that of QUICKSAT is
*strongly* biased to overstate the brightness of a satellite. Mike
McCants is looking at other options for computing this.

> That's NOT what I said.  I'm not combining element lists.  I'm taking 2
> different sets of PREDICTIONS, made with different control  files,
> with different criteria, and combining and sorting them  by time into 1 list of
> predictions.
> Again, I don't know of any program that will do that.

That sounds like "compromise between two political parties", not
a prediciton of an observable event. The satellite, when it passes
over, will have an unambiguous magnitude. I realize the many
variables and complications in predicting this; I am merely suggesting
that we need an "industry standard" for magnitudes, and a single
way for predictions programs to reference it. If a satellite's
magnitude turns out to be consistently over or under-estimated,
we will fix it in the "standard" file, not in dozens of little
files scattered about.


        Robert Sheaffer - - Skeptical to the Max!
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