Re: terminology: flare, alt/az, vulgar, Y2K

Wed, 03 Jun 1998 00:17:45 -0400

Walter Nissen wrote:
> > From: (Philip Chien)
> > BTW - since such an authorotative source as "Sky & Telescope" (who some
> > SeeSat subscribers have been reading since before I was born) 

I started reading it in the mid 50s.  When were you born?

>   On page 20, we find "light-years".  These units
> also are thoroughly obsolete, though "light-year" retains appeal even
> stripped of its status as a unit.  

I must have been light-years away and missed that news.  When did it
become obsolete?  If it was officially stripped of status, how come it
is still being illegally used?

>  And don't get me started on
> their insistent use of the astronomical slur, a-mateur.

I really don't want to get you started, but how is that a slur?
What to use instead?
I always took the difference to be compensation. Amateurs do something
for love, not money.  Professionals get paid.

> Various concepts have been advanced as the denotative meaning of "flare",
> but I haven't seen any consensus on which of these should be accepted and> which rejected.

Ok folks, let's reach a consensus right now.

> I have no idea how "flare" relates to or is distinguished from old
> reliables like "glint" and "flash".

> if I do use "glint",
> then what do others mean by using "flare"?  Are we approaching
> understanding here, or confusion?

I thought I had explained this before and had some people agree with
me,  but I'll do it again.

Glint: A bright reflection.  A good example is seeing the sun glint off
the curved window or bumper of a car. The whole car is visible by
reflected sunlight, but the very bright point reflection of the sun that
makes  you squint is a glint. The glint can be short or long lasting. It
can be a flash or flare. Time is not a factor.  Brightness is.

Flash: A bright, very short duration glint or reflection. Quick sharp
rise and decrease in brightness.  Like a camera flash, or EGP.

        . .
        . .              Light curve (sort of) of a flash
......... .........

Flare: A longer duration glint or reflection that has a slower
rise/decrease in brightness.   Like an Iridium flare.
     .  .
    .    .
....      .....   Light curve of a flare

Voting will now commence on this definition and will end as soon as I
feel I have enough votes to carry the point.   :)

> For a while, I tried using IRIDFLAR's az/el.  I missed a couple of OBS
> because I had difficulty switching back and forth and got confused.  I
> ended up writing a post-processor to re-format the output from IRIDFLAR
> and thus eliminate the necessity of ever looking at az/el.  Hopefully,
> I'll eventually regain my confidence in alt/az and be all better again.
> Meanwhile I'm feeling burned.

As discussed before, az/el has been used for sat observing since the
earliest days. I realize astronomical scopes may use different terms,
but az/el has always been used for sats.  Mike has even put az/el as an
optional column heading in QUICKSAT.  (Thanks again Mike).
With sats, altitude stood for sat height (miles or km) above the earth. 
Elevation was angle in degrees above the horizon. (0=horizon, 90=zenith)
These distinctions were not necessary when referring to objects at
astronomical distances.
I find it much easier to look for az before looking for el, so az/el is
appropriate.  To find a general area in the sky, I'll turn around to the
correct az, then look up to the predicted el.  It would be too awkward
to first look up to an el of say, 70 deg, then turn (rotate, not
revolve) while looking up to guess where the right az was.  It's much
simpler to find the spot on the horizon that you want, and then just
look up to the el.

> Jay, I haven't heard from you on the common vs vulgar issue.  I'd hate to
> think I've prevailed on the rational issues only to saddle you with
> constant "grating".  

Even more grating than that (and that's a lot) is the continuing legal
problems with Mastercard over baseless charges.  That's what takes a lot
of my time now.  But back to definitions.  Common and vulgar may
represent the same thing in certain circumstances, but the words do not
mean the same thing and may NOT be used interchangeably in all

You may call a street tramp common and mean vulgar.  That's ok.
If you told the average person you'd like their opinion as being
representative of the common man in the street, you'll get their
If you said they were considered the vulgar man in the street, you might
wind up stretched out in the street.

Many words share meanings, but also have completely separate meanings.
A gun is always a weapon.  A weapon is not always a gun.  It may be a
gun or any number of other things. You may use either term in some, but
not all instances.  You say, "gun the engine".  You may not say "weapon
the engine".  So even though weapon may mean the same as gun at times,
at other times, it is completely inappropriate.  

Same thing with common/vulgar.  In the context of common name meaning
the proper name that people commonly (usually) use, there is no way that
vulgar (meaning coarse, crude, rude) may be used.

>That's not a pleasant thought.

At least it's good that we can strongly disagree without being
disagreeable.  There are too many common (vulgar) people on the net that
offend everyone else.  People like Walter are always gentlemanly even
when arguing a point.  That's a very nice feature of SeeSat.

Jay Respler
Sky Views:
  Satellite Tracker * Early Typewriter Collector
           Freehold,  New Jersey