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(meteorobs) Re: Plotting Times/Dead Time+more
From George Zay:
>Norman, is 12 seconds your average time or is this your fastest time? Is this
>12 seconds only for the plot on your maps or does it include writing down the
>other info as well?
That's my average time, and it includes recording of data. I usually plot
on two AMS charts max, and almost always the equatorial ones. Facing south,
the top of the chart goes beyond my zenith, and the bottom is about 25
degrees high in the deep south. Meteors that project off the charts I skip
plotting since the radiant can't be accurately determined from so far away.
Familiarity with these charts dictates that I keep using them.
The key to fast plotting is star and constellation knowledge. I again have
to credit H A Rey's book, The Stars: A New Way to See Them, for my success.
Olivier remarked soon after I started that I learned to plot well very soon.
That extends to finding deep-sky objects as well, for I can point a
telescope within a degree of almost any object after consulting a chart. I
saw someone use a 17" to star-hop from Altair to M30 because he knew no more
than the first-magnitude stars ! If you learn the constellations with the
lines drawn to make the shape match the name, it is vastly easier to learn
the sky. I know of no other book besides Rey's that accomplishes this. It
took only four months to get a solid working knowledge of the sky, in
winter-spring of 1960, when I was in competition with a friend to find
Messier objects. He used a familiar magazine to learn the stars, and he
never came close to knowing the sky as well as I did. Charts that draw a
vague shape will only get you to learn a vague region of the sky as
containing a particular constellation. Rey uses stars down to fifth
magnitude to fill out shapes, and I learned these stars quickly as a result.
They are absolutely essential for plotting meteors. A book review of Rey in
S&T (1962 October, I think) criticized the use of such faint stars because
people in cities won't see them. Well, you need to be outside the city to
see anything anyway. In an excellent sky you won't have the syndrome of
couldn't-recognize-the-constellations if you know the Rey way, instead they
will stand out in bold relief.
I don't understand why anyone would not like the Rey shapes. They are
beautifully done. Leo and Taurus both have four legs, adding a lot of stars
to make plots easier, for instance. I cringe every time I see a chart of
Orion with his feet tied together; how is he supposed to walk? Learn his
club and shield stars, not just his belt. Ursa Major looks like a real bear
with his nose at the end of the Dipper handle, and it takes in a large
region of sky that otherwise would be very difficult to plot in. I could
cite a similar story with almost every constellation.
If a meteor doesn't appear to be directly between two stars, there are many
other ways to plan a plot. I can usually find two stars that it went
parallel to, if it didn't come from, or go toward, any star. Another common
way is using the midpoint between two stars as an aiming direction for the
plot. I have a piece of cardboard flat on the pavement to my left for a
writing surface. The paving is smooth asphalt of a cul-de-sac in an
undeveloped part of Lehigh Acres. My pads are old seat cushions from
living-room chairs placed on the pavement. It's a clean surface so I need
no ground cloth or plastic sheet. A recording paper is folded lengthwise
in four sections with one section being upright. If not plotting, I
generally wait until I have 3 meteors, then reach over and write without
looking, trying to advance down the paper each time. This way I have no
dead time at all. I just note the passage of each local hour (26 minutes
after the hour) at my longitude of 81.5W. Also the start and end minute,
and time for a meteor if -3m or brighter. I am not currently getting the
time for every individual meteor. Data I get is shower, color, magnitude,
train. Other items I stopped recording after accumulating about 40000
meteors as no change was taking place. For plots I label them with a number
for tenths of a day in UT combined with a letter for speed (S,M,F). The
date Sep 16.3 UT would cover the time on Sep 16 from 6:00 to 8:24 UT, for
instance, the range Sep 16.25 to Sep 16.35 with more precision. So, a plot
in that time range of a fast meteor would have the label "3F." This system
I devised for reducing my own plots a little faster. With each plot I also
put down the data, which takes only a couple of seconds with the light on
and data sheet next to the plot chart. The easiest plots I can do in just 5
seconds. I am looking up, get it planned, then slip the glasses off and do
the plot and record. Ground-level would surely be easier than being in a
chaise lounge, for I'm not holding on to anything. Just keep the charts
covered with something to stop dew.
George:
> You
>mentioned that you wear glasses while observing. No doubt that helps your
>distant vision to look at the stars. But when you look down, do you have to
>remove or adjust your glasses to see your charts up close?
I do have to remove the glasses to see the charts. A bit past age 42 I
suddenly experienced severe eyestrain using the glasses for reading within a
few days' time. Thereafter, I can't accommodate up close with the glasses
on, and now I need to hold the page 26 inches distant to be comfortable.
Seeing my nephew playing a video game only 6 inches from his eyes, I
wondered how he could see anything meaningful. That close for me would
resolve the screen into colored dots.
On other matters, there was a lot of talk about green fireballs a couple of
nights ago on the big overnight radio show. Oh, those poor people waxed
mysterious, egged on by the host and the director of the UFO reporting
center. Green is probably the most common color for the brightest meteors,
and almost every report was an obvious meteor. I am skeptical of the ones
that reported a sudden change in direction ; while freaking out from
excitement, who knows what was going through their heads. Much speculation
about some of the fireballs being reentering space junk I could lay to rest
-- this stuff is orange, not green. It is vastly easier to fantasize than
to think rationally or get educated. Hope against hope that we are being
visited. It has been more than 50 years since I started looking up, and I
have yet to see something that I couldn't identify. The fireballs being
discussed on this list in recent weeks were also seen by the people herein
described.
From Bob and Lew:
>
>>the first satellite I have ever seen pass in front of the moon.
>
>That sounds like it WOULD be a thrill, Bob! Has anyone else ever seen this?
Not me. Hopefully some time in my life it will happen. In 1994 and 1996 I
got to see an airliner cross the face of a nearly full moon. The silhouette
flashed starkly into view with astonishing detail, even the engines were
visible on planes 5 miles high. It wasn't longer than 2 minutes of arc
against the moon at 30 minutes of arc. The planes were probably on the
Houston-Miami run.
Leonids I consider to be very fast, while Perseids and Orionids are fast.
There's a big difference between them in speed. Leonids of mag 2 or 3 I
can't say the meteor part is visible at all, only the train suddenly
appears. I have to go by some kind of impression to get a magnitude. Very
fast I don't find that numerous, but definitely more than very slow. Fast
is the most numerous category after midnight.
No observing in sight around here, just clouds and rain. Would be nice to
get a couple of September nights this year followed by a whirlwind finish in
the fall months. I haven't added up 1998 totals yet but doubt if I'm
anywhere near 1000 meteors yet.
Norman
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