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(meteorobs) Re: sky measuring sticks+reentry+more
Norman,
Does the altitude of Polaris vary due to whether you are standing or
sitting? (Sorry, I could not pass that one up).
Actually Norman makes some very good points that newbies should take to
heart.
Bob
nmcleod@peganet.com wrote:
>
> The recent thread on measuring angles in the sky brought up some rather
> involved mechanical methods of doing the measuring. I have used the
> following natural measuring sticks throughout my life, in degrees :
>
> Pollux - Castor 5
> head of Aquila 5
> belt of Orion 3
> Deneb - Albireo 23
> open bowl of Big Dipper 10
> pointers of Big Dipper 5
> Mizar - Alcaid 7
> W of Cassiopeia width 14
> altitude of Polaris for my location - variable
>
> That's it. Once these are known, you don't need to rely on body parts.
> Southern hemisphere observers will need something additional that they can
> see from there. The short distances are far more important for meteors,
> and I saw little discussion on these. Once you reach 20-degree meteor path
> lengths, a length to the nearest 5 degrees is sufficient. I frankly can't
> tell the difference between 39 and 40 degrees, for example, anyway.
>
> The public is unable to judge any kind of angle. They understand "horizon"
> all right. The term "overhead" sounds like a precise term but it is
> actually vague. An uninformed person might say a bright meteor "passed
> overhead" if it was as low as 65 degrees ! Just because your neck hurts
> when you look up doesn't mean you are looking at the zenith. Try deciding
> where the zenith is just by looking up. Then get a star chart with
> declinations on it and find out where your zenith really is. I could be off
> by 10 degrees going by feel alone.
>
> Any elevation between "horizon" and "overhead" the public tends to call
> "45 degrees." That is the best-known non-right-angle angle. Be suspicious
> any time someone reports seeing something at elevation 45. That happened to
> me in one astronomy class ; a student saw a fireball in the north 45 degrees
> up. I went over to his place and had him point out where he saw it --
> turned out it was only 15 degrees up ! It was below Polaris, which was 27
> degrees. That's quite an oversight when I had discussed this in class.
>
> To plot meteors it is essential to know stars down to at least 4th
> magnitude. There aren't enough brighter stars to work with and get any
> semblance of accurate plots. Learning the constellations should be done
> first. I used the Rey book, The Stars : A New Way to See Them, the best
> available, and had a good working knowledge of the sky in just four months.
> A year of just recording some meteor data along with learning constellations
> ought to be done before trying plots. Few plots occur right between two
> stars. Most often I have to use a couple of stars that the meteor missed by
> a degree or two to anchor the path. I use a ruler against the sky.
>
> There was another reentry last week which Chip in Pensacola definitely saw.
> It also passed over the Tampa-St. Petersburg area and caused yet another
> ruckus on the Art Bell show with Peter Davenport. We lost a pastor in Tampa
> to the UFO side because he saw this one, and for the first time he didn't
> know what he was seeing. The radio principals lament the refusal of
> scientists to return telephone calls and wonder why. They conjecture that
> scientists don't know what it was either, that secrets are being withheld
> from the public, and that we are being lied to. I can help them out : calls
> aren't returned because Mr. Davenport won't believe scientists anyway hence
> they know not to waste their time with him. I found that out for myself two
> years ago with the Seattle reentry ; nothing I said was accepted. We can
> reach people numbered in the hundreds with rational scientific discussion,
> but Art Bell reaches millions with grossly and willfully ignorant
> discussion, outnumbering us by 10000 to 1. I still haven't seen one of
> these spectacular reentries and this latest one missed me by only a hundred
> miles, plus it was mostly cloudy here.
>
> On Aug 19 GWG wrote :
>
> > In Norman's case, his glasses may allow him to see 7th
> >magnitude stars, but restrict his field of view; thus making the
> [perception] correction
> >inaccurate for him. For most others, the correction probably works just fine.
>
> My glasses have a field of view 140 degrees wide and 110 degrees vertical.
> I see so few meteors near or beyond the frames that I don't consider them to
> be any restriction. I have always gone after the largest lenses possible.
> That was a bit hard in the late 60's when small lenses became fashionable,
> some little more than slits. Then big lenses returned by the early 70's,
> and since then plenty of very big ones have been available.
>
> On July 11 Kim wrote :
>
> >Meteors 14 and 13 were, for all practical purposes,
> >simultaneous, with 14 occuring immediatly after the
> >appearance of 13.
>
> A strict definition of "simultaneous" needs to be observed, that is, both
> meteors had to be visible together for any noticeable portion of their
> appearances. If any break between them occurs, or if one starts just as the
> other ends, then they are not simultaneous. I have noted all occurrences of
> simultaneous meteors from my beginning. Probably the easiest way to see two
> at once is to have a slow one in progress, then have a fast one flash into
> view. Many times I have noted a beginner or casual Perseid observer saying
> "several were visible at once," when he meant to say "several were visible
> in quick succession." There have been only six times in 39 years when I saw
> three simultaneous meteors, and I have never seen four.
>
> In Chris Crawford's group setup, will meteor data be recorded? I hope
> individual rates will be produced rather than an attempt to find how many
> unique meteors appeared. The latter can't be used for comparison with
> individuals.
>
> We got by without any problem from Floyd. Tomorrow night I would expect to
> be clear. What sky I could see yesterday was free of haze.
>
> Norman
>
> Norman W. McLeod III
> Asst Visual Program Coordinator
> American Meteor Society
>
> Fort Myers, Florida
> nmcleod@peganet.com
>
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