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Re: (meteorobs) Angular velocities
GeoZay wrote:
> In reference to plotting, I think I mentioned speed's importance or perhaps
> just implied in another post? At least that's what I had in mind when I
> mentioned if you have a plot, you have something to utilize speed estimates
> and refer to. Whereas when just using the Counting method you don't. Whether
> you use a speed scale or angular estimates, they both can be used about
> equally when investigating minor showers.Neither method will provide precise
> speeds. They both can provide some hint as to a velocity range that is
> involved for each meteor when either a radiant position is considered or
> suspected.
To quote George, "I agree". (-:
The Counting context wasn't clear. The post I read sounded dogmatic,
this bit
> For what purpose other than shower association is visual meteor
> speed estimates used for? I can't think of any.
in particular. Both methods are inaccurate compared with other
techniques as you say, but that's an argument about the worth of
visual observations and we've had plenty of that recently (all started
from George's joke). The angular-size estimate has more precision.
> malcolm>>One disadvantage to a scale over degrees/s is that the normalisation
> to
> degrees/s needs to be determined for radiant analyses. <<
>
> This would be a disadvantage, but a problem that could be worked out at a
> more leisurely pace than while doing the actual gathering process.
Sure as long as it's done.
> I've
> talked to Rainer Arlt about this several times in the past. Of course he
> would rather I go to angular velocity estimates predominantly to make his
> work easier,
It does take lots of extra work during the analysis. Been there, done
that, not nice.
> but I think there should be less pressure as possible on the
> observer while gathering data for a plot.
It depends how you do it, and how practised you are with the method.
Choose the method you are most comfortable with but please provide the
poor co-ordinator the calibration, or even better record using the scale
but convert these to numerical angular speeds in the submitted report.
> The less a person has to mentally
> juggle in their head for each meteor while out in the field, collectively the
> more accurate the plots will probably end up being.
That is indeed true.
> A disadvantage while
> determining degrees/second to using a speed scale, is that you have about 2
> or 3 more active things to think about than you would with just a speed
> scale for the same purposes.
If you know how long a second is with having to think about it, then I
believe it's just one extra number or datum---the apparent speed
against the stars. OK I concede you need some rulers in the sky, but
any experienced observer should know these with placing extra demands
on the memory.
Malcolm
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