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Re: (meteorobs) Somewhat unusual (?) telescopic obs.

> Monday evening here was unusually clear.  A friend and I went 
> satellite observing, and during about two hours (2:00-4:00 
> UTC on Tuesday 6 April) each of us observed two or three faint 
> coincidental meteors cross the 1-degree field of the eyepiece 
> of my friend's 8-inch dobsonian telescope.

Multiple sightings of parallel telescopic meteors separated by a short
time interval are not as uncommon as you might think.  I presume yours
were travelling in parallel paths.  My records are still in transit
so I can't quote a frequency.  I suspect that these are where a 
meteoroid crumbled after a minor impact or from stress, leaving the
orbits virtually unchanged.

The best I saw were a couple though a 1.9m telescope, which might have
been pi-Puppids back in 1977 April.

  That seemed unusual 
> to me, as my experience in the last three years is that it's 
> rare to see even one telescopic meteor in a given session.  I
> believe that the magnification with that eyepiece is about 80

Telescopic meteors are best seen with a lower power, say 4x the aperture
in inches, and a wide apparent field of field (at least 50 degree).
On average, people specifically looking for telescopic meteors
see 5-15 meteors per hour under dark skies with this combination.
If you look casually, in other words, you are observing something else
like a comet or star cluster, the rate is more like 1-3 per hour.

So for an 8-inch you'd want around 30x giving about a 2 degree true
field.  I imagine that your actual field was nearer 0.5 degrees, or
about an eigth of the field I recommend.  Also the angular speed of
meteors is magnified.  Not only does this make the meteors whiz by so
quickly you may not even notice them, but also the apparent brightness
compared with the true meteor brightness is also fainter.  All in all
you won't see many telescopic meteors with that set up, as you've
observed.

> Also during the evening both of us noticed simultaneously a 
> bright flash from the sky, but neither of us saw a fireball.  
> To my knowledge there were no thunderstorms nor even clouds 
> within 50 or 100 miles or more of our location, [snip]

The thunderstorms can be hundreds of miles away.  Used to see this
regularly in cloudless skies observing from rural England during the
summers of the 1970's.  It could be quite distracting.

Malcolm
tele@imodot net

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