[BAA-ebulletin 01015] Meteor observers wanted - No experience necessary!

[BAA electronic bulletins service]

METEOR OBSERVERS WANTED: NO EXPERIENCE NECESSARY!

Always the summer’s main attraction for meteor enthusiasts and casual 
observers alike, the Perseids are one of the year's most active meteor 
showers. This year the peak coincides with New Moon so conditions are 
very favourable and maximum activity takes place over a long weekend 
which is also most convenient.

Many people may be intending to go out and observe the Perseids this 
coming weekend, but they may not be planning to collect any data.  This 
is a shame because meteor observing requires the minimum of equipment 
and even newcomers can obtain results of value. So why not give it a try 
this weekend?

With maximum expected early on Monday, August 13, the period from Friday 
evening through to the pre-dawn hours of Tuesday morning is likely to 
yield the best observed rates.


OBSERVING METEORS VISUALLY

First find a dark site away from town lights, and recline on a deckchair 
or sun-lounger so you can comfortably look at the sky.  All you need is 
an accurate watch or clock, a dim red torch and something to record 
information with – either a notepad or a digital voice recorder. Warm 
clothing is essential; it can be quite chilly even on August nights!
Then just watch. It doesn’t matter what direction you look, but do make 
a note of the sky conditions in terms of the amount of cloud and the 
stellar limiting magnitude if you can estimate this. Write down the date 
and time you started observing and whether you are using BST or UT, to 
avoid confusion later.

When you see a meteor, note down the time and what kind of meteor it 
was. Was it a Perseid or a sporadic meteor? You can work that out by 
tracking the path of the meteor back to see if it came from the shower 
radiant. Meteor watches should ideally be of an hour’s duration or 
longer (in multiples of 30 minutes). Then have a break and start again. 
Note the start and end times for each new watch, making sure it’s clear 
what the date is when it changes at midnight.

You can also work in a group, such as with other members of your local 
astronomical society. Set yourselves up so you’re all covering a 
different piece of sky and record your observations as individuals. The 
Meteor Section welcomes reports from such groups as well as individual 
observers. Please send them to: meteor at britastro.org.

In its simplest form, a list of times and meteors seen (Perseids or 
sporadics) in each watch, with details of the observer’s location and 
the date and time of each watch can be of value. The BAA’s visual meteor 
report forms, available as downloads in both pdf and Excel formats from 
https://www.britastro.org/node/4944, may be used to record the details 
of each meteor seen.

More experienced observers may attempt to measure the brightness of the 
meteors by comparing them with nearby stars. You might also note if the 
meteor flared or fragmented in flight, or had an obvious colour, or if 
you saw a persistent train and how long it lasted (the Perseids are rich 
in persistent trains).


IMAGING METEORS WITH A DSLR

The Perseids are well known for the abundance of bright, swift meteors 
in the five-day interval centred on the maximum. This makes them an 
excellent target for digital imaging, particularly given the lack of 
interference from moonlight this year.

With a tripod-mounted camera, lens (usually a wide-angle) at full 
aperture (f/2.8 or similar) and a high ISO setting, one hopes that a 
bright meteor will flash through the field of view while the shutter is 
open. DSLR cameras are very efficient at collecting background light 
from the sky, particularly at a setting of ISO 1600 or 3200, so 
exposures should be kept short – no more than 30 seconds’ duration in a 
really dark, rural location, and probably only 10 to 15 seconds from a 
more typical observing site. Such short exposure times also aid the 
identification of aircraft and satellite trails which may sometimes be 
confused with those of meteors. A meteor trail will usually appear on 
only one frame; a satellite or aircraft trail may overlap several 
consecutive frames.

Such a camera set-up, under good sky conditions, can capture meteors of 
magnitude 1 and brighter. Ideal aiming directions are about 30-40 
degrees to either side of the radiant at 50 degrees altitude above the 
horizon – Cygnus in the early evening, the Square of Pegasus later in 
the night, or towards the north celestial pole, for best results.
With some DSLRs, the camera can be operated in 'continuous' mode or 
using a programmable timer attached to the shutter control to take 
repeated exposures one after the other for as long as required, provided 
the battery is fully-charged beforehand.  Ideally, run the camera for an 
hour or longer in ‘continuous’ mode making a note of the start and end 
times of each run.  Beware of dew forming on the lens front element, 
even in the summer. Later, check the frames carefully for meteor trails 
and compile a list of the times of any trails recorded and whether they 
were of a Perseid or member of a minor shower/sporadic.

Please remember to accurately set the clock on your camera to UT, so it 
is possible to link meteor trails captured from different observing 
sites, and do send a summary of your results to meteor at britastro.org.

Happy meteor hunting!

This e-bulletin issued by:

Dr John Mason
Director, BAA Meteor Section
email: docjohn at dircon.co.uk

8th August 2018