Meteor Photography

by Michael Oates

This is one of the easier subjects to photograph, but only in terms of the equipment required. It is not that easy to actually capture good images on film. The main problem is you don't know for sure if a meteor is going to appear when the camera is pointing in the right direction, and even if it was pointing in the right direction, the shutter was probably closed at the time.

As these objects can be so elusive it is quite rewarding to manage to get a good image of one. Its a matter of chance whether you succeed, but with a bit of knowledge you can tip the odds in your favour.

What are meteors ?

As the Earth travels in it's orbit around the Sun it passes through patches of dust and particles that are the remnants and debris of comets. As one of these particles passes through the atmosphere it is heated up to very high temperatures so much so that the surrounding air gets ionised and glows visibly. We then see a streak of light that lasts maybe for only a fraction of a second, some times a few seconds. In some cases the meteor is seen to explode in a flash at the end of its travel. These particles are generally very small, i.e. the size of a grain of sand or smaller. Very cccasionally the odd ones get through and hit the ground.

Aurora / Fireball Meteor, Joe Billington. 8 November 1991
More information on this photo.

Meteors can be seen at all time of the year (called sporadics) but there are a number times during the year when there are peaks in the number of meteor seen. These are called meteor showers. If you was to watch a number of meteors during one of these showers you will notice that they seem to come from the same point in the sky, this is called the radiant. To find the radiant just trace the track back that the meteor took on a star chart and the radiant will become apparent.

A number of the major meteor showers are listed here, but I would recommend reading further from another source.

    Name		   Dates		Maximum		Approx Max meteors/hr
				
Quadrantids		Jan. 1-5		Jan. 3-4		20-80
Alpha Aurigids		Jan. 15-Feb 20		Feb. 7-8		12
Zeta Bootids		Mar. 9-12		Mar. 10			10
Lyrids (April)		Apr. 19-24		Apr. 22			12
Eta Aquarids		May  1-12		May  5			20
Lyrids (June)		Jun. 10-21		Jun. 15			15
Delta Aquarids		Jul. 15 Aug. 15		Jul. 28			35
Perseids		Aug. 1-18		Aug. 12			65
Beta Cassiopeids	Sep. 7-15		Sep. 11			10
Orionids		Oct. 17-26		Oct. 20			35
Leonids			Nov. 14-20		Nov. 17			10-100
Geminids		Dec. 4-16		Dec. 13-14		50

Equipment

All that's required is a camera that has a "B" shutter setting and the ability to set aperture manually. A tripod is needed to hold the camera steady during the exposure and to enable the camera to be aimed. A cable release for the shutter also comes in handy to help stop the camera moving when operating the shutter.

If you want to increase the chance of capturing a meteor on film you can double your chances by using 2 cameras at the same time pointing in different directions. And if you want to take that further, as I did, mount 4 (yes four) cameras on a bracket that fits on the tripod. You might think that's going a bit over the top, not to mention expensive. Well all the cameras were very cheap Zenit SLR's with standard lenses, so there was very little expense there. It only gets a bit expensive when you consider using 4 rolls of film at a time !!

The lens used should be the standard or wide-angle, the reason for not using telephoto lenses is that you are restricting the angle and therefore the amount of sky the camera can see therefore decreasing your chances. Also telephoto lenses do not generally have a wide enough aperture, so the fainter meteors will go undetected.

Film

Meteors vary greatly in brightness, and you will find that only the brighter ones will record on the film. This is due to the fact that the meteor is moving very fast and the light from it does not have much time to expose the film. In order to photograph as faint as possible you should use a fast film, at least 400 ISO or faster. 1000 being a good choice. Whether you use slide, print, colour or black & white film it's all down to what you want to do with the image afterwards. The cheapest (if you are going to use lots of film is black & white and develop it your self. The best choice if you want to display the photo to your astro society is slide. Colour print film can prove more expensive and the results can be quite disappointing if the processing is done at a photo lab.

I think the first choice is colour slide, and black & white negative film second especially if you can process it your self.

How to Photograph a Meteor

First choose a night that is during a meteor shower to increase your chances, note there are usually more meteors after midnight.

With the camera loaded with fast film and the aperture open fully aim the camera about 45 deg from the radiant, this will increase the chance of capturing a meteor travelling across the sky rather than coming directly at you (they are not as easy to detect).

Perseid meteor.
50mm lens, f2.4. T-Max 100. 12 August 1989, 23h 21m 55s UT.
Photographed with 3 different films T-Max 100, Fujichrome 400, and Infra Red.
Prestwich , Manchester. M Oates.

The exposure needs to be as long as you can give it without the film getting fogged with light pollution, so if you in or near a town this may only be 30sec to 1 min long, if the skies are darker you might be able to give 5 - 15 mins. The longer the exposure the better are your chances, it is also cheaper too. If you see a meteor that you think passed in the cameras view, then stop the exposure and note the time. Then as soon as you can open the shutter again. You will surprised at how many meteors you NEARLY get, but the shutter was not open or it was just outside of the cameras view.

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If you want to take up meteor observing seriously there is a meteor section of the British Astronomical Association. (BAA) as well as other organisations, who can help and advise on making observations that are of scientific value. I have not dealt with the more serious side of meteor observing here, this is just an introduction to the subject for those who want to capture the elusive object for fun.