Meteor Spectroscopy and the Amateur

Written by Ed Majden

First a bit of history.

In the second half of the 1800’s attempts were made to observe meteor spectra visually using prisms.  Because of the short duration of meteor phenomenon this was difficult but it was established that meteors produce discrete line spectra.  The bright lines neutral sodium and neutral magnesium where correctly identified visually by experienced observers.

The first photographic meteor spectrum was secured by chance during a routine stellar spectroscopy program by Pickering in 1897 at Harvard. S. N. Blazhko in Russia set up the first successful photographic program in 1904 – 1907.  This pioneer program yielded the spectra of three bright meteors. Up until 1931 only 11 meteor spectra had been secured, mostly by chance, except for the tree obtained by Blazhko.  Canadian astronomer Peter M. Millman while getting his Ph.D. at Harvard was asked to look at the meteor spectra secured thus far.  This resulted in two papers, the first can be down loaded at: and the second at: Peter Millman made meteor spectroscopy a life long interest and was considered a World Authority in this field.

From 1897 to 1958 the total number of known meteor spectra secured was only 318.  This was partly due to the few people engaged in this field and also because it was only possible to obtain spectra of meteors brighter than -2.0 magnitude and brighter with conventional cameras and films available at this time.  Most were obtained using objective prisms but in the latter part of the 1950’s transmission diffraction gratings were introduced to obtain spectra.  This was a great improvement as gratings produce near linear dispersion spectra unlike prisms which have good dispersion at the blue end but crowded dispersion at the red end making line identifications more difficult.

Dr. Millman encourage amateurs to get involved in this field and he published a paper promoting this, Amateur Telescope Making – Book Two, Scientific American included this paper, Meteor Photography.  Few took up this challenge because of the difficulty in securing a meteor spectrum.  The technique is simple but one cannot predict where a meteor bright enough to produce a spectrum crosses the camera field of view in the correct direction so some got discouraged and did not continue trying.  During this period conventional cameras fitted with a dispersive element, a grating or prism were used.  At the end of WW11 good quality aero cameras hit the surplus markets at very reasonable cost and these were adopted for use as meteor spectrographs.

Millman, and later with Ian Halliday and others established the Meanook/Newbrook Meteor Observatories in Alberta and later the Spring Hill Meteor Observatory near Ottawa.  The latter also used radar detection systems to study meteors in conjunction with photographic and visual observations.  Sadly these programs were shut down as a result of budget cuts by the federal government.  Ondrejov Observatory in the now Czech Republic became the centre to carry on this work.  Others have since taken up the challenge mostly in the USA, England, Spain, and Russia.

As mentioned before it was only possible to obtain the spectra of meteors brighter than -2.0 magnitude.  Hi speed cameras like the large aperture Maksutov Cameras were introduced by Gale A. Harvey NASA/LRC, in the late 1960’s and and 1970’s.  These cameras were capable of producing spectra as faint as +1.0 magnitude or so.  This effort produced 746 photographic meteor spectra during the four years they were in operation.  The results of this was published in various journals including Sky & Telescope magazine and IAU Symposium publications.

Also during this time, TV systems were being experimented with increasing the faint magnitude capability down to around +3 visual magnitude.  A paper on this, Spectroscopy of Perseid Meteors with an Image Orthicon by Peter M. Millman, A.F. Cook and C.L. Hemenway was published, refr. NRCC No. 11822 and I believe also in Sky & Telescope.

Since this time military night vision devices using image intensifiers became available and have been adopted by both professionals and some amateurs to obtain and record faint meteors and also meteor spectroscopy. Sirko Molau from the IMO runs a direct meteor recording program using image intensifiers systems and also faint lux security type cameras with fast lenses for his programs.  He can be contacted at if your interested in doing this.

I personally use second generation image intensifier systems to record faint meteor spectra.  As a Canadian I was lucky enough to buy a surplus 2nd Generation 25mm Image Intensifier, type MX9944/UV, before the U.S. government put export restrictions on these devices after 9/11.  Now they are difficult to obtain from U.S. sellers as you have to apply for an export permit.  Sometimes they are available outside of the U.S.A. so I scan eBay looking for them.  New ones are probably too expensive for an amateur’s budget so one hopes that a surplus one still has some life left in it.  You just take your chances buying a surplus intensifier and hope it will work.  Non U.S. made intensifies are also made by other countries, Russia, China, etc.  so all is not lost.  I recently bought a XX1335/Q image intensifier from a British surplus dealer which is nice for meteor spectra as it has a 50mm diameter input screen which will accommodate higher dispersion spectra.  I would love to get a 3rd Generation 25 mm ITT Intensifier as these have a longer life but alas the U.S. export restriction is in effect.

I once asked Canadian meteor astronomer Ian Halliday if this was still considered worth doing.  He said yes, but noted that the utility of running a meteor spectroscopy program for an individual can be difficult.  Conventional photographic meteor cameras require about 100 hours of exposure time to secure one spectrum. That’s a lot of film! One can of course concentrate your efforts during major meteor showers like the Perseids or Geminids to increase your chance of success.  One must obtain a very good spectrum from these showers to get a professional interested in measuring your spectrum.  One can of course attempt to measure your spectra yourself as there are computer programs available that are made for this purpose.  Unlike stellar spectra most meteor spectra have relatively low dispersion so identifying a line can be difficult.  In some cases you must have the experience in knowing the most probable line that should be present in that region.  I once tried a program and had Jiri Borovicka at Ondrejov measure the same spectrum and nearly 1/2 the lines I had identified were not the correct ones even though the computer program said they were correct.

There are other issues to deal with also such as distortions produced by the lenses you use.  It is very desirable to get a high dispersion spectrum but this requires a long focus lens a large grating and large format film, at least 4X5, 8X10 even better but the cost goes up exponentially.  I would love to find a large grating for a Kodak F-2.5 – 12 inch focal length lens and use 8X10 film but alas, this costs money.  I was lucky enough to find a surplus large reflection grating that should work using the method employed by the BAA member Mr. Aires.  A reference for his BAA Journal paper can be found elsewhere on this web site.  I still need to build the camera and find a source of inexpensive  Tri-X or Ilford HP-5 – 8X10 film.  No luck so far.

When doing spectroscopy one should try and work with another person situated 50 or so km away so heights of the start and end point can be arrived at.  One can then study the height of where certain spectral lines become visible or fade out.  One should also use  chopping shutter to arrive at the velocity and also the spectrum of the meteor train between the shutter breaks.  This also allows longer exposures as it takes longer for sky fog to build up on the film as it is exposed to the sky for 1/2 the time.  Our fireball camera network is very useful as it can provide height and velocity of your meteor spectrum if your doing this on your own as I’m doing.  That is, until I  get others in this network interested in doing meteor spectroscopy.

We could even accomplish a first, getting the spectrum of a meteor dropping fireball and recovering the meteorite.  This would answer many questions about the presents and formation of spectral lines by comparing it to the analysis of an actual recovered meteorite.  One can always dream!  😉

Too bad on can’t get a large format ccd detector for meteor spectra but robbing a bank to pay for one is probably not a good idea!  A Polish fireball group did have a nice success using a Canon 20D digital camera using crossed thin film gratings, a first by the way, using crossed gratings.  If you do this, the direction of the meteor flight path is less important.  Attached is their digital camera spectrum.  They deserve congratulations!  One feature is incorrectly identified as Cr at 427.4 nm.  Jiri Borovicka says this is probably an Fe iron line.  This spectrum is also unique as it’s in colour.  B&W is preferred as this simplifies photometry intensity scans as this is established for B&W films.  Jiri says this can be done with colour film also but is more complex to do.

I will try and answer any questions on meteor spectroscopy and if I can’t I will ask my friend Jiri Borovicka for an answer.  Hope some of you take up the challenge!

Ed Majden



EMO Shower Spectroscopy Results

A typical Leonid meteor spectrum secured with an image intensified video spectrograph at EMO Courtenay, B.C. CANADA is shown below. This spectrum was secured using simple equipment. An experimental grade type MX9944/UV – 2nd generation 25 mm diameter image intensifier purchased on the surplus market was used. A standard Canon F-1.4 – 50 mm lens fitted with a precision 600 g/mm blazed B&L replica transmission diffraction grating imaged the spectrum on the image intensifier input screen.

The intensifier output screen was imaged by a Super 8 video camcorder recording on a standard  VHS recorder. The field of view is around 25 degrees. The “zero order” image of the meteor is on the extreme left. The “first order” spectrum is recorded with blue on the left with red to the right. The intensifier has rather limited sensitivity at the blue end so recorded lines are weak. Part of the red end of the spectrum was not recorded as it was off the screen to the right. The intensifier is mainly sensitive from around 450.0 nm to around 900.0 nm but as noted features below 450.0 nm are faint. Of special interest in this spectrum is the so called forbidden line of oxygen O I  3F recorded at 557.7 nm which is clearly recorded trailing the main spectrum. This line was first identified by Canadian astronomer, Ian Halliday in 1958. Earlier film spectra were reviewed and this was also found in an early Leonid spectrum designated as Number 29 on Millman’s World List of Meteor Spectra. See: R.A.S.C. Journal, Vol. 54, Number 4, p.189-192, August 1960.

This program was conducted on the morning of November 18, 2001. A total of 110 video meteor images were recorded during this program, 60 “zero order” images and 50 “1st order” spectra. A similar program was planned for 2002 but was unfortunately clouded out at my location.

I would like to thank Dr, Jiri Borovicka at Ondrejov Observatory in the Czech Republic for doing the scan of this spectrum.


Figure 1.  Leonid spectrum.  Time stamp is PST Pacific Standard Time +8 hrs for U.T.



Perseid Spectra

Figure 2.  Perseid Meteor Spectra


For comparison purposes a past Perseid meteor spectrum has been added.  It was secured with the same set-up as above. Frame capture was done on a MAC computer and saved in grey scale format.  The spectra scan is a composite carried out by Jiri Borovicka at Ondrejov Observatory.

Compare Perseid

Figure 3.  Perseid spectrum.  Time stamp is PDT  Pacific Daylight Time   + 7 hrs U.T.



Comare Fig 4

Figure 4. Sample of Photographic Meteor Spectra


Fig5 Perseid 1986

Figure 5. 1986 Perseid Meteor Spectrum with Objective Prism


Holographic TF

Figure 6. 8/9 June 1997 Holographic Thin Film Grating Spectrum

This sporadic meteor spectrum in Figure 6 was obtained using a Learning Technologies thin film holographic type grating. The spectrum is undergoing measurement by Dr. Josep M. Trigo Rodriguez of the Spanish Photographic Meteor Network. This is to establish whether these inexpensive type of gratings are useful for meteor spectroscopy by amateurs. The preliminary report was published by Ed Majden as a Research Note in the Journal of the Royal Astronomical Society of Canada: Vol 92: 91-92, 1998 April JRASC


Fig 7 spectra

Figure 7, 1983 Objective Prism Perseid Meteor Spectrum

A faint Perseid spectrum showing the O I forbidden line of Oxygen at 557.7 nm. Not published but sent to Peter M. Millman at NRCC for his evaluation. Sadly Dr. Millman passed away so I don’t know what became of the negative.

Edward Majden – R.A.S.C. Victoria Centre – A.M.S. Meteor Spectroscopy

EMO Courtenay B.C. CANADA Lat.49o 40′ 33.5″ N-Long. 125o 00′ 37.1 W (GPS)

Useful papers on Spectroscopy

Here are some useful papers that can be downloaded from ADS-Harvard and the IMO.

A Perseid Meteor Spectrum

Meteor Spectroscopy with Inexpensive Holographic Gratings

Canadian Scientists Report-XII Meteor Spectroscopy with Transmission Diffraction Gratings

Current trends in meteor spectroscopy

One hundred and fifteen years of meteor spectroscopy

High resolution spectra and monochromatic images of a flaring 1991 Perseid meteor (Using Reflection Gratings)

IMO Photographic Handbook part 3



The Spectrographs used by Ed Majden

Here is some of the spectral equipment in use at EMO.

F-24 Aero Camera lens cone with an f-2.9 – 8 inch f.l Pentac lens fitted with a 27 deg 45′ objective prism with a refractive index of 1.71 for the 589 nm line. This unit has been modified to accept a 4X5 inch 6 platen Graphmatic film holder.


Two Camseras


Two, 2-1/4 X 2-1/4 inch roll film type cameras mounted with objective transmission gratings behind a chopping shutter.  The grey Camera is a Bronica and the other is a Hasselblad. An automatic system using used Hasselblad EL/M motor driven cameras is being worked on.


Video intensifier


This is a video image intensifier spectrograph recording system using a 2nd generation 25 mm MCP Image intensifier and a Canon L2 Super 8 – 1/2 inch format video camera. Such a system will record spectra as faint as +3.0 magnitude where photographic systems using film with standard lenses are limited to meteors brighter than -2.0 magnitude. This unit is still under construction. I have recorded several video spectra of Perseids and Leonids with a prototype system. Copies have been sent to Peter Jenniskens at SETI/NASA for his meteor spectra archives. Hopefully they will eventually be measured. Since 9/11 it is unfortunately difficult to get U.S. built 2nd and 3rd generation intensifiers unless you are a U.S. resident.