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.
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.
Figure 3. Perseid spectrum. Time stamp is PDT Pacific Daylight Time + 7 hrs U.T.
Figure 4. Sample of Photographic Meteor Spectra
Figure 5. 1986 Perseid Meteor Spectrum with Objective Prism
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
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)