Bill Ward has continued to work on the images that he captured during his trip to Tenerife to monitor the maximum of the 2017 Geminids
(you may already have seen his impressive Geminid timelapse video in the earlier section report)
He has recently posted this video via youtube which shows a spectrum captured on the morning of Dec 14th, which he describes as “My best spectrum in several years. Nicely focused with good resolution. Lovely!”
He has also produced this graph which compares the spectra, from the near UV through to the red, of a number of different Geminid meteors:
As can be seen, they are rather similar.
A notable feature is that the green magnesium emission line near 5180A is much stronger than the yellow-orange emission line of sodium near 5890A, differentiating the Geminids from the spectra of many other meteor showers, such as the Perseids, for which the two lines are similar in strength.
Bill adds “VERY strong Mg lines in near UV. Images suffer from bad de-focus there and spectra get a bit wobbly at this end“.