First spectrum obtained by the telescope

This is an image of the first spectrum obtained by the telescope in May 6, 1918. Above the glass negative of the spectrum is the paper envelope in which the glass plate is stored. The name of the star is Beta Canum Venaticorum ( Β Van Can) which is written on the envelope and glass plate. Also, note the number “1” written on the plate to indicate this is first spectrum. Imagine the excitement that night in 1918.

The spectrum of the star is the dark streak surrounded on both side by dark vertical lines. These lines are from an electric arc and the wavelength of the lines are precisely known. This allows for an accurate determine of the spectral lines, e.g., Hydrogen, in the spectrum of the star. The measured wavelengths can be compared to the actual wavelengths to determine the motion of the star towards or away from us.

A copy of this spectrum was taken to the International Space Station by Julie Payette as part of the International Year of Astronomy