www.galaxies.se - by Ivar Hamberg

SLITLESS SPECTROGRAM of PLANETARY NEBULA M57. 

By using a slitless spectrograph you get this nice image of the emission nebula Messier 57. Since the nebula emits light only in distinct emission lines, you get this "multiple image" of the ring nebula. The photo is a combo of two 30 second exposures with a SA200 grating.

- The leftmost ring is the zero order spectrum.

- To the right you see a TEAL colored strong emission of O-III (4959Å+5007Å) and H-Beta (4861Å)

- Further to the right a RED emission in H-Alpha (6563Å) and N-II (6548Å+6584Å).

Also, fainter images of He-II (4685Å) and H-Gamma (4340Å), as well as O-I (6300Å+6363Å) and He-I (5876Å)

Camera: Canon EOS Ra

Telescope: 12" RC

Grating: SA200 mounted 40mm in front of sensor

Date: 2021 Oct 11, 20:30, 2x30 sec exposure