Prototype 1.25 inch filter cell grating - M57 and TYC-2643-823-1 29th May 2005

The SC3 "PIPCAM" modified webcam was used with the VC200L for this image.

The 100 l/mm grating was screwed into a low profile webcam adapter adapter, followed by a spacer and an ATIK focal reducer. The focal length was reduced from f9 to approx f3.6 and the dispersion was 20.2 A/pixel.

A mosaic of two sets 20 exposures of 10 secs each were stacked to cover M57 and the adjacent star which was seen to have an interesting spectrum.

The diffraction grating has split the zero order image of M57 (top) into two component images at the principle wavelengths emitted by the glowing gas of the planetary nebula.

Here the M57 spectrum has been isolated from the image and the components colourised to show the actual spectral colours. The source of the colours can be identified from the wavelength. [OIII] at 4959/5007 A and H alpha at 6563

Also visible in the image is a 9th magnitude star whose spectrum showed some interesting broad absorption bands. This was identified as TYC-2643-823-1. The resulting spectrum confirms it to be a cool class m2 star showing many molecular absorption bands and emitting radiation well into the infra red.