NGC 7662 Spectrum

4th October 2004

Popular name: Blue Snowball Nebula

Type of object: Planetary nebula
Magnitude: 9.2 Size: 12.0"
Right ascension: 23h 26m 8s Declination: +42 33' 45"
Constellation: Andromeda

200mm F5 newtonian , SC1.5 toucam RAW mode. 100 lines/mm grating.
80mm F5 refractor @ F10 guidescope with SC1 toucam and GuideDog

The top image is 50x10s exposures at prime focus of my newtonian. The "Blue Snowball" nebula lives up to its name.

Being a planetry nebula, most of its light comes from a small number of emission lines of oxygen and hydrogen. Taking the spectrum of this object produces a most curious result!
The spectrum was 100x30s exposures using my grating.
The grey blob on the far left is the actual nebula, with the spectrum running left to right. The bright blue "echo" is the oxygen emission, and the red "echo" is Hydrogen. The other streaks are not hot pixels, they are the spectra of nearby stars.

It is also possible to try and graph this spectrum. I have tried to pick up on what I think the spectral lines are. I suspect the kink around 4700 belongs to something.. but not sure what. The large peak involves lots of OIII lines, and is spread out a bit by the non point source of the nebula - so my markings around there might not be terribly accurate, but you get the idea.

Clearly shows why we use an OIII filter to observe planetaries.. see Pease 1.

All data captured in k3, debayered in Aviraw, stacked in registax and processed in Photoshop.

Details of how I make these spectra.

Location: Curdridge, Southampton, UK. 51N 15W.

Details of equipment

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