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M27 in Narrowband


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About this observation
David Davies
Time of observation
21/08/2015 - 00:00
Observing location
Cambridge, UK
QSI 683
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David Davies took his first images of M27, the Dumbbell Nebula in Vulpecula three years ago with a DSLR camera, and this year he thought to return to it to see what his QSI camera would reveal. He had read that in 1991 it was discovered that the object has a very faint outer halo around the main nebula which extends out to at least twice the 8 x 6 arc minute extent of the 'normal' nebula, but is around 1000 times fainter. He wondered, therefore, if he had any chance of revealing this outer halo.

David gathered nine hours of H-alpha, Oxygen III and Sulphur II narrowband data and 3.5 hours of LRGB data during the three weeks 22 July to 10 August and generated this images using the HST palette.

The image is a narrowband HST palette rendering with an LRGB image of the stars blended in. In this image S II data are assigned to red, H-alpha to green and O III to blue.

You can see the chaotic boundary as the hotter core pushes outwards into the cooler regions. You can also see the cool outer halo of gas from the original supergiant star, penetrated by columns of glowing
hydrogen-alpha originating from the central star in the regions from the top to the left side: 1 o' clock round to 9 o'clock. At the 4 o'clock location there is a powerful jet which seems to extend as an extremely faint extension beyond the outer halo itself.

Image details:
23' 35" X 16' 51" at 0.97 arc sec / pixel

Exposure times: three hours, each of narrow band data in 20 minute frames; two hours of luminance and 30 minutes each of RGB in five minute frames.

254 mm Newtonian at F/4 plus TV Paracorr giving F/4.5.  QSI 583 plus Astrodon LRGB and 3 nm narrow band filters.

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