M76 Little Dumbbell Nebula
Little Dumbbell Nebula
Planetary Nebula in Perseus



M27: M76, also known as the Little Dumbbell Nebula because of its vague resemblance to the much larger M27 (the Dumbbell Nebula), is a planetary nebula, the type of nebula which it is generally thought our Sun will produce as nuclear fusion slows and then dies in its core, and it expels its outer layers of gas. Unlike M27, most of M76 is quite dim, which presents a challenge both in taking the image and in processing it. M76 appears about 4 arcminutes across (including the faint parts). Its distance from Earth is not known with any precision, with estimates ranging from 1,000 to 15,000 light years; 3,400 light years is perhaps the most common estimate.


Technical Information:

LRGB: 240:100:110:140 (Luminance were 10 minute images, unbinned; RGB consisted of ten minute images, binned 2x2).

Equipment: 10" LX200 at f/12, an SBIG ST-8E camera/CFW-8 color filter wheel, guided by an SBIG AO-7 adaptive optics device, guiding at 7 Hz.

Image Acquisition/Camera Control: CCDSoft V5.

Processing: All images calibrated (darks and dawn flats) and registered in AIP4WIN. All layers average combined using Ray Gralak's sigma reject program. Five iterations of Richardson-Lucy (high frequency only) applied in AIP4WIN. Color combine, very gentle unsharp mask on the luminance layer, gaussian blurs, and adjustment of curves and levels, performed in Photoshop 6.0.

Location: All images taken in my yard in Redmond, WA, USA, elevation 500'.

Date: Luminance images taken on the night of September 30, 2002; color images taken during the nights of October 1 and 2, 2002.

CCD Temperature: Luminance images taken at -28C; RGB at -25C.

Moon Phase: Waning crescent.

Seeing: 2.6 Arcsecond FWHM

Copyright Mark de Regt, 2002