NGC 7662 - The Blue Snowball Nebula
NGC 7662 - The Blue Snowball Nebula
NGC 7662 - The Blue Snowball Nebula
NGC 7662 is a planetary nebula located in the constellation of Andromeda. A planetary nebula develops from a star that is in it's later stages of evolution. As the star runs out of hydrogen to fuel itself, it begins blowing off shells of gas. These hot expanding gases will glow, commonly emitting light from Oxygen (Oiii) and Hydrogen (Ha and Hb). The Blue Snowball nebula is dominated by the blue green light from Oiii, although the inner core of the nebula contains a fair amount of red light from Ha emissions.

NGC 7662 has an extraordinary range of brightness, making it difficult to capture all aspects of the nebula. The inner core is quite bright and is easy to see in amateur telescopes. However, the bright core is surrounded by an extremely faint halo and an even fainter jet. To bring out these features, I captured a wide range of exposures and employed some selective techniques to display the tremendous dynamic range of this beautiful target.

In this image, North is to the right. This image was drizzled to 2 times it's original size, and then cropped to 17% of the original full frame.

Exposure Details
Lens Nikon 600mm f/4 ED IF
Focal Length 600mm
Focal Ratio f/6
Mount Schaefer GEM - 7 1/2 inch Byers gear
Guiding QSI 690 OAG, Lodestar Autoguider, PHD2 Guiding, Starlight Xpress Adaptive Optics @ 20 Hz
Camera QSI 690wsg-8 (set point -10C) with Astrodon Gen II Series E LRGB filters, Astrodon 5nm Ha filter, Astrodon 5nm OIII filter
Exposure Ha: 14x300 Oiii: 81x600 Lum: 49x120 RGB: 20x20x20x120, all binned 1x1 (18.3 hours total exposure)
Calibration 50 darks, 40 flats, 200 bias
Date November 18 and 23, December 2, 3, 4, and 28, 2016; January 25, 2017
Temperature 11/18-50F, 11/23-34F, 12/2-28F, 12/3-45F, 12/4-42F, 12/28-42F, 1/25-23F
SQM Reading Bortle 4 on all 7 nights - 11/18-21.20, 11/23-21.35, 12/2-21.50,12/3,-21.50, 12/4-21.35, 12/28-21.20, 1/25-21.25
Seeing 2/5 on 11/23; 3/5 on 11/18,12/2, 12/3, 12/4 and 1/25; 5/5 on 12/28
Location Pine Mountain Club, California
Software Used Images Plus 6.0 and Sequence Generator Pro 2.6 for camera control. Plate Solve 2 for plate solving. Images Plus 6.5 for calibration, stacking, ArcSinH stretching, adaptive Lucy-Richardson deconvolution, Feature Mask, and star size reduction. Photoshop CS5 used for levels and curves, lab color, saturation adjustments, selective color, and match color. Gradient Xterminator for gradient removal. Carboni Tools for additional noise reduction and smoothing. HLVG for additional color correction. Registar 64 for subexposure alignment. Focus Magic for focus restoration. Pixinsight 2.8 for drizzle integration.
Notes This was an extremely challenging target to capture due to it's very small angular size and huge dynamic range. The bright core of this planetary nebula is only about 1/2 arc minutes across. My 600mm lens is less than ideal for capturing such a small object and it's fine details. Nonetheless, I was determined to push my equipment and skills to the limit. Although there are certainly more detailed images of this nebula, I was very pleased with how well I did with my far from optimal equipment.

The extended halo is only about 2 1/2 minutes across. Although somewhat noisy, I was very happy to have captured this halo and even more pleased to capture the faint jet. Although there are probably more, I was only able to find 3 images that displayed the halo and jet!

This image was published by Astronomy Magazine as its Picture of the Day for March 5, 2018!