The Crystal Ball planetary nebula, NGC 1514, looks nothing like a ball at this point in its life, though it is thought that it began as a spherical shape, but now distorted by bubbles. Instead my wife and I agreed that it looked like a Monkey Face. Whatever we name it, at 1500 light years away the faint outer shell extends 1.6 ly, or 2’ across in apparent size. Infrared imaging shows the PN is surrounded by a huge area of dust 8.5 ly across.

The nebula is a product of the binary star system HD 281679: composed of the  bright, visible horizontal branch giant A0III-type star and the  nebula-generating  hot, sub-luminous O-type star. Their orbit takes about nine years, one of the longest periods known for a planetary nebula. Horizontal branch stars are post red giants, whose core is no burning helium as the shell burns remaining hydrogen. That more massive star strips gas from its companion, forming the nebula, and exciting and ionizing the gas with its intense UV radiation, which in turn causes the OIII and Ha emission. 

One interesting tidbit is that William Herschel had been convinced that all nebulae consisted of masses of stars, that were just too remote to resolve. But on  first observing NGC1514 and the bright central star on November 13, 1790, he realized that this was indeed nebulosity that was not made of stars.

Processing
Two sets of data were collected over five nights starting in December and ending in February, one set using an L-eNhance LP filter the other an L-eXtreme dual narrowband filter with my ASI2600MC Pro camera. My original plan was to collect much more data than this, but to only get 5 nights in 3 months was pitifully below expectations.

All images were calibrated, registered and stacked together. The L-eXtreme data had lower background and thus somewhat less noise (Poisson noise from the background signal), but the two data sets otherwise were very similar, thus stacking them all together seemed the way to go. The images are cropped to 1/2 size.

Using Startools, Ha (Red) and OIII (Green+Blue) were extracted. 

Then Ha was loaded to Red, with OIII to Blue and Green. Blue exposure was set to 3X the actual exposure, and Green to 0 exposure. This way I accounted for the 3X pixels for OIII: two Green and one Blue, compared to one for Red. I could have equally done 1.5x each: since Blue and Green channel data are  identical, that would give an equivalent result. 

I used the Startools modules: background wipe, film development, contrast, HDR, Sharpen (to enhance fainter details), and gamma correction.

I used Photoshop with StarXterminator to separate stars, APF-R (as used by NASA, a multi-scale unsharp mask) on the starless layer, added stars back in with linear dodge (add), then separate instances of NoiseXterminator on each  layer, and a final tweak to color saturation and background color balance.