Posts Tagged ‘Hubble Palette’

Sh2-132 in Narrowband

November 7, 2014 3 comments

Both of my WO Star 71s are back from China (see previous post), cleaned, and as good as new.  Maybe better.  It took a few days after their return for some clear weather to arrive, but I was so happy to have them back.  William Yang was a good guy to deal with in this whole matter.

Sh2-132 is an odd nebula in that it can be hard to find.  Not so much because it’s not a reasonably bright narrowband target, but because it has no appeal to visual observers, so it’s not well-marked in most atlases.  Not all of the Sharpless objects are worthy targets (in fact the majority are duds), so it can be hard to tell that this one stands out from the emission nebula crowd.

It’s a photogenic target in the Hubble/SHO palette if you can take enough exposures to reveal the details, and several amateur images of it have popped up this season.  The SII is particularly dim, and if I could do it again, I would double the exposure time there.

Sh2-132 in the Hubble/SHO Narrowband Palette

Sh2-132 in the Hubble/SHO Narrowband Palette

Image data:

  • Exposures: 42 x 10 min Ha, 41 x 10 min OIII, 43 x 10 min SII
  • Telescopes: Two William Optics Star 71s (360mm f/5)
  • Cameras: SBIG ST-8300M and QSI 583wsg, 2×2 binned
  • Mount: CGEM
  • Guiding: QHY 5L-II mono, guided using PHD2
  • Conditions:  wind gusts over 25 mph… far from ideal
  • Processing: DeepSkyStacker, PixInsight, Photoshop
  • Dates: Oct 25-27, 2014

NGC 6888 Narrowband (plus some PixelMath)

September 29, 2013 Leave a comment

Finally, some color images!  (Or at least false color.)

This is one panel from my earlier Crescent Nebula 4-panel H-alpha mosaic, with OIII and SII data added.  The first version is in a slightly modified “Hubble” narrowband palette (R=70% SII+30% H-alpha, G=100% H-alpha, B=100% OIII).

NGC 6888 in Hubble Palette

NGC 6888 in Hubble Palette

Image data:
Exposures: 13 x 1200s Ha, 16 x 1200s SII, 18 x 1200s OIII (Total exposure time: 15 hours, 40 minutes)
Software: guiding by PHD, stacking in DeepSkyStacker
Processing: PixInsight 1.8
Telescope: Takahashi FSQ-106ED (530 mm f/5)
Camera: SBIG STL-11000M with Astrodon 6nm narrowband filters, 2×2 binned
Mount: CGEM
September 16, 17, and 28 2013

PixInsight allows you to easily blend and mix images or color channels to create alternate palettes, so let’s use this image as a simple example.  Consider the following simple PixelMath parameters.


PixelMath refers to the color channels in an RGB image as [0], [1], and [2] respectively.  So this tells PixInsight to create a new image with the:

  • red channel composed of the original green channel
  • green channel composed of 70% of the original red channel + 30% of the original green channel
  • blue channel unchanged

The result is a false color image with a different flavor.

NGC 6888 Red-Green Reversed

NGC 6888 Red-Green Reversed

IC1318, The Butterfly Gamma Cygni Nebula

August 31, 2012 Leave a comment

The constellation Cygnus is awash in nebulosity.  Point your telescope almost anywhere in the constellation and you’ll find something.  The usual suspects are the North America Nebula (NGC 7000), the Crescent Nebula (NGC 6888), and all of the pieces of the Veil Nebula.  But right at the heart of the constellation, at the center of the “cross,” there’s another beautiful area.  The picture below shows the area around the star Gamma Cygni, including IC1318, the Butterfly Nebula.  The whole area is swimming with emission nebulae, so it’s hard to say any single feature is a separate entity, but the Butterfly shape is fairly obvious.  The little open cluster at the top center is NGC 6910, but that hardly seems important given the rest of the image.

IC1318 in Narrowband

IC1318 in Narrowband

Image data:

Exposures:  29 x 900s Ha , 8 x 900s O-III, 8 x 900s S-II (11h 15m total), all binned 2×2

Software:  guiding by PHD, stacking in DeepSkyStacker

Processing:  Photoshop CS3, tone mapping using modified Hubble palette

Telescope:  Televue NP101 with 0.8x reducer (at about  f/4.3)

Camera:  SBIG ST-8300M with Baader standard narrowband filters

Mount:  CGEM

Taken August 13, 14, 16, 18, and 22, 2012 from Whitehouse Station, NJ.

%d bloggers like this: