Archive

Posts Tagged ‘deepsky’

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

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

Sh2-129, The Flying Bat Nebula

September 28, 2013 Leave a comment

This is another monochromatic image I captured while the moon was near full this month. Sh2-129 is a very dim, but very large H-alpha region at the bottom of Cepheus. It’s close to the far brighter and more famous IC1396, which explains why it is so often overlooked among the sea of emission nebulae in that area. I’ve seen it referred to as the Flying Bat Nebula, but it probably has more claim to be a “Tulip” nebula than Sh2-101. This is definitely a challenging object to capture.

Nicola Montecchiari recently captured a terrific image of this nebula with the OIII-emitting planetary nebula OU4 at its core.  Looks like I will have to go back and capture some OIII data here soon!

Sh2-129, The Flying Bat Nebula, H-alpha

Sh2-129, The Flying Bat Nebula, H-alpha

Image data:
Exposures: 19 x 1200s Ha exposures
Software: guiding by PHD, stacking in DeepSkyStacker
Processing: PixInsight
Telescope: Takahashi FSQ-106ED (530 mm f/5)
Camera: SBIG STL-11000M with Astrodon 6nm narrowband filters, 2×2 binned
Mount: CGEM
September 15, 2013

IC443, The Jellyfish Nebula

March 4, 2012 Leave a comment

This galactic jelly isn’t even mentioned in most star atlases, despite being huge (almost a degree across) and easily locatable in the constellation Gemini. It’s probably an extremely difficult visual object, but astroimagers are quite familiar with it because of its distinct shape.  IC443 is a supernova remnant that exploded thousands of years ago, and the filaments you see are the interaction of shock waves from that supernova with surrounding gases.

This is another narrowband image, representing a total of 11 hours of exposures taken over two nights (26-7 Feb).  I’ve used color to emphasize the regions where there is a lot of Hydrogen alpha emission alone (red) from where there is a combination of Oxygen-III and Hydrogen-alpha (green-yellow).

I can’t help but think that the Jellyfish is going to eat the bright star, Eta Geminorium…

The Jellyfish Nebula, IC443

Image data:

Exposures:  25 x 600s Ha, 21 x 600s O-III, 20 x 600s S-II, a total of 11h 0m

Software:  guiding by PHD, stacking in DeepSkyStacker, processing in Photoshop CS3

Telescope:  Televue NP101, 530mm f/5.3

Camera:  SBIG ST-8300M with Baader narrowband filters

Mount:  CGEM

The Horsehead Nebula in H-alpha

February 27, 2012 Leave a comment

The 1983 National Geographic cover featuring this nebula really captured my imagination as a child.  I’ve always thought it was one of the coolest things in the sky, and it’s amazing that amateurs can now take images from their backyard that rival the best professional observatory pictures then.

This grayscale image represents 27 ten-minute exposures through a Hydrogen-alpha narrowband filter. This filter captures only deep-red light produced by ionized Hydrogen (and Nitrogen) in the nebula.  Consider that the visible light we see ranges from about 400 to 700 nm in wavelength.  Here, you are only seeing the light from a tiny sliver of the spectrum from 653-659 nm which, fortunately for us, is where nearly all of the light from this object is emitted.

The Horsehead Nebula in H-alpha

Image data:

Exposures:  27 x 600s Ha, a total of 4h 30m, taken 17 Feb 2012.

Software:  guiding by PHD, stacking in DeepSkyStacker, processing in Photoshop CS3

Telescope:  Borg 77EDII w/ f/4.3 reducer

Camera:  SBIG ST-8300M with Baader filters

Mount:  CGEM

NGC 1499, The California Nebula, in Narrowband

February 25, 2012 Leave a comment

This Borg 77EDII is just too much fun with the large narrowband objects.  Combining the f/4.3 focal ratio with 2×2 binning on the ST-8300, I can get a ton of data in a short time.  This image was taken over a single night (2/9).

NGC 1499 is also known as the California Nebula.  I’ve chosen to orient the image differently, but you can see the California shape if you turn your head to the side.  It’s a huge object at over 2 degrees across.  That’s more than the width of four full moons.

NGC 1499, The California Nebula

Image data:

Exposures:  15 x 600s Ha, 10 x 600s O-III, 10 x 600s S-II, a total of 5h 50m

Software:  guiding by PHD, stacking in DeepSkyStacker, processing in Photoshop CS3

Telescope:  Borg 77EDII w/ f/4.3 reducer

Camera:  SBIG ST-8300M with Baader narrowband filters

Mount:  CGEM

The Rosette Nebula in Narrowband

February 10, 2012 Leave a comment

This is my second narrowband image, and the debut of my new Borg 77EDII.  The best thing about this image is that it was gathered over three nights when the moon was over 85% full.  I could never have done that before moving to narrowband!

It could definitely use more S-II data, but I’m pleased with this first attempt.  I didn’t realize how dim the S-II portions of the Rosette would be, otherwise I would have used more of the total exposure time there.

This image is processed in a modified version of the teal-gold motif that Bob Franke describes on his website (http://bf-astro.com/hubbleP.htm).

The Rosette Nebula in Narrowband

Image data:

Exposures:  28 x 600s Ha, 20 x 600s O-III, 20 x 600s S-II

Software:  guiding by PHD, stacking in DeepSkyStacker, processing in Photoshop CS3

Telescope:  Borg 77EDII w/ f/4.3 reducer

Camera:  SBIG ST-8300M with Baader narrowband filters

Mount:  CGEM

M42 Orion Nebula in Narrowband

February 5, 2012 1 comment

Some weeks, everything goes wrong.

To quench the never-ending thirst for more concentrated photons, I sold my previous scopes so I could trade up to two high-end, fast refractors:  a Borg 77EDII at f/4.3 and a TeleVue NP101 at f/5.3.  I seized rare opportunities to get both used and at great prices.  Only if a Tak FSQ came my way would I have room to improve in the short focal length department.  But with all new scopes come new problems.  The NP101 needed rings to sit on my mount, and an adapter for my stepper motor to control the focuser — $200 and two weeks.  The Borg needed precise spacers to fit my camera, and I’m still working out other kinks — $100 and at least two weeks.

Now I find out that my SBIG’s cooling is not functioning correctly, so basically every piece of imaging equipment I have is “in the shop,” in one way or another.  But sometimes even with adversity, something fun or beautiful slips through.  I took the NP101 out on a hazy, moonlit night because I really wanted to start working with narrowband data.  The obvious, reliable target sat just above my roof:  M42.

The world needs another image of M42 like a hole in the head, but I couldn’t resist.  Before it set, I grabbed two hours of narrowband exposures, and here is my very first narrowband image:

Stats:  SBIG ST8300M, Baader filters, TeleVue NP101 on a CGEM

6x300s H-alpha, 10x300s O-III, 12x300s S-II, 25 flats, NO darks

Stacked in DSS, process in Photoshop CS3.

%d bloggers like this: