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Posts Tagged ‘narrowband filter’

The Astrophotography Sky Atlas

November 22, 2015 Leave a comment

TASA Cover 500px

The Astrophotography Sky Atlas is now available at Amazon!

I spent two years coding, researching, and writing this book with a simple goal:  to create a compact, reasonably-priced atlas designed for the imager. Over 2000 deep-sky objects are plotted in their correct size and shape, including many faint nebulae not shown in other atlases. Stars are shown down to 9th magnitude.  The entire sky is covered in 70 full-color charts.

A tabular index contains important details on each object, including a description, the best time of year to capture it, and the required field of view.

What’s shown:

  • 416 emission nebulae and supernova remnants, including the complete Sharpless (Sh2) and RCW catalogs.
  • 171 reflection nebulae, including the complete van den Bergh (vdB) catalog.
  • 146 planetary nebulae, including the complete Abell catalog
  • 52 dark nebulae and molecular clouds
  • 792 galaxies (larger than 3 arcminutes)
  • 38 galaxy groups from the Abell and Hickson catalogs
  • 108 globular clusters (larger than 5 arcminutes)
  • 309 open clusters (larger than 5 arcminutes)

Keeping a focus on what is important to imaging, sparse open clusters and galaxies smaller than 3 arcminutes (unless part of a group) were left off the maps.

With information on nearly every possible photographic object in the night sky, The Astrophotography Sky Atlas will help you choose your targets and plan your imaging.

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The Heart Nebula, IC1805, in Narrowband

January 27, 2015 Leave a comment

This is one of my favorite deep sky objects, especially for narrowband.  It just fits on an KAF-8300 chip at 350 mm focal length.  The small cluster in the core is Melotte 15.

I took three nights of exposures, which were spread over 41 days due to poor weather and holiday trips.  Maybe next year when Cassiopeia swings into view, I’ll make a similar project of the Soul Nebula nearby.

The Heart Nebula (IC1805)

The Heart Nebula (IC1805)

Image data:

  • Exposures: 32 hours total: 96 x 10 min Ha, 43 x 10 min OIII, 53 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:  mild winds on two nights
  • Processing: DeepSkyStacker -> PixInsight -> Photoshop
  • Date: Nov 21 2014, Dec 31 2014, and Jan 1 2015

The Bubble and the Lobster Claw

January 10, 2015 Leave a comment

There is an area on the border of Cassiopeia and Cephus that’s packed with deep-sky objects, including the assortment shown here.  The main nebula here is the Lobster Claw, Sh2-157.  Above it and to the right is the famous Bubble Nebula, NGC7635. In the upper right is the cluster M52.  The nebulae at middle right and lower right are Sh2-159 and NGC7538, respectively.  The very dim nebula the goes off the right edge of the image is Sh2-161, and the little star cluster at middle bottom is NGC7510. So that’s at least five distinct nebulae and two star clusters (there would be more if we considered how other catalogs, like the LBN and IC, define the objects).

The Bubble and Lobster Claw NebulaeWith all of that said, this is the second year I’ve imaged this area, and I haven’t been happy with either result.  The Lobster Claw is not particularly photogenic, and it’s fairly hard to process well.  Given the chance to do it again, I’d probably either use a longer scope to focus on the Bubble Nebula alone, or go even wider with a telephoto to capture the sea of nebulosity in the whole area.

Image data:

  • Exposures: 60 x 10 min Ha, 33 x 10 min OIII, 27 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:  strong wind gusts
  • Processing: DeepSkyStacker -> PixInsight -> Photoshop
  • Date: Nov 18 and 20, 2014

The Cave Nebula (Sh2-155)

November 22, 2014 Leave a comment

The Cave Nebula is probably better suited for 600 mm of focal length, but I thought I’d try a wide field view of the area.  The whole nebula is fainter than I expected, especially the diffuse OIII spread about the region.  20- or 30-minute sub-exposures would do a much better job of revealing it, but because it was so windy, I wanted to keep the subs at 10 minutes, so I really had to fight a lot of noise in the blue channel.

The Cave Nebula (Sh2-155) in narrowband SHO palette

The Cave Nebula (Sh2-155) in narrowband SHO palette

Image data:

  • Exposures: 55 x 10 min Ha, 28 x 10 min OIII, 28 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:  gusting winds
  • Processing: DeepSkyStacker -> PixInsight -> Photoshop
  • Date: Nov 9-10, 2014

NGC7000

November 18, 2014 Leave a comment

This is not exactly a shining moment as an astroimager, because I completely messed up the polar alignment routine, resulting in smeared stars.  (When the CGEM tells you not to pick polar alignment stars too close to the pole, it means it!)  But NGC7000, more commonly known as the North America Nebula, is such a compelling object, I’m posting the image anyway.  It also gives a sense of how wide the field of view on the Star 71 is.

NGC7000 "The North America Nebula" in Narrowband

NGC7000 “The North America Nebula” in Narrowband

Image data:

  • Exposures: 34 x 10 min Ha, 14 x 10 min OIII, 17 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 20 mph, gibbous moon
  • Processing: DeepSkyStacker, PixInsight, Photoshop
  • Date: Nov 2, 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

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

M16 and NGC 6604 H-alpha widefield

September 7, 2013 Leave a comment

I don’t usually post monochromatic images, but this is a nice example of how wide the view is with the STL-11000M through the FSQ-106ED (530 mm focal length).  Not only does the Eagle Nebula, M16, fit in the field, but the entire area of nebulosity around NGC 6604 fits as well.  It makes me wish I lived further south so I could spend more time on the Sagittarius/Serpens area of the sky.  It was all I could do to capture 3h 20 min of exposure time from here in NJ.

M16 and NGC6604 H-alpha

M16 and NGC6604 H-alpha

Image data:
Exposures:  10 x 1200s Ha
Software:  guiding by PHD, stacking in DeepSkyStacker
Processing:  PixInsight, Photoshop CS3
Telescope:  Takahashi FSQ-106ED
Camera:  SBIG STL-11000M with Astrodon 6nm narrowband filters, 2×2 binned
Mount:  CGEM
September 3-5, 2013

 

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