Celebrate Dark Sky Week - Revisited (warning long post)

Back around 14 April under the post “Celebrate Dark Sky Week,” I discussed a bit about astro-photography and stated “I am, however, but an amateur in this astro-photography field.”

I promised to provide a photo from one of the members of the astro-photography group I belong to, demonstrating the type of imaging these astro-photography pros (in my opinion) take and produce.

The image below, is used with permission of Dale Chamberlain, the individual who took the image. Dale is a serious astro-photographer with his own observatory, which he built to observe and photograph the heavens. More about Dale, his observatory and his amazing astro-photography images can be found at Dale’s website…https://chamberlainobservatory.com/

The image below is of NGC 2174 aka The Monkey Head Nebula. This is an emission nebula located about 6,400 light-years away in the constellation Orion.

Here is the meta data associated with Dale's image....

The image was taken over the evenings of March 31, April 1, April 2, 2021

Telescope used: Astro-Tech 14” RC with Starizona Apex-ED L 0.65x focal reducer

Mount used: Paramount ME II

Camera: ZWO ASI2600MM-Pro (cooled to 0C; Gain 100) Bin 1x1

Guiding scope: ZWO ASI290MM-Mini with ZWO M68 Off-Axis Guider (OAG)

Focuser: Moonlite Nitecrawler

Rotator: Moonlite Nitecrawler

Filters used:

Chroma Ha. H-alpha (Ha) filters are essential for imaging nebulae and other objects which are rich in ionized hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-alpha from the SII doublet (671.6nm and 673.1nm).

OIII. OIII (“oh- three”) emits light near 500 nm and is a blue-green- or teal-colored filter. OIII filters have been very specifically designed for the visual observation of gaseous and planetary nebulae. They show great structural detail, but have natural colors, looking like an RGB image.

SII (Suphur II) 3nm narrowband filters with a ZWO 7-position Electronic Filter Wheel (EFW). Sulfur is in the deep red of the spectrum near 672 nm. When combined with H-a and OIII (Hydrogen-Alpha and Oxygen III, or double ionized oxygen) SII will produce images with colors that are reminiscent of those taken by the Hubble Space Telescope.

Number of Exposures:

40x180 seconds with a Ha filter;

40x180 seconds with an OIII filter;

55x180 seconds with a SII filter;

Total number of combined images: 135

Total exposure time: 6.8 hours;

The final 135 images were stacked and calibrated with 40 dark frames, 40 flat frames with 40 dark-flats and 100 bias frames.

Note: Usually three different types of image are required for the stacking process: Light frames, Dark frames and Flat frames. The images containing the astronomical motive are called Light frames. Dark frames are images obtained by taking images with a closed lens cap. They do not contain any real image information but merely consist of sensor noise. These images provide important information on the electrical and thermal state of the imaging sensor. The third type of image is Flat frames. They are usually taken against a synthetic white background and help to eliminate effects caused by dust on the sensor and vignetting (source: https://bit.ly/3xpgLte).

Seeing Conditions: 4/5 above average. Bortle 5 region

Image capture and telescope control: Sequence Generator Pro and TheSkyX Pro

Processed with PixInsight, Photoshop CC 2022

There you have it…as I said, serious, pro-level astro-photography. I want to thank Dale for allowing me to share his amazing image with you.

As I mentioned in my original post, if you haven’t yet, put visiting a dark sky site on your bucket list. Just sit back and stare up into the heavens and be amazed by the billions and billions of points of light one can see, leave the camera in the bag and be spellbound.

Here is NGC 2174 aka The Monkey Head Nebula, taken by Dale Chamberlain...