Experimental / Narrowband

M20 test image with ASA 16″ astrograph

There’s a fancy new telescope and CCD camera setup at Siding Spring Observatory! An ASA 16″ F3.5 astrograph with an Apogee CG16070 Class 1 CCD, known as the T33. It’s a medium deep field imaging system and it’s a new addition to the fleet of astrophotography telescopes that iTelescope offers access to for imaging professionals and amateurs as well as science based work.

iTelescope T33 ASA 16" astrograph and 16 megapixel Apogee Aspen CG16070 Class 1 CCD
Pcitured is the new iTelescope T33 ASA 16″ astrograph, 16 megapixel Apogee Aspen CG16070 Class 1 CCD on a Paramount ME. Located at Siding Spring Observatory in Australia.

The resolution of this setup is quite impressive. It delivers an 87 x 58 arcmin FoV at an image scale of 1.07 arcsec/pixel. The light gathering capability of the large 16″ primary mirror, a 35mm format CCD and remote dark skies makes this a deep space imaging beast!

My first run with the T33 was narrowband imaging of the well known M20, the Trifid Nebula. This image was taken through the Astrodon 5nm Hydrogen-Alpha filter using 5-minute exposures. A total of 40-minutes was collected. Processing was minimal for this test image. The images were aligned and stacked in Pixinsight. The image was stretched using a quick method of applying the STF Auto to the Histogram tool. A range mask was created and applied so that HDRmutliscale transform could be applied to the central region of the nebula.

View a high resolution PNG file of this M20 H-alpha image here.

M20 The Trifid Nebula is in the constellation of Sagittarius, “the teapot” as it’s affectionately known. It’s an unusual combination of an open cluster of stars; an emission nebula (red portion), a reflection nebula (blue portion) and a dark nebula (the apparent ‘gaps’ within the emission nebula that cause the trifid appearance; these are also designated Bernard 85).

I’ve previously imaged M20 from here in Ontario, Canada using one of my own telescope/camera setups. You can read more about M20 and view an image I took of it a few years ago using an Orion 10″ astrograph and modified DSLR.  The M20 post can be found here http://visibledark.ca/m20-the-trifid-nebula/

For those interested in the specs of iTelescope’s new T33 ASA 16″ imaging platform here they are below:

Instrument Package:

Telescope T33’s OTA is a fast 16″ F/3.5 Astro Systeme Austria (ASA) Astrograph mounted on a Paramount ME. The OTA is coupled with a large format main imaging camera and guided with a Starlight Xpress Lodestar using a custom made Off-Axis adapter. This will be the first Off-Axis guided system on the network.

Telescope Optics:

The 16 megapixel Apogee Aspen CG16070 Class 1 CCD
The Apogee FW50-9R 9 Position Filter Wheel

The main imaging camera on Telescope T33 is a 16 megapixel Apogee Aspen CG16070 Class 1 CCD paired withan Apogee FW50-9R 9 Position Filter Wheel.  This configuration delivers an 87 x 58 arcmin FoV at an image scale of 1.07 arcsec/pixel.

Its filter wheel is filled with a fantastic compliment of seven Premium Astrodon 50mm Round Filters Imaging Filters:
  • Astrodon Series I Luminance, Red, Green, and Blue (LRGB)
  • Astrodon 5nm Hydrogen-Alpha, 5nm Oxygen-III, 5nm Sulfur-II (Narrowband)


Shawn Nielsen

My story began nearly 40 years ago looking up at the Moon with a small collapsible telescope my Father had. Encouraged by my parents, who bought me my very own telescope, a 4.5" reflector, I began to explore the night sky from my family home backyard. Today I do astrophotography from my home in Kitchener, Ontario and also with remote telescopes located in New Mexico and Australia. Some of my images have won awards and have been featured online and in magazines.

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