ClarkVision Photography: Night Gallery

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image m33-c07.10.2005-AdpAdd-v1.4-700.jpg is Copyrighted by Roger N. Clark,

M33: Spiral Galaxy in Triangulum

M33 is one of the galaxies in our Local Group (galaxies near our own). It is estimated to contain only about 20 billion stars, compared to M31's 300 billion. M33 is about the same distance away as M31, or possibly slightly closer.

Camera: Canon 1D Mark II 8-MPixel digital camera, set at ISO 800. Lens was a 5-inch aperture, 500 mm focal length F/4 (Canon's 500 mm f/4 IS L telephoto lens) with a 1.4x teleconverter giving 700 mm at f/5.6. Data were recorded in raw mode, 75 second exposures, and 17 exposures were added in ImagesPlus using raw files converted to linear output by ImagesPlus 2.5. Total exposure time = 21.25 minutes. Processing included light fall-off correction and dark frame subtraction in ImagesPlus. Contrast stretch in ImagesPlus using digital development and in Photoshop using curves and levels. Image restoration using ImagesPlus Richardson-Lucey deconvolution.

The Exposure Factors, CEF, CEFA are measures of the relative amounts of light received from a subject. It can be used to fairly compare wildly different lens/telescope apertures and exposure times. For this image:

Image guided with an ST4 autoguider on a 3-inch f/8 refractor and a Losmandy G11 mount.

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Keywords to this image = astrophoto-1 galaxy Messier night low-light digital_astro

Image ID: m33-c07.10.2005-AdpAdd-v1.4-700.jpg

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Last updated March 10, 2024