Moon 28th April 2013 02:23am ( 3 days Past Full Moon)

This is an image of the Moon taken in the early hours of Sunday 28th April at 02:23am at the WYAS observatory.

As per the image take on the 19th April, it was taken with a Celestron 8" SCT on the Large Pier with a Canon 40D DSLR. without a f6.3 reducer installed (see note below). 50 images were taken at 1/640th sec at ISO 1250 for approx. 1/2 the moon was imaged in each 50 image set (upper and lower). This is due to using the 8" SCT without the f6.3 reducer which does not give a full image of the moon within the DSLR image frame.  Each half moon image set was first stacked in RegiStax 5 using the RAW image frames. Then the stacked images was saved as 16Bit TIFF and imported in to Photoshop 6 using the MERGE option to combine the half moon images to a Full Moon image. Then it was lightly processed in Photoshop for the image as shown.

What is an f6.3 (f3.3) Focal Reducer:-
A focal reducer mounts directly to rear of a telescope and alters the field of view / focal length of the telescope for astrophotography. When an f6.3 reducer is fitted to an SCT which is normally f10 it reduces the f10 to f6.3 reducing the exposure time required to image a deep sky object. A typical 5 minutes exposure at f10 would be reduced to 3 minutes.  However, the focal length of the telescope is also reduced so the image object is reduced in size. A typical 8" SCT focal length 2000mm is reduced to 1260mm. This effectively provides a larger field of with within the DSLR image frame.  (The f3.3 does exactly the same changing an f10 to f3.3 but reducing a 2000mm focal length telescope to 660mm).

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