The January 2017 waning gibbous Moon on three successive nights

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Photographed from mid-town Toronto, Canada

* Temperature -6° C. the first night; 0° C. the second night; -4° C. the third night

 

This three-frame assemblage shows how the appearance of the Moon changes from one night to the next, as the terminator (the dividing line between day and night) moves from right to left across the visible face of the Moon. On average, the terminator moves across the Moon's face about 12.7° per 24 hours, as the Moon orbits planet Earth once per month.

 

The time difference between the right and middle frames was 25 hours, and between the middle and the left frames was 28 hr, 20 min.

 

In the right frame, the Moon is 96.2% illuminated by the Sun; in the middle frame, the illuminated portion has decreased to 90.6%, and in the left frame the illuminated portion is 82.1%.

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Nikon D810 camera body on Explore Scientific 152 mm (6") apochromatic refracting telescope (explorescientificusa.com/products/152mm-apochromatic-refr...), mounted on Sky-Watcher AZ-EQ6 SynScan mount (ca.skywatcher.com/_english/02_mounts/02_detail.php?sid=65).

 

1200 mm focal length, f/8

 

* ISO 100 or 125, multiple stacked 1/250 sec. exposures

 

Subframes stacked in Registax

Processed in Photoshop CS6

(brightness, contrast, colour desaturation, sharpening, image rotation)

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Done