Taken 24-Nov-16
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Photo Info

Dimensions2000 x 1619
Original file size3.4 MB
Image typeJPEG
Color spaceUncalibrated
Date modified24-Nov-16 16:25
Shooting Conditions

Camera modelCanon EOS DIGITAL REBEL XSi
Exposure332s at f/1
ISO speedISO 400
'Dragon's Mouth region (#51)

'Dragon's Mouth region (#51)

Sun. May 11, 2014 offered another opportunity to try and re-observe the unusual 'Dragon's Mouth' effect which was first seen in April, 2013. As with several other occasions that shared the lunar colongitude timing of the original observation, this one again came up short, indicating that a number of different parameters would have to closely approach the original conditions for the effect of concentric circles of small hilltops to be lit by grazing sunlight on the terminator around the time of the 12 day old moon.
The area in question is among the small craters between round, dark Mare Humorum and the terminator which had advanced further along when this picture was taken at 7.45pm.
This image was a 1/320 sec exposure with a Canon XSi camera at ISO 400 through an NGT 18" Newtonian using a 1.6 power Barlow which increased the focal length to f7.2.