Sirius, the Dog Star

 The brightest star in the night sky is Sirius.  As the brightest star in the constellation Canis Major (the Great Dog), it is also known as the Dog Star.

The waning Snow Moon is now rising late enough to provide a period of darkness in the early evening for testing lenses.  The newest lens is a Rokinon AF 75mm f/1.8 FE for Sony E-mount cameras.  The following images were obtained with this lens on a Sony A7iii camera.  Exposures were between 20 and 30 sec at ISO 1600.  The measured sky brightness was sqml=19.58 mpsas.

Sirius and Canis Major.  Hoya Sparkle-6 filter.

 

Hoya Softon-A filter.

Sometimes the diffraction pattern produced by the Sparkle-6 filter is too obtrusive.  In those cases the Softon filter provides a more natural aesthetic.  Unfortunately, the Softon filter does not preserve red star colors as well.  

Orion.  Softon-A filter.

Messier 41 (M41) is a nice open star cluster that lies about 4 deg south of Sirius.  These two image crops help to demonstrate the relative color response of the two filters. Note especially the trio of reddish stars to the right between Sirius and M41.

Hoya Sparkle-6 filter.

Hoya Softon-A filter.

Three Rokinon lenses.  The new 75mm lens is on the right.

Rokinon is the brand label used for Samyang lenses in the North American market, although the same lens is frequently available with either label from the same vendor.