Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2022 May 14

Visible are:
— The 22° halo
— A large partial halo that looks like a 46° halo but is actually a supralateral arc.
— A pair of paraselene (called parhelia when they are around the Sun) or colourful “moondogs” sit on either side of the Moon just outside the 22° halo.
— The top of the 22° halo has a colourful upper tangent arc plus a faint Parry arc.
— Tangent to the supralateral arc is a rainbow-hued circumzenithal arc.
— A paraselenic (?) circle (called a parhelic circle when it is created by the Sun) runs parallel to the horizon through the moondogs and Moon.
— A faint and wide vertical light pillar also runs through the Moon up to the top arcs.
This is a blend of 7 exposures from 30 seconds to 1/20 seconds to help retain the disk of the Moon amid the bright and hazy sky. All with the 11mm TTArtisan full-frame fish-eye lens at f/4 and Canon R6 at ISO 100. Exposures blended with luminosity masks created with ADP Pro v3.
Ice Halos by Moonlight
Image Credit & Copyright: Alan Dyer, Amazingsky.com, TWAN
Explanation: An almost full moon on April 15 brought these luminous apparitions to a northern spring night over Alberta Canada. On that night, bright moonlight refracted and reflected by hexagonal ice crystals in high clouds created a complex of halos and arcs more commonly seen by sunlight in daytime skies. While the colors of the arcs and moondogs or paraselenae were just visible to the unaided eye, a blend of exposures ranging from 30 seconds to 1/20 second was used to render this moonlit wide-angle skyscape. The Big Dipper at the top of the frame sits just above a smiling and rainbow-hued circumzenithal arc. With Arcturus left and Regulus toward the right the Moon is centered in its often spotted 22 degree halo. May 15 will also see the bright light of a Full Moon shining in Earth’s night skies. Tomorrow’s Full Moon will be dimmed for a while though, as it slides through Earth’s shadow in a total lunar eclipse.