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Posts Tagged ‘Crater Alphonsus’

02/19/2021 – Ephemeris – Let’s look at the first quarter Moon tonight

February 19, 2021 Comments off

This is Ephemeris for Friday, February 19th. Today the Sun will be up for 10 hours and 40 minutes, setting at 6:17, and it will rise tomorrow at 7:34. The Moon, at first quarter today, will set at 2:32 tomorrow morning.

I love a first quarter Moon. The terminator or sunrise line cuts the Moon in half. Lots of craters are easily seen due to the long shadows cast by their crater walls. Best seen in a small telescope or strong pair of binoculars is a three crater chain just below left of the center of the Moon. The top and largest crater is Ptolemaeus. Below and connected to it is Alphonsus. A bit below Alphonsus is Arzachel. Alphonsus is the interesting one. In the pre-Apollo days amateur and some professional astronomers saw glows or mists in Alphonsus. In 1958 a Russian astronomer obtained spectra of one such mist. In 1965 the last Ranger mission to impact the Moon was sent to Alphonsus, but it didn’t find anything unusual.

The event times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The first quarter Moon tonight at 8 pm, February 19, 2021, as it might be seen in binoculars. Created using Stellarium.

First Quarter Moon

A telescopic like view of the Moon via the Virtual Moon Atlas pointing out the craters discussed in the text.

Ranger image 1

Ranger 9 Image of Alphonsus #1. Credit NASA/JPL.

Ranger Program

Left: The Ranger spacecraft. Right: The floor of the crater Alphonsus form Ranger 9. Only the last 3 spacecraft were successful. They transmitted images all the way down as they crashed into the Moon. Credit NASA/JPL.

06/05/2014 – Ephemeris – A remarkable crater visible on the Moon tonight

June 5, 2014 Comments off

Ephemeris for Thursday, June 5th.  Today the sun will be up for 15 hours and 25 minutes, setting at 9:23.   The moon, at first quarter today, will set at 2:05 tomorrow morning.  Tomorrow the sun will rise at 5:58.

Near the Moon’s sunrise terminator at the southern half of our satellite are three large craters roughly arranged parallel to the terminator.  The northernmost is the largest named Ptolemaeus.  Just south of it is Alphonsus, and the third is Arzachel.  Of the three Alphonsus is suspected of activity over the years.  In 1956 Dinsmore Alter noticed a haze that obscured some of the cracks in the floor of Alphonsus and took photographs.  The ultraviolet photos showed something, but his infrared photos did not.  In 1959, Soviet astronomer Nicolai Kozyrev obtained spectra of a glow. In 1965 the last Ranger probe was sent to Alphonsus to see what there was to see, and apparently reported nothing unusual.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Moon

The Moon tonight, June 5, 2014. Created using Virtual Moon Atlas.

Ranger image 1

Ranger 9 Image of Alphonsus #1. Credit NASA.

Ranger Image 2

Ranger 9 Image of Alphonsus #2. Credit NASA.

Ranger Inage 3

Ranger 9 Image of Alphonsus #3. Credit NASA.