Posts Tagged ‘Crater Tycho’

08/18/2016 – Ephemeris – Viewing the full Moon tonight

August 18, 2016 Comments off

Ephemeris for Thursday, August 18th.  The Sun rises at 6:49.  It’ll be up for 13 hours and 53 minutes, setting at 8:42.  The Moon, at full today, will rise at 8:54 this evening.

The full moon, contrary to what you’d think is a poor time to observe it.  The moon is essentially gray on gray.  And at full moon we are looking at the moon from about the same perspective as the sun, so there are no shadows to delineate its fine features.   Since the actual instant of full moon occurred at 5:27 this morning, some shadows will be creeping in on the moon’s upper right face as it is seen in the evening.  Full moon is the best time to see the maria or lunar seas, the dark areas that make up the man in the moon.  In binoculars can be seen the bright rays* emanating from the crater Tycho near the south end of the moon.  Other craters have rays too, but none so long and distinctive. Night by night for the next two weeks the moon’s illuminated landscape will wane.

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

* Rays are caused by the ejecta from the impact that created the crater.  They are thought to be small craters themselves which show up best at full moon because they have no shadows in them.


High contrast full Moow

The full Moon taken last night, 7 hours before to was officially full. The contrast was greatly enhanced to bring out Tycho’s ray system. Credit Bob Moler.

09/02/2014 – Ephemeris – Viewing the first quarter Moon

September 2, 2014 Comments off

Ephemeris for Tuesday, September 2nd.  The sun will rise at 7:06.  It’ll be up for 13 hours and 11 minutes, setting at 8:17.   The moon, at first quarter today, will set at 12:52 tomorrow morning.

Tonight on the moon there are some very prominent craters on the terminator or sunrise line that’s cutting the moon in half.  From the top or north of the moon there’s Plato, which is also called a ringed plain because it has a flat floor.  South of there is Eratosthenes, at the end of the arc of the Apennines mountain chain.  At the south or bottom end of the moon are two other of my favorite craters.    First is the crater Tycho, that doesn’t look spectacular now, but will when the Moon is full with its rays of ejecta crossing a long way across the face of the moon.  A little bit farther south, partially entering sunlight is the large crater Clavius.  On my blog,, I’ll illustrate what the Moon’s image looks like in different types of telescopes.

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


The moon tonight

The Moon tonight at 9 p.m. (September, 2, 2014). Created using Virtual Moon Atlas.

Image orientation in telescopes

The orientation of what one sees in an astronomical telescope depends on the type of telescope and the placement of the eyepiece.  The orientations shown are for observers in the northern hemisphere.  For the images below the moon shown is due south.

Erect image

The orientation of the Moon as seen with the naked eye, binoculars, spotting scopes and telescopes with an erecting eyepiece.

Mirror image

The orientation of the Moon as seen in a refractor or a Schmidt-Cassigrain or similar type reflector with a diagonal at the eyepiece end, and the eyepiece pointing up. This is a mirror image due to an odd number of mirror reflections in the telescope.

Inverted mirror image

The orientation of the Moon as seen with a refractor or Schmidt-Cassigrain and diagonal with the eyepiece oriented horizontally. It is a n inverted mirror image.

Inverted Moon

The orientation of the moon through a Newtonian reflector or a refractor without an eyepiece diagonal. It is an inverted image, an image rotated 180 degrees.

For southern hemisphere observers for these images to work the moon would be due north and all the images would have to be upside down.

Correction 09/02/2014 11:07 p.m.

All images created using Virtual Moon Atlas.


02/14/2014 – Ephemeris – This full moon is a bit too cold for lovers.

February 14, 2014 Comments off

Ephemeris for St Valentine’s Day, Friday, February 14th.  The sun will rise at 7:44.  It’ll be up for 10 hours and 25 minutes, setting at 6:09.   The Moon, at full today, will rise at 6:15 this evening.

Tonight’s full moon won’t be the type that young lovers would want to look up to because, well it’s February, and it’s cold.  Let’s wait until June.  But one can bundle up and get the telescope or binoculars out to view the face of our only natural satellite.  Even though the actual reflectance is a bit less than 13% of the light that the sun sends its way.  If it were snow covered it would really be bright.  Looking at it with or without binoculars one can see the man in the moon face.  At the bottom of the moon or bottom right as the moon rises is the splashiest crater of all, the crater Tycho.  The crater itself seems to have a dark halo around it.  Also one can see rays extending great distances across the moon from it.

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


Full moom & Tycho

Tycho’s rays at full moon are actually secondary craters thrown by debris from the initial impact. At full moon they are no longer shadow filled so show as being bright. Image created using Virtual Moon Atlas.