Category: Charcoal

 

2007 Sept 01, 0450-0631 UT

10″ LX200 with diagonal, 21-7mm Zhumell

PCW Memorial Observatory, Erika Rix

Temp: 57.9 °F / 14.4 °C

Humidity: 75%

Seeing Antoniadi II, Transparency 2/6

Sketch media:  Rite in the Rain paper, charcoal

Moretus
Lunation 19.24 d

81.4% Illumination

Lib. Lat: -04deg44′

Lib. Long: +01deg35′

Altitude 35deg

Colongitude 139.9deg

According to the Virtual Moon Atlas the dimension of Moretus is 117x117Km / 69x69Mi
and it’s from the Eratosthenian period (From -3.2 billions years to -1.1 billions
years).

I’m having fun with Moretus.  Chuck Wood wrote “Moretus is a very fresh but rayless
115-km-wide, 4-km-deep version of Tycho that would be a major attraction if it were
better placed.” (page 126, The Modern Moon, a Personal View).  He also brought up
Harold Hill and the measurement of the central peak of Moretus that Mr. Hill wrote
as being the highest of all the craters Earthside at 2.12km.  Chuck then measured it
using Lunar Orbiter photos and found it to be very comparable to Mr. Hill’s at
2.66km.

This led me look for Moretus in Harold Hill’s “A Portfolio of Lunar Drawings” and on
pages 122-123 I found not only a superb description of this crater, but two sketches
that were very similar in comparison to each other as my two sketches’ were to each
other.  The purpose of this report was to compare my sketch of 2007 September 01 to
that of 2006 October 30.  I was pleasantly surprised to be led to the same type of
report from Mr. Hill…”two 1966 drawings demonstrate how greatly the presentation
of this magnificent formation can alter under near extremes of libration in
latitude.”(page 122)

Here is the sketch from Oct 2006:

http://www.cloudynights.com/photopost/showphoto.php?photo=8052&password=&sort=2&thecat=500

The details for comparison are:

Lunation 7.8d

51.4% Illumination

Lib. Lat: +05deg39′

Lib. Long: -06deg08′

Altitude 26deg

Colongitude 7.4deg

Note in the earlier sketch that not only does Moretus look narrower, but Cysatus and
Curtius are completely hidden and Gruemberger looks completely invisible except for
the telltale crater within it, Gruemberger A. 

Now look at the Moretus sketch from the other day.  Everything has opened up,
Moretus, Short on the other side as well as the three craters on the Northern
borders (to the bottom in both sketches).

It’s easy to see how a person could get lost in the rugged terrain of the Southern
hemisphere and even more so, how difficult it would be to make accurate studies. An
example of this is the measurement of the central peak.  I’ll make no claims that I
could begin to measure the central peak myself.  But I thought I could see a
craterlet in my observation the night just plain as day on the southern rim of
Moretus towards Short.  In the sketch, you can even see the craterlet.  My
observation from Oct of 2006 does not include this.  I began to doubt myself on
whether this feature was actually there.  Thank goodness for Hill’s observation. He
confirmed this depression in the rim with his sketch done on 1966 Dec 4th, with a
higher percentage of illumination than his second sketch.

We already knew that repeated observations are necessary during our studies of the
Moon.  These two observations as well as the two that Mr. Hill did in 1966 are
perfect examples why.

 

Poor transparency started the session and I was standing there next to the Big Fella
with disbelief showing across my face…no doubt the Big Fella’s face too, but the
dew shield was hiding his expressions from me.  I took another swig of my tea and
said to heck with it, a few thin clouds aren’t going to get the best of me…not
after all that time setting up.  So I pulled up my socks, changed the expression on
my face to determination and began my date with the Big Fella.  Destination Moon.

I had already printed out VMA’s globe showing ideas for tonight’s session.  But
peering the terminator and then working my way East, the Big Fella kept tugging me
to a triplet of craters just south of the border and a stone’s throw from the
terminator.  It sure did look familiar, but I couldn’t put my finger on it.

Rays were streaking the surroundings like a burst of light just itching to break
free from the crust.  And inside the main crater a peak so high and creviced that it
looked like a mini mountain reaching up to soak in the sunshine.  If I walking in
that crater, I could easily have scaled the terraced walls, as well defined as they
were this night. 

But wait…there wasn’t that much detail at first!  I pulled free of the Big Fella
and looked up.  The clouds were gone!

At this stage, I’ll end the actual tour to fill you in on what really excited me.
After I walked the Big Fella to his door (ok, so that door happens to be downstairs
from my door) I checked out on VMA what the mystery craters were.  Of course…it
was Bullialdus and his two sisters A & B.  Quickly flipping through my journal, I
came across this sketch I did with the Little Fella 6 months ago!

With that burning mystery put out, I was free to eat my supper, realizing that I had
forgotten all about the Enchiladas I cooked earlier.  Big Fella was too cheap to
take me out for a meal…guess I can’t complain though, he gave me a grand tour on
the moon.

Erika Rix
Zanesville Ohio
 

Extra image from url:

Rite in Rain sketching paper, blending stump, stick of charcoal, charcoal stick in a
wooden holder.

Sketch Image courtesy Springer Science and Business Media, LLC from “Astronomical Sketching: A Step-by-Step Introduction” (2007)

 

Copernicus 

Erika Rix

Zanesville Ohio

Charcoal on Rite in the Rain white paper