Western rim of Mare Crisium

Crater Line Linne
Mare Crisium (Move mouse over image to view labels)

2012 09 04, 0330 UT – 0615 UT Mare Crisium
Erika Rix, Texas – www.pcwobservatory.com

AT6RC f/9 1370mm, LXD75, Baader Planetarium Hyperion 8-24mm Mark III (FOV 68 degrees at 171x), no filter
84F, 56% H, winds gusting 5-10 mph, clear, Antoniadi IV increasing to II, T 3/6
Alt: 11deg 43´, Az: 83deg 22´ to Alt: 46deg 21´, Az: 105deg 21´
Phase: 318.4 degrees, Lunation: 17.48 d, Illumination: 87.4%
Lib. Lat: -03:07, Lib. Long: +03.74

Type: Sea (Sea of Crisis)
Geological period: Nectarian (From -3.92 billion years to -3.85 billion years)
Dimension: 740km
Floor: lava-filled and is ~ 1.8 km below lunar datum
Outer rim: ~3.34 km above lunar datum

Eyepiece sketch on black Strathmore Artagain paper, white Conte’ crayon and pencil, Derwent watercolor pencil, black charcoal, black oil pencil.

The evening started off with DSO hunting while waiting for the Moon to come up, even though the stars were and faint galaxies were starting to wash out from the moonlight rounding the eastern horizon. I started a sketch of M12 that will have to wait for another night to complete when the Moon isn’t so much of a factor.

Once the Moon rose between two short junipers behind me, I switched to black paper and scanned the terminator. Mare Crisium looked like it was taking a bite out of the Moon. I’ve always been a bit intimidated at sketching rough terrain, but took a stab at it nevertheless. Sketching in the highlights makes it incredibly easier in fast moving areas such as along the terminator. The trick is to have very sharp pencils at hand, and I made sure of that during set up before it got dark outside – although I did have to resharpen once or twice during the session (as well as stand up and stretch.) It was a rush against time to render the basin’s western edge before the shadows swallowed the view.

I began with the inner ridge line along the terminator, marking each highlighted crest individually with a very sharp Conte’ pastel pencil. Then as quickly and accurately as I could, started working my way west, alternating between the Conte’, charcoal, Derwent and oil pencils, focusing first on the highlights, then the shadows, followed by albedo.

Of particular interest, Crisium sports the crash landing site(although not visible from last night’s lunar phase) of the Soviet’s Luna 15 in 1969 and the landing site of Luna 24, 1976, when soil samples where successfully brought back to earth.

This was my first time observing the Moon with the AT6RC and once seeing sharpened up, the views were crisp and clear with good contrast. It’s especially good that we’ve never had to collimate this scope and I’m looking forward to trying it out on Jupiter soon.

Partial Annular Eclipse

Partial Annular Eclipse Sequence - May 20, 2012

2012 05 20 Partial Annular Eclipse
PCW Memorial Observatory, Texas, Erika Rix

H-Alpha Sun - May 20, 2012
H-Alpha Sun - May 20, 2012
H-Alpha Eclipse Diagram - May 20, 2012
H-Alpha Eclipse Diagram - May 20, 2012

Knowing that we fell within a good band to view a partial portion of the annular eclipse, Paul and I scoped out the local county roads earlier in the day for optimal horizons. The partial eclipse for our location was due to start at 1932 ST (0032 UT) which would only give about 50 minutes of eclipse viewing before sunset. The skies cleared up and we were fortunate to have perfect viewing conditions that evening.

I started off drawing the full solar disk in h-alpha. Four active regions lined up east to west with two more to the south (depicted to the top of the first sketch in the animation). I then made a quick second sketch to use for recording the times and placements of the Moon as it passed between Earth and the Sun.

First contact was at 0032 UT. The first marking was at 0035 UT. I set my iPhone’s timer to go off every five minutes until sunset, marking the Moon’s progress each increment with my oil pencil along with the times. In between, Paul and I would alternate using a pair of solar glasses from solarastronomy.org and the views from my double-stacked Coronado Maxscope 60mm h-alpha telescope.

The first image of the animation shows the original sketch in its entirety. Later, I used the second solar disk sketch as a reference to recreate the eclipse on the original sketch with a cut out circular piece of black Strathmore paper. This animation is the result.

As the solar disk became too dim to view (represented in the last couple frames of the animation), I was forced to leave the eyepiece and enjoy the last several minutes with the solar glasses and my camera.

Two original sketches created at the eyepiece with black Strathmore Artagain paper, white Conte’ crayon and pencil, white Prang color pencil, Derwent charcoal pencil, black oil pencil.

Prominence Ejection Sequence – May 17, 2012

Prominence Ejection Sequence - May 17, 2012
Prominence Ejection Sequence - May 17, 2012

2012 05 17, 1245 UT – 1845 UT
NOAAs 11476, 11477, 11478, 11479, 11482, 11484, NE Prominence

PCW Memorial Observatory, Texas – Erika Rix
Temp: 20-30C, calm – S 5mph, clear.
Seeing: Wilson 4.8-1.2, Transparency: 5/6-4/6, 50x.
Maxscope DS 60mm H-alpha, LXD75, Baader Planetarium Hyperion 8-24mm Mark III.

Sketches created at the eyepiece with black Strathmore Artagain paper, white Conte’ crayon and pencil, white Prang color pencil, Derwent charcoal pencil, black oil pencil.

Link to gallery of individual sketches within the sequence.

During the time I observed, a very large prominence off the northeast limb was enlarging and in the process of ejecting as it broke free from the magnetic fields supporting it. I’ve never visually witnessed that large of a prominence breaking away from the Sun before. What really stunned me was how bright it remained over several hours that far off the limb. I grabbed an 8-sketch sequence spanning over 6 hours of the event, not including the full disk rendering I recorded earlier in the day. The last 35 minutes of my session, the prominence became very faint and diffuse. I stopped seeing any connection from the limb after 1717 UT. Of course, that doesn’t necessarily mean there wasn’t, but was perhaps too faint for my tired eyes to see.