Gassendi Crater

Gassendi Crater
Gassendi Crater
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2012 06 01, 0238 UT – 0446 UT Gassendi
PCW Memorial Observatory, Texas, Erika Rix
www.pcwobservatory.com

Celestron Omni XLT 102mm, 24-8mm Baader Planetarium Mark III Hyperion, 2x Barlow, 250x
Temp 71° F, 60% humidity, S: Antoniadi II, T: 5/6
Eyepiece sketch black Strathmore Artagain paper, Conte crayon and pastel pencil, charcoal pencil
Phase: 45.8 deg, Lunation: 11.21 d, Illumination: 84.8%
Lib. Lat: +05:08, Lib. Long: -04:13
Az: +209:11, Alt: 41:03

Located on the northern border of Mare Humorum, crater Gassendi is an impact crater formed during the Nectarian period (-3.92 to 3.85 billion years ago) that later was modified after volcanic activity, becoming a fractured-floor crater. Gassendi is believed to have been filled with lava from the inside, raising its floor, creating stress fractures in the process. This would explain it being considered a walled plain with a shallow depth of 2.8 km. The central peaks (~1200 m high) remain and several rilles (called Rimae Gassendi) were formed on the lava-filled floor during the Imbrian geological period -3.85 to –3.2 billion years ago.

Crater Gassendi A was formed during the Copernician period (–1.1 billion years ago to the present day) and overlaps Gassendi’s northern rim. The pairing of Gassendi and Gassendi A resembles a diamond ring and makes a very striking feature to observe 3 days after first quarter or two days after last quarter of lunation. My observation was nearly three days after first quarter.

Gassendi’s southern rim was swallowed by the lava of Mare Humorum leaving only a thin crest line to support its circular shape. Dorsa ran from the southern rim to Gassendi O (11 km wide). The sharp ridge that defines the border of Mare Humorum to the SW of Gassendi adds to the crater’s unmistakable identification.

At the beginning of my session, Spica and Saturn lined up to align with the Moon. Spica was 2.08 degrees north of the Moon and Saturn was 6.9 degrees north of the Moon. Extending further north, Arcturus was nearly in line as well at 31.8 degrees north of the Moon

An Interesting Contrast – Riccioli and Grimaldi Craters

Riccioli and Grimaldi Craters
Riccioli and Grimaldi Craters
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Aloha!

After a bit of a slump, I decided to get out & observe a little of our Moon. On the lunar west limb I spotted 2 craters that appeared so different from one another that I was intrigued. I knew that one was Grimaldi but was not certain about the other. I sat down to sketch at the eyepiece on a night of good seeing conditions in Hawaii.

Riccioli Crater is the large (140 km) lunar impact crater at the western terminus of the sketch. It is bordered to the southeast by the larger (230 km) Grimaldi & to the northwest by Hevelius. Hedin is still in the darkness and only the edge becoming lit.

Riccioli appears elongate with rough crater walls casting sharp jagged shadows into the basin. There is also visible roughness & debris within the crater. This debris & other striated formations in the region are believed to have been created by ejecta from the formation of the Orientale impact basin to the southwest not seen here. The roughness of Riccioli is in stark contrast to Grimaldi which appears smooth by comparison. Grimaldi, covered in lava makes it appear more like a mare than a crater.

There appears to be a dark line or peak running from Riccioli to crater Lohrmann directly to the east. Multiple small brightly lit rimmed craters surround this area. A double crater with 2 bright rims of light can be seen at the northeast edge of Riccioli.

Both Riccioli & Grimaldi craters were named by 17th century Jesuit priests & colleagues Francesco Maria Grimaldi & Giovanni Baptista Riccioli, who were responsible for many of the names given to features on the Moon today.

Thia (Cindy) Krach
12.5” Portaball 169x
Maui, Hawaii
4/23/13
Black Fabriano paper
white & black charcoal pencils

Eta Carinae Nebula

Eta Carinae Nebula
Eta Carinae Nebula

Aloha!

I submit a recent sketch from 4/14/12 of the Eta Carinae Nebula. It was not much above the horizon this night, perhaps 10 degrees. I had to sit on the ground to observe it using my 12.5” Portaball. Well worth the dirt on my bottom. A gasp was all I could manage after seeing it for the first time. The night was superb, with no wind & excellent seeing.

The nebula is massive, ~4 times larger than the Orion Nebula covering about 3 degrees of sky. It also contains Eta Carinae, one of most luminous & massive stars known. If we could put this star the same distance as our sun it would appear 5 million times brighter. It is partly obscured by gas & dust making it appear dimmer than it actually is.

Eta Carinae Nebula in Carina NGC 3372
Diffuse Nebula
Haleakala, Maui Hawaii ~10,000 elevation
4/14/12
Charcoal pencil & white paper
Sketch inverted with Photoscape
12.5” Portaball, NPB filter
27mm Panoptic 56X

Messier 42

Messier 42
Messier 42

Object Name: M42

Object Type: Orion emission nebula

Location: Iran_Sabzevar

Date: 21/9/2012

Media: Black Cardboard with white Charcoal Lead Pencil

Im Shadi from a little town of Iran and I have pretty good conditions for observing!!! I can almost Observe most of Messier Objects and NGCs with my little 80 mm refractor telescope!

Shadi Shahraini:) happy

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
www.pcwobservatory.com
www.solarastronomy.org

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.
http://i201.photobucket.com/albums/aa201/ErikaGRix/20120520-animation.gif

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
www.pcwobservatory.com
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.

Solar h-alpha, Prominences – May 3, 2012

H-Alpha Sun - Full Disc - May 3, 2012
H-Alpha Sun - Full Disc - May 3, 2012

2012 05 03, 1845 UT – 2130 UT.
Solar h-alpha, Prominences and NOAAs 1469, 1471, 1472, 1473, 1474.

PCW Memorial Observatory, Texas – Erika Rix,
Temp: 33°C, winds SE 7 mph, occasional light cirrus,
Seeing: Wilson 2-3, Transparency: 4/6, 50x,
DS 60mm Maxscope, LXD75, Baader Planetarium Hyperion 8-24mm Mark III .

Sketch created scope-side with black Strathmore Artagain paper, white Conte’ crayon and pencil, Derwent charcoal pencil, black oil pencil.

With five active regions, the Sun made quite an appearance today in spite of the limb. There were a few decent prominences, especially to the eastern hemisphere. My favorite view, though, were magnetic fields surrounding 1471 made apparent by the very thin active region filaments (ARFs). They reached down like fingers from the sunspots in that region. Plage was very intricate and meshed into what I believe was AR 1472.

The quiet region filaments (QRFs) were in abundance in the southern northern hemisphere with a few speckled to the south. AR 1474 seemed a bit washed out with plage and faint darkened areas. There was only slight plage definition and no sunspots observed in h-alpha. I didn’t set up a white light filter today for comparison.

1473 and 1469 were blended together by the plage and many lines of ARFs, including filaments reaching out over the edge for short, bright prominences. Plage was very bright, forming the shape of a tuning fork in 1469. These were impressive sets of active regions when paired up.

This was my first solar observing session since moving to Texas about two and a half weeks ago. With all that took place in preparing the old house for sale and the move to Texas, I’ve been deprived of any observing other than naked eye. It was a relief to be behind an eyepiece once again.

H-Alpha Sun - Prominence - May 3, 2012
H-Alpha Sun - Prominence - May 3, 2012