Nov 052017
 

Although the bottom portion of this image is largely Mare Imbrium (The Sea of Rains) what I was concentrating on was catching sunrise in the large circular area towards the top and just right of center. This area is Sinus Iridum (The Bay of Rainbows). The ‘bay’ is a 236 km (146 mi.) crater that predated the impact that formed Mare Imbrium. The crater was flooded by basaltic lava that resulted from the much larger Imbrium impact.
 

There are very few named craters in the bay, but several surface ridges called dorsa are visible. A dorsum is a ridge formed when the lava cools and contracts.

To put the size of the ‘bay’ into perspective, this is a 146 mi. wide circle centered on Niceville, FL.

Sinus Iridum, along with most large features of the Moon, were named by Giovanni Battista Riccioli (1598-1671). Riccioli was an Italian Jesuit priest who included the names as well as detailed maps of the Moon in his seminal work, Almagestum Novum (New Almagest). Published in 1651 and consisting of 1500 pages, the work was used as an astronomical reference for many decades. His names and naming conventions are still used today.

 Posted by at 13:40
Jul 042017
 

After wrapping up the last JunoCam series on the 1st I noticed that the Moon was in a good position to get some terminator images. The Moon’s terminator is the line dividing the daytime side of the Moon from the nighttime side. So, at the terminator, the Sun appears to be rising. This puts the light from the Sun hitting that area of the Moon at a very low angle. At that low angle, mountains and crater walls cast long shadows providing a noticeable 3D effect.

The image below is a heavily cratered area of the south central section of the Moon. The large, deeply shadowed crater towards the top center of the image is crater Maginus. A notch in the crater wall allows a beam of sunlight to spear into the shadows illuminating an area of the crater floor.

Also visible toward the bottom, again deep in shadows, is a crater rim just catching the rising Sun. In fact, the illuminated rim looks like a sickle with the pointed end angled to the right. This is the rim of crater Hell. No, not that Hell. The crater is named for the Hungarian astronomer and Jesuit priest Maximilian Hell. He was appointed director of the Vienna Observatory in 1756.
 

Map generated with Virtual Moon Atlas

The next image is from a little farther north. The dark area to the lower left is the southern portion of the Sea of Tranquility. Of note in this image are the two rilles toward the bottom center and right. A rille is a long narrow depression that looks like a channel. The horizontal rille at center bottom is Rima Ariadaeus. Rima is the latin name for a rille. Rima Ariadaeus is over 180 miles long and was formed when the surface of the Moon pulled apart at parallel faults and the section of crust between sank.

The other rille, Rima Hyginus, is split into two sections by the crater Hyginus. However, this crater is not an impact crater. It is a volcanic caldera. So, the associated rille is thought to be formed by ancient collapsed lava tubes. It is most visible in the section to the right of the crater. Upon close examination it appears the roof of the tube collapsed in a series of connected craters.

Map generated with Virtual Moon Atlas

Also visible in the above image are the landing sites for Apollo 11 and 16. Apollo 11 is in the southern part of The Sea of Tranquility along with the three craters named in honor of the crew members. The Apollo 16 landing site is further south just to the right of the small but prominent crater Kant which is right of the largest crater Theophilus.

 Posted by at 16:18
Jan 312015
 

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The three major craters in the image above are Ptolemaeus (top center), Alphonsus (mid left) and Albategnius (bottom right). The image was taken on the 27th of January when these craters were just on the terminator. This places the Sun low on the lunar horizon. The low light angle accentuates shadows highlighting the Moon’s terrain. The image is a stack of 150 frames.

Map generated with Virtual Moon Atlas

Map generated with Virtual Moon Atlas

Ptolemaeus is named after the ancient astronomer and mathematician Claudius Ptolemy. Classified as a walled plain, the crater is about 95 miles in diameter and about 1.5 miles in depth. The crater has a smooth lava filled floor with one prominent sub-crater: Ammonius. Notice the depression just to the upper right of Ammonius. This is a pre-existing crater that was filled in when lava filled the primary crater. There are several visible in Ptolemaeus and are known as ghost craters.

Albategnius is named for the ancient Muslim astronomer known for refining the length of the year to 365 days, 5 hours, 46 minutes and 24 seconds. His calculation is only 2 minutes and 21 seconds shorter than that accepted now. The crater appears more damaged by additional impacts than Ptolemaeus, the most obvious being the 27 mile wide crater Klein that interrupts the rim of Albategnius. Both Albategnius and Klein exhibit a central peak where lunar material rebounded after impact.

Alphonsus also has a central peak. In fact, the tip of the central peak is just about all that is visible in the image with the majority of the crater deep in shadow. The central peak is about 4,900 feet high. One of the numerous sub-craters in Alphonsus is manmade. The 1965 NASA probe Ranger 9 impacted the crater floor after sending back more than 5,800 photographs.

 Posted by at 01:30
Jan 012015
 

Even though the clouds and near full Moon prevented any deep sky imaging this evening, together they provided the first image of 2015.

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In this case, the ring visible around the Moon is a 22⁰ halo formed by light refracting through randomly aligned hexagonal ice crystals. The phenomenon lasted well over 4 hours. This image is a single exposure by the NMSU All-Sky camera.

 Posted by at 22:31
Oct 232014
 

The PTO made its first road trip today to get a view of the partial solar eclipse visible from the panhandle. The tree line here at the observatory would not allow a view so I had to pack up everything and head to my favorite western horizon; the military drop zone just south of I-10.

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I had not used the new Point Grey camera with the Lunt H-Alpha scope before so some time was spent this morning in the driveway figuring out the correct configuration for the telescope / camera combination. A new voltage converter also made its debut to ensure the laptop wouldn’t stop mid eclipse and to power the camera. With so much equipment making its rookie start a dry run was in order. I wanted to make sure all the cables would reach where they needed to and that I brought along everything I would need. It was time well spent as all the bits and pieces were on hand, the cords and cables got where they needed to go and I was up and running and focused a good half hour before the estimated time of first contact. I also brought along a filtered Orion 4.5″ Starblast telescope so I could view the event in white-light and in case the spectacle drew any passers-by.

My plan was to start taking images 5 minutes before the eclipse started and get an image every 10 seconds from then until the celestial pair dropped below the distant tree line.

At least, that was the plan.

First deviation: timing. Luckily, my impatience took hold and I started the camera about 7 minutes early. First contact is just visible in image 4. Yep, between 30-40 seconds after I pushed the button.

And as always, Mother Nature marches to her own drummer and well before the tree line came into view, the Sun-Moon pairing dropped behind some distant clouds and the event was over.

The above image was taken just before the clouds made their entrance. This H-Alpha view does not give active region 2192 its due. The white-light view shows the largest sunspot complex that I have ever seen. The sunspot is large enough to view naked-eye with an old pair of eclipse glasses. Along with active region 2192 there are also two impressive filaments visible. Ultimately, I got 241 images before the clouds became objectionable. I will massage those into an animation and post it when finished. All the equipment played well together and there were no injuries. All-in-all a successful event.

Finally, I would like to thank one of our county’s finest. Just after the clouds started to intrude into the eclipse a patrol car passed by, saw the hood open on the van (remember the voltage converter), turned around and came back to make sure I didn’t need any help. Of course, I didn’t, but could have. Thank you Officer.

 Posted by at 22:25