Nov 202017

For a number of years now the PTO has sponsored a youth soccer team. This year I was invited to one of the games and my schedule finally allowed me to attend (on the second try). So, here they are, the 2017 Pear Tree Observatory U8 boys soccer team after their quarter final match.

I would like to thank Coach Blake for the invite and the team for the much appreciated plaque. We are looking forward to the 2018 season.

 Posted by at 13:53
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
Sep 222017

As many of you know the OSIRIS-REx spacecraft made an Earth gravitational assist fly-by today. The spacecraft needed the slingshot maneuver to make it to its rendezvous with the asteroid Bennu in August 2018. The spacecraft will orbit the asteroid for up close study, then drop low enough to grab a sample of the surface for return to the Earth in September 2023.

NASA put out a call to amateur astronomers to take images of the spacecraft as it approached the Earth. So, for the past week I have been attempting to do just that. Last night the spacecraft was finally bright enough for me to catch it in a series of exposures. Even so, the speed, brightness and size of the spacecraft makes it very difficult to see.

The above image is the third of eight 300 second exposures that I was able to get before the clouds closed in. The circle shows the location of the automobile sized craft which should give you an idea where it will be in the following animation. The craft’s motion is from upper right to middle left.

I had to stretch the images as well as invert them to make the faint streak a little more visible. This close to the Earth the apparent velocity of OSIRIS-REx is obvious.

 Posted by at 14:37
Sep 152017

This morning the Cassini spacecraft entered the atmosphere of Saturn and ultimately became part of the planet it was sent to study.

Artist rendering of Cassini’s atmospheric entry.
Credit: NASA/JPL

The spacecraft entered orbit around Saturn on the 1st of July 2004 after a six year trip to the planet. It has been studying Saturn and its rings and moons since that time. One of the first things the spacecraft did was to deploy the Huygens probe toward Saturn’s largest moon, Titan. The probe became the first lander on a solar system moon other than our own.

Artist rendering of Huygens’ landing on Titan. Credit: NASA/JPL

Image from the surface of Titan. Credit: ESA/NASA/JPL/ University of Arizona

There are too many discoveries over the 13 years Cassini spent in the Saturnian system to list. Probably the most surprising was the discovery of geysers erupting from the southern pole of the ice covered moon Enceladus.

Geyser plumes from the southern pole of Enceladus. Credit: NASA/JPL

Subsequent study has revealed the material being ejected from the moon to be salty water carrying organic molecules. This implies the conditions necessary for life exists in the outer solar system in a place scientists never expected.

In addition to the scientific discoveries is the vast archive of images that Cassini took. The beauty of the planet and rings was worth the investment.

Saturn as seen by Cassini.
Credit: NASA/JPL

To the entire Cassini/Huygens team, thank you. Well done.
 Posted by at 10:24