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
Aug 202017

Last night I took images of a comet. My standard exposure length of 300 seconds was too long and during that period the comet moved enough to smear into a streak rendering the images useless for analysis. The video is an animation of 11 300 second exposures and shows the amount of movement over 55 minutes. In this case, North is to the top.

Currently, the comet is between Mars and Jupiter and above the plane of the ecliptic but headed south to where most of its orbit lies.

I will try a different tracking technique and exposure duration later tonight to see if I can get accurate astrometric data to report to the MPC and to get a prettier picture of the tail.

 Posted by at 13:34