Taking a break from asteroids

 General Commentary, Wide FOV  No Responses »
Apr 292018
 

Most of the images taken by the PTO are used to monitor asteroid and comet orbits. Collisions or gravitational interactions can, over time, change the orbits of small solar system objects. This could bring them closer to the inner solar system and potentially closer to Earth’s orbit.

By necessity the PTO will be taking a break from its primary tasking as well as any deep sky imagery. Recently, I have noticed an interfering pattern in some of the images. It has become worse over time. Troubleshooting has not identified the usual suspects (USB cable, USB hub, etc.). So, my primary camera is now on its way to the service center for diagnosis and hopefully repair.

Early interference was about 1 in 10 images.

Most recent interference is about 5 in 10 exposures.

So, for now, I will leave the telescope configured for planetary/lunar imaging. I also piggy-backed my Nikon along with a 105mm lens and will do some very wide FOV imaging. I have always planned on developing that capability; now looks like a good time. It will take learning a different software package and processing procedure. One of the first wide images is the constellation Lyra. The new software package can annotate each image and an example is below.

Lyra (The Lyre or Harp)

The FOV has increased from 37.85′ x 25.5′ to 12.⁰ 57′ x 8⁰ 35′.

 Posted by at 15:28

NGC 2149 and friend

 DSO, General Commentary, Nebulae, Spacecraft  2 Responses »
Jan 312018
 

The target of this image is NGC 2149, a small reflection nebula in the constellation Monoceros (the Unicorn). It is quite near the constellation Orion and often gets overlooked due to the more flamboyant objects in “The Hunter”. I routinely exclude images taken of deep sky objects when a satellite intrudes into the photo. The brightness of the intruder skews the desired object’s post processing. I must admit however, last night I intentionally chose NGC 2149 because of the impending satellite pass. The guilty party this time was the Hubble Space Telescope.
 

I decided to attempt the exposure knowing full well the Moon’s brightness would cause a strong gradient in the exposures. After all, the Moon was only a few hours from entering the Earth’s shadow and the resultant total lunar eclipse. Hubble would cross my FOV in just over one second. It takes 10 seconds to download an image from my camera, so in order to not miss the pass I set the exposure to 300 seconds and started it a couple of minutes before the expected arrival. I then joined family members in the front yard to watch the flyby. Hubble silently glided west to east and near the point where it disappeared, it did its best imitation of an Iridium flare. The scope’s solar arrays were at just the right angle to reflect the Sun’s light right back at us. It then faded as its orbit took it into the Earth’s shadow.

Luckily, the satellite’s orbital elements used to predict its path were right on and the 300 second exposure showed the very bright telescope streaking through the image. I then took additional images of the nebula to increase its brightness a little. The result is a stack of one 300 second image and 25 sixty second images.

 Posted by at 15:17

The Stars of the Pear Tree Observatory

 General Commentary  No Responses »
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

OSIRIS-REx Earth gravity assist fly-by

 General Commentary, Minor Planet, Solar System, Spacecraft  No Responses »
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.

[Update: 03 Jan 2018] OSIRIS-Rex is now projected to arrive at Bennu in December of 2018. Approach operations will begin in August.

 Posted by at 14:37

Well done Cassini!

 General Commentary, Planet, Saturn, Solar System  No Responses »
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
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