Moon | Diffraction Grating View

I headed home after attending the public lecture on aurorae by University of Iowa professor Craig Kletzing. One part of his talk included a demo of color emissions from the element oxygen. It is responsible for nearly all the colors associated with aurorae. We needed diffraction grating glasses to see the demo effect such as these.

As I drove home, I noticed the bright crescent Moon. I stopped the car to look through my grating glasses. Once home I set up the camera with the grating over the lens. It was a nice way to end the day.


Opportunity | Rover Enters Teenage

On 24 January 2004, NASA’s Mars Exploration Rover Opportunity landed and started exploration. It joined the Spirit Rover which landed three weeks earlier on a different part on the Martian surface. The twin rovers were designed for mission lifetimes of 90 days.

Spirit’s last communication with Earth was 22 March 2010 more than six years into the mission. Opportunity is still operating well and continues to return images and data to Earth after thirteen years. It recently completed a marathon of distance travelled. Detailed maps are available here. To celebrate entering teenage, NASA Jet Propulsion Laboratory released this entertaining video about the milestone.

Nuclear Options | Dialogue & Planning Needed

This post is a follow-up to one from a week ago. See below the line break for the original.

Thanks to comments by readers, there are three resources to promote which discuss the need for careful, considered dialogue and planning with regard to our nation’s domestic and military nuclear capacity. Readers shoreacres and Jim Wheeler discussed two resources by Thomas Nichols. The third resource is a recent NOVA program about the nuclear option.

First, what if we could rebuild our nuclear weapon forces from scratch? How should it be done?

Second, read the preface and introduction to the Nichols book No Use: Nuclear Weapons and U.S. National Security

Third, the NOVA program Nuclear Option is available for viewing until 8 Feb 2017.

All three urge bi-partisan discussion by all interested parties. One of the reasons hinges on the need for safety and security in our world today. The other reason hinges on the need for a viable solution to the challenges of climate change and global warming.

I believe nuclear energy should play a role in our future. To not examine the ideas and technologies formed in the 50s, 60s, and 70s which brought us to our current position is foolhardy. The world has changed very much since then.

Nuclear Weapons | Do Accidents Happen?

Have there been nuclear weapon accidents or incidents? Yes, there have been many. We are lucky to not have detonations or major spills of radioactive material. An accident near Damascus Arkansas on 18 Sep 1980 illustrates how a simple event can cause a situation of monumental potential for disaster.

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Nuclear Weapons | Do Accidents Happen?

Have there been nuclear weapon accidents or incidents? Yes, there have been many. We are lucky to not have detonations or major spills of radioactive material. An accident near Damascus Arkansas on 18 Sep 1980 illustrates how a simple event can cause a situation of monumental potential for disaster.

Local PBS television stations will broadcast on 10 Jan 2016 a program on the American Experience detailing this accident and others. Here is a short preview. Here is a Q&A with the director and the author.


Two airmen technicians were servicing a Titan II missile in an underground silo with a hydrogen bomb mounted on top. The bomb had 3x the explosive energy of all the bombs dropped in WWII including the two nuclear bombs dropped on Japan. It was based on the design of this one, the B53, developed during the Cold War. It had a 9 megaton yield.

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Dial-a-Moon | 2017

How will the Moon look today, on your birthday, or any date in 2017? Find out at NASA Dial-a-Moon. Enter any month, day, and universal time (UT) hour to see a high definition image. The composite images of Dial-a-Moon are made from those of the Lunar Reconnaissance Orbiter (LRO) in low altitude orbit around the Moon since 2009. Here is the link for southern hemisphere readers.

You may leave the universal time (UT) at the default 1 value. If you are a curious type, Universal time conversion can be done at this link. Enter UTC in the lower right box if it isn’t already set. You can switch from 12 hr to 24 hr at the bottom of the entry boxes. You may also enter any other local time in the upper left box. Go back to Dial-a-Moon to enter the UT.

The collection of accurate images of the Moon for each hour have been made into a movie lasting 5 minutes. Try watching full screen and increase the speed by 2x. Speed can be changed using the gear icon ⚙  after the movie starts. Two versions of the movie are available for readers in northern and southern hemisphere.

I explain the peculiar wobble and tipping motions at this blog post.

Northern hemisphere


Southern hemisphere

Jupiter and Mercury | Iridium 98 Flare

Mercury has been visible in the early morning twilight recently. Jupiter is on the opposite side of the Sun from our location. But, Earth is coming around in our orbit catching up to Jupiter. As a result, Jupiter is also a morning twilight object in the same vicinity as Mercury. They were to be very close to each other low in the eastern sky on 11 Oct 2016. Guess what. It was cloudy. But, I did go out on 10 Oct at 6:45 am when it was very clear to capture the view.

The first image is how it looked to my unaided eyes. The second image is zoomed into the center part of the first just above the tallest trees in the vicinity of a faint jet trail.

They are in there somewhere in the middle.

They are in there somewhere in the middle.



The evening on 9 Oct was also clear. An email notice told me about a bright reflection off of a communication satellite that was to pass right over my location. The satellites are part of the Iridium system consisting of 72 satellites in polar orbits that provide worldwide coverage for satellite phones. Their 3 antennae shown in the image below are flat and highly reflective of sunlight. The positions and angles of each antenna are known allowing predictions of those reflections across the surface of the Earth.

Iridium LLC

The email notice said the location in the sky was toward 148˚ in the southeast and 50˚elevation. It would last about 10 sec due to the 17,000 mph speed of the satellite.

The sky was dark. I set the camera using a protractor for elevation and Google Earth for direction over my neighbor’s house. I started recording a minute before the due time of 7:52 pm. Success. Here is the video trimmed for time to the actual event.

Juno | Welcome to Jupiter

UPDATE: The Juno spacecraft was successfully captured into a long eccentric orbit. The main engine burned about 35 minutes to slow down as planned when Juno was at its closest to Jupiter depicted in the animation below. The spacecraft performed as expected. All scientists breathed a sigh of relief.

Original Post: The Juno spacecraft launched in August 2011. It coasted away from Earth and returned for a gravity assist flyby in October 2013. That flyby boosted the speed of Juno enabling it to coast away from the Sun and toward Jupiter. It arrives at Jupiter on the 4th of July at 9:30 CDT.

The trajectory brings Juno toward Jupiter over the north pole going 160,000 mph (257,000 km/h) . Its rocket will fire for about 35 min to slow it down in order to be captured in a highly eccentric polar orbit. Previous spacecraft have never visited Jupiter in this kind of orbit or this close. What will Juno encounter?

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