The Half-Astrophysicist Blog

The Planets Line Up, Comet PANSTARRS and a Globular Cluster

I was doing a telescope training session for students last night, but of course I took along my camera. I got several photos of the planets and stayed after they left photographing a few other objects.

First, I have been posting a lot about the ongoing planet conjunction. All the planets are now starting to spread out more each night and I thought it might be a nice time to look at where all the planets are in our solar system so I created a little view of the planets (out to Jupiter) in their orbits using Stellarium. Click if you want a bigger version.

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First find Earth (it’s labeled). Mercury is the innermost planet and I couldn’t get it to print the label, but you can see its orbit and find Mercury to the slightly to the right of the Sun. Now find Venus and Jupiter. You might notice you can almost draw a straight line through all four of these objects (not quite, but very close!) This line shows that if you are standing on Earth and look in that direction,you will see Mercury, Venus and Jupiter very close together in the sky which is exactly what has been going on the last couple of weeks. You also will notice this line passes pretty close to the Sun…therefore, we see them close to the Sun in the sky, in this case, after sunset (if they appeared on the other side of the Sun, we would see them in the morning…Mars is about to move into the morning sky).

Now think about the motions. From this perspective, the planets will orbit counterclockwise around the Sun.Planets closer to the Sun move faster and planets farther from the Sun move slower. Therefore, Mercury and Venus are catching up to Earth. As they orbit, the line you have to draw from Earth to Mercury or Venus will get farther away from the Sun so they will appear higher in the sky…until they really start catching up to Earth as they prepare to pass between the Earth and the Sun…then they will appear lower in the sky. This will happen pretty quick for Mercury. On June 13th, it will be as far away from the Sun as it gets this time and turn around and start getting lower in the sky each night (and pass Venus again on the way down as Venus keeps going up!)

Remember Earth moves around the Sun faster than Jupiter so in the not too distant future, Jupiter will appear directly behind the Sun from Earth’s perspective. Therefore, Jupiter is getting lower in the sky each evening and will soon disappear behind the Sun. After that, Jupiter will reappear in the morning sky.

So now that you know a little bit about why the planets have been doing this dance, let’s get to the latest pics from last night. They planets appeared almost in a straight line. Mercury is at the top,Venus is in the middle and Jupiter at the bottom.

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By the time the students left, it was totally dark so I went for Comet PANSTARRS again. I have the tracking mount and decided to push the exposure further this time. I got a little trailing (not a perfect alignment) but was still pretty pleased with the pics I got showing its nice long anti-tail. I honestly have no idea whey more people aren’t trying to photograph this…I know there are more skilled people out there with better equipment than I have…if I can do something this nice, they should be cranking out some jaw dropping stuff.

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Finally, I turned my sights toward something a little different. There is a globular cluster (M4) very close to the bright star Antares. A globular cluster is a gravitationally bound collection of 100,000 stars or so. M4 is one of the closer globular clusters at about 7,200 light years away. Globs (as the are affectionately known) consist of very old stars and this cluster is over 12 billion years old. Since it is so closer to Antares and close to Earth, I thought it might make a good target to photograph.

378101_10152844297420104_1691406866_nAntrares is the bright orange-ish star near the center with the cluster to the upper right of Antares. Not bad for a first try. Antrares is one of the brightest stars in the sky and is a red giant, hence the color. You also see a lot of background stars. Antares is in Scorpius, one constellation over from the center of our galaxy in Saggitarius so you get a higher density of background stars the closer you get to the plane of our galaxy.

I only have two more nights to get potential photos here before I head up to Alaska for a couple of weeks where it will never get dark!

May 30, 2013 - Posted by | Astrophotography, Comets, Conjunctions, Jupiter, Mercury, Venus

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