The Night Sky This Month: May 2015

Take in a shower

Like bowties, meteors are cool! May provides us with three showers. May 1st gives us the Boötids at only 6/hour, followed by the Scorpiids on May 3rd. On May 4, however, the Eta Aquarids come along with the least 20 per hour as the Earth passes through dust left behind by Halley’s Comet. Sadly we will be faced with a gibbous Moon which will wash out a great deal of detail. You’ll only be able to see the brightest ones, and its best viewed just before dawn in the east about 10-12° above the horizon.


Jupiter: Last night (April 28th) I was standing on my front porch and there, in the southwest, was Jupiter staring me in the face. I hauled out the old 7 inch reflector, and targeted Old Jove about 40° above the horizon. Unfortunately I’m within the city, with all the atmospheric disturbances which that causes, compounded by the fact that it has finally started to warm up and the air was pretty unsteady overall. I couldn’t even make out the Galilean moons. I think I’ll be heading out into the country tonight. Jupiter is always worth a look, even though it is past its prime viewing time at the moment and about magnitude -1.9.

On May 5th however it reaches east quadrature, meaning it’s at 90° to the Sun from our perspective. This means it really well-lit and it makes it easy to see the Galilean moons and track their motions over the course of the night, in over the course of a few days. Actually seeing them move gives you a really good concept of orbital mechanics. It brings it home to you that these things actually do move.

Saturn: The Ringed Planet is great this month. It’s now sitting at an inclination of almost 24° compared to our angle of view. That’s just about as good as it gets so the rings are really broad. Since we’re now at opposition, where the Sun is directly behind your head, when you look at Saturn (on the other side of the Earth, obviously), it is as bright as it ever gets at magnitude 0.0! It is positively scintillating so make sure you utilize this premium viewing opportunity!

Messenger ProbeMercury: If you remember last month, we mentioned that the Messenger Probe was set to crash into Mercury on the April 30th. By the time you read this that should have already happened at 7:26 UTC (8:26 pm London time/3:26 EST for North Americans). What a great little probe! This is the little probe that could! Instead of the original 704 orbits planned, the control team hoarded its fuel and managed to complete 4,000 orbits and extend the mission by four years. They gathered over a quarter of a million photographs, evidence of vulcanism, and located ice deposits at the poles of the sun’s nearest neighbor.

Since Mercury will be visible about an hour after sunset, it makes me wonder if observers are going to be looking for the plume from the crash. Traveling over 8,700 miles an hour, the probe is expected to make a crater over 16 meters wide. If you recall, we used a similar crash several months ago, with a probe on the Moon, to see if we could measure hydrogen ejecta from the crash site to confirm water.

Mars: The Red Planet is quickly disappearing in the Sun’s glare, so if you want a quick peek before it vanishes now is your chance.

Venus: The Evening Star is back and with us all month long. If it should peak at magnitude -4.4, so now would be a really good time to start tracking it for the month and watch it go through its phases. Yes that’s right, if you never thought about it before, planets have phases just like our Moon. Like I always say, there’s nothing like seeing it with your own eyes to make it tangible.

For Android Users

I found a new app you might enjoy. I’ve been using a lot because it’s convenient and fun. It’s called Star Tracker and it’s available in the Play Store. I know there are lots of similar programs available, but I like how I can just pull of my phone with a single touch turn it into a star-identifier. As long as your phone has GPS and an accelerometer built in, just hold the screen in your line of sight between the object you want to identify and yourself, and everything you need to know just pops up. I have no financial interest in this program, and benefit from mentioning it in no way. I just think it really cool. It even identifies some interesting deep sky objects like Messier 51 and M57.

Clear skies everybody!

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