Bob’s Ephemeris Blog

This is the month the big guy had named for himself. In the skies of the present month of July, we find it starts with a bang as on the evening of the first of the month the Brilliant planet Venus passes the dimmer planet Saturn. In the animation below created with the free planetarium program Stellarium we see both planets in the western skies from June 29th through July 6th.

The funny thing, as you view thin animation is that after the 1st Saturn stays at the same altitude as Venus. Now this is an artifact of viewing these planets from 45 degrees north latitude. If you’re south of here, Saturn will sink below Venus. If north Saturn will stay higher than Venus. Now even here during the latter part of the month, when Saturn is overpowered by evening twilight, Venus will actually drop below Saturn.

Venus is a great sight in telescopes with its dazzling crescent. But it will become difficult to spot itself by month’s end.

Tags: Events, Observing by Bob Moler
No Comments »

At 2:06 p.m. Eastern Daylight Time, or 18:06 UTC on June 21st, 2007 the sun will reach its farthest north of about 23 1/2 degrees north of the celesctial equator. At that instant the sun will appear directly over the earth’s Tropic of Cancer a line at latitude 23 1/2 degrees north on the earth’s surface. The important thing is that the season of summer will start in the earth’s northern hemisphere, while winter starts in the southern.

The day and the point in the sky where the sun will be are called the summer solstice. Solstice simply means sun standstill. Of course the sun appears to continuously move eastward in the sky. As the ancients, measured the sun’s motion, it was its height in the sky at noon that was important. On June 21st the sun would stop its northward motion, poised to begin its 6 months journey southward.

Space.com has a nice explanation. Then there’s my favorite summer song.

Tags: General, Events by Bob Moler
No Comments »

But none are easily seen from northern Michigan. The big occultation of Venus by the moon will end on Monday morning June 18th at about 9:58 a.m. with the moon and Venus just 3 degrees above the eastern horizon. Here’s a simulation of the end of the occultation using the free program Stellarium. Phil Plait, the Bad Astronomer has more.

Tags: Events, Observing by Bob Moler
No Comments »

Don Herbert died yesterday. He was nearly 90. I remember him with his 1950’s program. It was one of the greatest Saturday morning programs of the 1950’s and was called Watch Mr. Wizard. It ran from 1951, before we had television at home, to 1964. Most of those years he produced 39 shows.

Don Herbert was Mr. Wizard. He was a decidedly normal father figure, shirt, tie with sleeves rolled up. He and a young assistant, who “happened”, to come by would explore all kinds of wonderful kitchen science “magic”. He would perform this amazing feat, whether collapsing a can with a glass of cold water, exploding a metal canister by blowing into a tube, or making a baking soda volcano. After explaining the scientific principles involved, he’d let the young assistant try the experiment for him or herself. The young assistants were evenly divided between boys and girls. None of this “science is just for boys” for Mr. Wizard.

Bill Nye and Beakman are much geekier, playing to the nutty scientist stereotype. In actuality scientists, astronomers included, are just ordinary people who have a lot more fun at work than most of us. Don Herbert came across as a normal person, who knew a lot of cool science stuff.

He made science fun, and inspired many kids to grow up and pursue science for a career, or at least grew up with a positive attitude about science.

Here’s some links:

Wikipedia entry - http://en.wikipedia.org/wiki/Don_Herbert

Mr Wizard’s website - http://mrwizardstudios.com/

L.A. Times obituary - http://www.latimes.com/news/local/la-me-herbert13jun13,0,7656221.story

Tags: Uncategorized by Bob Moler
1 Comment »

The MESSENGER spacecraft has passed only 210 miles above the surface of Venus earlier today to put it on course for its first look and slingshot pass of its target, the planet Mercury next January 14th. It’s going to take two more passes of Mercury before settling into orbit of the 1st rock from the sun on March 18th, 2011. Here’s two links for the MESSENGER mission: The Johns Hopkins Site, and the NASA Site. Johns Hopkins University Applied Physics Laboratory is operating the spacecraft for NASA.

Tags: Planetary Space Missions by Bob Moler
No Comments »

However thre’s lots to see in the evening twilight early in the month.

On the 2nd Mercury will reach its greatest eastern elongation. So of course you’ll see it in the west. What’s implied is that Mercury is east of the sun., so sets after the sun.  The chart was created using Stellarium the free planetarium program.  The red lines are the orbits of Mercury and Venus as they would appear from here.

On the 5th Jupiter will pass in opposition from the sun. Being opposite the sun in the sky, Jupiter will rise about sunset and will set about sunrise. Jupiter, this year is located in the constellation Scorpius, above the red star Antares.

On the 8th, eastern daylight time at least, Venus, that bright beacon of a “star” in the west will reach its greatest eastern elongation. After that, Venus will have a rather precipitous fall from grace, so to speak. Venus is heading south and will be retreating toward the western horizon faster than it retreats sunward.  The chart was created using Stellarium.  The red lines are the orbits of Mercury and Venus as they would appear from here.

Summer in the northern hemisphere of the earth will start at 18:06 UT on the 21st.  That’s 2:06 p.m. eastern time.  The event is called the summer solstice.  Solstice means “sun stand still”.  The sun doesn’t stop its eastward apparent motion against the stars, but it stops its northerly motion for an instant before heading southward once again.

Here’s the star chart for June. It’s for 11 p.m. on the 15th, But twilight, astronomical twilight that is, doesn’t officially end till midnight.

Check out the Ephemeris website for more planetary events this month.

Tags: Events, Observing by Bob Moler
1 Comment »