June 27, 2012

Delightful Sights for early Summer Nights!

I stepped out on my deck the other evening at around 11 pm local time just to look around. Earlier this week our area was treated to a stretch of unseasonably mild weather, daytime temps in the low 80’s, nights around 60 with low humidity.
I am glad I did because I was treated to a reminder of why the star patterns visible late evenings in June are among my favorites. Two of the zodiacal constellations appearing now which are easiest to spot and really resemble what they are “supposed” to represent are the Lion and the Scorpion.

28-jun-12-0230-w-horizon-90.gif Late evenings in June and early July are the best time to catch them gracing opposite corners of the southern horizon. Around 10 pm Leo appears to the southwest. The Lion seems to be ready to leap over the western horizon and disappear into the night. By midnight he will be gone.

The chart at left shows the view to the southwest at 10:30pm local time, on the evening of June 27/28. Prepared using Your Sky

Casting a glance to the left while facing south the Scorpion can be seen slowly crawling above the southern horizon. Scorpius’ red giant heart, Antares, blazes in a fiery orange glow from a distance of over 600 light years. If Antares were at the heart of our solar system instead of our Sun all the planets out to Mars, including Earth, would be incinerated inside of it.

28-jun-12-0230-se-horizon-90.gif The view toward the south-south east toward constellation Scorpius. Above constellations Lyra, Aquila, Hercules and Corona Borealis can be seen. Can you spot the “keystone” in Hercules?

The brightest object in the sky, the Moon, is now one day past first quarter (27/28 June) and positioned between Saturn and Mars. See the chart. Yellowish Saturn is just east (left and above) the Moon. Rusty orange-red Mars is about 20 degrees west (right) of Luna and Saturn on this night. Compare the color of Mars to the Scorpion’s heart, Antares, and Arcturus the brightest star up in the western part of the sky.

Next turn 90 degrees to your left so you are facing east. Focus your gaze about halfway up above the eastern horizon and see whether you can discern the “Summer Triangle”. The three stars are, clockwise from the lower left, Deneb (Cygnus, the Swan), Vega (Lyra, the Harp) and Altair (Aquila the Eagle). Next look between the two brightest stars in the sky, the aforementioned Vega and Arcturus.

This one is a little difficult, especially in extremely bright, light polluted skies, but try to find constellation Hercules. The strong man’s most obvious feature is an asterism or group of stars resembling the outline of a keystone. Within that keystone, near it’s western edge is a beautiful globular cluster of stars which is called Messier 13 or M13. Binoculars or a telescope will be required to spot M13 except in the darkest of skies.

Finally, turn and face north. Can you spot Ursa Major, the Big Dipper? This time of year the BD is tipped with its “bowl” facing downward. Ursa Minor, the Little Dipper is standing upright on its handle, bowl high off your northern horizon just east of the Big Dipper.

I find the sight of the Lion and Scorpion majestically dancing above the southern horizon opposite each other one of the most breathtaking views in the night sky. Early last Spring I was venturing out at 3 am to enjoy this view. I just shared it with you for viewing at a much more convenient hour. Get out and enjoy it!

From Hubblesite enjoy this video on observing highlights for the month of June

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June 25, 2012

Venus “stars” in the Morning

After her historic June 5th transit, Venus next “starring” performance is in the pre-dawn sky with Jupiter. Venus will climb quickly, rising nearly two hours before sunrise by the end of June.

During the last week of June Aldebaran, Venus and Jupiter will form a vertical line, with the star on the bottom. The first week of July Jupiter and Venus will appear within 5 degrees of each other in a “quasi-conjunction”.

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The chart left, prepared using YourSky, shows the eastern horizon for 38 north latitude at 9:55 UT (5:55 AM EDT) June 30th. Plan your observing for 45 minutes before sunrise at your location. Click map to enlarge

Sunday morning, June 17th using binoculars I spotted the very thin crescent of Venus just off the NE horizon in the brightening dawn twilight. Before sunrise Saturday morning, June 23rd I spotted Venus’ thin crescent 45 minutes before sunrise.

If you have a telescope watch as Venus’ angular size shrinks and its illuminated phase increases. The planet will be at its brightest while finishing its retrograde motion in early July. This is easier if you imagine Venus’ counterclockwise orbit around the Sun in front of you as it passes us one lane nearer the Sun!

We’re into the period of earliest sunrise here in the northern hemisphere. The summer solstice and longest day will be June 20th. The cycle is earliest sunrise, longest day, latest sunset.

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June 20, 2012

Watching the Seasons Change

June brings the summer solstice for those of us living in the Northern hemisphere and winter in the Southern hemisphere.  Today’s solstice  (June 20th) brings the longest day (most hours of daylight) here in the north and shortest day south of the Equator.

But this doesn’t happen all at once on one day. It occurs in a sequence.  The earliest sunrise, at latitude 40 degrees north, was June 14th and the latest sunset June 28th.

Incidentally, our planet and every creature and lifeform living on it will be at aphelion (furthest from the Sun) on July 3rd. This fact is counter intuitive, but true. Earth’s orbit is slightly elliptical. We’re closest to the Sun each January (perihelion) and furthest away in July. The variance is on the order of 2%. I guess it makes more sense if you live in the southern hemisphere!

The seasons, and hours of light and darkness change because Earth is tilted 23 degrees on it’s axis. As we orbit the Sun our hemisphere tilts toward (Summer) and away (Winter) from the Sun. When it’s Summer here our hemisphere is tilted into the Sun, the Sun tracks much higher, or further north, across our sky.

You can observe this for yourself. Go out at sunrise or sunset, get your bearings and make a mental note of how far north of east (sunrise) or west (sunset) the Sun is. When Fall or Winter come around again make the same observation and compare how much farther south the sunrise/sunset is on your horizon.

If you’re impatient and can’t wait until December check out the composite panorama image below. This image is a composite of 3 images I took looking west at sunset. Look closely at the sky and it’s easy to see where the images join. The sunset to the left was taken in November, the middle near the equinox in September and the Sun glinting through the trees to the right was taken at the summer solstice on June 21st.

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Click on the image to enlarge it. Try this for yourself and enjoy the changing of the seasons!

 

 

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June 8, 2012

Catch ISS above your backyard this weekend!

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June is the best time to watch the ISS orbit over your backyard. Because our hemisphere is tilted toward the Sun (remember summer solstice is June 20) now any nighttime ISS pass where the station is above your horizon will likely be visible. It’s all about the sun angle

Here in southern Indiana and in the Louisville area the best visible passes for the weekend will be:

Saturday 9 June 5:03-5:09 AM peaking 48 degrees off SW horizon. WSW-SSE pass

Saturday 9 June 9:40-9:47 PM peaking 69 degrees off NW horizon. WSW-NE pass

Sunday 10 June 4:09-4:15 AM peaking 76 degrees off NE horizon. NW-SE pass

As you watch an ISS pass remember there are 6 crewmembers orbiting up there. The station orbits at 17,500 MPH or 5 miles per second

At this  speed you’d run I-5 from L.A. to San Diego in 20 seconds or Chicago to Louisville in I-65 in one minute

Image above left: Space Shuttle Endeavour and ISS above Indiana, 30 May, 2011. Click image to enlarge and note the two “streaks” which are the Shuttle and Station in this 30 second exposure

Check the Heavens-Above website for pass times at your location

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June 6, 2012

Reflections on the Venus transit

I arrived at Granny’s restaurant, the site of our Venus transit party, later than I had planned Tuesday afternoon. I worked much too late into the night Monday night putting finishing touches on my pre-transit presentation and was giddy anticipating the transit. The manila folder safety viewers still had to be made, but that would have to wait until morning.

Taping pieces of aluminized mylar into the folders and sealing them with glue would be the first order of business on Tuesday morning. Tuesday was beautiful and mild with temps in the mid 70s but the cloud cover was a concern. I arrived at Granny’s around 2pm. Our guests started arriving at 3.

dscn7045.JPG We began with the pinhole viewer workshop. There were shoeboxes of all sizes and fortunately Alan, who was there with his daughter, brought the all important duct tape which was needed to seal light leaks in some of the boxes. We must have made about 20 pinhole viewers. There were shoebox versions, oatmeal boxes and just plain boxes. Granny’s Elise had set aside oatmeal and other boxes in case we needed them. Once the pinhole viewers were complete and “first lighted” we enjoyed Venus transit cupcakes the Granny’s crew prepared. There were chocolate and white cake cupcakes which were topped with yellow frosting accented with “Red Hots” candies depicting Venus.

Next it was time for the “Who wants to be an astronomer” quiz. Isaiah, James, Jared and Hannah were prize winners in the quiz. Granny Carol was our scorekeeper and Hunter, Kathryn and the other kids joined the fun.

15 year old Austin who works part time at the restaurant was on assignment as my assistant. He helped with the construction of the pinhole viewers and learned how to “drive” the telescopes by the time we finished.

About 5:30 we walked over to the observing field where the scopes were set up. I was in “low tech” mode using a 50 mm “Galileoscope” with a cardboard shade screen and cardboard shadow box for projection. The other scope was a 10 inch Orion Dobsonian with Kendrick full aperature white light solar filter.

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Since I was hosting a crowd of about 50 people there wasn’t much time for “serious” observing but I had resolved that I was going to try to time first and second contact or at least when Venus’ disc ingressed the solar disc. I logged the planet’s penetration onto the Sun at 21:06:05 UT and second contact at 21:21:27. Prior to second contact I was amazed to see an arc of refracted sunlight over Venus’ western limb while it was still off the Sun’s disc. Venus’ atmosphere! We were not able to detect Venus’ shadow with the pinhole viewers. With “eclipse glasses” and manila folder/aluminized mylar viewers we were able to discern Venus’ shadow on the solar disc. We did manage to do some imaging with a hand held camera on the Galileoscope projection viewer. I put the Galileoscope together over the weekend and configured it with a 20mm Meade Plossl eyepiece. The scope made a very good account of itself. Image above left: Just before sunset I captured this image with the Galileoscope projection

I managed to quiet myself for a few moments to take in the amazing sight we were experiencing. Clouds were intermittent and obscured our view as old Sol lingered at the horizon around 00:25 UT Wednesday. I took a break about 20 minutes later. Quite a few guests expressed an interest in observing Mars, Saturn, the Moon and an ISS pass which concluded our evening at 02:05 UT.

After packing up the gear I got back to the house a little after 11pm local time. The transit would continue for another hour and fifteen minutes. Exhausted, I plopped in my favorite chair, clicked on the TV and switched to NASA TV. I was pleased to see they were carrying the Sun-Earth transit feed from Mauna Kea. As I sat there enjoying the waning moments of the transit I felt a profound connection with Horrocks, Copernicus, Brahe, Halley, Kepler, Galileo, Franklin, Mason and Dixon. I reflected on Le Gentil, Cook and Green who sailed on year long journeys around the world two, three or four centuries ago to observe the celestial spectacle and David Peck Todd who imaged the 1882 transit from the building site at Lick observatory. I was able to watch part of the 2012 transit from the comfort of my living room.

I am very grateful to Carol, Elise, Margey, Jane, Suzie, Austin and everyone at Granny’s. The experience of this transit was made all the more special by our guests. The kids: Hunter, Hannah, Isaiah, James, Jared, Kathryn and others whose names escape me now. Among the “big kids”: Jennifer, Katie, Jessica, Jan, Alan, Frank, Ernie, Ray, David, Terry, and John. There were others but I’m tired and still a little overwhelmed by it all. I was also great to see my long time friends Tim and Alan who made the transit all the more special by stopping by. Finally a shout out to my assistant, Austin, who wants to be a meteorologist. Austin was a great help and quickly learned how to aim the scopes.

I’m already thinking about the next Mercury transit which is only 3 years, 11 months away!

Next: Venus marches east of the Sun for a morning dance with Jupiter

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