Archive for August, 2012

The next full Moon occurs on Friday, August 31 at 8:58 AM CDT.  This is the second full Moon for August 2012.  For a discussion of blue moons, see my August 1 post. 

I took this photo of the nearly full (waxing gibbous) Moon last night (8/29/12) through our Celestron Nexstar 130 equipped with the variable polarizing filter.

Tycho crater with its prominent rays is visible near the top.

This weekend saw the passing of Neil Armstrong, the first human to set foot on another celestial body, commander of a mission that was the culmination of arguably one of the greatest technological achievements in human history.  He was 82.  Much more at the link below. 

http://www.msnbc.msn.com/id/48792135/ns/technology_and_science-space/

Venus achieves greatest elongation today which means this is the farthest it will appear from the Sun.  You can view it still in eastern sky before sunrise.  If you view it through a telescope, Venus appears half lit.  This photo is from yesterday morning so it’s not quite half lit, but you can compare it to the photo I posted on July 31.

From today forward it will appear lower in the sky with each passing day.  Through the telescope it will appear more gibbous, but will dim as it continues to pull away from us and will eventually swing behind the Sun from our perspective.

The late evening hours of Saturday, August 11 and the early morning hours of Sunday August 12 coincide with the peak of the Perseid meteor shower this year.  It is arguably the best meteor shower of the year.  With rates of about 1 meteor per minute at peak viewing it is slightly behind the average peak rates for the Geminids in December, but many find summer viewing in the early morning hours preferable to winter viewing.  Though named for appearing out of the constellation Perseus rising in the northeast, you can generally just look skyward to see these meteors.  The best viewing is typically from midnight to the pre-dawn hours, but don’t be afraid to go out earlier to try and catch a stray meteor.  The waning crescent Moon rises in the early morning hours of August 12, but shouldn’t interfere too much with viewing.  Also don’t shy away from looking prior to and after this weekend, as the Perseids can last for several weeks.

One of the better shows in the night sky unfolds above the southwest horizon just after sunset over the next several evenings.  Saturn, Spica, and Mars are the three bightest objects in that part of the sky and some of the first to appear as twilight fades.  Tonight they form a near perfect equilateral triangle.  This is a great opportunity to test your ability to discern colors.  Saturn is the highest point in the triangle and appears golden yellow.  Spica is almost directly below it and takes on a blueish hue.  Mars is the farthest to the west at this point and is distinctly red.  Watch over the next several evenings as Mars moves towards Saturn and Spica and the triangle collapses.  The three will line up around August 13 and 14.

I have compiled some of the better viewing opportunities for the International Space Station (ISS) for the general area around Waterloo, IA in the table below.  The directions indicated are for horizons.  The ISS will arrive in view and depart from view at a point above the indicated horizon.  Because it is very bright and moving quickly across the sky, it is difficult to miss if you are looking in the correct general vicinity at the right time of course.   Only viewing opportunities of 4 minutes or longer are listed in the table.

For viewing opportunities at your location, more detailed information on the opportunities listed, or for additional viewing opportunities be sure to visit the following link and enter the pertinent information for your location:

http://spaceflight.nasa.gov/realdata/sightings/

You can enjoy the full Moon this evening, August 1 (10:27 PM CDT) and again on August 31.  

You’ve probably heard the phrase “once in a blue moon” used to describe a rare occurrence or event.  It has become popular to refer to the second full Moon in a month as a blue moon because it does occur relatively infrequently.  However, at once every 2.5 years or so, it is certainly not as rare as some astronomical events such as a transit of Venus for example.  As it turns out, this usage is perhaps based on a misinterpretation that was published in Sky & Telescope magazine in 1946.  You can read about it here:

http://www.skyandtelescope.com/observing/objects/moon/3304131.html

So what does a blue moon actually refer to?  Well, it could refer to a Moon that literally appears blue due to atmospheric phenomena such as particulates being present.  This is indeed a rare occurrence.  The article above goes on to provide another interpretation used by the Maine Farmers’ Almanac that defines a blue Moon as the third full Moon in a season that contains four full Moons.  Since a season is traditionally about three months, seasons that contain four full Moons would be worth noting.  This interpretation is complicated by different definitions of “seasons.”  Seasons can be defined by the solstices and equinoxes, or, as in the Maine Farmers Almanac, they can be defined by historical calendar systems. 

So here’s the kicker, the August 31 full Moon in 2012 is technically not a blue moon – the second full Moon in a month is not a formal definition of a blue moon and the next full Moon occurs after the September equinox meaning only three occurred in our summer season.  Unless of course, the August 31 full Moon actually appears blue.