Summer Triangle rising before Sunrise

Event Date: January 1st (2013)

Time: 7:00 AM

Brief

   Happy New [Calendar] Year!  Okay, so there are different calendars, yet in this case, I am just emphasizing that I am talking about that starting with the January date above; not the astronomical New Year date, which happens on the 1-year anniversary of this blog: March 20th, for the next equinox--vernal for this hemisphere.

   On a different note, let's return our attention to the (so-called) summer triangle: I half-kiddingly use that parenthesized wording, since we are about exactly a half-year's worth of weeks and months from when the triangle has its best summer appearance in the sky, and high enough all night long to view from just about anywhere in North America and the equatorial latitudes of the southern hemisphere.  During this month, we will lose Altair in the evening sky completely; Vega is low in atmospheric pollution during early evening hours (yet refracting light beautifully with rainbow patterns); Deneb is dimly setting higher in the west.  However, what about the morning??  Take a look below!

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   Back when I showed the Triangle last March and April morning skies, during my first 20 or so entries, it was much higher, with 1-2 hours of darkness left for viewing.  Vega and Deneb can still be seen in dark skies now, with the date of this entry more than 9 months after my first ones.  As seen with the celestial guidelines, both of those stars have made slow "arcs" from the horizon.  If seen from further north, these two stars would be seen rising even more slowly, with the changes in altitude more gradual at first.  As for the third star to rise, Altair, it is barely visible in the morning during the first week of this month, yet will rise about four minutes earlier each day.  Being the least-north star, at only 9º compared to about 38º and 45º for Vega and Deneb respectively, Altair spends more time below the horizon than either of the other two, when viewed from mid-northern latitudes.

   Watch Deneb and Vega weekly, and eventually Altair.  By springtime, they will be high above the horizon--long enough before Sunlight washes them out--to see with the eyes alone.  This will act as a preview of how we will see them in the summer evening skies!