This morning the planet Mercury is at maximum western elongation. This means we will be able to see Mercury in the early morning just before sunrise especially for the next few days.
Yes, western elongation means Mercury will be in the eastern sky before sunrise. It can be a little confusing at first. The western/eastern elongation is the position relative to the Sun not the Earth.
So western elongation means Mercury is west of the sun and that being true will rise in our eastern sky before the sun. Mercury this morning will reach an altitude of 22 degrees before sunrise. If you have a good view of the eastern sky you will get to see it (for the next few days at least) in the twilight before the Sun gets too bright. I know, it’s early morning for the northern hemisphere but so worth it. I am pretty close to a mountain range and that interferes so I’m taking a drive to get a better look IF the clouds stay away.
In September the planet will reach eastern elongation so it will appear in the western sky just after sunset.
Check it out if you can.
NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Yesterday was the anniversary of the discovery of Pluto’s moon Charon. The moon was found by astronomer James Christy while using the 1.55 meter telescope at the US Naval Observatory Flagstaff Station on 22 June 1978 and announced to the world on 07 July 1978 by the IAU.
Above is the image the moon was spotted in. The image above is Pluto, the image on the left shows a “bulge” near the top that is not in the iamge on the right. The so-called bulge would appear and disappear over time and the period between subsequent “bulges” corresponded to the rotational period of Pluto.
It also turns out this “bulge” was seen and confirmed in hindsight on photographic plates going back to 29 April 1965.
Just think in a few short weeks we will be treated to a very good look at this moon. Quite a difference between then and now already and we haven’t seen anything yet!
Image: USNO / NASA
Today the Sun reaches its most northern point in the sky in the northern hemisphere and the lowest in the southern hemisphere.
Put another way, for the northern hemisphere: the June solstice is when the subsolar point or that point where the sun is perceived to be directly over head, is at the northern most latitude it will attain before due to the tilt of the Earth on its axis and is on the Tropic of Cancer (23.44 deg). After the June Solstice the Sun will day by day become lower in the northern sky until the December solstice when it rises to its lowest point of the year.
The southern hemisphere experiences the opposite, so today the Sun is at its lowest point and after today will gradually reach higher in sky until the December solstice.
The moment of the June Solstice occurred today concurrent with the publishing of this post at 16:38 UTC. US Naval Observatory.
Note: I am going by the USNO time, it’s being reported in other media the time is 16:39 UTC – see timeanddate.com
My typical June solstice tradition is to take a nice long walk at sunrise, heavy rain made me skip the walk.
Image: Creative Commons
For those of you who don’t know, Venetia Burney Phair was an accountant and taught economics and math to school girls.
She at age 11 is the person who gave Pluto its name. This interview was recorded in 2006.
Sadly Venetia passed away on 30 April 2009.
This interview and more is available at the New Horizons site.