Friday, July 31, 2015

Once in a Blue Moon...

When someone says "Once in a Blue Moon," you know what they mean: rare, seldom, even absurd.

This year it means "the end of July." For the second time in July, 2015, the Moon is about to become full.  There was one full Moon on July 2nd, and the second on July 31st.  The above shot is one I took on that evening... photoshopped blue (LOL). 

According to modern folklore, the second full Moon in a calendar month is "blue." 

Strange but true: Sometimes the Moon really turns blue. 

You can see a blue moon several ways. The image below was photographed on July 25th by Giuseppe Petricca of Pisa, Italy. In it he increased the saturation of the natural colors of the Moon.

The areas that emerge in a strong blue color (mostly in the Maria regions) are areas rich in Titanium, proof of ancient lava flows, and those contain more titanium in contrast to the Maria orange regions, that are poorer of this material.

A truly-blue Moon can be seen after a major a volcanic eruption. Back in 1883, for example, people saw blue moons almost every night after the Indonesian volcano Krakatoa exploded with the force of a 100-megaton nuclear bomb. Plumes of ash rose to the very top of Earth's atmosphere, and the Moon became an azure-colored disk.

Krakatoa's ash was the reason. Some of the plumes were filled with particles 1 micron wide, about the same as the wavelength of red light.  Particles of this special size strongly scatter red light, while allowing blue light to pass through. Krakatoa's clouds thus acted like a blue filter. People also saw blue-colored Moons in 1983 after the eruption of the El Chichon volcano in Mexico. And there are reports of blue Moons caused by Mt. St. Helens in 1980 and Mount Pinatubo in 1991.

Forest fires can do the same trick.  A famous example is the giant muskeg fire of Sept. 1953 in Alberta, Canada.  Clouds of smoke containing micron-sized oil droplets produced lavender suns and blue Moons all the way from North America to England. 

Comments or questions are always welcomed (well, as least nice ones)!

Monday, July 20, 2015

Crescent Moon and Earthshine

A beautiful evening in the high desert of central Oregon!
The crescent Moon was hanging low in the west after sunset so I thought I would take two photos of it. The first is a standard shot with the exposure set for the sunlit side and the second set to show the light that is hitting the Moon that has bounced from the Sun, off our planet, off the Moon and back to us! This is visible with the "naked" eye and even with binoculars! Give it a try!

Comments or questions are always welcomed (well, as least nice ones)!

Saturday, July 18, 2015

Ah, SUMMER again! The Ring Nebula

Summer has returned with clear skies and I am back in the observatory again! Yea!
But I am out of practice with my equipment and so a lot of time was spent recalibrating and refreshing my poor memory, lol. But I did catch Saturn (not all that exciting now since it is dropping low in the southwest) and the Ring Nebula (high overhead). Didn't do any regular visual viewing (eyeball to the eyepiece) but did do some astrovideo (see photo of the Ring Nebula below) with my old Celestron C8 scope. Lot's of work still to do to bring my technique back up. Stay tuned!

Wednesday, July 1, 2015

Jupiter - Venus Conjunction (on closest approach to each other) and The Nearly Full Moon

The planets were even closer this evening than the previous! This was taken with the same 1000mm lens as the previous night's.

Here is a map of Jupiter's moons seen in the above shot:

Here is the previous night's shot, side by side, with tonights:

To give some perspective, here is a wide angle shot from a friend:

NOTE: Some media reports have compared the June 30, 2015, conjunction to the 2 B.C. conjunction of the same planets often identified as the "Christmas Star" reported in the book of Matthew. In fact, there is no comparison. The conjunction of 2 B.C. was almost 200 times tighter than last night's meeting. In "The Star of Bethlehem: An Astronomical and Historical Perspective," Susan S. Carroll writes:
On June 17, 2 BC, Venus and Jupiter joined .... in the constellation Leo. The two planets were at best 6” arcseconds apart; some calculations indicate that they actually overlapped each other. This conjunction occurred during the evening and would have appeared as one very bright star. Even if they were 6” arcseconds apart, it would have required the sharpest of eyes to split the two, because of their brightness.
By the numbers: The June 30, 2015, conjunction was 0.3 degrees (1080 arcseconds) wide. The 2 B.C. conjunction was no more than 0.002 degrees (6 arcseconds) wide. Last night was beautiful, but the Christmas Star blew tonight's away!

The Moon was especially bright and beautiful last night and deserving of inclusion in this blog!