You will find I replaced photographs in the original post and well, all the major elements of Cancer are labeled. Here is an explanation of the new elements.
You can now trace the “Y” constellation pattern, with Alpha and Beta Chancri (Latin for “of Cancer”) the two claws and Iota the tail. Both elemetns of Iota, a visual binary star system, are there. They are wonderful viewed with a telescope. Near Alpha is M67 (Messier Object 67), another galactic cluster of gravitationally bound stars. It is quite faint in this photograph.
Colored lights of our skies are a trigger for the imagination. The sky is a storybook to be written by the mind and passed along in language. The 3,000 observable stars and planets visible on any one moonless, clear night away from artificial lights draw on the human obsessional skill for pattern recognition.
Over millennia, stars along the path of the planets and sun through the sky held a special place for careful observers. Twelve patterns were imagined, each a named constellation. The word “constellation” means “to know from the stars.” Indeed, we can know much from the constellations. For example, it is winter in the northern hemisphere when the constellation “Cancer” (The Crab) is high in the night sky.
On the evening of January 20/21, 2019 the full moon climbed from the horizon (Click this link for the first post of this series “Total Lunar Eclipse of 2019…”) to a point high overhead were it appeared to float among the stars of Cancer, the crab. On the way, the disk darkened as its orbital path brought it into the earth’s shadow. The surrounding stars emerged from the darkening full moon glow. I captured the sight using a Canon dslr, the Canon EF 24 mm f/1.4L II USM lens mounted on a tripod by setting the ISO to 3200 to reduce the exposure to 1.3 second and placing the auto exposure area (a feature of the dslr/lens combination) away from the full moon.
Additionally, the moon is overexposed on the original image, for the following I used Photoshop to cut and paste the moon from the last photograph of this blog, reduced it to the approximate angular diameter of the moon and pasted it over the overexposed disk. There are better astrophotography images of this event, this image is mine to use and adequate for this purpose.
The Moon on the Crab’s back
Cancer is difficult to trace, the constituent stars are all dim. Hint: click on any of the following photographs and a new page will open with a larger resolution image. What is striking in the following photograph are the number of apparently paired stars. Our sun is an exception, it is not part of a star system; even so, most of these pairings are line of sight, not physical star systems. For example, starting from the “red” moon there is a faint star, “Delta” of Cancer. Trace an imaginary line between the moon and Delta, in your mind move the line down and a little to the right to a pair of dim stars, “Nu” and “Gamma” of Cancer (left to right). The two are not a system, being 390 and 181 light years away. Each is a multiple star system in itself as is Delta. The three are on the back of Cancer, with two stars on the upper right being “Alpha” and “Beta”.
A most interesting object of this photograph, well worth the price of binoculars, is between Nu and Gamma and a little higher, towards the moon. It was what I saw the first time viewing this photograph: a cluster of stars called “The Beehive.” This was how I identified the location of the moon on the back of this crab.
For the following photograph I cut/pasted/enlarged a square with the (enhanced) Moon, Delta. Nu and Gamma, below, with the Beehive between them. See that the stars, though “fuzzy”, have colors. Delta is a orange giant, also known as the “Southern Donkey”. Gamma, the “Northern Donkey,” and NU are white. The back of the Crab holds a two donkeys eating from a manger, a Galactic Stellar Cluster name “The Beehive.” This night the moon joined the feast.
With binoculars (or telescope with a wide field eyepiece), the Beehive is a glorious spectacle of 1,000 gravitationally bound stars, a mixture of colors from blue to red. It was one of the first objects Galileo viewed through the telescope, picking out 40 stars. In later years it was here we found the first planets orbiting sun-like (i.e. having the characteristics of our yellow star) stars within a stellar cluster. In spite of being 600+ light years distant the Beehive was known since ancient times, being visible without a telescope in clear, dark skies.
The Total Eclipse
A glorious moon at full totality is captured in the following two photographs. I used the dslr at 3200 ISO with the Canon EF 70-300mm f/4-5.6L lens at 300 mm. Setting the exposure area to the Moon, the exposure was 3.2 seconds.
In the first photograph, I especially enjoy the effect modeling of the shadows does to make the disk appear round. The field of view does not include Delta, Gamma, Nu or the Beehive. At this time I was not aware how close the Beehive was, or even that the Moon was in Cancer. The beauty of the moon floating among the stars is apparent.