Astronomy Picture of the Day

Explanation: Sometimes falling ice crystals make the atmosphere into a giant lens causing arcs and halos to appear around the Sun or Moon. One Saturday night in 2012 was just such a time near Madrid, Spain, where a winter sky displayed not only a bright Moon but four rare lunar halos. The brightest object, near the top of the featured image, is the Moon. Light from the Moon refracts through tumbling hexagonal ice crystals into a somewhat rare 22-degree halo seen surrounding the Moon. Elongating the 22-degree arc horizontally is a more rare circumscribed halo caused by column ice crystals. Even more rare, some moonlight refracts through more distant tumbling ice crystals to form a (third) rainbow-like arc 46 degrees from the Moon and appearing here just above a picturesque winter landscape. Furthermore, part of a whole 46-degree circular halo is also visible, so that an extremely rare — especially for the Moon — quadruple halo was captured. Far in the background is a famous winter skyscape that includes Sirius, the belt of Orion, and Betelgeuse — visible between the inner and outer arcs. Halos and arcs typically last for minutes to hours, so if you do see one there should be time to invite family, friends or neighbors to share your unusual lensed vista of the sky.

Source: APOD

Astronomy Picture of the Day (7/20/2021)

Thor’s Helmet
July 20, 2021

Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor’s Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages. Heroically sized even for a Norse god, Thor’s Helmet is about 30 light-years across.

In fact, the cosmic head-covering is more like an interstellar bubble, blown with a fast wind from the bright, massive star near the bubble’s center. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away toward the constellation of the Great Overdog.

This remarkably sharp image is a mixed cocktail of data from broadband and narrowband filters, capturing not only natural looking stars but details of the nebula’s filamentary structures. The star in the center of Thor’s Helmet is expected to explode in a spectacular supernova sometime within the next few thousand years.

Navigating to the Moon — Remembering the Apollo Sextant

The Apollo sextant was used in Earth and lunar orbit, as well as while en route between Earth and the Moon. It played different roles in each of those contexts: in orbit around Earth or the Moon, the sextant could be used to compute the spacecraft’s altitude and position; whereas in transit between Earth and the Moon, it could be used to compute the spacecraft’s attitude (orientation), position, and velocity. A proper attitude during the flight to and from the Moon was critical for accurate course corrections and burns to reach the Moon and correctly insert the spacecraft into the desired lunar orbit. The device was used repeatedly throughout the Apollo program across many phases of the missions, up to and including re-entry.

Pretty impressive advanced technology! Also shows how the basics will never be outdated.

Source: Navigating to the Moon — Remembering the Apollo Sextant

State to homeschoolers: Watching eclipse not educational

“In the nearly hour-long home visit, the assistant director told Hope that the trip that her family took to observe the solar eclipse wouldn’t be counted as school time. The school official also belittled her ability to educate her children, stating that even as a professional educator he wasn’t qualified to teach his own children at home,” the report said.

This ‘school official’ is human excrement. I AM qualified to teach anyone anything I know. This includes home schooling my kids, or any kids, through high school. I am a high school graduate. If you aren’t qualified to teach what you know, then your high school diploma is worthless and you should sue your school district.

Source: State to homeschoolers: Watching eclipse not educational

Racial History in the Solar Eclipse Path of Totality – The Atlantic

On August 21, 2017, a total solar eclipse will arrive mid-morning on the coast of Oregon. The moon’s shadow will be about 70 miles wide, and it will race across the country faster than the speed of sound, exiting the eastern seaboard shortly before 3 p.m. local time. It has been dubbed the Great American Eclipse, and along most of its path, there live almost no black people.

The eclipse is racist!

(Hat tip: Bayou Renaissance Man

Source: Racial History in the Solar Eclipse Path of Totality – The Atlantic