Search results
Results from the WOW.Com Content Network
The Bortle dark-sky scale (usually referred to as simply the Bortle scale) is a nine-level numeric scale that measures the night sky's brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution .
John E. Bortle is an American amateur astronomer. He is best known for creating the Bortle scale to quantify the darkness of the night sky. Bortle has made a special study of comets. He has recorded thousands of observations relating to more than 300 comets. From 1977 until 1994 he authored the monthly '"Comet Digest" in Sky and Telescope magazine.
The scale used to indicate magnitude originates in the Hellenistic practice of dividing stars visible to the naked eye into six magnitudes. The brightest stars in the night sky were said to be of first magnitude ( m = 1), whereas the faintest were of sixth magnitude ( m = 6), which is the limit of human visual perception (without the aid of a ...
The limiting magnitude for naked eye visibility refers to the faintest stars that can be seen with the unaided eye near the zenith on clear moonless nights. The quantity is most often used as an overall indicator of sky brightness, in that light polluted and humid areas generally have brighter limiting magnitudes than remote desert or high altitude areas.
This scale is widely referred to by various names, including very commonly "Bortle scale". A large number of the instances of "Bortle Dark-Sky Scale" in books are references to Bortle's paper title "Introducing the Bortle Dark-Sky Scale", which is usually but not always capitalized.
What links here; Related changes; Upload file; Special pages; Permanent link; Page information; Cite this page; Get shortened URL; Download QR code
On clear nights around new moon, the sky darkness of Joshua Tree is rated a class 2–4 on the Bortle scale. [51] [52] This ranges from an "average dark sky" (class 2) in the easternmost region of the park to a sky quality typical of a rural/suburban transition (class 4) in the western regions near Palm Springs.
Calamity James, a British comic book character from The Beano; Calamity Jane, a 1953 film based on the person; Calamity Town, a 1942 novel by Ellery Queen; The Calamity, a central plot point for the 2011 video game Bastion; Calamity, a mod for the 2011 video game Terraria "Calamity", a song by Zayn from his 2021 album Nobody Is Listening