from Hacker News

Three Different Types of Twilight

by benknight87 on 9/14/22, 7:22 AM with 12 comments

  • by anovikov on 9/16/22, 4:17 AM

    In addition, there is a notion of "photometric nights" which include, among other requirements, Sun being at least 24 degrees under the horizon. These conditions are necessary to conduct precise photometry, because an extremely tiny amount of scattered sunlight still makes it through when sun is between 18 and 24 degrees. So in a way, we can add "photometric twilight" to the list, although the number of people who are affected worldwide will probably fit into one big room.
  • by perilunar on 9/16/22, 2:07 AM

    I made a web app that shows twilight times: https://sunclock.net

    Also shows sunrise and sunset times, and moon position and phase.

  • by mordechai9000 on 9/16/22, 2:14 AM

    I love the daylight chart they use on this site.

    https://www.timeanddate.com/sun/usa/utqiagvik

    (Scroll down for 2022 Sun Graph for Utqiaġvik)

  • by bananarchist on 9/14/22, 12:11 PM

    Some trivia make people more interested in you. This one will actually probably lose you friends, if my experience is any indicator
  • by dudeinjapan on 9/16/22, 2:56 AM

    I count 4 types, 5 if you consider Breaking Dawn parts 1 and 2 as separate.