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Cees Bassa (cgbassa@astrodon.social)'s status on Sunday, 05-Jan-2025 00:28:40 JST Cees Bassa

For the 4th year in a row, my all-sky camera has been taking an image of the sky above the Netherlands every 15 seconds. Combining these images reveal the length of the night changing throughout the year, the passage of clouds and the motion of the Moon and the Sun through the sky. #astrophotography
In conversation about 2 months ago from astrodon.social permalink
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1. This image shows the hourglass shape of the nights shortening and lengthening from winter to summer and from summer to winter, passing clouds, the Moon passing through the night sky every month (diagonal bands) and the Sun climbing higher in the sky during summer.
  https://media.astrodon.social/media_attachments/files/113/770/317/059/357/999/original/0cf0b65a42cf71d6.png
- Bill repeated this.
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  Javier Jimenez Shaw (jjimenezshaw@mapstodon.space)'s status on Tuesday, 07-Jan-2025 07:00:15 JST Javier Jimenez Shaw
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  @cgbassa This is marvelous! 😍
  It is nice to see how the dates of the earliest and latest sunrises and sunsets of the year do not occur on the dates of the solstices. (Something I learned 20 years ago, that somebody explained to me with the analemma https://en.wikipedia.org/wiki/Analemma#Estimating_sunrise_and_sunset_data )
  In conversation about 2 months ago permalink
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  1. Domain not in remote thumbnail source whitelist: upload.wikimedia.org
    
    Analemma
    
    In astronomy, an analemma (; from Ancient Greek ἀνάλημμα (analēmma) 'support') is a diagram showing the position of the Sun in the sky as seen from a fixed location on Earth at the same mean solar time over the course of a year. The change of position is a result of the shifting of the angle in the sky of the path that the Sun takes in respect to the stars (the ecliptic). The diagram resembles a figure eight. Globes of the Earth often display an analemma as a two-dimensional figure of equation of time ("sun fast") vs. declination of the Sun. The north–south component of the analemma results from the change in the Sun's declination due to the tilt of Earth's axis of rotation as it orbits around the Sun. The east–west component results from the nonuniform rate of change of the Sun's right ascension, governed by the combined effects of Earth's axial tilt and its orbital eccentricity. One can photograph an analemma by keeping a camera at a fixed location and orientation and taking multiple exposures throughout the year, always at the same time of day (disregarding daylight saving time). Analemmas (in the modern sense of the term) have...

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