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Moon and Regulus

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Manage episode 486325057 series 178791
Content provided by McDonald Observatory and Billy Henry. All podcast content including episodes, graphics, and podcast descriptions are uploaded and provided directly by McDonald Observatory and Billy Henry or their podcast platform partner. If you believe someone is using your copyrighted work without your permission, you can follow the process outlined here https://staging.podcastplayer.com/legal.

The Moon has regular dates with the stars. It returns to the same position relative to the stars every 27 days and eight hours. As an example, the Moon cozied up to Regulus, the bright heart of the lion, on May 5th, and it does so again this evening – 27 days, eight hours later. This encounter is especially close as seen from the United States – the Moon and Regulus will appear to almost touch each other.

That time span is known as the lunar sidereal period – “sidereal” meaning “related to the stars.”

The planets have their own sidereal periods.

Mars, for example, returns to the same point relative to the stars every 22 and a half months. Tonight, Mars is well to the lower right of Regulus, and looks like an orange star. It’ll return to almost the same position in April of 2027. The match won’t be exact because our viewing angle to the Red Planet changes a bit from year to year.

The sidereal period is different from the period relative to the Sun – a difference caused by Earth’s own orbital motion. For the Moon, that period lasts 29 and a half days – the length of a cycle of phases. And for Mars, the Sun-related period is almost 26 months. That’s how long it takes Mars to return to the same angle from the Sun – part of the precise but sometimes confusing motions in the night sky.

More about the motions of the planets tomorrow.

Script by Damond Benningfield

  continue reading

2884 episodes

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Moon and Regulus

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Manage episode 486325057 series 178791
Content provided by McDonald Observatory and Billy Henry. All podcast content including episodes, graphics, and podcast descriptions are uploaded and provided directly by McDonald Observatory and Billy Henry or their podcast platform partner. If you believe someone is using your copyrighted work without your permission, you can follow the process outlined here https://staging.podcastplayer.com/legal.

The Moon has regular dates with the stars. It returns to the same position relative to the stars every 27 days and eight hours. As an example, the Moon cozied up to Regulus, the bright heart of the lion, on May 5th, and it does so again this evening – 27 days, eight hours later. This encounter is especially close as seen from the United States – the Moon and Regulus will appear to almost touch each other.

That time span is known as the lunar sidereal period – “sidereal” meaning “related to the stars.”

The planets have their own sidereal periods.

Mars, for example, returns to the same point relative to the stars every 22 and a half months. Tonight, Mars is well to the lower right of Regulus, and looks like an orange star. It’ll return to almost the same position in April of 2027. The match won’t be exact because our viewing angle to the Red Planet changes a bit from year to year.

The sidereal period is different from the period relative to the Sun – a difference caused by Earth’s own orbital motion. For the Moon, that period lasts 29 and a half days – the length of a cycle of phases. And for Mars, the Sun-related period is almost 26 months. That’s how long it takes Mars to return to the same angle from the Sun – part of the precise but sometimes confusing motions in the night sky.

More about the motions of the planets tomorrow.

Script by Damond Benningfield

  continue reading

2884 episodes

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