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01/07/2020 – Ephemeris – What the heck is an ephemeris? Plus my Betelgeuse update

7 Jan 2020, 05:01 UTC
01/07/2020 – Ephemeris – What the heck is an ephemeris? Plus my Betelgeuse update
(200 words excerpt, click title or image to see full post)

Ephemeris for Tuesday, January 7th. Today the Sun will be up for 8 hours and 58 minutes, setting at 5:18, and it will rise tomorrow at 8:19. The Moon, 3 days before full, will set at 6:09 tomorrow morning.
What the heck is an ephemeris? According to Wikipedia: “In astronomy and celestial navigation, an ephemeris (plural: ephemerides; from Latin ephemeris, meaning ‘diary’, from the Greek,… meaning ‘diary, <or> journal’) gives the positions of… astronomical objects… at a given time or times. Historically, positions were given as printed tables of values, given at regular intervals of date and time.” My tables are now databases which I generate for the year during the prior December from published algorithms. I will show all on my blog today: It’s at bobmoler<dot>wordpress<dot>com. (You are already here) I used to have to interpolate values from printed ephemerides for the first 5 or so years.
The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addenda
An Ephemeris Example
Here’s an ephemeris for the Interstellar comet for 2I/Borisov AKA C/2019 Q4 (Borisov) from the Jet Propulsion Laboratory’s (JPL) Horizons system.
R.A. is right ascension – East-west position in the ...

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