Questions tagged [right-ascension]

Questions regarding the second ordinate of the equatorial celestial system.

59 questions
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Calculating the time a star is at my local meridian based on its right ascension

I've been watching an astronomy course on YouTube and I'm struggling to calculate stars' positions based on their right ascension. What I'm trying to achieve: Calculate when a star (Sirius in this example) will be exactly on my local meridian. What…
Pouria P
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Right Ascension of North Celestial Pole

My scope simulator is pointing to the celestial north pole. My position is 41º 27' lat and 2º 15' long. At 12h 43m local time (11h 43m UTC) the coordinates read from the scope are: RA: 16h 14m 25s DE: 90º 00'00" There seems to be a constant 4h 31m…
joaquin
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Right Ascension for epoch 2000 - physical location?

I understand that Right Ascension is a longitude-like celestial coordinate that varies from 0-24hrs, taken from a reference point of the vernal equinox. More specifically, for star maps that are based on the epoch 2000.0, this specifically means…
WillK
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Date and Time of Year given Sun's Right Ascension

Can anyone tell me how to calculate date of year given a specific sun's Right ascension (RA)? I know RA at Vernox (21 March 00hh:00mm:00ss)is 0 degrees. How can I get date and time for a given RA, say 1h 29m 6.69s? Thxs vm
jaoc
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Sidereal time and right ascension

I'm new to astronomy and have to make a star map that displays the stars above a current location. From the information I've pieced together I understand that declination is equal to the current latitude of the observer, however I am slightly…
user16454
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Distance from W(West) to vernal equinox

I am pretty new to astronomy and the project I am currently working on requires some knowledge of equatorial coordinate system. As long as I have been researching this question, I understood that vernal equinox is the origin of this system. At this…
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What is the right ascension overhead at Greenwich at noon on 21 march

My question is seen in the title: What is the right ascension overhead at Greenwich at noon on 21 march I'm a little bit confused since the right ascension is set by the vernal equinox and don't understand how this is related to Greenwich.
Amaluena
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