What does RA mean in astronomy?
Right ascension, in astronomy, the east–west coordinate by which the position of a celestial body is ordinarily measured; more precisely, it is the angular distance of a body’s hour circle east of the vernal equinox, measured along the celestial equator.
How do you read RA and DEC?
RA (right ascension) and DEC (declination) are to the sky what longitude and latitude are to the surface of the Earth. RA corresponds to east/west direction (like longitude), while Dec measures north/south directions, like latitude. RA is indeed measured in hours, minutes, and seconds.
What are the right ascension and declination of the star Aldebaran in the constellation Taurus?
Its apparent magnitude is about 0.85, making it the 14th brightest star in the night sky. Aldebaran’s location is: Right ascension: 04 hours 35 minutes 55.2 seconds. Declination: +16 degrees 30 minutes 33 seconds.
How is declination measured?
Declination is measured as degrees north or south of the celestial equator. It is common to use either “N” or positive (+) for north declinations, and “S” or negative (-) for south declinations.
Why do stars have more than 1 name?
There are swarms of stars per constellation but only 24 Greek letters. Sometimes one letter is used repeatedly with superscripts to cover several adjacent stars. But as more and more stars needed names because of better sky surveys, astronomers adopted numbers.
What is the zenith?
1: the point of the celestial sphere that is directly opposite the nadir and vertically above the observer — see azimuth illustration. 2: the highest point reached in the heavens by a celestial body.
What does RA Dec mean?
R.A. means “right ascension” and Dec. means “declination”; these are the two parts of the equatorial coordinate system. Astronomers developed it to correspond to longitude and latitude on Earth.
How do you convert RA to Dec degrees?
Convert the right ascension into decimal form using the following formula: hour + minute/60 + second/3600 = decimal value. For example, if the right ascension is 2 hours, 30 minutes and 45 seconds, then this time in decimal form is 2 + 30/60 + 45/3600 = 2.5125. Multiply the decimal time by 15 degrees.
How do I know my longitude?
The Earth rotates one full turn (360º of longitude ) in one day. It therefore turns one degree of longitude in 1/360th of a day, or every four minutes. To calculate your longitude, you therefore simply need to work out the time difference between noon at your location and noon at the Prime Meridian.
Is Pollux a red giant?
Pollux is a star that lies in the constellation Gemini. Along with Castor, Pollux is one of the two main guideposts for the asterism, which is sometimes nicknamed “the twins.” The star is a red giant that has finished fusing hydrogen in its core and is now fusing other lighter elements into heavier ones.
Is Capella a red giant?
It is a red dwarf separated from the pair of G-type giants by a distance of around 10,000 AU. It has its own close companion, an even fainter red dwarf that was 1.8″ away when it was discovered in 1935.
Does Aldebaran twinkle?
If Aldebaran were placed where the sun is now, its surface would extend almost to the orbit of Mercury. Science of Aldebaran. Aldebaran is about 65 light-years away, much closer than the stars of the Hyades with which it misleadingly seems associated. The Hyades are about 150 light-years away.
What is the sun’s declination today?
The Sun is currently in the constellation of Aquarius. The current Right Ascension of The Sun is 22h 46m 25s and the Declination is -07° 47′ 23” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current magnitude of The Sun is -26.76 (JPL).
How do you find declination angle?
The following equation can be used to calculate the declination angle: δ=−23.45°×cos(360/365×(d+10)) where the d is the number of days since the start of the year The declination angle equals zero at the equinoxes (March 22 and September 22), positive during the summer in northern hemisphere and negative during winter
What does a negative declination mean?
A negative number for declination indicates west declination, so you should set your compass so that the orienting arrow for the magnetic needle points to 344°. The example compass in the article is being set to a declination very close to what you need.