Astronomy Equations

Question 1

Circumference of Earth calculation

Answer 1

Measured diamter/circumference of Earth = measured angle/360

Question 2

Diameter of Moon calculation

Answer 2

Diameter of Moon/Diameter of Earth = Time interval from U1 to U2/Time interval from U2 to U4.

Question 3

Longitude Calculation

Answer 3

(LMT-GMT)/4

Question 4

Altitude at upper culmination

Answer 4

Codeclination + latitude

Question 5

Altitude at lower culmination

Answer 5

Codeclination - latitude

Question 6

Codeclination

Answer 6

90 - declination

Question 7

Hour Angle

Answer 7

Local Sidereal Time - Right Ascension

Question 8

Polaris Altitude

Answer 8

Observer’s Latitude

Question 9

Polaris Azimuth

Answer 9

0°

Question 10

Circumpolar Equation

Answer 10

Circumpolar if codeclination<latitude

Question 11

Law of Mass

Answer 11

Constant 1/Constant 2 = Mass 2/Mass 1

Question 12

Factor of Gravity on a Body

Answer 12

1/number of times further away^2

Question 13

Solar Rotation Period Equation

Answer 13

Time interval/solar rotational period = difference in longitude/360

Question 14

Light grasp

Answer 14

Diameter of objective element^2

Question 15

Field of View

Answer 15

Time to cross the field of view/4

Question 16

Heliocentric Parallax

Answer 16

Distance (parsecs) =1/parallax angle (arcsecs)

Question 17

Sidereal Day Length

Answer 17

Length of exposure/length of sidereal day = angle of star arc/360

Question 18

Factor of Brightness

Answer 18

1/number of times further away^2