- Practical Exercise 1 RADIANS OR DEGREES?
- Practical Exercise 2 MARS IN OPPOSITION AND QUADRATURE
- Practical Exercise 3 MEASURING MERCURY AND VENUS
- Practical Exercise 4 “MERCUAN”
- Practical Exercise 5 THE EARTH FROM MARS
- Practical Exercise 6 HOW BIG IS THE MOON?
- Practical Exercise 7 THE MOON AGAIN
- Practical Exercise 8 PARAMETERS OF PLANET TRAJECTORIES
- Practical Exercise 9 LIKE FROM ANOTHER PLANET...
- Practical Exercise 10 FEET FIRMLY ON THE EARTH...
- Practical Exercise 11 GREEK, HOW BIG IS THE EARTH?
- Practical Exercise 12 THE MOON IN ACTION FOR THE THIRD TIME
Practical Exercise 7: THE MOON AGAIN
ahe measurement showed that the angular size (average) of the Moon in perigee is θ☽per = 33,5' and in apogee is θ☽per = 33,5' and in apogee is θ☽apo = 29,9'.ahe radius of the Moon is θ☽per = 33,5' and in apogee it is θ☽apo = 29,9'. and in apogee it is R☽ = 1 737 km, determine the numerical eccentricity of the elliptic orbit and its main half-axis.
Answer:
The key is to start from the definition of angular size:
a teda
By modifying the last equation we get: 
.
ahe actual value of the numerical eccentricity is 0,055. The trajectory is therefore almost circular.
where 
. We determine the main half-axis based on this relation 
, i.e. 
, where . After substitution we get a ≐ 378 000 km. We can check the result by using the second relation (for apogee): 
, kde . After substitution we get a ≐ 378 000 km. VWe can check the result by using the second relation (for apogee):
, where 
, where . After substitution we get a ≐ 378 000 km.
We can check the result by using the second relation (for apogee):
.