Okay, this question is actually quite simple and requires some background on the relations between gravity and time.
The property that can be used to answer this question is :
Time is affected by gravity in the following way : Imagine you are on an exoplanet. The gravity there is twice that gravity here on Earth. Now, assuming that we take Earth Time as ...
Why does the Moon never set in Svalbard, Norway?
As can be deduced from the diagram or knowing that the Moon's orbit is inclined by only 5 degrees with respect to the ecliptic while the Earth's axis is inclined by more than 23 degrees, the moon can not always be above the horizon, nor always be below it. Over the course of about 20 years all ...
If you look on the main SIMBAD page, you will see the following in the box titled "Content":
The SIMBAD astronomical database provides basic data, cross-identifications, bibliography and measurements for astronomical objects outside the solar system.
The Moon and the Sun are inside the Solar System, thus they are out-of-scope for ...
The manual says the original eyepieces had 1¼ inch barrels and focal lengths of 25 mm, 20 mm, 12.5 mm, 8 mm (all reasonable) and 4 mm (not so much).
If I had to pick two replacements for a beginner, I'd get a 25 mm and a 10 mm.
You can probably get an entry-level Plössl by Meade, Celestron, or Orion for US \$20-25 from the Cloudy Nights classifieds or \$30-...
For the moon, you would normally not need a very high power eyepiece. 20mm would seem sufficient, on a telescope with a focal ratio of f/9.8. As this is a refracting telescope, if you get too much magnification you end up just magnifying the chromatic aberration. Smaller numbers mean more magnification.
Planets would require more magnification, on the other ...
TL;DR: because of the Earth's atmosphere.
When the Moon is low on the horizon, the light we receive from the Moon has to go through a lot of layers of the atmosphere. Rayleigh scattering makes this light more yellowish/orangish, for the same reason sunsets look orange.
A very thin layer of clouds can also change the appearance of the Moon.
Sometimes, the ...
Since the Moon is tidally locked to the Earth, it rotates with the same orbital period as it orbits the Earth. Thus, tracking the Moon's rotational velocity is essentially the same thing as measuring the changes in its orbit - if you know one, then you know the other.
The recession of the Moon has been measured using laser ranging (see links in the answer ...
This page contains all the formulas for calculating Sun position in sky as seen from any planet in Solar System, with plenty of details and explanations:
This page shows and explains Analemma and Equation of Time for Earth, and shows analemmas for all planets: