A spotting scope is a small telescope that has been modified for use by day. A spotting scope differs from an astronomical telescope in several important ways.
First, a spotting scope always produces an upright image whereas a telescope used in astronomy may produce a reversed image or even an upside down image (not a problem for astronomy).
Second, a spotting scope is much smaller in size than an astronomical telescope, mainly for the sake of portability.
Third, a spotting scope is a lower magnification instrument than a telescope, since the atmosphere by day does not allow the high magnifications used in astronomy.
Fourth, a spotting scope is mounted on an ordinary photo tripod, but a telescope for astronomy requires a very specialized mount, often unsuitable for daytime use.
Lastly, many, if not most, spotting scopes are waterproof and fogproof - a rare feature in an astronomical telescope.