Telescope

Telescopes exist in The Sims and The Sims 2. They can be bought in buy mode. Using the telescope is Fun and increases your Logic.

Sims 1

The Horrorwitz 'Star-Track' Outdoor Telescope is a good way of increasing your Sim's Logic. However, if your Sim spends a long time looking through it (two or three points without taking a break), he or she will be abducted by aliens! A blue sphere will appear and your Sim will vanish for a few hours. When they return, their personalities will have turned upside down and they will think about aliens for quite a while afterward.

Sims 2

In The Sims 2, there are 2 telescopes, one cheap and one expensive. The Astrowonder (§550) and the Farstar e3 (§2100). But the price isn't the biggest difference - Sims using the Astrowonder won't ever be abducted, but with the Farstar it's possible. A male Sim who gets abducted may come back pregnant.

In The Sims 2: FreeTime, all of the telescope actions have a chance of alien abduction, but the Aspiration Benefit for Knowledge, Summon Aliens, allows your Sim to create a spotlight with a flashlight and the telescope, giving them a huge chance of abduction. In FreeTime, your Sims can also earn money discovering new celestial and astral bodies.

Using either telescope during daylight and accidentally (or "accidentally", with mods) looking at a Sim through the telescope will make those neighbors mad at you.