What Planets Are Visible Tonight?

Almost always one of four things:

1. Too much magnification. Every telescope has a limit of about 2× its aperture in millimetres. A 70mm scope tops out near 140x. Beyond that you only magnify blur. Switch to the Eyepiece View tab above to see this effect simulated live.
2. The scope is still warm. Carry it outside 30–45 minutes before observing so the optics cool to air temperature.
3. Unsteady air. Looking over rooftops, AC units or hot roads adds shimmer. Objects low on the horizon look worse because you look through more air.
4. Focus or collimation. Focus slowly on a bright star until it is the smallest possible point. Reflectors may need their mirrors aligned (collimated).

At Full Moon the Sun shines straight onto the surface, so there are no shadows and craters look flat. The best views come a few days either side of First and Last Quarter (the "half Moon"). Look along the terminator, the line between light and dark, where long shadows make crater walls and mountains stand out.

Your pupils open within seconds, but the chemical in your eyes that handles dim light (rhodopsin) needs 20–30 minutes to build up. One glance at a white phone screen resets much of it. That is why this site uses a dark interface and offers Red Mode: red light affects night vision far less than white or blue light. Turn your screen brightness down as well.

Aperture (the width of the main lens or mirror) decides how much light and detail a telescope collects. Magnification only enlarges what the aperture gathers. A box that advertises "675x power" on a 60mm telescope is marketing: the realistic maximum is about 120x. When choosing a telescope, compare aperture, not magnification.

A 2x Barlow sits in front of an eyepiece and doubles its magnification. A 10mm eyepiece on a 900mm telescope gives 90x; with a 2x Barlow it gives 180x. It is useful, but it is also the most common way beginners go past their telescope's limit.

Yes. The Moon, Venus, Jupiter, Saturn, Mars, bright double stars (like Albireo) and bright open clusters (like the Pleiades) cut through city light easily. Faint galaxies need darker skies. Switch to "Naked Eye" mode above to see what is visible without equipment.

No, never, unless you use a certified solar filter that covers the front of the telescope. Even a brief look through an unfiltered telescope can cause permanent eye damage.