What can I see tonight?

One of the more common questions everybody has (including us, ngl) is "What are we looking at today?" This is, unfortunately, not very easy to answer. Of course, for the skies we usually observe in (IIT Bombay), the light pollution from the city limits observations to the point that answering the question becomes almost trivial. But that is not the question we want to be answered; and so, no more references shall be made to the disappointingly bright skies of Mumbai (bright skies are bad; dark skies with bright stars are good), at least in this page.

Table of Contents When can you observe When should I go out and observe How can I see X in my telescope Where is Planet X?

When can you observe

There are many things to think about before answering this question. For example, when do you want to observe an object (since time is directly reflected in the motion of the sky, this is the same as asking 'where in the sky do you want your object to be when you observe it'). The 'scientific' answer is whenever it is at a high enough altitude that the atmosphere doesn't mess up your observations. However, let us assume that you don't care about accurate photometry, for this page, and you just want to see pretty things in your telescope/binoculars, or even naked eye. This changes the answer a bit. We no longer want to exclude things below a certain altitude; in fact, it is better to observe a bright star or a bright star cluster (like the Pleiades) near the horizon (a tip courtesy of Prof. Varun Bhalerao), because we get to see sparkly stars changing colour! You also do not want objects near the zenith , unless you have no problem staring straight up for several minutes. The zenith is also the pole for the horizontal system, which means that an altaz mounted telescope is pretty much a nightmare.

You want to observe extended sources when they are fairly high in the sky. Things like planets, nebulae, galaxies and fainter clusters (these objects are basically the bulk of our observing targets through a telescope) come here. A notable exception is the Moon; it is a good sight pretty much anywhere.

When should I go out and observe

At night! Usually around twilight is a good time to start particularly if you want to see Venus or Mercury. Keep an eye on the phase of the Moon. Bright Moon = Bright Sky, which we have established is bad for star gazing, especially when there are clouds.

You should also check if you are in the right time of the year. If your object doesn't come up to a good enough altitude during the night, try again in a few months! A very useful planetarium app that we use to plan out observations is Stellarium

How can I see X in my telescope

This is a question better left for Using a telescope.

Where is Planet X?

The most common questions we get are 'Is Jupiter visible tonight', 'Can we see Saturn's rings?', 'How can I observe Uranus?'. Our answers are usually based on experience; if we didn't see it yesterday, we won't see it today. The best way to find out if you can see a planet is to check online for rise and set times. Unfortunately, to the naked eye, all planets look the same: star-like. To see any actual detail, we must use a telescope. Even a modest 4-inch reflector will reveal the bands on Jupiter, the rings of Saturn and the phases of Venus. However, Uranus and Neptune, as well as the brighter asteroids, are slightly more difficult to find, as they are are not visible with the naked eye, and require star hopping.