The question, in fact, is not a very simple one.

All the necessary information is given in the almanac.
We merely notice that the planet is most favourably seen as an evening star in spring, and as a morning star in autumn.[11] The observer with an equatorial has of course no difficulty in finding Mercury, since he can at once direct his telescope to the proper point of the heavens.

But the observer with an alt-azimuth might fail for years together in obtaining a sight of this interesting planet, if he trusted to unaided naked-eye observations in looking for him.

Copernicus never saw Mercury, though he often looked for him; and Mr.Hind tells me he has seen the planet but once with the naked eye--though this perhaps is not a very remarkable circumstance, since the systematic worker in an observatory seldom has occasion to observe objects with the unaided eye.
By the following method the observer can easily pick up the planet.
Across two uprights (Fig.

10) nail a straight rod, so that when looked at from some fixed point of view the rod may correspond to the sun's path near the time of observation.