Do you know how a planisphere should be used?

If you want to use a planisphere properly you need to own all the planisphere first, obviously, and then a compass.

The planisphere is a map or model that we use to know the appearance of the night sky and the position of the stars and constellations at a given moment. For our latitude we recommend the use of a planisphere adjusted to 40ºN. It is also very useful that it is luminescent, since we are going to use it in dark conditions.

To start we need to adjust it to the local date and time. For that we must rotate the template or external calendar (month and day) until it coincides with the fixed template, the time. This time template is referenced to solar time, that is -1h in winter and -2h in summer.

Once the date is set, we must raise the planisphere and orient it to the north, the indications for east and west must also be referenced to these cardinal points. For this procedure, the compass is indispensable.

The planisphere has a central hole, this hole must coincide with the position of the pole star if we have successfully completed the procedure. In the northern hemisphere this star is the reference, as a fixed position. The other stars circle around you. If we alternate the use of the planisphere with an astronomical telescope we must bear in mind that the image of the telescope is inverted, therefore we must also invert the position of the planisphere.

It should be said that the position of the sun, the moon, the planets, asteroids and comets, are not indicated in a planisphere since their movement and position is independent of the common movement of the stars.

As a complement to the planisphere we can use certain bibliography, such as the Sky Guide. This booklet will be very useful to us, since with it we will know how the position of the celestial stars changes throughout the year, as well as the most important astronomical events, eclipses of the sun, eclipses of the moon, planetary conjunctions, etc ...

The position of the stars, planets and constellations varies each month and we must always take as a reference where they are.