BBC Sky at Night Magazine

Steve’s top tip

- Steve Richards is a keen astro imager and an astronomy equipment expert

Do I need to let my telescope cool down before observing?

When you take your telescope outside for an observing session, the column of air within the telescope generates a micro version of atmospheri­c disturbanc­e, in the form of tube currents, as it tries to reach temperatur­e equilibriu­m with the air outside. These tube currents distort and diffract the light from celestial objects, robbing your view of fine detail and giving stars distorted and smeared shapes.

To stop this from happening, it is important to set up your telescope outside some time before you intend to start observing to allow it to cool down to the temperatur­e of the surroundin­g air.

Newspapers in English

Newspapers from United Kingdom