Jump to content

How much of the celestial sphere do you see per 24hr as opposed to per year?

Featured Replies

Quick question to check I'm visualising this correctly:

 

Over the course of a day/night cycle, from any point on the Earth you actually see as much of the celestial sphere as you are ever going to during the year (ignoring precession of equinoxes etc).

 

The only thing that stops you seeing some stars is the inconvenience of the Sun; you have to wait for it to "move along" the ecliptic and stop blinding you with pesky daylight.

 

Is that correct?

Right. The earth's orientation with respect to the "fixed" stars does not change over the course of the year.

 

I thought that the tilt of the Earth affected what stars are visible at what times.

I thought that the tilt of the Earth affected what stars are visible at what times.

 

Yes and no. The orientation of the Earth's axis is nearly constant with respect to the fixed stars. Polaris is always in the same spot in the sky, day and night, summer and winter, and all stars (except the sun, of course) follow the same path across the sky (that is, concentric circles around Polaris) every sidereal day. What you actually get to see with the naked eye depends on the presence or absence of the sun, but that is affected by the Earth's tilt.

Archived

This topic is now archived and is closed to further replies.

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.

Configure browser push notifications

Chrome (Android)
  1. Tap the lock icon next to the address bar.
  2. Tap Permissions → Notifications.
  3. Adjust your preference.
Chrome (Desktop)
  1. Click the padlock icon in the address bar.
  2. Select Site settings.
  3. Find Notifications and adjust your preference.