Do Cassegrain telescopes need collimation?

Precise collimation is essential to good performance for any Schmidt-Cassegrain telescope. For SCTs, it’s done by small adjustments to the tilt and position of the secondary mirror in its cell.

Why do telescopes need to be collimated?

Collimation is the process of aligning all components in a telescope to bring light to its best focus. Mechanical collimation is necessary when the physical components in your scope don’t line up properly — a focuser isn’t square to the tube, a mirror isn’t centered in the tube, or a secondary mirror is misaligned.

Do you have to collimate a Schmidt Cassegrain telescope?

If done right, collimation should only be necessary every few months. If you find it necessary to collimate your telescope every few weeks, the mirror is probably not being locked down properly after adjustment.

How do I know if my SCT needs collimation?

There will be brighter rings of light surrounded by a dark hole (i.e. the shadow from the secondary obstruction) in the center (see Figure 2). If the telescope is collimated, the hole should appear centered relative to the rings. If the hole is not centered, then adjustment to the collimation is needed (see Figure 3).

What is the definition of collimated?

verb (used with object), col·li·mat·ed, col·li·mat·ing. to bring into line; make parallel. to adjust accurately the line of sight of (a telescope).

How does Schmidt Cassegrain telescope work?

Schmidt-Cassegrain telescopes are a catadioptric design, meaning they use both lenses and mirrors. It is reflected from a concave primary mirror at the back of the scope which focuses the light to the front of the telescope where it is reflected again by a smaller, convex secondary mirror.

How do you focus a Schmidt Cassegrain telescope?

Turn the knob in the opposite direction until the image is sharp. Once an image is in focus, turn the knob clockwise to focus on a closer object and counterclockwise for a more distant object. A single turn of the focusing knob moves the primary mirror only slightly.

Do refractor telescopes need collimation?

Collimation is the alignment of the optics in your telescope. If the optics are not properly aligned, they cannot bring starlight to an accurate focus. Refractor telescopes are permanently collimated at the factory and therefore should never require collimation.