Increase for 2.5 inch focus base, 1.25 inch extra length | Starlight

Can you get focus with a camera or without a diagonal if the focal point is further out than your focus ring can extend? A 2.5-inch extension for your focus ring solves that by placing the focus ring further from the tube.

This extension tube from Starlight Instruments has a diameter of 2.5 inches and sits between the base and the focus lens. The base is therefore 1.25 inches longer, which is more than 3 cm. This often plays a role when Newton reflector telescopes, where the focus is on a base on the tube.

First, measure how much extra length you really need. Too much magnification costs you the ability to focus inward, and then you can’t get any focus with a diagonal or some of the eyepieces. If you still don’t understand why your image isn’t sharp, read on. Why you sometimes don't see anything.

If you need more length, there is also one available. 2.25 inch increase.