Collimation eyepiece for refractors

Some people think that the biggest disadvantage of a Newtonian telescope is that it needs regular checking of collimation. This step can be done quickly and easily with some practice.

The collimation can be done in three steps: the focuser, the secondary and then the primary mirror needs to be adjusted.

1. Make sure that the secondary mirrors center falls right below the optical axis of the focuser.

2. Make sure that the light on the eyepiece optical axis falls exactly to the center of the primary mirror

3. Make sure that the primary mirror reflects the light right into the eyepiece's center.

Laser collimator. Can be used to check and correct collimation before each observing session. The GSO laser collimator fits to a 1.25" focuser, the process can be checked from behind the telescope while working with the adjustment screws. The laser brightness can be adjusted in 7 levels meaning that the laser won't be too bright even during nighttime work. Comes with an 2"->1.25" adaptor to make it possible to colimate telescopes with 2" focusers. The laser beam is parallel to the body of the device, but in case of need the beam itself can be collimated with the three small screws located on the sides. To check the collimator itself slowly turn in the focuser and check how the laser spot moves.

Collimating eyepiece is a device with a reticle on one end. Place the eyepiece onto the focuser and align the optical elements using the reticle. The longer one is for Newton relectors while shorter ones can be used for refracting telescopes. During nighttime the device can be used if it is illuminated from its side, in this case the illuminated disk should be seen as a bright disk in the secondary and primary mirror. The collimating eyepiece for refractors is a similar but much shorter design that can be used by checking the light reflected from the main objective lens.

Laser collimator or collimating eyepiece? Which one is more efficient? When working alone in the dark (and cannot reach both the collimating screws while looking into an eyepiece) then the laser is more convenient. As a drawback the laser collimator does not show if the secondary mirror is correctly positioned, which can be seen in the collimating eyepiece.