Table of Contents
Advertisement
Quick Links
SCT & EdgeHD Collimation Guide
To get the best performance from your Schmidt-Cassegrain (SCT) or EdgeHD telescope, its optics must be collimated—
properly aligned within the telescope. Your telescope was collimated at the factory when it was assembled, and its
collimation was QA-checked before it was shipped. However, if the telescope has been dropped or jarred during
transport or has undergone considerable temperature changes, it may need to be re-collimated.
You can achieve correct collimation by adjusting the tilt of the secondary mirror housed at the center of the Schmidt
corrector (see Figure 1). This is the only adjustment available to the end user and should be the only adjustment required
to bring the telescope's optics into excellent collimation.
NOTE: Do not attempt to make adjustments to the Schmidt corrector's orientation or positioning. Doing so will likely degrade
collimation and optical performance and may require return to Celestron to achieve proper optical alignment.
Secondary Mirror
Schmidt Corrector Side View
Collimation Screws
Schmidt Corrector Front View
Schmidt Corrector Front View
Optical Tube Side View
Optical Tube Front View
Fig. 1
Advertisement
Table of Contents
Subscribe to Our Youtube Channel
Related Manuals for Celestron Schmidt-Cassegrain
Summary of Contents for Celestron Schmidt-Cassegrain
- Page 1 SCT & EdgeHD Collimation Guide To get the best performance from your Schmidt-Cassegrain (SCT) or EdgeHD telescope, its optics must be collimated— properly aligned within the telescope. Your telescope was collimated at the factory when it was assembled, and its collimation was QA-checked before it was shipped.
- Page 2 CHECKING COLLIMATION – HOW DO I KNOW IF MY OPTICS NEED ADJUSTMENT? Checking optical collimation is quick and easy. We recommend taking a few moments to check collimation before each observing session. To do this, you’ll need to examine a star image through the telescope’s eyepiece.
- Page 3 COLLIMATION SETUP As you did when checking collimation, make sure your system is acclimatized to the outside temperature before you begin the collimation process. To collimate your SCT or EdgeHD, you will need a pinpoint light source. A bright star works great. A bright star near the zenith is ideal since there is minimal atmospheric distortion in that part of the sky.
- Page 4 COLLIMATION PROCESS To collimate your telescope, you’ll use a Phillips-head screwdriver to make adjustments to the collimation screws on the back of the secondary mirror assembly. Collimation These three screws are clearly visible when looking at Screws the front of most telescopes (see Figure 6). Fig.
- Page 5 Be sure to re-center the star in the eyepiece’s fi eld of view by moving the telescope on its mount after making any adjustments to the collimation screws. If the star is not centered in the fi eld of view, interpretation of the defocused star images will not be accurate to determine proper collimation.
- Page 6 5. Inspect the extra-focal diffraction pattern on the other side of focus to see if one side of focus provides a slightly better appearance of the light and dark diffraction rings. Whichever side of focus has clearer light and dark diffraction rings should be used for collimation purposes.
- Page 7 Doing so will not only likely put your telescope further out of alignment, it will also void your warranty. Instead, contact Celestron Technical Support by submitting a ticket here: celestron.com/pages/technical-support. Your telescope may need to be returned to Celestron for warranty evaluation (or paid repair, if the warranty has expired).
- Page 8 Collimation is not necessarily difficult to do but requires some learning and some patience. After adjusting your telescope’s collimation a few times, you’ll get the hang of it. The process will become easier and less time-consuming. Good luck and clear skies! © 2020 Celestron • All rights reserved celestron.com/pages/technical-support 2835 Columbia Street • Torrance, CA 90503 U.S.A.
Need help?
Do you have a question about the Schmidt-Cassegrain and is the answer not in the manual?
Questions and answers