Diving Deep with the Celestron Off-Axis Guider

The Celestron Radial Guider Lands – A First Look

As I mentioned a couple of days ago in my post about the LodeStar camera, my Celestron Radial Guider (an off-axis guider) just landed from Teleskope-Service in Germany!

An off-axis guider (OAG) like this one uses a small glass prism to skim off a tiny portion of the light cone. It lets you use your main imaging scope simultaneously for both capturing your primary images (with your DSLR, CCD, etc.) and for autoguiding with a dedicated autoguider (my LodeStar in this case). This means you don’t need a separate, secondary guide scope, which saves a significant amount of weight on your mount. Using an OAG also helps eliminate those pesky differential flexure issues. This particular Celestron model has the added benefit of providing the correct backfocus distance when used with a 6.3 focal reducer for an SCT.

Out of the box, the Radial Guider feels really well-made – rigid yet surprisingly light. The pick-off prism itself is actually larger than I expected. I reckon my little LodeStar will have absolutely no trouble finding guide stars with this setup.

Big thanks to my sweetheart for this awesome gift!