The Advantage of Using a 2-inch StarSplitter for Astrophotography

Astronomy Labs has recently debuted a 2-inch version of the starsplitter. It works in the same way as the smaller 1.25-inch version, but is better suited to astrophotography.  It accepts 2-inch accessories including eyepieces and cameras, and, with adapters, can be used with 1.25-inch accessories as well. The great advantage of this comes when doing astrophotography. Having two identical output ports means you can autoguide your exposures with the same optical path that you image with. Your autoguider will be at the same focal length as your main camera and will be more sensitive to tracking errors than if mounted on a separate guidescope. Flexure between a separate guidescope and the main scope is also eliminated. The results are striking.  The image below and on the left shows a 10 minute exposure that was autoguided with a separate guidescope. Mis-tracking on the exposure is profound. This is a ruined and unusable exposure. The image below right was taken right after the first but with the autoguider on the 2nd port of a 2-inch starsplitter. The exposure was also 10 minutes long but the guiding is much better. The star images are nice and round and the image is of good quality.