Step 1: play around with the lens during the daytime. Firstly, this is a manual focus lens when connected to a Canon EOS. A few shots using the focus scale on the lens didn’t produce sharp images. I looked online to find numerous reports that this lens is often shipped with a badly calibrated focus ring; good to know. So I tried a star test using Live View to focus on a bright star. And here is the result: the lens is actually focused at infinity when the lens scale is set to a distance of 3 feet! Now I have an Astronomik CLS filter added, which will affect the focus a little, but still, however you look at it the focus ring was incorrectly set in the factory:
Step 2: test the new lens without guiding. Here is the first result, a stack of 8 x 2min exposures with the lens pointing towards Polaris. A speed of ISO100 was used, with the lens wide open at F2.8. I stacked the images using the “Startrails” program. Dew ultimately coated the expanse of exposure lens.
Step 3: try out the same process capturing more frames. This time I shot 41 frames of 2 minutes at ISO 2.8/F2.8. Streaks of cloud came and went during the exposures so I eventually chose to stack 35 frames, having wrapped a Kendrick Dew strap around the lens to keep the moisture away.
Step 4: try the new IOptron Skytracker:
