Polar Aligning a Mount: This Astro Tip was snagged as one of the many great ideas shared by Astronomy Technology Today reader Paul Chasse. It focuses on helping to make polar alignment a smooth process. Pay attention, because this may save you some time and frustration down the road.
When polar aligning a German equatorial mount, it’s often necessary to make fine adjustments to the altitude and azimuth positions. The azimuth adjustment mechanism of many mounts involves turning knobs that push against an alignment pin on the tripod (or pier). This causes the entire mount to rotate and the simple design works quite well.
The problem with this design is that the mount rarely rotates smoothly on the tripod base. This makes the adjustments difficult and anything but precise. At worst, it can lead to mount damage. I’ve actually seen people bend and break knobs trying to adjust mounts that were just setup too tight. At best, it’s just a design that needs some tweaking.
This is where Paul comes in with a brilliant suggestion. He suggests installing four pieces of adhesive-backed PTFE (Teflon) tape on top of the tripod. Specifically, the 3.5-mil seems to work best, because it keeps the mount close to the tripod. It’s thin enough that you can actually just see daylight through the tape. There are dozens of different tape widths, but anything around an inch or so is fine. Try to space it evenly on the tripod so that the mount will sit level.
After installing the tape, set the mount on the base and snug it down just enough that a minor bump won’t rotate it. As you make your azimuth adjustments, notice how smooth and precise they are. Then, once you’ve polar aligned it, tighten everything just a bit more. That’s it. You’ve just simplified a once tedious task and really enhanced the functionality of your mount.
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