Shift a Little Weight

The trade-winds have returned for the evening. And while they are welcome for the comfortable temperatures they bring, the winds are unwelcome for the problems they create at the telescope. I am trying to get in one last exposure sequence for the evening, but the guider graph shows trouble. There are constant errors, not small errors either. The Right Ascension axis seems to be the issue, with errors of +/-3 pixels on the guider. This is just not going to work.

I watch the graph for a while, trying to figure out what I can do. I have had an issue where the guide star was the source of the problem, two stars to close together, a double star I did not notice when selecting my guide star. I stop the guider and select another star… The problem continues.

As I feared, my problem is most likely the wind this evening, a continual issue on this rock I live on. A speck in the middle of a very large ocean, the winds are a fact of life here. I only shoot with small telescopes, less sail area to catch the wind with a short tube. A TeleVue 76mm, an AT6RC, or simply a wide angle camera lens. The smaller scopes provide less loading for the old Losmandy G11 I mount them on.

I decide to try something else, shifting the balance to load the RA gear down. I gently slide the counterweight down the shaft about an inch. There is barely a blip on the guider as I make the adjustment. Better yet the guide error graph settles down! Looks like I will be able to get in a few more exposures before putting the ‘scope away.

Guider Error Graph
The guide error graph showing the effect of shifting a counterweight.

Author: Andrew

An electrical engineer, amateur astronomer, and diver, living and working on the island of Hawaiʻi.

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