... Um, no they don't. -Christopher Erickson, Electrical Engineer Very odd, since a PG&E engineer once told me that PGE did do that. How else to keep electric...
In a message dated 2/2/2006 7:54:04 AM Pacific Standard Time, NewtonianReflector@yahoogroups.com writes: The power utility counts the number of 60 Hz cycles in...
The North American Electrical Grid requires sinusoidal synchronization accuracy of one microsecond and is a non-trivial process. This is required because the...
Date: Sat, 04 Feb 2006 20:25:33 -0900 From: Christopher Erickson <cerickson@...> Subject: RE: Digest Number 310 The North American Electrical Grid requires...
In a message dated 2/5/2006 4:23:48 AM Pacific Standard Time, NewtonianReflector@yahoogroups.com writes: Anywhere from 50hz to 70hz might have been good...
Heh. I ain't all that young myself but I think you have a few years on me! That is some cool history and feel free to share more any time the urge strikes you....
When I finally went to check out the scope, it was a crisp dark night here in Central Texas. It produced pristine images, at least to my inexperienced eyes,...
Definitely not an f/4.6. Looks like an f/6 to me. Should make it easier to collimate, and will give you a larger aberration-free area at the centre of the...
The 40mm eyepiece is a 'modified achromat' Not sure what that is, but I'd guess it's probably a superior kind of Kellner. The others ('wide angle') may be of...
Group - an earlier post of mine contained a statement that power utilities counted cycles of the 60 Hz line and corrected in the middle of the night to keep...
And I don't think it is really a big deal as it applies to the original telescope-drive related question. 1. The frequency of the grid is certainly accurate...
... original telescope-drive related question. 1. The frequency of the grid is certainly accurate enough for any telescope drive around. 2. The frequency of...
In the telecommunications industry we now use GPS signals for everything that needs a precise clock reference. Even going back 40 years I don't think we ever...
I have to agree with all of that. Usually what moves a scope off is alignment problems, not the error in the 60 HZ clock. (Personally, I suspect that the...
... everything that needs a precise clock reference. Even going back 40 years I don't think we ever used the power line for an accurate clock reference. We...
In a message dated 2/9/2006 8:24:19 AM Pacific Standard Time, NewtonianReflector@yahoogroups.com writes: It's a different world now. It sure is! Programs I...
Date: Wed, 8 Feb 2006 16:13:38 EST From: mhholl@... Subject: Re: Re: Power Line Frequency Considerations Even going back 40 years I don't think we ever used...
Reminds me of the story of the store keeper (years past) that set his clock by the noon whistle every day. One day the man who blew the whistle was in the ...
Greetings all, Many weeks ago, I sought (and received) advice about 'trilobal' images plaguing my 8½-inch f/5 Newtonian reflector. I got rather worried at ...
Does anyone have any experience with the 12" Orion Intelliscope? I have the opportunity to buy one that has been tricked out with a Jim's Mobile Next ...
How about putting the Cave Newt on a smaller GEM mount? I sold the monster Cave Astrola mount under my 10" Newt on Astromart recently and switched to a...
Some years ago, I used an astrometric eyepiece to measure the focal length of my f/5 Newtonian. The mirrors are of plate glass, and take some time to...
I guess it might depend on what tensions might exist in the glass, what direction the "grain" of the glass developed during manufacture and what temperature it...
Christopher, Thanks for this. You've reminded me that I perhaps should have given more detail about the construction of the tube. It is made from rolled ...
Some further thoughts (but I am not an engineer...). I would expect the figure of a mirror to be correct when it is in a state of thermal equilibrium. In...
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