On Monday, April 27, 1998 4:08 AM, Bill Arnett wrote:

> At 10:39 PM -0700 4/26/98, ken milburn wrote:
> >.... I usually recommend the DMW [Deluxe Milburn Wedge?] for
> >... those with a permanent pier.
>
> While I'm sure Ken's wedges are fine examples of the machinist's art, I'm
> not sure why I would want one on top of a permanent pier. That pier isn't
> going anywhere, nor is its relationship to the Earth changing. Thus I
> would think that careful polar alignment done once would be done for all
> time. And thus, a fine wedge like Ken's is not needed since its primary
> virtue is ease of adjustment. Would not a junky old Meade Superwedge do
> just as well in this case?
>
> Now you're probably saying, "This guy obviously doesn't have a pier. If he
> did, he would know <crucial fact> and not make such a silly statement." It
> wouldn't be the first time :-) So, does the wedge get out of adjustment
> just sitting there? (Due to thermal cycling or metal fatigue?) Do the
> effects of precession happen fast enough to require yearly realignments?
> (What do they do at Palomar?) Heck, for that matter, until I get into
> photography is there any reason not to continue to use altaz mode even on a
> pier?
>
> Can I do lunar CCD imaging in altaz mode?
>
> (All this is no longer as theoretical as it once was for me. I am about to
> move to a new house where I will have the opportunity to build a pier and
> an observatory for my 12" LX200. Hurray! )
>
> ---
> Bill Arnett "Science is a way of trying
> San Jose, CA USA not to fool yourself." -- Feynman


Your correct Bill, polar alignment on a permanent pier is a one time
concern. A Superwedge is probably overkill as well. The next time
I use my 12" LX-200 for a remote imaging excursion, I will replace the
Superwedge with a short section of plain welded steel rather than the
longer version Meade uses for the 16". The 16" pier is adjusted by
3 bolts and shims, crude, but quite effective for a one time job.

I prefer a concrete pier to help dampen oscillations, so my welded
wedge will be mounted on top of the current pier I'm using with
three 1/2" bolts provided.

By the way, if my inexpensive welded steel permanent wedge fails
to dampen vibrations as well as the Superwedge (quite possible), the
Superwedge goes back on. The idea was to free up the Superwedge
for portable imaging.



--
Michael Hart
Husen Observatory




--
Michael Hart
Husen Observatory

View index by [date] [author] [subject]
Previous message: Re: [M]: GMT Confusion, Nigel Puttick
Next message: Re: [M]: LXD650 problems.. help!, Stephen Speicher
Next message in thread: RE: [M]: Re: Buying a wedge... Addendum, Bill Arnett