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Subject: Re: [M]: No periodic error ?
From: Wayne Watson
Reply To: mapug@shore.net
Date: Tue May 01 20:10:33 2001
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While you're here, how about checking out the
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You are a bit south aren't you? Austrlia! So that's an 8" Newtonian on the mount? Yes, that mount is
massive. I think our 12.5" at the museum weighs in at 350 pounds. I've never looked inside the
drive, but could it be that their is no worm gear? Maybe non-worm gear drives do not produce much
periodic error. Someone out there probably knows. I have a friend who is intimate with such
equipment. I'll ask him. Whoops! I see you said 'worm'. I'll ask him anyway.
How'd you get the granularity into the photos? Is that (digital) posterization?
Paul Luckas wrote:
> The mount is about 15 years old - the optics are a bit younger (I bought it in two stages).
> Originally I also had a 12.5 inch Newtonian on it, but the tube size was unmanageable (at f6 it
> was a looooong tube) so I opted for the much more portable 8 inch assembly. You can imagine how
> stable it is on this massive mount. (for those interested: http://web.one.net.au/~paul_luckas)
> Apologies in advance for the image upload times. It definitely has no periodic error correction
> capability - ie, it's a very simple arrangement (synchronous motor, worm and wheel - that's it). I
> have an original Meade drive corrector - the old 'joy stick' type, which I still think are much
> better (easier to use) than the push button variety, but that's it. I appear not to have any
> periodic error to train out ! Thanks Wayne, Paul
>
> ----- Original Message -----
> From: Wayne Watson
> Sent: Wednesday, May 02, 2001 2:20 AM
> Subject: Re: [M]: No periodic error ?
> Yes, that's quite good. How old is the unit? I have access to one that is about 15
> years old (a 12.5") and I do not believe it has PEC training available. It's not
> completely functional, and was donated to our local museum.
>
> You are doing quite well if you trained out the PEC. I spent about 1 hour training and
> updating my PEC on my LX-200 8" f/10 and could see a slight crawl over 8 minutes. I
> don't know what it amounted to in arc seconds. I'm using a 12.5mm Celestron graduated
> eyepiece. I could see drift from the top of the 3 in '30' to the top of the 0. That's
> about one graduated unit on the scale. I'll probably erase and try again tonight. It
> seems like near zero should be possible.
>
> Paul Luckas wrote:
>
> > Is there such a thing as no periodic error ? I've just spent that past few evenings
> > engaged in accurate polar alignment of my aging Meade Research Series Newtonian. I've
> > cancelled all of the declination drift out, and am now trying to ascertain the
> > periodic error of the old RA drive. I've been tracking Achernar (yes, I'm in the
> > southern hemisphere) for the past hour, and have not been able to see any drift
> > whatsoever in a 9mm illuminated reticle eyepiece. Notwithstanding the excellent (if I
> > do say so myself) polar alignment which has accounted for the zero drift in dec., is
> > it possible that Meade manufactured sub-arcsecond accurate RA drives way back in the
> > 70's ? I'm impressed to say the least. BTW: I "was" thinking of selling the unit to
> > buy an LX200 - (http://web.one.net.au/~paul_luckas), but now I'm having second
> > thoughts ?
>
> --
> Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet)
>
> He allus said, "Don't take life too serious, it ain't nohow permanent."
> - Walt Kelly, Pogo
>
> Web Page: http://home.earthlink.net/~mtnviews
>
>
--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet)
He allus said, "Don't take life too serious, it ain't nohow permanent."
- Walt Kelly, Pogo
Web Page: http://home.earthlink.net/~mtnviews
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You are a bit south aren't you? Austrlia! So that's an 8" Newtonian on
the mount? Yes, that mount is massive. I think our 12.5" at the museum
weighs in at 350 pounds. I've never looked inside the drive, but could
it be that their is no worm gear? Maybe non-worm gear drives do not produce
much periodic error. Someone out there probably knows. I have a friend
who is intimate with such equipment. I'll ask him. <font color="#FF0000">Whoops!</font>
I see you said 'worm'. I'll ask him anyway.
<p>How'd you get the granularity into the photos? Is that (digital) posterization?
<p>Paul Luckas wrote:
<blockquote TYPE=CITE> <font face="Arial"><font size=-1>The mount
is about 15 years old - the optics are a bit younger (I bought it in two
stages). Originally I also had a 12.5 inch Newtonian on it, but the tube
size was unmanageable (at f6 it was a looooong tube) so I opted for the
much more portable 8 inch assembly. You can imagine how stable it is on
this massive mount.</font></font> <font face="Arial"><font size=-1>(for
those interested: <a href="http://web.one.net.au/~paul_luckas">http://web.one.net.au/~paul_luckas</a>)
Apologies in advance for the image upload times.</font></font> <font face="Arial"><font size=-1>It
definitely has no periodic error correction capability - ie, it's a very
simple arrangement (synchronous motor, worm and wheel - that's it). I have
an original Meade drive corrector - the old 'joy stick' type, which I still
think are much better (easier to use) than the push button variety, but
that's it. I appear not to have any periodic error to train out !</font></font> <font face="Arial"><font size=-1>Thanks
Wayne,</font></font> <font face="Arial"><font size=-1>Paul</font></font>
<blockquote dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<div style="FONT: 10pt arial">----- Original Message -----</div>
<div
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><b>From:</b>
Watson</a></div>
<div style="FONT: 10pt arial"><b>Sent:</b> Wednesday, May 02, 2001 2:20
AM</div>
<div style="FONT: 10pt arial"><b>Subject:</b> Re: [M]: No periodic error
?</div>
Yes, that's quite good. How old is the unit? I have access to one
that is about 15 years old (a 12.5") and I do not believe it has PEC training
available. It's not completely functional, and was donated to our local
museum.
<p>You are doing quite well if you trained out the PEC. I spent about 1
hour training and updating my PEC on my LX-200 8" f/10 and could see a
slight crawl over 8 minutes. I don't know what it amounted to in arc seconds.
I'm using a 12.5mm Celestron graduated eyepiece. I could see drift from
the top of the 3 in '30' to the top of the 0. That's about one graduated
unit on the scale. I'll probably erase and try again tonight. It seems
like near zero should be possible.
<p>Paul Luckas wrote:
<blockquote TYPE="CITE"><style></style>
<font face="Arial"><font size=-1>Is
there such a thing as no periodic error ?</font></font> <font face="Arial"><font size=-1>I've
just spent that past few evenings engaged in accurate polar alignment of
my aging Meade Research Series Newtonian. I've cancelled all of the declination
drift out, and am now trying to ascertain the periodic error of the old
RA drive. I've been tracking Achernar (yes, I'm in the southern hemisphere)
for the past hour, and have not been able to see any drift whatsoever in
a 9mm illuminated reticle eyepiece. Notwithstanding the excellent (if I
do say so myself) polar alignment which has accounted for the zero drift
in dec., is it possible that Meade manufactured sub-arcsecond accurate
RA drives way back in the 70's ?</font></font> <font face="Arial"><font size=-1>I'm
impressed to say the least.</font></font> <font face="Arial"><font size=-1>BTW:
I "was" thinking of selling the unit to buy an LX200 - (<a href="http://web.one.net.au/~paul_luckas">http://web.one.net.au/~paul_luckas</a>),
but now I'm having second thoughts ?</font></font></blockquote>
--
<br>
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet)
<p> He allus said, "Don't take
life too serious, it ain't nohow permanent."
<br>
- Walt Kelly, Pogo
<p>
Web Page: <a href="http://home.earthlink.net/~mtnviews">http://home.earthlink.net/~mtnviews</a>
<br> </blockquote>
</blockquote>
<p>--
<br>
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet)
<p> He allus said, "Don't take
life too serious, it ain't nohow permanent."
<br>
- Walt Kelly, Pogo
<p>
Web Page: <A HREF="http://home.earthlink.net/~mtnviews">http://home.earthlink.net/~mtnviews</A>
<br>
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