Roy,

Don't see where you got 110 lbs and AP-1200.
Granted, "old" AP-1200 carried that without breaking into a sweat, with bar
space to spare.

But, my post was actually about the new AP-1600, I was actually
wondering about fitting 220 lbs. of "counterweights" on the STANDARD bar,
to handle new maximum OTA load capacity on the AP-1600. I just can't
envisage 220 lbs made up from AP-18 lb cwts, and still being able to fit on
an 18.5" bar.

Just as an exercise, to prove it:
Using my own "Counterweights Calculator" Spreadsheet, and configuring a
220 lb (20" diameter OTA), on an AP-1200 as a stand-in, (since I don't have
dimensions for the AP-1600 yet), I found that with just the standard 18.5"
bar alone, there is room for just six AP-18's - leaving ONLY 1/2 inch of
bar to spare.
Even with this fully occupied bar, the scope is still 106.33 lbs too
heavy!
If you want torque value, the 220 lb OTA would still be unbalanced by
1,978.74 inch-lbs.
So, that is why I can't see a 220 lb scope being able to use the "Standard
AP-1200 bar" (alone), and still using "Standard" AP counterweights.

However, to prove to myself the the benefit of new AP counterweights, I
reran my calculations for the fully loaded 220 lb OTA (using AP-1200
dimensions as a stand-in)
- BUT this time ... I used the AP (8.75", 6.53 lb) BAR EXTENDER, with
"potentially NEW", AP 30 lb (7") & 40 lb (8") counterweights, to see what
it might take, to reach near equilibrium for such a heavy max'd out OTA.

Surprisingly, a 220 lb OTA would indeed balance, (with all cwts positioned
at the BOTTOM of the bar), and using one of these set-ups:

(a) 8 x AP-18 lb + one AP-10 lb ... Standard + EXD BAR - 2.08 lbs
cwt-heavy, & 1.25" of empty bar remaining at the top
- or -
(b) 4 x AP-30 lb .......................... Standard + EXD BAR - 4.72
lbs cwt-heavy, & 15.25" of empty bar above all weights.
- or -
(c) 5 x AP-30 lb ........................... Standard + EXD BAR - 0.26
lbs cwt-heavy, & 7.25" of empty bar above all weights - BUT all cwts. moved
up 5" from stop.
- or -
(d) 5 x AP-40 lb + one AP-18 lb ... Standard - NO EXD - 8.85 lbs
cwt-heavy, & 0.5" of empty bar to spare at the top of all cwts. - no
adjustment space!


So, if AP were to manufacture 7" diameter (30 lb) counterweights, just
for the "maximum load capacity" AP-1600 situation ... then configuration
(c), with five of these at middle of the (Extended) bar, would not only
perfectly balance a 220 lb (20" diameter) OTA, it would also leave about a
total of 12.5" of adjustment space on the bar, for accessories to be added
or removed.

In fact, if all 5 of these 30-lb weights were positioned right at the
bottom of the bar, this set-up would be enough counterweight to carry &
balance another 44.56 lbs of CCD camera at the back of an RC-14 shaped
OTA. Of course, the OTA load would then be whopping 265 lbs, but Roland's
mounts seem to have "extra capacity" beyond spec.

NB: In my spreadsheet, I assumed a fictitious 20" diameter 220 lb OTA,
mounted on an "AP DOVELM162", for these calculations, with AP-1200
"Stiction" & size dimensions, and set-up for 44 deg. Latitude.
But, the results are indicative of what "might" be achieved.

Joe Z.

-----Original Message-----
From: roywellington
Sent: Thursday, May 03, 2012 12:37 AM
To: ap-gto@...
Subject: [ap-gto] Re: Larger "diameter" Counterweights for AP-1600 ?

Joe,

Balancing 110 pounds on an AP1200 with three weights not all the way out the
extender and (eyeballing) space for maybe six more weights (true most would
be close in but not all) seems to be quite enough except for one of those
squattish 24in Ricardi-Honders leviathans.

This almost certainly means the next R-H will be 20in only. Where do I sign
up?

Roy



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