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#1 Chuck/divenuts

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Posted 13 March 2009 - 02:24 PM

I'm about to install a new PierTech3 pier in a 7'6" dome. I will be receiving an AP1200GTO mount in a few weeks(Feb. was the original delivery date}. It is going to be a close fit. Can someone tell me if the pier will need to be installed 6-12" south of center? I don't think dead center will work. I'm mounting a Meade 14" with a Tak FSQ piggybacked. I would like to get the pier in before the mount arrives. ANY advice would be appreciated.
Thanks,
Chuck/divenuts

#2 HunterofPhotons

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Posted 13 March 2009 - 02:57 PM

Hi Chuck,
You'll find what you need at the AstroPhysics website.
Look under AP1200/Dimensions.

dan

#3 Chuck/divenuts

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Posted 13 March 2009 - 04:15 PM

Hi Dan and thanks for the reply. I'm embarassed to say I cannot work the spreadsheet on the AP site. I enter the numbers that I think are correct and nothing changes on the spreadsheet(it's setup for 42* and I'm at 28* lat). I have never used or seen a GEM work. I have just had my fork mount on a wedge. My pier will adjust vertically without losing my alignment so that wil help some.Using a SCT is obviously shorter than the refractors and Newtonians it seems the spreadsheet is set up for. I have taken the OTA out of the forks and now I'm stuck at pier placement. Is the spreadsheet designed to have the dimensions change when figures are entered? If so, mine do not and that could be part of my problem.Any suggestions? I'm pretty sure I don't place the pier dead center...I wish I had a larger Observatory..I'm tight so I need to get pretty close with placement. If the counterweight bar clears all the way around that should give my sct clearance as well, would it not? Any additional ideas?

#4 JerryWise

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Posted 13 March 2009 - 09:48 PM

Hi Chuck and a warm welcome to CN.

Looks like you have a fine outfit on the way. Its going to be snug though.

I have a 10' ProDome with the 14" LX200R and a Tak FS 150 on a side by side plate. With the standard CW bar horizontal (looking at the Meridian) it is going to be very tight. If you move the pier off center it will be even less room for the CW bar. I would mount the pier dead center to give your CW bar and scopes the best clearance. Unlike the fork mount on a wedge, the pivot point on the EQ mount will be directly over the pier. I would site the final pier location after all equipment arrives to make certain you have the clearance you need. That is one huge outfit. Good luck.

#5 David Pavlich

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Posted 13 March 2009 - 10:06 PM

I have to agree with Jerry. You going to need as much room as you can get. And since you're going to be imaging as much as you can near zenith, you know that counterweight shaft and scope combination is going to make it just about impossible to get around the scope without crawling on your hands and knees.

I've never seen an AP1200 in the flesh, but my rolloff is a little less than 8' square. I have an MI250 with a 12" Meade and a TMB 80/480 piggybacked and if I'm imaging near zenith and I have to get to the other side of the scope, I have to crawl under it. I need to qualify that and say that I have shelves in the way. The scope and CW shaft clear the shelves, but by about 5" and this big person can't squeeze through that!

David

#6 Chuck/divenuts

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Posted 14 March 2009 - 12:12 AM

Hi Jerry...that's the answer I needed. Dan loaded me up with valuable information but I didn't know if the AP spreadsheet was supposed to help figure placement or I just couldn't get it to work. Anyway, I guess I'll need to wait and do a mock up and see if the center will work. The wedge does throw the weight and positioning off center. I'm also not sure whether to go side by side or piggyback...that's another factor I can figure once I have the equipment.
THANKS!

#7 DeanS

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Posted 14 March 2009 - 10:07 AM

Chuck,

Side by side makes balancing trickier, however our AP's can be used not perfectly balanced. I think piggyback is the way, IF you can be sure to remove the flex.

I never got rid of my flex entirely so am using an eFinder as a guide scope and it works perfectly. Oh, and I got a Mach1GTO for my wide field scope. Sure glad I made my roll off big enough just in case.

Congrats on the new mount, you will love it.

Dean

#8 Chuck/divenuts

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Posted 14 March 2009 - 10:11 PM

Hi David....do you have your pier centered in your observatory and directly under your mount with no offset? My true North is only 4* East of magnetic North(which really doesn't matter except I'll be able to get my pier pretty close to true North with just aiming at Polaris.)
Oh yea, I think having the PierTech3 is going to help big time. I'll be able to setup everything and with the punch of a button raise it to any height from 28 to 49 inches.
http://www.pier-tech...escope_pier.htm

#9 David Pavlich

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Posted 14 March 2009 - 10:16 PM

Hi David....do you have your pier centered in your observatory and directly under your mount with no offset? My true North is only 4* East of magnetic North(which really doesn't matter except I'll be able to get my pier pretty close to true North with just aiming at Polaris.)
Oh yea, I think having the PierTech3 is going to help big time. I'll be able to setup everything and with the punch of a button raise it to any height from 28 to 49 inches.
http://www.pier-tech...escope_pier.htm


Yep...dead center. I didn't mess with any offsets. I just knew that if I moved it one way or the other, it would have some adverse effect on observing/imaging. I'm glad I stuck it there since it's working nicely.

David

#10 GJJim

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Posted 15 March 2009 - 10:17 AM

Hi David....do you have your pier centered in your observatory and directly under your mount with no offset? My true North is only 4* East of magnetic North(which really doesn't matter except I'll be able to get my pier pretty close to true North with just aiming at Polaris.)


The best way to find "true North" is a shadow cast at solar noon. Find solar noon for your location. At your planned pier position, hang a string with a weight to cast a shadow on the ground. The shadow at solar noon will give you exact North with much better accuracy than any compass or nighttime measure.

#11 EddWen

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Posted 15 March 2009 - 10:41 AM

Chuck,

My advice would be to wait until you get the mount before bolting the pier down. I had my AP1200 in my 8x8 roll off and it was a tight fit even with some offset from the center. The mount is now much more comfortable in my 12x12,

Good luck,

#12 DrBuck

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Posted 15 March 2009 - 12:35 PM

The best way to find "true North" is a shadow cast at solar noon. Find solar noon for your location. At your planned pier position, hang a string with a weight to cast a shadow on the ground. The shadow at solar noon will give you exact North with much better accuracy than any compass or nighttime measure.

That is really interesting. And a great tool to have. Thanks. :)






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