Orpington Astronomical Society

Astronomy => Technical => Topic started by: Simon E on Dec 16, 2009, 12:11:10

Title: Wedgeeeee
Post by: Simon E on Dec 16, 2009, 12:11:10
I am now the proud owner of one of these..

(http://stargazerslounge.com/attachments/sale/29389d1258714232t-nexstar-wedge-tripod-sky-atlas-wedge.jpg)

It fits fine to the field tripod and i'm sure it will make fitting the scope easier to the concrete piller.

My question is, Ican read up on how to polar align the scope via the Wedge, but my question is about the pier. I have herd of talk about lining up the piller to North :o How the hell does one do this, cause my piller is round, or do they mean that the scope has to be facing North, or does it not matter with an Alt mount as the wedge is polar aligned anyway.

cheer

si
Title: Re: Wedgeeeee
Post by: JohnP on Dec 16, 2009, 12:24:50
Simon take a look at this thread by Mac it may help you...

http://forum.orpington-astronomy.org.uk/index.php?topic=3402.0

The pier can be orientated in any direction it's the mount that goes on top that needs to be polar aligned N.

John
Title: Re: Wedgeeeee
Post by: Simon E on Dec 16, 2009, 13:08:11
Cheers John, just been reading up about wedge aligning on my scope. And your right all i need to do is make sure the wedge face is pointing towards Polaris, with the scope attached and in the centre of view. As I will be casting some screw rods straight into the top of the pier they need to be aligned correctly so the wedge can be in the right place.

Thanks
Si
Title: Re: Wedgeeeee
Post by: Ian on Dec 16, 2009, 13:10:36
it is important to ensure the pier is level though. Just ask Fay about all the trouble that can cause...
Title: Re: Wedgeeeee
Post by: Simon E on Dec 16, 2009, 13:16:10
Will do, although at the end of the day I will have three threaded rods coming out of the pier, and i should be able to get adjustment for the level from these, ie one nut could be slightly lower than the others if need be.

I have a single arm Nexstar, do you guys with the celestron dual arm cpc's have any problems tracking objects, because what i have read up on, is that the single arm units are rubbish, and I may have to mount the OTA on a different mount anyway, Trouble is I'm gonna find it difficult convincing the other half that I need to spend a further £600-£700 on an EQ mount....

I have found a motorised Skywatcher HEQ5 mount with motors (No goto inc) for £499

si
Title: Re: Wedgeeeee
Post by: JohnP on Dec 16, 2009, 13:34:06
Si - No experience myself but I would imagine a single arm side mount scope would cause you a lot of issues with guiding etc. due to stress etc. especially when you mount guide scopes & camera's etc.....
Title: Re: Wedgeeeee
Post by: Ian on Dec 16, 2009, 13:46:13
I think Mick does single arm observing. His other one is usually dedicated to beer to mouth logistics.
Title: Re: Wedgeeeee
Post by: Mac on Dec 16, 2009, 14:23:25
Tip on polar aligning.

I use the itieritive method.

http://www.covingtoninnovations.com/astro/iterating.pdf (http://www.covingtoninnovations.com/astro/iterating.pdf)

http://www.astroshow.com/astrotip/align.htm (http://www.astroshow.com/astrotip/align.htm)

takes about 4-5 goes and is very accurate.

1) select a star on your hadset and goto that star.
2) Center star using handset and then sync on the star.
3) Use handset and goto Polaris
4) USING THE ADJUSMENT ON THE WEDGE bring polaris back to the center, of the eyepiece. (don't completely centre it, just remove half the error)
5) go back to 1

If your scope dosent have goto, just use a planetarium to control the scope and sync on the star.

Mac.

I do have a polar alignment scope you can borrow if you want.
Makes setting up easier