Posted 28 January 2013 - 08:45 AM
Posted 28 January 2013 - 11:53 AM
A very warm welcome to CN and to this forum. :bow:
Other opinions may differ, but my advice, based on my erstwhile purchase and subsequent use of the now withdrawn for sale, Celestron wedge, is to forget the idea completely and invest in a good German equatorial, mounting your 130SLT's OTA separately on this.
Not only will this give you good GoTo accuracy throughout the entire sky, as opposed to that you will, without doubt, experience with an imprecise wedge arrangement plus an off-balance, single arm mount designed only for Alt./Az use, but also, far improved tracking ability due to a superior worm gear drive.
Posted 28 January 2013 - 02:28 PM
Thank you for the welcome.
Posted 29 January 2013 - 06:23 AM
I fully understand the situation. I think most of us are watching the pennies these days !
But yes, if you think you can build a wedge for your 130 SLT mount: and it will require quite a degree of precision coupled with a fine degree of adjustment potential if it's to work: then do give it a try !
I take it that your reason for requiring one is imaging ?
But as I said and as a cautionary tale, I bought a Celestron wedge for my Nexstar 8i back in '07 but never got it to work with any satisfaction. Indeed much was discussed on the topic at that time on the Nexstar 8i Yahoo forum.
The main problem was the varying accuracy of GoTos and subsequent tracking variations, depending on to which part of the sky the 'scope happened to be pointing. The conclusion we reached was that much depended on whether the OTA was "resting" on the single arm of the mount or "hanging" from it ! In essence, a constantly varying imbalance which, in turn, lead to wide inconsistencies in the quality of the images obtained. Couple this with the amount of backlash inherent in the spur gear of the standard Alt./Az. mount, (compared to the usual worm drive of GEMs), and well, you can imagine that the whole assembly was, at least to my mind, less than ideal.
I too remember however, that someone on this forum managed to use the same wedge with his 'scope successfully. I might even have a record of it somewhere. If I can find it, I'll willingly pass it on to you.
Posted 29 January 2013 - 11:08 AM
bottomed like the other nexstar drives/mounts. Need to take the time and go over all that info you linked me to. May still give it up as a lost cause and put that little scope on a CG-4 mount. Then put one of my little refractors on the slt mount.
Now need to get my observatory built. I live in the city and need to block all the light I can.
Posted 29 January 2013 - 12:47 PM
Well I hope that information helps somewhat but you don't tell us what you are aiming ultimately to accomplish by attempting to construct a wedge ?
I make the assumption that you require it, or perhaps a CG-4, so that you can take some longer exposure images ?
If this is the case, have you already pursued all the possibilities open to your 130 SLT in its existing state ? If not, maybe we can help in this direction. (?)
By the way, good luck with your observatory. I got one about three years ago to house my Nexstar 8i and my 4" refractor on a Skywatcher HEQ5 Pro and have never looked back !
Now if only our constant cloud cover would disperse so that I can use it !
Posted 29 January 2013 - 12:52 PM
Good luck with the building of your Obsevatory. Hope you can get started on it soon. It will help block stray light, protect you against the elements, allow you to have your scope permanently set up and ready to go, and overall, improve your enjoyment of this wonderful hobby of ours many fold.
Posted 30 January 2013 - 01:50 PM
This is the same method used in the Meade ETX,Bausch 4000, and even the esteemd Questar tabletop legs.
Two legs are fixed in length and the one aligned with the north pole is adjusted shorter to achieve the correct tilt.
This is practically no cost just tedious to adjust.
And be certain ro secure the two southern legs so the whole scope doesn't fall over.
Posted 30 January 2013 - 08:35 PM