Re: [NexStar Group] Equatorial wedge for NexStar 102?
Hi Richard,
It's very doable, and in the five months of so that I've had it in the
equatorial configuration it hasn't suffered any ill effects. I've had it with
about 8lbs of weight sitting on it most of the time, and recently, about 10lbs.
I know I'm pushing the mount (max load weight is supposed to be 8lbs) but if
you're very careful about balance (especially along the DEC axis), it's no
trouble at all.
I have even been able to autoguide it that way. Currently, my setup is a
William Optics ZS66SD and dsi pro camera as the guider setup, mounted on top of
a Astro Tech 80ED and canon Xti/400D as the imaging train. My previous setup,
one I've used for several months was the ZS66SD and dsi pro as the guiding setup
with the 400D and a 70-200mm f2.8 lens perched on top for imaging. I have
posted a few articles on the baby nexstar yahoo group, here they are reposted.
Another guy had also posted a nice homemade wedge pic and writeup, but I can't
duplicate it here without permission. It is very much like the one you
suggested to build.
Here are my writeups:
---
Since I bought the wedgepod for the mount I have been able to get unguided
frames of 30 and on occasion 90 seconds. Good enough to catch some of the nice
brighter dso's like M31 but tough on the dimmer ones, like M45. So, the
question that remained, can the slt mount be autoguided?
Well, I am happy to say that mostly due to the magic of Craig Stark's
PHDGuiding, the slt mount can definitely be autoguided. So, 5 minute guided
shots with the little mount are now a real possibility.
A bit of info on my kit. Nexstar SLT mount on a slightly modified wedgepod
wedge and pier mounted (and occasionally dismounted for field trips). William
Optics ZS66SD scope in place of the 60mm celestron one. Canon Xti/400D mounted
on the back of the scope or piggybacked on it with a 70-200mm f2.8 lens. All in
all a pretty minimalist and very portable setup.
Pics I have taken with this setup on this page:
http://ciobota.googlepages.com/astronomy---
As promised, here's a pic of the scope and wedge setup. I also mounted the
camera and lens to show how it's piggybacked on the scope.
Sorry for the duct tape, it's there to keep the ac adaptor from wiggling or
coming out. Like I said, my setup, she ain't pretty but does the job.
http://ciobota.googlepages.com/IMG_0336resized.JPG---
Here's a link to a pic taken from the other side, showing how the lens is
mounted on the scope. It's not the sturdiest design, but for a lightweight
combo like that one and fairly short focal length, it does ok. I got the
ring from either Orion or ScopeStuff, can't remember. They come in pairs
and one ring has the camera adaptor thingie as shown. I think the pair was
like $20 or so.
http://ciobota.googlepages.com/IMG_0337resized.jpgAs for the wedge, it came from the celestron nexstar wedge tripod, here's a
link to one:
http://www.telescopes.com/products/cele ... wwedge-120\
35.html
Here's a piece of a writeup I did for anouther group that talks about the
mod to make it work with the SLT mount:
----
The first piece was my newly acquired nexstar wedge tripod. I knew it was
only intended for the SE series scopes, but I said, what the heck, I'll try
it anyway. When the tripod arrived, I realized one of the reasons why it
was not meant for the slt. Instead of a center bolt hole, there are instead
three hold down bolts with a center pin for alignment. Luckily, the center
pin unscrewed off. However the remaining center hole was too small for the
1/4" bolt required, so a gentle enlargement with a 17/64" drill bit now
allows me to put the bolt through, and also retains enough shoulder for the
center pin to be remounted.
----
To mount it on the pier, it depends on your pier arrangement. Mine has a
plate that screws into the pier, so I just drilled a hole in the middle and
put a bolt through where the center bolt normally goes. Oh, and of course,
I removed the legs. You can see the bare mount ears in the pic. That's it
really, not much modification tbh. And it works well in the field as well.
----
PS: The AT80ED pic listed there was imaged at about 2 arcsec/pixel and guided
at about 4arcsec/pixel. So, imho, the platform is stable and accurate enough to
guide at almost the limit of seeing conditions for most places.
Hope this helps.
Daniel
.
