hi. i am just look first, but i am interested in getting a mount 4 my 16". does any one have any plans on how to make a mount of that size? if i were to buy new where would i look?
thanks.
les
Hi Les,
glad you asked that question - not because I have an answer but because I have been asking it myself. The suggestions I have received have largely been to avoid an equatorial mount and go with an English-style where the weight is better supported - but at the cost of access to circum-polar areas of sky.
I saw the 'suggestion' about the cement mixer - very amusing but I have seen something I think might provide a sufficiewntly stable basis for a hoime-made Samson-type mount. I used to have a largish (1.5 metre) satellite dish for internet connection out here is the bush. When I switched service-providers, I ended up with a dish that was useless except asd a goldfish pond. But the mount it sat on is another matter. They have a huge and very strong mount which has an adjustable latitude scale similar to a equatoirial wedge. I'm having a look at using it as the basis for mounting the polar shaft of a pier-mounted equatorial.
I'd be happy to hear how you get on in your quest; and also to hear any other good ideas anyone else has - except for the cement mixer.
The Titan is cetainly a beautiful piece of work. It has a capacity of 100Lbs though and that would be stretched if not exceeded by most 16" Dobs - especially with a bit of kit attached. My 16" Meade Starfinder weighs in at 100Lbs (OTA only). I read a suggestion in another thread that this weight could be cut back by using a 2" hole saw (like the ones used for door knobs etc and cut a few hundred hols in the sonotube. The premise behind that isea was that you would lose little in terms of rigidity and cut up to 20% or so of the basic weight. The more you can cut back, the mnore you can start looking at mounts tha aren't quite as expensive as the $6 grand for the Titan.
Anbother possibility mnight be to look aty converting it to a truss scope first. Is there an y particular reason why a truss can't be made to work on an Equatorial mount? Wiser heads than mine will undolubtedly have an answer/opinion about that. I'd be really interested to head what they are.
Nothing stopping you putting a truss tube dob, or a solid tube dob, on an EQ mount of an appropriate size, just so long as you have the right mounting plates and brackets to attach it and the right amount of counterbalance weights attached to the mount. The main thing is to match the size of your scope to the mount you want to use. A 16" dob is going to be heavy and even heavier once you stick all the fiddly bits to it. Like EP's, finders/guidescopes, cameras, cables etc etc. So, you're going to need a big mount...one that can carry all the extra baggage as well as your OTA. I would go as far as saying instead of a Titan, you look at an even heavier mount such as a PME or a large Astro-Physics mount (AP1200 or larger). You could also try a mount from these guys... Parallax Instruments. You can get all the parts you need from them to mount your scope.
If you really wanted to get technical, you can even get fork-type EQ mounts to cradle the scope in, but they would require a bit more to work upon than a normal GEM mount.
Hi Les..
I have been thinking about trading up to a larger scope and build an eq mount for it...namely a horseshoe type ( Mt Parlamor) which would accomodate heavy ep's..etc
Most materials can be purchased from the larger hardware stores and bearing suppliers.
Cheers!
Hi Les,
I have a 16" F4.5 Newt on a GEM that I designed and built.
This was designed for my observatory and is a very heavy duty mount that works quite well. I have Annsen Technologies dual axis drives with drive corrector from Peter Mellander which I have had now for about 15 years and has been exceptionally reliable.
I designed the mount with star drift polar alignment in mind. There is an internal shaft within the pier, located in bearings. By loosening two locknut's I can make extremely fine adjustments in azimuth of the mount.
By loosening the altitude lock nut I utilize a turnbuckle to make extremely fine adjustment in altitude.
The load end of both RA and Dec shafts spin in thrust bearing while the other ends of both shafts spin in double row ball bearings. The shaft are about 2 1/2" stainless steel.
I have no worry about what ancillary equipment I hang off of my scope, the mount and drive have handled everything thus far.
I must add that I am a Fitter & Machinist by trade and that I have my own lathe and when making my mount I spent a lot of time at our local Tafe which ran night time hobby courses. The machine shop at the Tafe was where most of the machining was done.
If you wanted to go a similar way I suggest checking out your nearest Tafe for an appropriate course.
I would never have been able to afford to buy a mount as good as the one I built.
You could try mounting it like the AAT, on a horseshoe mount. I had a friend who I helped make one for, who was going to put a 20" f/4.5 on. It was easy to build (see pic), but he ended up putting onto a Dob mount and driving it with a Dob Driver and using the old Eureka 2000 system on it (see other pic).
You could try mounting it like the AAT, on a horseshoe mount. I had a friend who I helped make one for, who was going to put a 20" f/4.5 on. It was easy to build (see pic), but he ended up putting onto a Dob mount and driving it with a Dob Driver and using the old Eureka 2000 system on it (see other pic).
20"??!!!. That scope is big enough to heft a 40" mirror!!!!.
does anyone have any plans for a horse shoe mount? how reliable is it? is this a good cheep option?
have any one built one before? also i dont know if i mentioned that my 16" is a truss tubed.i would like your experience too.
les
Back in 1986 there was a magazine called Telescope Making, in Edition number 26 there was an article on "An Equatorial Split-Ring Telescope" which has a great description on how to go about designing and building such a telescope. As one point the author, Joe Pearson, had made his plans for this mount available to ATM's. It is an easy build and there are several ways in which the mount can be driven. The easiest would be the same way that the drive is constructed on an equatorial platform. Not that hard to do.
For the price of a Titan I'd recommend an AstroPhysiks AP900 or AP1200.
Dave
Sorry Dave, I think even the AP1200 would be struggling with a
16" GSO.
Fair enough , RCs and open truss dobs up to 16"
There is simply no good sense in paying what would be a lot of money
and finding the mount inferior to the task even by just a small
fraction.
Better to do some homework and over-engineer a homemade job as-per
Trevor Barry's example or look bigger than the AP1200 IMHO.
have a look at opticraft for ideas but beware unless you have access to a friendly machinist or access to equipment and cheap material any thing to support a 16" has got to be big and very heavy i will post a pic of my effort shortly
.
and there are several ways in which the mount can be driven. The easiest would be the same way that the drive is constructed on an equatorial platform. Not that hard to do.
