This is my 1st ATM and I have dived in at the deep end. First a little about my reasons for starting this project. I began this new hobby only a couple of years ago after selling my boat and retiring from target rifle shooting plus at 65 it was time to slow down from my job as an electrician. I had an interest in astronomy so bought a 5" Meade and enjoyed using it for a year before aperture fever grabbed me. I had the opportunity to by a 14" Meade for a reduced price and built a ROR to house it and was very content viewing & taking images with my converted Canon 600D. Then one day I had a phone call from a chap who was planning to visit my area and had heard I had a polar mounted 14" and wondered if he could use it with his camera to take images of planets. NP I replied not knowing what I was letting myself in for. Bird arrived a few weeks later and spent some time collimating and adjusting my badly setup scope. I spent 2 weeks watching with amazement as he created many wonderful images of Mars and got hooked on planetary imaging. Several visits during the next 18 months during which he brought his 16" Newt culminated in Bird buying a block not far from me and starting to build a new observatory. With lots of help from Bird I have had some success with my 14" & although it is good all round scope not ideal for planets so the new build begins.
Gary Mitchell has built the 3 part 600mm tube. Normand Fullum is making the 508mm F3.95 Tech Mirror which is in the polishing phase. The Titan mount has been purchased. Moonlite 2.5" focuser and Atik 9 pos filter wheel will align the ZWO174mm camera. I'll upload photos and update as parts arrive, the observatory is extended and tuning begins getting ready for Mars in 2016.
These images from Normand this morning and he has confirmed the weight as 17.7kg which is just below my anticipated 18kg, figuring tomorrow.
Cheers, Phil.
Last edited by ags_; 04-04-2015 at 09:10 AM.
Reason: add images
Wow that is a big tube. Re the three sections, how do you give it the necessary stiffness to carry a 508mm mirror (which is going to be a heavy). Tube rings, dovetail, etc all the components are going to have to be custom made or do you have that sorted already?
Wow that is a big tube. Re the three sections, how do you give it the necessary stiffness to carry a 508mm mirror (which is going to be a heavy). Tube rings, dovetail, etc all the components are going to have to be custom made or do you have that sorted already?
Tube rings, Mirror cell, radius blocks, end cap, all made by Gary.
Mirror is a Tech type front and rear 5/8th " supported by piers and a 100mm hole in the base and an estimated weight of below 20kg I'll have exact weight in a couple of days.
My estimated total including focuser, filter wheel, camera, guide scope, 2 x dovetails, cables, spider with 112mm Antares secondary under 40KG.
Nice. I'm doing something very similar but with an 18" f3.3 mirror and an alloy truss scope. I have the mirror done but not coated yet and the scope is just about done. The main use for mine will be planetary imaging and some visual work.
Mines looking so far to be just under 30kg.
Nice. I'm doing something very similar but with an 18" f3.3 mirror and an alloy truss scope. I have the mirror done but not coated yet and the scope is just about done. The main use for mine will be planetary imaging and some visual work.
Mines looking so far to be just under 30kg.
Here's a shot of mine. The secondary is just a make do setup for now. I'm going to make a spider that holds the camera(asi120) at prime focus so no secondary will be needed.
It ended up being 24.5KG and the CGE mount seems to be able to take it ok.
The mirror is still uncoated as I've made it myself.
Here's a shot of mine. The secondary is just a make do setup for now. I'm going to make a spider that holds the camera(asi120) at prime focus so no secondary will be needed.
It ended up being 24.5KG and the CGE mount seems to be able to take it ok.
The mirror is still uncoated as I've made it myself.
Haha yeah, the paint has been falling off them for a long time but i then used them for weights when I was making the mirror so they are a bit rusty now. The mount is an old spare I have, my main(good) imaging mount is a Tak NJP.
I need to get a 2.5X powermate, I've got a 5x powermate i use with my 10" f4 scope.
If your mirror figure turns out good you are going to have an awesome planetary scope.
Here's a shot of mine. The secondary is just a make do setup for now. I'm going to make a spider that holds the camera(asi120) at prime focus so no secondary will be needed.
It ended up being 24.5KG and the CGE mount seems to be able to take it ok.
The mirror is still uncoated as I've made it myself.
I hope to have the tube in a few days so I can try it on the Titan mount which I have stripped and serviced. Also the counterweight extension and 25kg weight.
I chose this type for it's advanced thermal cooling properties and light weight. Active cooling via an exhaust fan in the cap then passive via the hole in the centre should keep the mirror very close to ambient all night. That is why the tube is so large it is 100 mm larger than the mirror but very light using 1.1mm aluminium sheet. We will see.
that is looking like a great project - you will end up with a great scope in time for Mars next year so cannot wait to see your results!
Did you consider using a carbon fibre tube instead or would that have created a weight issue?
John K.
Cheers, John. I considered carbon as well as truss construction and both would have been too heavy for the Titan. Plus aluminium has very good ambient properties. I am starting to design a cable pre-stress system to prevent tube sag with resultant and constant collimation changes.
One more question, how are you planning to mount your mirror, and are you going to be using some edge support brackets as well on the mirror cell?
Also - gather there is no need to peltier cool a mirror like this and fan cooling is more than sufficient?
Hi John,
I'll use 2 flexible steel wires which will be supported by old antenna parts as in this image, they are sikaflex'd to the bottom only.
Yes no need of a Peltier as the Observatory is air conditioned and the top cover fitted extractor fan will be run prior to the roof opening and natural convection through the mirror central hole will work continually during use.