6" f/8

[glenm]

A little update on the next project of a 6" f/8.

I have now obtained a focuser for the new refractor build. It's the same as the one I used for the 6" f/10,Skywatcher 2 speed. I like this focuser,it's a good price and there are a few used ones around due to people 'upgrading'. I'm pleased that they think they need to upgrade

I have also more or less finished the fibreglass countercell and fibreglass focuser holder. These need just the holes drilling and tapping for the cell and focuser.

I've cut the postal tube to length after drawing out the light cone on a piece of paper so that I could place the countercell,focuser holder/focuser and diagonal into the light cone. I've also cut out a few pieces of the 6" postal tube to add a little extra strength. I intend to use a baffle system to be part of the 'structure' also.

That's about it for now.

Regards.
Glen.

[Watcher3]

Sounds great Glen. Til now, any comparisons done to the commonly available F/8 scopes were made with the ISTAR F/10s. I'm anxious to see how the F/8 performs. It would be really nice if you could get the opportunity to set up next to someone with a good example of a Celestron/SkyWatcher.

[glenm]

The lens was tested against a mass produced 6" f/8 and was found to be better.

I bought the lens from someone who didn't want to carry on with the project.

I've done a little more work today on the focuser end. Glued in three split rings of paper tube to strengthen the tube. Fitted the focuser into the holder.

I've given the outside of the tube just one coat of outdoor varnish so far. Lots to do yet.

Regards.
Glen.

[glenm]

I've just added a sheet of 40 gram glass cloth to the outside of the tube. I did this by using outdoor varnish. I'm not sure if this will work but I do have plenty of tube if it doesn't.

What worries me is delamination. I suppose if it's properly sealed it shoudn't be a problem.

What do you think people?

Regards.
Glen.

[glenm]

I have now changed my mind about this build.

I am going all aluminium again. It's such a nice material and polished up the thermal qualities of the OTA are excellent.

Regards.
Glen.

[borispider]

I always wondered about tube material in my day-dreaming's of building a refractor. To see someone trying
lesser expensive stuff like postal tubes or maybe sonotubes excites me.
If I EVER had the $$ to build a refractor it would possible be a 4"-ish and weight, I don't think, would be
an issue with this size and these materials.

[Watcher3]

I like your polished aluminum trade mark OTAs, but I'm curious. How did the glass cloth with varnish turn out? I'm sure there are lot's of folks looking for budget solutions.

[glenm]

Well,it just delaminated for some reason. I've had a ponder on how it did this,but can't find the answer. I've laminated glass and carbon cloth before on model boats and aircraft. The only thing that it might have been was the age of the varnish and the cold damp weather.

I only went down this road due to the closure of the jobbing shop in the village. I have since found another machine shop which I visited yesterday at 2pm with the aluminium and 2 drawings. One for the focuser and one for the countercell. The owner called me this morning at 10 am saying they were ready.

I was a little gobsmacked about the quick service. The machining is some of the best I've seen in a long time and everything fit perfect. The price was also what I expected. Well impressed. I'm going to drill and tap the pieces myself.

I started polishing the tube yesterday. The tubes were wrapped in heavy duty plastic and are in good condition so polishing should be quite a bit easier. Again,I'm using nylon pan scrubs for the initial polish.

Regards.
Glen.

[glenm]

Just a pic of the countercell and focuser holder.

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[glenm]

Sorry it's been such a while since being on the site last. It's just that things go on the backburner for a while.

I thought I would update on the 6" F/8 build.

I did finish it some time ago. I think I may have to keep this one instead of selling

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[glenm]

Another.

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[glenm]

Last one I promise

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[Watcher3]

That's a promise I hope you don't keep! Beautiful scope Glen. How does it do compared to the F/10?

As you are the king of polished aluminum, maybe you can answer a question for me. I'm looking for a slightly different look for a 60mm Carton build. When you're polishing up the aluminum, is there a point where it looks good, before you get to the mirror finish? I'm wanting to use polished brass for the connecting bits, and I'd like more of a rich luster, maybe with a high gloss clear coat, on the aluminum. Is there something in between dull gray metal, and a chrome look?

Thanks
Joe

[borispider]

That is a beautiful scope Glenn.

[Mike]

That is one good looking scope Glen. I love that polished finish. Just beautiful. Can you tell me what kind of rings?

Mike