A DIY Lazzarotti

[MattT]

A 'grinder' Truss Very nice. How much weight did cutting it up save?

I did the same on my dew shield on my 6" f12 frac and have an idea to do the same with the main tube (3mm thick Aluminium) and then rivet .5mm aluminium over that, might cut out 3kgs...but I digress.

[pmrid (Peter)]

Hi Matthew,
"Grinder Truss" - you've coined a phrase that will stick, I think.

All up I guesstimate I have shed about 25-30 Kgs from the original.

The original OTA was quite heavy - about 12 Kgs from memory. It's 8mm thick and made from a sort of compressed wood. I've forgotten what it's called (sonotube perhaps). Meade used to use it in their big dobs. Doing a grinder on it cut about a third off its weight.

The big savings items included discarding the solid metal pieces that had been crafted by the original owners. The focuser end included 2x20mm thick aluminium collimating plates that were a full diameter (400mm). On top of that was a solid steel primary cell and a steel spider made out of 5mm rolled steel bar about 20mm wide.

I estimate that I have reduced those components by 80% or so and shed at least 20Kgs.

What I couldn't alter is the weight of the primary mirror. If you scroll down a bit you'll find a side-on pic of the mirror showing its depth. It's massive.

Now, we have a heat wave and the concept of "seeing" has just gone out the proverbial door. And I gather the present heat cycle is not going to be short-lived. It may well be (as it so often is) well into 2016 before we see any decent astro weather patterns returning.

Peter

[RobF (Rob)]

Interesting read Peter and Alex. Sounds like the mad scientists have been very busy in the "evil lair", even if sky conditions aren't co-operating

Worried you both seem to be having too much fun - where is the frustration with things not working? - this is astronomy dammit!

[pmrid (Peter)]

Originally Posted by RobF

Interesting read Peter and Alex. Sounds like the mad scientists have been very busy in the "evil lair", even if sky conditions aren't co-operating

Worried you both seem to be having too much fun - where is the frustration with things not working? - this is astronomy dammit!

Hi Rob. Got a break in the early hours of this morning and was able to get in a couple of hours with this scope. Collimation/optical and mechanical alignment seems to be a problem. Not sure just where the issue is though. And after a couple of hours of frustration, I remembered that I have developed astigmatism of recent years. Never interfered with my imaging but now, it seems, visual astronomy will be compromised.

I think I'll have to pass this project on to someone else to use and go back to my imaging.

Blow, blast and ... well, you know the rest of the script.

Peter

[astronobob (Bob)]

This build is quite an eye-opener Peter, Constructing and applying modifications to the main assemblies.
Ive just for the 1st time googled "Lazzarotti Optics" and what an interesting configuration the "GLADIUS" is !

Also came across this relative article on "Astigmatism" with one of the initial scope lines - may be of interest to you Peter, or maybe you have already ?

Anyway, Totally enjoyed reading your thread all the same !

Rgrds - 3rd or 4th paragraph down introduces the astigmatism.

http://astro-foren.de/index.php/Thre...%80%93-part-I/