I couldn't help noticing the 7 zone foucault test claiming an 0.99 Strehl ratio. Such tests are useful for small slower mirrors but in larger fast mirrors are often idealized in relation to the reality as measuring the all important edge zones edge zones is much harder this way and of course complex figure distortions ( not just simple astigmatism ) more common with large fast and laminated mirrors are pretty much invisible to the maker using these methods. Do trust your eyes and star test diligently before making decisions on the optical quality.
I found the 16" F4 Fullham sandwich mirror I tested that was mentioned earlier in this thread , looked at with sensitive null interferometry to have results nothing like the documents presented here though I didn't see original foucault test results it was supplied with . I do wish you the best results with your new optics and as always trust your eyes.
Yes nothing is caste in stone until I star and planet test it. I never take much notice of tests other than actual usage, fingers crossed it will be of a high standard we will see in the next month or two. It will be very close to a 14" Meade and Bird's 16" so a direct comparison should be easy enough. I did a comparison between Bird's 16" and my 14" Meade the other night on Jupiter which we were imaging at the same time and with the same cameras, the contrast was much better on the 16" as expected but I was impressed also with the finer detail apparent nr the GRS.
The external main mirror adjusters with extensions installed and also the 5 internal tensioners. Work has commenced on the experimental mk1.1 mirror support system which leaves me with 9 alterations before I start the mk2. lol
I did a comparison between Bird's 16" and my 14" Meade the other night on Jupiter which we were imaging at the same time and with the same cameras, the contrast was much better on the 16" as expected but I was impressed also with the finer detail apparent nearr the GRS.
cheers, Phil.
( EDIT )
Hi Phil
I will take that as a complement then as its not often I hear feedback A good mark for Australian manufacturing I hope.
I've seen similar looking pods hanging off the sides of Russian warships in the Persian Gulf, big nasty SS-N-22's (Sunburn Missiles) sitting inside of them. The resemblance is uncanny
First mirror cell completed this will be an interesting project with so many different ideas whirling around.
Now awaiting custom spider and secondary support so that can be fitted.
Observatory addition commences this week.
50:1 gearboxes and new Maxon high res motor for RA on the Titan to be purchased.
Progress is being made, thanks to Bird who knows his collimation 1st light in poor seeing showed a clear image of Saturn. Much still to do re wiring etc.
Phil... by what mechanism is the force applied by the mirror support pads (on the back of the mirror blank) equalised?
It'll be interesting to see how it performs. One would think an 18 point cell would be the go.
But if it works and the stars are round that is the main thing.
Phil... by what mechanism is the force applied by the mirror support pads (on the back of the mirror blank) equalised?
The mirror edge was supported above the cell at 3 points whilst the support glide bases were built up with a type of silicon inside hollow felt pads as the bottom plate of the mirror is curved the same as the top. It was a slow process but when completed the 18kg mirror contacts all glides and can be easily rotated with my little finger. I decided to do this to keep the profile as low as possible and add little extra weight. Not until I start processing planetary images in good seeing will I know if it was worth the effort or successful.
When the good seeing returns I'll know if it was worth doing, until then here are some details of the completed build. The MK2 secondary cell is in design mode and should be complete before November.
wow, what a magnificent Newt. that must weigh a lot, is the Titan up to the challenge ?
That was one of the main things I thought may be a problem but it turns out the Titan handles it easily. The original 25/1 gearboxes have been upgraded to 50/1 and the motors have never even been warm. The counter weight shaft is carrying 60kg and I estimate the scope weight at 65kg. Tracking is excellent with a good polar alignment showing a minor drift after 10 minutes. For deep sky I would spend some time on the alignment but for planetary it's no so important. The seeing is not good at the moment although brief moments show the optics look 1st class. The only Saturn image I have processed so far although in poor seeing l am happy with. When the seeing improves I shall find out how good it really is.
A good mark for Australian manufacturing I hope. 
..... What a piece of ' kit ' this is going to be.....let alone what will be ' seen ' with it. 
