Looks like GSO will be releasing their 16" mirrors for ATM'ers

[centauri]

Ok just got an email saying they have stock and preferred payment is T/T.
So I guess that means they will deal with us.

Now I just have to make a decision whether to go for this or my original plan of an ED refractor.

[CoombellKid]

Hmmm, when I first emailed them before I posted this thread, they quoted me
somewhat cheaper than the price you have quoted, US812.00 door to door.

Have them do what Imaginova do, class the shipment as educational. It might
work!

regards,CS

[Satchmo]

Originally Posted by ausastronomer

Keep in mind that these aren't premium mirrors but certainly quite good and most people wouldn't pick a difference except when the scope was fully cooled, expertly collimated and seeing was very good.
CS-John B

Having owned such a mirror ( 16" 50 mm thick plate glass ) I feel I can speak with experience . With a typical lag of 3 or 4 degree C even with a fan between mirror and ambient , and a temp induced figure bend of 1 or 2 waves on a 14kg 45mm thick chunk of glass this size , even a rank beginner will certainly picks the difference against a thinner Pyrex when they try to use anything but low power. The quoted 1/2 wave P-V wavefront ( 1/12wave RMS surface ) is a reasonable aim for the manufacturers for such a thermally unstable chunk of glass. Experience with the smaller Chinese mirrors can be thrown out the window when you talk blanks of this kind of thermal mass. You guys probably need to inject a dash of realism about what is being offered for AUD $1500 There are no `free lunches' with optics.

Mark

[mick pinner]

just for comparison Mark what sort of $ figure would you put on a mirror of this size and good quality?

[Satchmo]

Mick

There are many companies doing this sort of mirror from thinner fine annealed Pyrex and you could expect to double that price.

When it comes to building your own 'scope I'm biased towards quality of course, though I understand the attraction of cheap ready made telescope that brings such aperture: just urging realism about the potential problems.

Mark

[mick pinner]

thanks Mark, l was just trying to get it into context from someone in the buisness.

[centauri]

I hear what your saying Mark, and thanks for your input.
It is just a case of you get what you pay for in the end.
Cheers for the insight.

[AstroJunk (Jonathan)]

Originally Posted by Mark Suchting

The quoted 1/2 wave P-V wavefront ( 1/12wave RMS surface )

I brought this up in another earlier thread, but didn't have Marks wisdom to draw on ...

1/2 PV isn't very good is it? (ignoring all other factors auch as temp/flex etc). At best that will be ok, but as has already been mentioned - useful for low power only.

I haven't quite got to grips with RMS - I still understand PV better - my mirror making was rather unscientific however!!