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View Full Version here: : 16" GSO Quality issue?

AstroJunk
13-01-2007, 07:45 PM
I see in the latest Andrews add in S&S that the 16" is described as having a wonderful 1/2 wave primary mirror.

That's not even diffraction limited:(

Well, I suppose it was too much to hope for a good 16" mirror at that price. I hope that Meade do a better job.

On the other hand, it does more closely follow John Dobsons original paradigm of building a big cheap poorly made, poorly performing light gathering machine that can at least cut through the city lights sufficiently to show a faint fuzzy to a passing stranger who knows no better!
mick pinner
13-01-2007, 07:50 PM
what are the quoted specs on the 16" Lightbridge?
CoombellKid
13-01-2007, 07:55 PM
Could easily be a typo on the web developers part, could really mean 1/12
which I think (but dont quote me) is the standard.

regards,CS sunny days
mick pinner
13-01-2007, 07:58 PM
l would have thought that the mirrors would have been made by the same supplier for both companies, for mass produced scopes like these the mirrors will cost the manufacturer next to nothing anyway so why bother with a rubbish mirror.
CoombellKid
13-01-2007, 08:13 PM
Mick,

They are, they're made by GSO

regards,CS sunny days
AstroJunk
13-01-2007, 08:21 PM
Fingers crossed it's a typo then!
CoombellKid
13-01-2007, 08:29 PM
As quoted from here

http://www.gs-telescope.com/content.asp?id=95

"Our parabolic mirror size from 6" to 16", all of these mirrors were made
by BK7 or B270 quality optical glass and all the mirror surface quality
over 1/16 wave RMS at the least, typically better."


Sorry I got it wrong oooop's : )

regards,CS sunny days
AstroJunk
13-01-2007, 08:39 PM
Which is 1/8th wave in old money - and that's perfectly ok.

What a relief, I was hoping to get one for an ultra portable (it's all relative!)
matt
13-01-2007, 08:48 PM
That's good news...

1/2 wave would have been a huuuuuge disappointment.