For years, GSO has made dobsonian telescopes sold under various labels. Users of these scopes know the excellent quality of the optics included, and they have a well-deserved reputation for being the finest mirrors in their price range. We are now pleased to offer virtually the entire line of GSO's Newtonian optics in the US market.
GSO's elliptical flat mirrors have the same high quality as their parabolic primary mirrors. Made from optical grade BK-7 glass, all mirrors have a reflective aluminum coating with a reflectivity of approximately 92-93%. The aluminum coating is protected by a silicon oxide (SiO2) over-coating.
GSO uses high-volume, state-of-the-art, high quality manufacturing and test lines. GSO guarantees diffraction limited performance, but their secondary mirrors typically have a mirror surface quality of 1/12 wave RMS at least, and often better. This very smooth mirror surface results in excellent optical performance with practically no light scatter.
Besides elliptical secondary flats, we also offer matching GSO parabolic primary mirrors, mirror cells, and spiders (all sold separately).
Aug 23, 2017
Great job with a great pricePros: Cons: Comments:
Less than a few weeks before the 2017 eclipse I found my secondary mirror surface was peeling from a bad protection coat. So I found this mirror and ordered it as I didn't have time to send the existing off for a resurface. This mirror did the job for a price that didn't break the bank.
This review was provided courtesy of AgenaAstro.comMay 16, 2017
AWESOME MIRRORPros: Cons: Comments:
I bought this for my latest project. I had my primary mirror refigured and coated and it came out to be very accurate. I began to have doubts about this- because it said "at least 1/12wave" and so I wasn't sure if I should try to buy a better mirror or not because I was skeptical that it was even that-
The mirror (of my primary mirror) offered to test this free. He told me its minimum 1/14 wave flat and is an excellent mirror. So, when GSO says at least 1/12 wave, they mean it- and given that, its a high quality mirror especially for 60$. (for the 62.5mm) I would not hesitate to buy one- and would do so before spending upwards of 200$ for a secondary mirror. My feeling is that since I already own it, I will try it. If it doesn't work out, I can always buy a more expensive one later. My review is for a "minimum 1/12 wave" mirror for 60$ and this surpasses that so I give it 5 stars. If it tested less than, I would give 1-2 stars.
This review was provided courtesy of AgenaAstro.comFeb 11, 2017
Better than I expected it to bePros: Cons: Comments:
The original flat that came in my AD10 dob was tested and was a dog - about 1/2 wave flatness, so I wanted to replace it. The usual alternative sources don't make this exact size, so I was stuck with buying another one from GSO, and did so with some reluctance. I was pleasantly surprised to see it fringe test at around 1/6 wave (and better than that in the center), which is not perfect but hugely better than the original. And the cost is quite reasonable. I'm pleased.
This review was provided courtesy of AgenaAstro.comSort by