Bob Curtiss

I have owned numerous SCTs, Newts, MAKS and Refractors of both varying size and focal lengths over the past 50 years. I purchased two GSO f:12 classic cassegrains, the 6" a year ago and an 8" very recently but long enough to draw some conclusions. The f:12 is free of coma and that is to the edges of an UWA 20mm Meade series 5000. Both scopes are 100% achromatic, they feature quartz mirrors with 96% reflectivity. This is just about equal to a 7" and a 9" in either configuration given the difference between standard reflectivity found in many scopes. There is no corrective lens, the tubes are fully baffled and while the secondary is present as are the spiders, the contrast is excellent with a velvety black background against fully corrected objects. I have heard the 14mm Meade UWA compromised in another forum but those who use it don't know how fine an eyepiece it truly is. Again, edge to edge sharpness with a huge field of view. The same holds true of the 8.8mm and 5.5mm. These are bargain basement eyepieces compared to TV and some others and yet the panorama and field flatness is negligible for the price. Collimation is critical in the classic cassegrains. Yet, if you find collimation of the secondary an issue, you will likely find the same with a reflector or SCT. I purchased Bob's Knobs for these fine scopes and precise collimation can be had with a collimation eyepiece and results in images that are incredibly sharp. I am confident that magnification on transparent skies at a decent altitude above the horizon will allow me to push these to 60x - 80x/inch on close doubles or planets with no more degradation than you'd get at the suggested 50x max. They are compact, lightweight for size and best of all, feature three large setback rings of 2" and to of 1" to be used alone or stacked or removed completely. I find the 2" incredibly well made. Taiwan GSOs are light years ahead of Synta/Chinese optics and the rings will allow the use of cameras, autoguiders and on the 8" it features a top Vixen rail for accessories. I paid tax free, $499 US with free shipping for the 6" and $899 US for the 8" from Agena Optical. They have a master optician check each and every GSO (only) scope they sell out for optical perfection, cosmetics and more. Also featured is a dual speed 10:1 Crayford focuser on the back of the OTA. They are about as good as you can get and a lot more for the money compared to what is on the market. No mirror flop because they are not a part of the focusing....GREAT TELESCOPES! I would know and if you want to compare field flatness, light gathering power and all of the things that a similar priced MAK or SCT can't beat...try a GSO classic cassegrain....you won't be displeased. In fact you'll wonder why you bought either the MAK or the SCT instead.....Oh, standard features also include a full length Vixen dovetail on the 6" and a Losmandy D plate 20" long on the 8". If you have a Celestron mount that doesn't accept the wider Losamady, two adapters are available that allow the 8" to fit a Vixen dovetail. I used one from Orion that needed shimming to fit, a simple and easy way to go for about $5 in parts. 5 STAR RATING ON GSO and I own another GSO f:5 newt that performs marvelously with flat fields with the 82 degree UWA's and using an inexpensive GSO coma reducer. Enhanced mirrors in that scope as well!