Telescope Review: Guan Sheng GS-600 8 inch f/4 EQ

2003-05-31 by Rick Towns

Telescope:	Guan Sheng GS-600 8 inch f/4 EQ
Type:	Reflector
Description:	200mm f/4 Newtonian reflector, 8x50 achromat finder, 25mm & 10mm eyepieces, $899 CAD.
Setup:	I traded in my Orion StarMax for this scope just a few months ago. The deal involved just swapping the OTA's, so my test sample doesn't have the 8x50 finder (I have a custom made 12x60 finder instead) and I don't have the 10mm eyepiece, although I did use my 13mm NexStar Plossl with it. The scope is now my primary unit, designed to deliver the deep sky views that the StarMax 127 simply couldn't.
Appearance:	I already owned the Sky Mentor EQ-3 mount, which this Newt is sold on. So at the time of the swap, Ray Khan sold me an extra counter weight and included the tube rings. My overall impression of the mount is that it's super sturdy. It's identical to Orion's SVD mount. There is a small amount of play in the right ascension axis, but nothing that causes problems during use. The OTA itself is an enameled steel tube, with a four vein spider holding the large (22%) secondary in place. The 8 inch F4 mirror is advertised as a 1/8th wave PTV parabolic primary. Everything looks awesome down the tube, although the inside seems a bit glossy. I'm sure some Flocking paper would improve the contrast on this beast. The all aluminum rack and pinion focuser is a 2 inch job with a 1.25 inch stop down. It has a focus lock and the draw tube is flat black (imagine that!). The tube rings are thick, sturdy and felt lined. The whole scope is very solidly built and has a nice heft to it. Overall, I'd rate the appearance very good and the construction also very good.
Performance:	I've only had the "big gun" out under dark skies once so far, and I've not had a chance to star test it yet. However, the views of Saturn and Jupiter were very good - exactly what I'd expect from an 8 inch scope. The views were crisp with decent contrast. On Saturn, the Cassini Division was plain as day, and the GRS on Jupiter actually jumped out at me. In my StarMax 127, the GRS was visible, but it was tough to pull out. Perhaps I had good seeing that night? Where this scope really excels in on the deep sky stuff. M13 in Hercules was a gorgeous swarm of sharp stars. Actually, this scope gives very tight star images (tight little pin points) for a fast Newt. I viewed a variety of other clusters and galaxies, and they all showed an adequate amount of detail. I'd say this scope performs as well or better than most 8 inch SCT's I've owned/used. One member in our club has a Celestron Ultima, and it has the best optics I've seen on an 8 inch SCT. I'll report back once I get these two scopes to go head to head. The motions on the mount are extremely smooth with little to no backlash, and no excess travel once you stop turning the slow motion controls. When properly balanced (both for/aft and with the counter weights), everything is very easy to move and holds it's position well, even with the axis clamps off. On the night I was out, I had a Skywatcher Red Dot finder on the OTA, and it was very easy to get targets dead center in the 25mm eyepiece. With a short 800mm focal length, the scope is certainly a wide field instrument - the 25mm provides a mere 32x and a huge 1.5 degrees of view. This is 50% more than the MAXIMUM possible with the Starmax and double what the Starmax shows with the 25mm. The scope is actually very portable for an 8 inch unit. The OTA in the original cardboard box (with the provided styrofoam mouldings) and the EQ mount - EVERYTHING fits easily into the trunk of my 1995 Grand AM GT. My old 10 inch Meade wouldn't fit at all in the trunk, and had to be transported in the back seat, with the Dob base occupying the passenger's seat. Now, I can haul my entire scope plus three passengers to a dark sky site! All that, for only giving up two inches of aperture and gaining an EQ mount (with tracking as an option). This is the ultimate deep sky companion for a travelling astronomer.
Pros:	Good aperture Very portable for it's size Sharp optics Excellent deep sky images Surprisingly good planetary images Excellent 2 inch focuser Very sturdy EQ mount Good quality eyepieces and finder Very smooth controls and very easy to use for an EQ Fantastic price - half the price of an 8 inch SCT!
Cons:	Fast f/4 optics require very accurate collimation to keep images sharp Although portable, it's still a handful for someone of smaller stature
Conclusions:	Overall, this scope is a very strong performer. It's an excellent choice for those who want good aperture, but still want to be able to travel with the scope. It is basically an 8 inch Dob with an bonus of an EQ mount. For those that don't mind a Dob mount, they should buy a 10 inch Dob instead, but for those like myself who really want an EQ, this scope is about the best bargain going. The bottom line? Recommended (Great optics, sturdy build quality, excellent price).
Reviewer:	Rick Towns
Review Date:	5/31/2003

My name is Rick Towns and I am an amateur astronomer and computer programmer from Canada. This is a collection of interesting posts I've gathered over the years.