When it comes to astrophotography, sometimes less is more. But when it comes to having a capable mount to drive your gear, sometimes more is more – and that is certainly the case with the Sky-Watcher CQ-350 Pro. Weighing in at a relatively modest 33 lbs., but supporting a 77 lb. payload capacity, this mount is what I would call a “portable beast.” So how well does it work?
This mount is beefy. As is its tripod – the Heavy Duty Field Tripod weighs as much as the mount, has a whopping 2-3/4” leg diameter, and spans between 39 and 56 inches depending on how far out you extend the legs. Despite the heft, the mount isn’t too difficult to move around – it weighs much less than my Celestron CGE and CGE Pro, and about as much as my Paramount MyT that I consider quite portable.
Assembling the mount proved a bit challenging. I was glad I have a lot of experience putting various mounts together. If I was new to the hobby, I would have had serious trouble. The instructions sent with the mount were incorrect in places, not matching what was in front of me and missing a few important steps. The tripod spreader knob reached the end of the threads on the center post before the spreader made contact with all three legs in the tripod’s lowest position. The tripod plate doesn’t have any grooves or marks to help you line it up, so trying to find the center bolt was tricky, especially since the center peg for the azimuth bolts had a lot of room to move back and forth under the mount. On the other hand, both the mount head and the tripod have bubble levels built in, which made leveling much easier.
The mount comes out of the box set at the lowest-latitude position, but a giant hand knob for adjusting the altitude made relatively quick work of raising it to my latitude. The latitude adjustment is ingenious, the best design I have seen. It moves the polar axis up and down on a gear-like semi-wheel – no need to move a bar to different slots, or to change a bar or set of screws from one group of altitudes to another when you realize your latitude is right in between them. This mount has a continuous movement through the latitudes from 10 to 70 degrees. The manual does not mention the altitude locking bolts, which are not very visible on the mount either, although the correct-size Allen key was provided in the box.
Speaking of knobs and bolts, the RA and declination axis clutch knobs are one of my favorite features of this mount. Similar to iOptron mounts, the CQ-350 has a knob on each axis that flips between two positions – free and locked. Flip the switch to the OFF position to rotate the axis by hand for balancing, and then back to the ON position when you are done (you may need to move the axis a bit to allow for the gears to mesh properly). On top of each knob is another knob, which is also labeled, that locks or unlocks the ability to flip the clutch knobs, providing an extra layer of protection from the clutch accidentally being released.
Another exciting feature of this mount, which turned out to be both a blessing and a curse, is the built-in USB and power hub. It’s located on the front of the declination axis and contains four USB 3.0 ports and three 5.5×2.1mm 6-24V DC power ports. The cables are internal, coming out of the RA axis with a single USB 3.0 B port and a 5.5×2.1mm DC power port for you to plug USB computer cable and device power source into. The 3-prong power port on the front is for powering the mount and a 12V cigarette lighter jack cable is provided. The front box also houses the hand controller and ST-4 ports. The power port and USB port for the dec axis hub are cabled internally, as are auxiliary ports for use with equipment requiring RJ-10, RJ-12, or RJ-45 connections. There’s also a SNAP port on the front panel for sending shutter and focus commands to a DSLR camera with the appropriate cable. A cable for use with Canon EOS cameras is included but cables for other manufacturers are readily available since they’re also used with intervalometers. The SNAP port can be controlled by the SynScan hand controller or the SynScan computer app.
Now, I was very excited to have a built-in USB 3.0 hub; nearly every other mount I am aware of only has USB 2.0 ports despite many new CMOS cameras requiring USB 3.0, along with some focusers and other devices. However, there is probably a good reason for this: USB 3.0 is tricky. You must use short cables, with a total length of less than 6 meters from device to computer, unless you use powered USB 3.0 cables. The first night I used the mount, I had all kinds of trouble with devices getting randomly kicked off, including the mount itself, which I had plugged into the hub as well. I was using a 6m unpowered cable to run from the USB 3.0 B port down the mount and over to my control computer a few feet away. After realizing that this was probably a USB 3.0 cable length issue, I switched to using the powered USB 3.0 jumper cable that Sky-Watcher provided in the box, and I plugged a 5V power supply into the port on the side of the jumper cable. Unfortunately, this was still not enough, and devices continued to get kicked off randomly. Finally, I hauled out my 25-ft powered USB 3.0 cable, which I plugged the 5V power source into as well; this finally solved all of the problems I was having. Sky-Watcher does mention in the manual that a USB cable from the mount to the computer must be less than 1m long. If you are using only USB 2.0 devices and cables, this may not be an issue, but be sure not to plug too many in.
One more head-scratcher of a design choice is that the front control panel, which houses the USB and power-in ports, USB mount control port, aux ports, and hand controller port, is located on the RA axis. That means that all those ports move when the RA axis moves. The hand controller has a rather short, spiraled cable, and slewing the mount yanks the hand controller right out of its cradle. You will need to make sure your cables are long enough and free enough to move with the RA axis. For this reason, I did not use the hand controller at all during my testing of the mount – I used computer control only through the USB control port. If you want to use the hand controller, I suggest getting a longer RJ-45 cable for it.
My astrophotography is automated, so computer control of the mount is essential. There is a dizzying array of apps that control Sky-Watcher mounts, partly because they are on the same architecture as the old Orion mounts. I wasn’t sure what app to use for my application so it took some trial and error. The SynScan app is the one Sky-Watcher mentioned most often but it did not work with NINA – NINA could connect to it but sending commands didn’t work. SynScan is available for Windows and MacOS, and for Android and iPhone if you have the wifi module. EQMOD is an old favorite of many Orion and Sky-Watcher mount users, although it is clunky, lacking in features, and only works on Windows. Green Swamp is a relatively new, nice-looking app that worked great with both the mount and NINA once I got the COM port and baud rates set correctly, but it lacks mount-specific features like star alignment and PEC (Periodic Error Correction), as well as SNAP port control. It also works only on Windows since it works through ASCOM. It also does not have a star and object catalog like the SynScan app does. The Green Swamp app will send the AutoHome command, which is great – all of these control apps assume the mount is in the home position (counterweights down, pointed at the celestial pole) on startup, which is problematic during a power loss or remote operations. AutoHome (which is also available in the SynScan app and hand controller) will move both of the axes in small increments until it detects that it is in the home position. Moving slowly is nice, allowing you to catch any errant behavior before the camera or telescope hits the tripod. I settled on the Green Swamp app for nightly mount control via NINA, and the SynScan app for special functions, although you must home the mount when switching between the two and the SynScan app lacks a go-to-home command (it has only AutoHome and Hibernate, aka “park here”). Green Swamp may not work on some older computers. So, basically, there is no single app with all the functionality needed to operate this mount from a computer.
I don’t star-align my mounts for doing astrophotography, since plate solving and centering will get me on target relatively quickly. But for those who want or need to do a star alignment, it can be done on either the hand controller or the computer via the SynScan app. On the SynScan app, after you have entered your location and time, a list of bright southerly stars is presented from which to choose the first star, and then northern stars for the second, and finally another southern star for the third. Hopefully, you have a view in all those directions, especially since the list of northern stars for the second star is quite short. After polar aligning using SharpCap, the mount’s guess on the first star’s location was far enough off that it took some time to find (a Telrad or finderscope is helpful here), but its guesses for the second and third stars’ locations were pretty close after the first star, even at my 2,350mm focal length. The app and hand controller have a polar alignment routine that I did not test.
The critical question for astrophotographers is “How well does it track and guide?” The short answer is, very well.
On a particularly nice night, the three-hour span shown above had a total guiding RMS of 0.40 arcsecs, which is as well as my Paramount MyT performs under similar sky conditions. Shorter segments of the log showed similar results. Note that I was using an off-axis guider on my Celestron Edge HD 9.25”. Over the course of 12 nights, the average RMS was 0.68 arcsecs, with a maximum of 1.04 arcsecs and a minimum of 0.39 arcsecs. With my ZWO ASI2600MC Pro on my Celestron Edge HD 9.25” without the reducer, my pixel scale is 0.33 arcsecs; with this guiding performance, with both 1-minute and 5-minute subframes, I only threw away a few frames per target per night, other than on nights with poor seeing and transparency where a few elongated or jumpy stars were removed. In general, the stars in the images I’ve taken using this mount have been quite stable and round, even without using PEC.
I’ve done a lot of good imaging with this mount even with my most challenging setup – a 2,350mm focal length telescope and a total imaging payload of 26 lbs. This is far below the mount’s rated capacity but a long focal length is a critical test of a mount’s tracking and guiding ability. The CQ-350’s payload-to-weight ratio is impressive; a 77-lb payload capacity for its 33-lb mass. Together with the heavy-duty field tripod, it may not be the most portable rig but it’s certainly not meant to live only in an observatory shed; I would take it to a star party or astronomy club member’s night outing. The tracking performance was impressive, rivaling my Paramount MyT for less cost. Sky-Watcher made some strange design decisions, such as having the mount power and USB connections on the moving RA axis instead of a fixed point, requiring putting extra planning of cable runs, but the number of built-in through-the-mount connections was nice, especially with the USB 3.0 hub and DC power connections. There are some other design elements that I love, particularly the clutch knobs and the altitude adjustment mechanism. Sky-Watcher could do a better job of clarifying the confusing software landscape, but there is something to be said for having flexible software options. Despite some initial headache in getting the mount built and reliably connected to my computer, it is running smoothly now, and I have acquired a lot of good images with it from my backyard.