cq350 review

Who is this mount for?

To do astrophotography seriously you need a seriously big telescope. And to carry a big telescope you need a big mount. Up until now that meant splashing out about five thousand pounds but Skywatcher’s new CQ350 astrophotography mount claims to allow you to image with a massive and I mean MASSIVE 35kg telescope for just £2.5k. Wow. A potential game changer. But can it really do it?

Check price for CQ-350

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In this review I test the CQ350 mount with a Celestron C14 HD Edge. It’s a massive scope. Having lugged the C14 around for a couple of months I can’t imagine anyone wishing to use anything bigger. I’ve just weighed the C14 on the bathroom scales and I can report its nearly 25kg and with camera gear we’re hitting 27kg (60lbs).  Close enough to 35kg (77lbs) to be a good test and anyway goodness knows what scope you’d need to hit 35kg. It would be a monster.

cq 350 carrying celestron C14

Quick Verdict

Sky-Watcher’s CQ350 PRO mount is great for astrophotography. It’s not perfect but it is great. It can guide a 27kg load with an accuracy better than 0.7 arcseconds even on targets close to the horizon. On targets higher in the sky the accuracy increases up to about 0.5 arcseconds or more. It’s easy to use. It’s well designed. Its excellent value for money. All in all Sky Watcher’s dominance of the budget mount market is spilling over into mounts for serious scopes too.

PROS

  • Built for astrophotography
  • Expect guiding accuracy of 0.8 – 0.4 arcseconds rms without PEC.
  • Its ‘car’ portable (no mean feat for such a heavy duty mount).
  • Excellent value

Cons

Unboxing

Massive thanks to my lovely patron Andrew Abbott-Tarrant who lent me his CQ-350 mount which he hadn’t even had a chance to use. You sir are a real gent.
cq 350 boxes
Boxes containing the tripod, counterweights and CQ-350 mount
cq 350 packaging

The mount head  itself only weighs 15kg. 10kg lighter than the sky-watcher eq8. This makes the CQ350 mount an option for packing up in your car and taking to a dark site. And for me that is a big deal. I live in London so to get the best out of a mount I need it to be ‘car’ portable… and this heavy duty mount is! The two counterweights are 10kg each and the tripod is 15kg – the same as the mount head. You can buy this mount with or without the tripod. On its own the tripod costs about £500.

If you need to carry this lot any distance then you’ll know about it but critically nothing is so heavy that the prospect of carrying it fills me with dread and prevents me from actually setting up. I think the size and weight of this heavy duty set up is most impressive. If this mount works Sky Watcher are surely onto a winner.

The mount doesn’t come with a polar scope. But that’s fine for me because I use Sharpcap’s astrophotography software to get accurate polar alignment. You can buy an £89 polar scope if you wish.

The syncscan handset in included but in this test I will be controlling the mount with a computer through an eqmod cable.

The power cable screws into the mount’s GX12-2 pin female  power socket for a secure fit – this is great. I love power cables that lock in. At the other end the power cable fits into a car cigarette plug socket. Cigarette plug power sockets are absolutely useless. They are so likely to briefly cut the power connection and ruin your astro session that in my opinion they should be banned. Luckily clever old Andrew ( a trained electrician) had already bought a £22 lynx Astro silicon power cable 2.1mm DC Socket to GX12-2 DC Jack which not allows you to hook the mount into a normal 2.1mm dc power jack it also won’t go brittle and snap in the cold. I used a 13.8v regulated PSU for this test.

The saddle can hold vixen or losmandy dovetails and its got nice big tightening knobs which are critical when you use bigger scopes. Well done sky watcher.

cq 350

The Ra and Dec Clutches are in a really nice position on the side of the mount. Gone are the days of awkwardly contorting your hand round the counterweight bar to reach them. Unfortunately the locking mechanism took a bit of getting used to. I struggled to lock the clutches which is a bit scary when you have a massive scope like the C14 mounted. It turns out you need to wiggle the scope a bit before the locking mechanism can be turned and locked. I’m guessing the reason is something along the lines of the clutch doesn’t like locking when the teeth of the ra/dec gear aren’t aligned. This means that it’s not possible to point the scope manually in exactly the direction you want as you will always need to wiggle the scope a little bit before the clutch can be locked. This isn’t a big deal and overall I like the clutches.

Setting Up

balancing the cq 350 mount

Setting up  was straightforward until I discovered that the 2x10kg counter weights weren’t enough to hold the 27kg of telescope and camera gear. An extra 10kg counterweight costs about £100 so I decided to botch and old 5kg counterweight onto the end of the shaft. And that seemed to work ok.

Annoyingly the mounts very useful power sockets which feed power from the mount’s aux power source to your various astro devices is made up of 3×2.1mm female jacks. So to plug into them your gear you need a cable with a male jack at both ends. I don’t have such a cable so I couldn’t check the mount’s power outputs.

GOOD NEWS: when I connected my camera (qhy269m), my filterwheel, the off axis guider and the mount (via the  eqmod cable) into the  mounts internal USB hub and fed a 5m active repeater usb 3 cable from the roof through to my the office computer everything loaded up in my astrophotography software (NINA) first time. This is brilliant. Either I’m getting better at this or mounts are getting less finikity!

BAD NEWS (see usb hub update for more on this): When I took a test image with the lens cap on the image came out looking segmented (see pic).

Untitled

Something had gone horribly wrong with the way the data is coming off the camera and going into my computer. I asked some of the meganerds on the astrobiscuit discord server and got feedback that the reason can be a poor quality usb hub. When I plugged all my gear into my own £15 usb3 hub which I bought on amazon using all the same cables as before the images from the camera were back to normal. One has to imagine I was doing something wrong because it’s hard to believe Sky-Watcher would have made this big a mess of the usb hub. Maybe I need to power it differently. Maybe some helpful person will comment below and tell me the fix but at this moment I think the CQ350’s internal usb hub is astonishingly BAD!

USB HUB UPDATE

I’ve just been speaking to a very clever meganerd from across the pond and he says I should have been powering my 5m usb 3 repeater cable. Turns out all companies making internal usb hubs for their mounts face a particular problem. To make the usb cable link from the saddle down through the head of the mount calls for a number of connections. Every time the signal passes through a usb connection it loses strength. So the internal usb hubs lose as much signal as an unpowered 6ft usb cable. This isn’t problem for usb2 but for usb3 the additional connections make the signal too weak to then pass along my 5m long usb3 cable to my computer. Hence the need to power my usb3 repeater cable. If I’d have done that the mount’s hub should have worked. The reason my simple £15 usb3 hub from amazon worked was because it isn’t hampered by the power draining connections of the internal hub. I hope that makes sense. FYI I’m guessing all usb3 internal mount hubs will face a similar problem.

Polar aligning

I polar aligned by temporarily piggybacking a small guide scope onto the C14 and using the sharpcap software’s polar alignment routine. The mounts azimuth and altitude adjustment knobs are fantastic. The heavy load rotated smoothly on the tripod’s special slippy plastic pads that the mount head sits on. And the large altitude adjustment knob was the best I’ve ever used. When polar alignment was close I started tightening bolts for locking the mount head into place and then ran the polar alignment routine again. Everything worked as it should. Polar alignment took 10 minutes. Well done skywatcher.

First Light

Ultimately to judge a mount for astrophotography you need to find out how little it wobbles when guiding. Now everyone loves to show off about how good their guiding is. They love to show you their phd2 guiding graph and tell you that their mount is wobbling by less than 0.00000000000001 arc seconds. If you want to show of too simply point your telescope within 30 degrees of Polaris and your guiding will be excellent. The real test of guiding is when you’re pointing as far away from Polaris as possible and you can’t get much further away than Orion. This is where the earth’s rotation causes the stars to move at their fastest and it is the region of space where I will be testing how much this mount wobbles whilst guiding. The guiding I get in this region of space will be the worst that this mount will deliver. So if you buy this mount you can expect to get better guiding that this when you shoot galaxies or nebula that are higher in the sky.

The first test is phd2’s calibration routine. Sometimes excessive backlash can cause PHD2 calibration to fail. This is something that happens with cheap mounts. I’m happy to report that the backlash on this mount seems fairly small.  But when I started guiding the mount was all over the place. After about 5 minutes the mount was wobbling with an rms of 1.7arcseconds which is bad. The wind speed was 6-7mph and this may have been enough to cause the mount to wobble. By the end of the first night the guiding was down to 1.1arc seconds rms which is still disappointing.

CQ350 PHD2 GUIDING GRAPH
This is what a not very good phd guiding graph looks like! But read on because the cq350 mount does transform the more you use it.

Second light

cq350 mount by sky-watcher test using Celestron C14
astrobiscuit collimating the C14

A few days later I took the mount and the C14 to a dark site on the South Downs near Bignor Hill. The wind was a bit lighter about 5 mph. This time she guided much better. Round about 0.8 arcs on the Horse Head nebula (this nebula is near the left hand star  in Orion’s belt). I would consider this to be good guiding for a mount in this price range. Later in the night I aimed at a much higher target, the galaxy M106. Guiding was now down to 0.5 arc seconds of wobble (rms). Wow! As I said before targets nearer Polaris are much easier for astrophotography mounts but still this was good. According to my mount specialist mate Dave from Darkframe optics it takes time for mounts to bed themselves in and I think we are seeing exactly that in these results. First light was poor but second light was much better. I wonder how good it will get…

Third light

The last time I took the mount out I was on my roof once again. It was a calm night, I aimed the C14 at the horse head and shot 6x 20minute long exposures using my new 3nm bandwidth optolong Ha filter. Each shot was fine. My guiding averaged 0.7arc seconds rm. The mount had gotten even better.

The Horse Head Nebula in Ha with the C14 on the CQ350 mount. Integration time 2 hours (apologies for the website’s compression)

Conclusion

I am now happy to declare that this mount is very good. The competition would be the iOptron’s CEM70 which is a tiddly bit more expensive, has less load capacity (although at 31kg its enough) and only 9.5kg of counter weight. I don’t know if the CEM70’s usb hub needs a powered usb3 repeater cable but if it doesn’t then that is a bonus. But the big thing for me is guiding. All a mount has to do is counteract the rotation of the earth. Everything else is just dressing. I’ve not seen the CEM70’s guiding graph whilst carrying a decently heavy load. I know that the CQ350 can deliver at least 0.7 arcsecond rms error carrying a 27kg load whilst shooting a low target like the Horse Head. It will of course perform better still with a lighter load and much better on targets that aren’t so low on the horizon. I expect the mount will improve even more and as it gets run in which is why if I had the money to buy a CQ350 I would. Its exactly the mount I need for the bigger telescopes that I would like to start using. So congratulations Sky-Watcher you’ve done a good job. This Segues nicely into mentioning my affiliate links. If you are thinking of buying one please, please, please use one of my affiliate links😁 the next astrobiscuit video depends on it! Thanking you kindly. And thx Andrew for lending me the mount. You’ve got a goodun!

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