iOptron Smart EQ Pro – quick review

About two months ago I purchased iOptron Smart EQ Pro mount. It is a tiny equatorial mount with GoTo that, according to manufacturer, can be used for visual with small optics and for wide field astroimaging. This second application is the one that interested me 🙂  Smart EQ Pro has maximum payload of 5kg, and I really would not recommend to exceed it. On the other hand however, mount is really small and lightweight. It can be easily carried as ready setup with instrument already fixed to the saddle. 

iOptron Smart EQ Pro mount with wide field imaging setup

Mount tripod is steel with plastic fixing between legs and top plate. Mount head has place to put 8 AA batteries that should be enough for one night session (up to 16 hours of work). There is also small counterweight that can be used to balance the mount. RA axis has standard clutch, and Dec axis is fixed to worm wheel, and there is only a saddle that can be rotated manually, and this construction has a small side effect. There is a hole in Dec shaft for polar scope, and if you want to align the hole with polar scope field of view you need to rotate Dec shaft with hand controller button – it cannot be done manually, because only saddle rotates then. The mount itself is fully equipped equatorial mount – worm wheels and worm gears are metal, there are DC motors with encoders in both axes, there is ST4 autoguiding port (version Pro only). Polar scope is standard iOptron construction with precise scales engraved. Hand GoTo controller has all basic capabilities – many ways of alignment, large object database, you can control polar scope LED brightness. And it also has built in real time clock with battery, so it remembers both date and time and you do not need to enter it before every session.

Smart EQ mount with max extended legs

A few days ago I had a first chance to use this mount. I set it all up with QHY163C camera, 135mm lens and small guidescope with QHY5, aligned to north pole, and choose Multi star alignment from menu. First star – Arcturus – landed about 15 degrees from the frame centre – pretty far. I centred it and choose second star – Deneb. Not much better – about 6 degrees. Huh 🙁 Ok, probably I entered some wrong values to hand controller, so I moved the mount with buttons to my target and started imaging session. Guiding with Maxim worked fine, RMS error was about 1.5 arcsec in each axis, and maximum peak error was never larger than 4 arcsec. It was more than enough for my wide field setup with pixel scale about 6″/px. I collected over 2 hours of RGB material. 

Test setup ready for session

Next day I checked what is wrong with GoTo. With help of iOptron support I recognised, that problem was in Dec motor encoder – it loose some steps. I disassembled the mount head. You need to unscrew four screws in the top plastic cover, disconnect connectors for RA and Dec motors, and for battery holders. Then unscrew four allen screws in the mount head bottom and then you have access to both motors. It quickly turned out, that plastic encoder wheel was fixed in wrong position – I pushed it more towards the DC motor and bended IR transmitter a little more to the wheel. Then assembled all pieces together.

Next night it turned out that repair was successful 🙂 GoTo worked fine, first star landed about 2 degrees from the field of view centre. Then Deneb and Vega close to centre. I had no problem to point my setup exactly to the same target as night before and collect another 2 hours of the narrowband Ha images with QHY163M camera. Single frame exposure time was 5 minutes and guiding worked very well. Only one frame among thirty was trailed in Dec direction, but it is possible that I kicked accidentally mount leg. Mount can be also connected to PC computer with iOptron ASCOM driver. I tested this configuration as well and encountered zero problems – MaxIm DL built in planetarium recognised driver and showed position in the map. Also slewing to selected point or object worked well. 

HaRGB composite of Cygnus constellation centre. Imaged with Smart EQ mount
Annotated image

After this two sessions I am pretty happy with this mount – it meets my expectations for deep sky wide field imaging. However for 135mm lens I recommend guiding, because even with exact polar alignment 180s unguided images were a little bit trailed in RA. Mount periodic error is significant, about +- 30 arc sec, and unguided deep sky imaging is possible only with short focal lenses (no more than 50mm in my opinion). On the other hand guiding accuracy should be good enough to handle 200-300 mm lenses, even with long time narrowband exposures. GoTo sounds are a little bit scary at the first time 🙂 I recorded it and sent to iOptron support, but they confirmed it is normal and no reason to worry. And I really do not recommend to overload this mount – if you want to put your 150mm Mak for visual or 90mm triplet imaging setup with camera and guider – look for other mount, like ZEQ25. Smart EQ Pro in my opinion is not for it. But as portable mount for holiday imaging and sky gazing – yes. 

Cygnus constellation centre in hydrogen alpha band. Imaged with Smart EQ mount

Clear skies!

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