The mount is essential in astrophotography. There's no point having a great telescope or refractor, a fancy camera or a sensational astro camera if the mount isn't capable of properly tracking your target. Is the price difference between frames related to quality? The more it costs, the better? I offer you an article on my experience with the Skywatcher EQM-35 pro which I used for almost a year.
This motorized equatorial mount with Goto is one of the most affordable on the market in terms of price (around 650£ /900 $). In addition to accommodating a telescope or a telescope, it can be adapted to accommodate a digital camera if you wish, for example, to do astrophotography of the milky voice or star trails. Its maximum load of 10kg allows it to support a weight of around 7kg at most for astrophotography. It is therefore intended rather for astronomical glasses and more generally for light optical instruments.
My Set-up
My Skywatcher 80ed evostar scope is ideal for a mount of this type: light, reasonable aperture of 80 mm for a focal length of 600 mm, it adapts very well to the capacities of Frame. Added to this is my digital camera (Canon EOS RP) or my 533mc pro color camera which I control with my Asiair plus. Little by little, I also added accessories like an autofocuser and a zwo filter wheel. In the end, a weight of around 5 kg for this frame where I could go up to very 7 kg.
Balance adjustments
During the first outings, a surprising problem appeared when balancing: the mount seemed to have so much friction between the axes that the mount remained stable in all positions even if the balancing was completely wrong. After researching on the internet, I was able to realize that this was regularly the case among other users and that it was a completely solvable problem. Thanks to this YouTube video from Kamil Pekala:
In reality, it is enough to simply disassemble the polar viewfinder and unscrew the discs between the axes in order to reduce friction and thus improve the fluidity of the mount to achieve precise balancing.
Mount performance: advantages
This mount, the best price for a motorized equatorial mount (gears), is perfect for beginners and for a light set-up like an astronomical telescope. Thanks to my set-up, I was able to very often obtain an RMS below 1, around 0.80, when the conditions were good. Once the friction problem had been resolved, the balancing was done very precisely and the polar station was also set up, very often reaching 0.2'' precision. With a telescope and an autoguiding camera, I was able to achieve exposure times of 600 seconds (10 minutes) with the best performance however for exposures of 180 to 300 seconds (3 to 5 minutes). It is therefore surprising for its cheap price and will make beginners already very happy with the result!
Mount performance: disadvantages
Although it is excellent for its price, some disadvantages arise with the frame due to its backlash. Indeed, in addition to its fairly large periodic error, the mount presents a certain mechanical play (backlash) which tends to deteriorate the precision of polar stationing. In addition, the altitude adjustment is done by two screws that you have to play with. To achieve excellent precision, it is therefore necessary to make extremely fine movements which are difficult when managing two screws at the same time. The one-screw system like on the Zwo AM5 is much more appropriate for example. Its weight can also be problematic. With its 13 kg, without the rest on it, you shouldn't need to go too far in the garden with it! Last negative point, while other mounts can be modified to change the motorization by installing belts, this is unfortunately impossible with the EQM-35.
Conclusion
The EQM-35 has many advantages both in terms of price and performance (with some adjustments). It is perfect for small set-ups and allows, with autoguiding, exposure times of 3 to 5 minutes, even reaching 10 minutes in good conditions. So it's worth a try if you're on a tight budget?
Did you like this article? Do not hesitate to write to me with your questions and visit lesson no. 3 intended for purchasing a frame to learn more about the elements to take into account to make an intelligent and sustainable purchase.
See you soon!
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