Equipment Evolution Part 2: A new Mount

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My old NexStar Evolution mount is a really great "grab and go" mount for visual observation. It is pretty light as it doesn’t require a counterweight, it comes with its own rechargeable battery and its own Wlan - so basically everything you need to start observing super quickly. I was surprised how far it took me on my astrophotography journey and it is probably viable with a small telescope or tele lens. However, undoubtedly it has quite substantial limitations when used for photography with my Celestron C9.25:


  • The mount is not really balanced on any axis. So it was very hard to make guiding work in many cases. It usually took a while of adjusting parameters or guiding in only one direction depending on the weight distribution.  
  • For higher declinations guiding did not work at all.
  • Even when it worked tracking and guiding accuracy was not really good enough for imaging at higher focal lengths. Typical guiding errors were in the 3“-4“ range.
  • The mount geometry requires the use of a diagonal to have enough clearance at the bottom.  This constrains the possible optical configurations and  can introduce unwanted reflections. 


The most common way to address these issues is the use of a german equatorial mount. So that is what I started looking for. 


Skywatcher EQ6-R Pro vs. Celestron CGX


The mounts most commonly used by astrophotographers for telescopes like my C9.25 are at the moment probably the Celestron CGX and the Skywatcher EQ6-R Pro.    Looking at reports on the Internet both have happy and unhappy users, particularly the CGX appears to have had some issues in the beginning. The CGX is about 45% more expensive, so I was looking at the potential benefits:

  • max payload of 25kg is slightly higher than the EQ6 at 20kg
  • it has encoders that allow readout of the mount position even if it has been moved manually 
  • cabling is happening internally, so no cables connecting to moving parts
  • it would directly interface with my celestron focuser, without requiring a separate USB connection 
  • the black/orange color scheme matches the rest of my equipment better than Skywatcher‘s white/green 

Given the way I intended to use the mount these items were really more in the "nice to have" category. I decided that they didn’t justify the price premium for me and went with the EQ6. As many are using the EQ6 I expect it will be easier getting advice and help from fellow astrophotographers and repairs may be done locally. 


The new setup with the EQ6-R Pro mount
The cabling probably still needs some work 



So far the mount is performing as expected and I am getting guiding accuracy <1“ RMS. The polar scope is a nice feature to quickly do a polar alignment, if I don’t want to go through the process with Ekos or NINIA.  I moved all the electronics in a plastic box and removed the diagonal from the optical setup, adjusting the distances to meet the backfocus requirements. 

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