EQ6-R first time look
I recently received from Delta Optical company for tests new Sky Watcher EQ6-R equatorial mount. It will be a successor of well known EQ6/NEQ6 mounts that found their places in many astronomy amateurs setups all around the world. Mount design has changed a little. Mount base with altitude and azimuth regulations is now more solid, and mount head looks more modern. Polarscope cover is not screwed anymore, and in the control panel one can find SNAP port to control DSLR shutter for long exposures. There are also some changes inside – belt drive system,
auxiliary encoders (there is no auxiliary encoders in EQ6-R) and permanent PEC ability.
Azimuth adjustment bolts are thicker, but most important fact is, that main altitude adjustment bolt is now very solid – it has 15mm diameter (it was 10mm in the EQ6). Additionally there is small plate between altitude adjustment bolts that makes polar alignment very easy even when mount is fully loaded. PPEC curve that can be stored in the RA motor controller has 100 measurement points. Mount itself seems to be a little bit faster than EQ6 – it rotates 90 degrees within less than 20 seconds. Power supply voltage can be within range 11 to 16V DC and recommended supplier should be able to provide 4A of current.
Mount has arrived in two heavy boxes – mount head and tripod with counterweights. Boxes contains following items:
- EQ6-R mount head
- 2 inches legs tripod (the same as EQ6)
- accessory tray
- counterweight rod extension
- SynScan V4 controller with handle
- two 5kg counterweights
- PC cable, power supply cable, Canon shutter release cable
- two allen keys
For testing I used ESPE 12V 7.5A power supplier. I unpacked tripod first. It is the same item as for EQ6 mount. That is good news for telescope pier owners, because they do not need to replace pier head if they want to upgrade from EQ6 to EQ6-R model. Plus this tripod has proven to work pretty well.
Next item I unpacked was mount head and I smiled – there is nice handle in the mount head, that helps a lot. It is pretty comfortable now to carry the head and also to put it on the tripod. Then I checked SynScan remote control. It is V4 device, that allows to control new mount functionalities: PPEC, DSLR shutter sequences, star lapses, etc. SynScan handle is mounted to one of tripod legs, but this is not fortunate, because above each leg there is either azimuth or altitude adjustment bolts that are in the way.
I connected all elements together, turned power on and started to play with mount. All mechanics worked very well, noise level is pretty low, similar to my belt modded version of EQ6. But noise is different, with higher pitch, similar to EQ8 I’ve heard some time ago. During this dry runs I tested most of SynScan functions plus connection with PC. It worked well with ASCOM SkyWatcher 6.0.5999 driver, but not yet worked with EQASCOM 2.00i and 1.29a. More about it later.
Next night I saw some stars. Not many, I estimated NELM for 4.5mag top – there were some high clouds hanging above, but it was enough to start tests. I put Sky Watcher EQ6-R outside, attached SCT8” and one counterweight, and placed my ES 68* 24mm eyepiece. This combination gave about 90x magnification and real field of view about 45 arc minutes.
Using SynscanInit Android application I set all required data to SynScan remote and aligned mount to north pole using pole finder. New polar alignment adjustment bolts were easy to operate using gloves as well. I set the mount in home position (without any spirit level) and started three star alignment process. First star – Capella – has been found about two degrees from the centre of 6×30 finderscope. I centred it and then went to Pollux. Last alignment star was Deneb. Process was easy and quick and I have not noticed any backlash during alignment when RATE was set to 6 and 3. After alignment has ended SynScan informed me that pole alignment error is almost zero in altitude and 5 arc minutes in azimuth. Then I spent some time on observing different targets scattered around whole sky. Here is a few of them:
- M15 globular cluster. After GoTo ended the cluster appeared about 6 arc minutes from centre. It was clearly visible at this poor conditions plus low latitude
- NGC7331 – galaxy has landed very close to eyepiece FOV centre. I was not sure it will be visible this night, but it was an obvious prolonged shape using direct vision
- M35 open cluster in Gemini. It occupied almost whole FOV
- Venus – has landed about 10 minutes from eyepiece FOV centre. Nice view and very bright object, although low latitude
- Mars – orange ball without any details
- Castor – almost in the centre of eyepiece FOV, both components clearly visible and separated
Pointing accuracy and stability
All other targets was located with precision better than 10 arc minutes. Conditions became worse, so I turned mount off and went back home. This first night mount worked very well. I set it all up without extra precision (no home position markers, pole finder polar alignment) so it better reflected common usage in the field. I suspect if one put more effort on precise alignment the pointing accuracy would be better, although I think the one I achieved with 90x eyepiece is pretty enough.
SCT8” telescope is not any challenge for Sky Watcher EQ6-R. Focusing caused no significant vibrations and pressing eye to eyepiece resulted in minimal tilt. Tapping on telescope tube or tripod legs caused vibrations that stopped within 2-3 seconds. Probably most annoying element that night was SynScan controller display. When temperature dropped to minus 10*C it became very slow. Contrast was still ok, but displayed characters changed with significant delay, so I needed to pay some attention when entering values.
I am also not sure what is the purpose of auxiliary encoders (there is no auxiliary encoders in EQ6-R). I imagined they would work like in GoTo dobsonian telescopes, however when I released the clutches and rotate telescope manually, the position that controller displayed has not changed at all.
Imaging at 740mm focal length
Few nights later I put Sky Watcher EQ6-R on the pier in my astro shed. Then I put onto it my astro imaging setup – 130mm Photoline refractor with QHY163M camera and filter wheel. That is a little bit over 13kg of gears, but I was able to balance it using two 5kg counterweights without rod extender. I connected mount to PC using cable and USB-RS232 converter. At dusk I polar aligned mount as precise as possible, but using only polar finder. At first night session I used Sky Watcher driver 6.0.5999 to control mount. For telescope control I used Maxim DL application.
After alignment telescope pointed into targets pretty well, however each time some corrections were needed. First task was recording periodic error curve. It turned out to be +-6 arc seconds periodic error with worm cycle 479 seconds – pretty decent result. Next task was checking auto guiding. I tested both pulse guide option and guiding with ST4 cable. Both worked pretty well and both axis total RMS error was about 1 arc second. Guiding camera was ASI290MM and guidescope was 50mm diameter refractor with 2x barlow lens. It is not extremely precise guiding combination, so I suspect the result can be better when using larger and better optics.
Then I recorded PPEC into the mount controller. For this task I needed to use ST4 cable, because when PPEC recording mode was activated in the SynScan controller mount did not react for pulse guide commands. PE curve after PPEC was applied looks little bit better with peak PE about +- 3.5 arc seconds, however autoguiding precision did not improve (I have been using 3 seconds guide cycle). There should be more significant improvement for longer guide cycle time, but I recorded PPEC mainly to test mount with telephoto lens astro imaging without autoguiding.
Another night has come and I wanted to test Sky Watcher EQ6-R mount using EQASCOM drivers. Unfortunately both 2.00i and 1.29a versions did not cooperate properly – possibly they are not yet compatible with this new product. In both versions the same error occurred – after some time tracking has stopped without any reason. It makes any work impossible, so I switched back to ASCOM SkyWatcher driver and spent this night on collecting LRGB frames for M35 open cluster and recording light curve for TV Lyn variable star.
Imaging at 200mm focal length
For next imaging session mount went to backyard and it was loaded with Canon 550D plus 70-200mm telephoto lens – I wanted to test unguided exposures with the scale 5-10 “/px. Periodic error was small, and after applying PPEC it was even smaller, so I had high hopes. I used SNAP port to control camera. I align mount with three stars using LiveView – it was very comfortable and quick process. After few 300s shots at 200mm it turned out that stars are rock solid and there is no trails in the images and also there is no star movement between subsequent frames. I suppose 300mm telephoto lens should also work perfectly well with this unguided mount.
I also found one drawback: you cannot enter to SynScan RA and Dec coordinates to move mount there. There is workaround – you can use User Object list, but I think this functionality should be provided out of the box. To point my DSLR setup to desired frame center I used Utility Functions -> Show Position and moved mount using direction keys.
After few nights with Sky Watcher EQ6-R mount I think it is quite good successor of EQ6/NEQ6. GoTo accuracy is good, autoguided tracking precision is also very satisfying, even for my demanding image scale 1″/px. Also unguided astroimaging with lenses 200-300mm should provide pinpoint stars with PPEC recorded. EQ6-R mount is pretty quick and quiet, mount head is stiff, and polar alignment mechanics was significantly improved.
- PPEC recorded to RA motor controller
- improved polar alignment mechanics
- belt drive system
- fast GoTo
- SNAP port to control DSLR
- good GoTo accuracy with SynScan remote control
- backward compatible tripod and mount head base
- small periodic error out of the box
- tracking error RMS less than 1″ (with 13kg setup)
- laggy SynScan display in the cold
don’t really know what auxiliary encoders are for(there is no auxiliary encoders in EQ6-R)
- little bit complicated PPEC recording procedure
- lack function of pointing mount to specific manually entered RA and Dec coordinates
- still missing home position markers on the mount head