Anthony's Astrophotography

Hi Everyone,

Well I had my first chance to have a play with the new EQ8 mount, this wasn’t under dark skies or anything flash but I did find a few interesting things and thought I would share. So where do I begin?

Set up of the mount is a bit more effort to that of the EQ6 but for someone that is reasonably built it is still a on person job (just), while it takes a bit longer it is worth the extra effort for the results (in my opinion anyway). The only thing I don’t like in the set up is that the Azimuth and Altitude knobs need to be removed prior to the mount being put back in its case, not a big issue but annoying nonetheless.

As one would expect the operation of the mount is smooth and quiet and the motors are very responsive and feel very powerful, there is absolutely no backlash in the RA Axis and the clutches are rigid enough to provide accurate movement when driven by the mount but not too rigid that when pushing the scope around as the EQ8 allows with the encoders. As a side note EQMod is updated when doing a scope push as the Encoders feed this detail back to the software, you possibly knew that already but I found it really cool when I saw it in action (no more resetting everything just because of a slip in a clutch etc.). The only fault so far that I can find (and it may not be a fault) is there is a little backlash in the Declination Axis, I will see how this performs on 10 minute exposures at the next dark sky outing but from testing did not cause any problems (up to 5 minute subs).

All in all I am quite happy with my purchase to date and think this mount will take my imaging efforts to the next level. I can see from initial testing that guiding is more accurate and tracking is far more precise and smooth. In relation to my first test with guiding using PHD (and after a very rough polar alignment) that the mount managed to perform with an average oscillation Index of 0.24 and an RMS of 0.09. By comparison to my EQ6 that averaged an oscillation index of about .45 and an RMS of about .35. This was using the same guide scope and camera by the way so it is fair to say the EQ8 is a whole magnitude increase in performance, in fact the evening I tested this was quite windy so I suspect the oscillation Index is a bit higher then it could be due to that. See graph here:

Most importantly to note is that Sky Watcher are listening to the community and making changes to the mount even this early on in the release, the mount I have purchased could almost be classed as a version 1.1 mount given some of the things that have been modified. So what are these changes I hear you ask? well they are:

• The Tripod Pier now has a travel limiting bolt mounted to prevent the collar from sliding up and hitting the mount head fastening knob. As pictured here:

•  The Declination clutch leaver has been shortened to prevent it from clashing with the Declination motor housing. This was definitely a modification that was needed and a major oversight in the original shipped product. See the old lever (Top) and the New lever (Bottom Two):

   

•  I also noticed that Sky Watcher have changed the cover plate on the Declination worm housing, this allows easier access to the adjustment screws for the Declination worm gear. The top image is the old plate the lower one is the new plate with the grub screws allowing access.

 

I haven’t seen anything else different that stands out but if I do you will be the first to know.

Lastly for those that are interested in the mechanic of the mounts, Gerard Dangl of www.dangl.at has plenty of images of the EQ8 with it’s covers off etc. showing the encoders and drive trains. Thanks Gerhard for the time and sharing the information.

Please let me know if you have any specific questions or things you would like tested?

Cheers

Anthony

 

 

3 Responses to “Sky Watcher EQ8 First Thoughts”