Connecting and using the ZWO EAF on the Esprit 120ED

Hi, I’m Ian and I live in Surrey in the UK.

In this video I explain how I attached and calibrated the ZWO Electronic Automatic Focuser on to my Sky-Watcher Esprit 120ED telescope and then how I used it to image M33, the Triangulum galaxy.

I’d not been sure whether to buy an electronic focuser as I’ve done really well with just a Bahtinov mask until now, but I thought the benefit of re-focusing when I’m asleep would be great!

I looked at a few videos on line and realised there are some scaring approaches out there on how to connect the EAF to the Esprit 120ED.

However, if you buy the Takahashi bracket it is fairly easy to attach with no drilling etc. just using the supplied screws and washers.

In the video you will see all the parts that come with the EAF and how I attached it to the Esprit 120ED. I then go on to show it’s first use, though for some reason my ipad video seemed to stall a few times but you will see the main areas of calibration, such as setting the starting position to zero and then working out how many steps to the maximum position. In my case about 18,000. I have ended up setting my maximum as 17,800. I tend to get focus around 12,300 at the moment.

I then show that you need to set the small and course step levels, which I set at 10 and 1,000 and then run a calibration to estimate the backlash. This is really done by moving the focuser out to a point and then moving it in by the small steps of say 10 and see how many times you need to press the advance button before the focuser actually moves. In my case it was 7 presses or in other words 70 steps. I saw elsewhere that it might be worth making the actual backlash a little higher so I’ve currently set it at 90 and will see how it goes.

Finally, I set the steps for the Auto focusing at 30.

You will see me use this for the first time to focus on M33 and I think I ended up with a reasonable image of the Triangulum galaxy.

The final image is from the 13th January with 30 five minute (300 second) exposures at a gain of 120. 60 flat and Dark flat frames and one master dark frame.

Thanks for everyone who watches and all those who have subscribed to my channel.

Main Equipment:
• Sky-Watcher Esprit 120ED (Super APO Triplet)
• Sky-Watcher Esprit 120ED Field Flattener
All above acquired from FLO

• Sky-watcher EQ6-R-PRO equatorial mount
• ZWO ASI 294MC-Pro single shot colour camera
• ZWO 60mm Finder/Guidescope
• ZWO ASI 120MM Mini
• Baader 610mm Longpass Red Colour Filter
• ASIAir Pro
• ZWO IR/Cut Filter
• PixInsight
• Topaz Denoise
• Photoshop

Music (at the beginning):
Isolated by Kevin MacLeod is licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/...)
Source: http://incompetech.com/music/royalty-...
Artist: http://incompetech.com/

Music (at the end):
Dream Escape by The Tides