ED-100 Focuser Swap pt 2

Testing, Testing…

First Light came a few nights later. I mounted the scope on my Vixen GP driven mount and headed for a dark sky site. A crescent Moon and the summer constellations were the main targets.

The Baader focuser has 360-degree rotation built in. This means that you can loosen the locking collar, rotate the main body of the focuser (complete with diagonal, eyepiece and finder-scope) to a comfortable position, and then tighten the collar again. This has the advantage of making it easy to place the eyepiece comfortably when using the ‘scope on an equatorial mount, and for photographers it allows them to easily ‘frame’ their target within the confines of their camera’s CCD chip or film exposure area. I loosened the collar, rotated the focuser to a good position, and tightened the collar again. The focuser body would not quite stay locked in place though, even with the collar done up very tight. The weight of the finder-scope, offset to one side, kept pulling it round in that direction. This was a bit of a worry.

I found out later that there are several very small screws around the focuser body, just below the locking collar. These screws affect the locking collar mechanism, so that tightening them slightly removes the ‘play’ that was evident when I tried it out. A mere quarter turn of these tiny screws solved the problem completely. I found this out by trial and error, though it was later confirmed as being the correct thing to do in an email from the manufacturers!

Back to the test night, and the focuser worked very smoothly. The drawtube action was light and smooth, the wheels rotated easily with no rough spots in their travel, and overall I was very impressed! I took the ‘scope up to high power on the Moon and the image remained sharp and contrasty. Similar results were shown when viewing double stars Mizar, Albireo and Epsilon Lyrae, and so I carried out a high power star test. I used a 7mm orthoscopic eyepiece and 2X Celestron Ultima Barlow lense to provide 257x magnification, and centered the view on Polaris. The star appeared bright with multiple diffraction rings around it, and the rings were definitely ‘rings’- they were round, not elliptical or oval, so I knew then that the focuser was in alignment with the optics! Phew! That was a moment of great relief, as it meant I would not have to undo the focuser placement screws and then jiggle the focuser about trying to find the point of best alignment.

Happy with initial results, I called it a night. (Saturday night)

Further Use

I have gone on to use the ‘scope and its new focuser many times since then and have found it to be a very great improvement over the old Synta focuser in all areas. I had no problems getting any of my eyepiece to focus in the ‘scope, be they of complicated or simple design. Although, I did find that when using a heavy Moonfish 30mm 2” eyepiece the old problem of ‘slippage when pointing at zenith’ began to rear its head again! It was not as bad as the Synta had been, but I felt it shouldn’t be there at all. When focusing the eyepiece ‘inwards’ and the tube was pointing high up, I had to give it a helping hand from behind to overcome the gravity holding it down. Slightly disappointed, I turned to the Internet again…

I found that someone on an American forum had asked about the same problem. A diagram was produced, and it showed yet another tiny little screw, an Allan Screw this time, just below the tension adjuster. This screw was to be used to adjust the base level of tension on the drawtube, and then the large thumb-knob could be used as a total locking mechanism. It seemed the base level of tension on mine was a little low for the weight of eyepiece I was using, so I fished out my small Allan keys and gave it a turn. Voila! Now when pointing upwards I can use all my heavy eyepieces and the drawtube moves easily in either direction with no slippage. The locking mechanism works fine too, and actually stops the focuser wheels from moving the drawtube at all- they can spin freely and the drawtube is completely locked in place, unaffected by the wheels until the lock is unscrewed (half a turn is all it takes).

With this newfound knowledge I was able to set up the focuser exactly as I wanted it, and since then it has performed like a charm. The whole job was quite easy to do, though I did have to refer to the Internet for advice a couple of times, and this might have been avoided if a proper instruction sheet had been included. The only technical information I could find on it was in the form of a downloadable PDF from the Baader website, which did not include instructions on how to make the various adjustments. As always, dealing with Telescope Service in Germany was a pleasure and the goods came swiftly and very well packed.

To me, the Baader focuser is a vastly different unit from the old Synta one (which I sold on to help fund the purchase) and I now feel the ED-100 is a much more ‘complete’ telescope. There may still be one or two modifications I can find to keep me busy though, if I look hard enough. I keep thinking about blackening the tube interior more and flocking the dew shield. Stay tuned!

Click here to go back to part 1.