CN FORUMS ARCHIVE Telescope Reviews: Cordrap problem

Hi Starwars,
It's going to be difficult to explain in writing how I avoid cord wrap but I will try an abridged version. You can either take the description on board, ask more or dismiss it. Firstly though a quick word about alignment.

I don't know what you're expecting from the 'scope but my experience with the N8i is that, depending on what you have selected to "GoTo", the chosen object can either be on centre, just off centre and sometimes at the edge of the FOV of a 20mm EP. However, this, at least to me, is entirely of no consequence because if I can see it, I can centralise it.

As far as I'm concerned, the secret of good tracking is not where it lies initially but the WAY that it is centralised and, as you probably know, I wrote a CN article on the subject. Even then I can expect, depending on the EP, a slight drift of the object with time, usually a tad to the left of centre and (I can't remember specifically), slightly up when east of the meridian and down when west. Remember, you're dealing with a 'scope equipped with spur gears which are not the most accurate means for tracking celestial objects.

OK, so now to "Cord Wrap".

Firstly let me say I don't use it! In other words I don't switch it on. Also, I keep 8 X AA rechargeable batteries in base of the mount.

As best then as I can explain, here's my set up. And you can test this out in your living room. All you need to do is "kid" the 'scope by setting up a false time site.

Test therefore as follows:-

Set the "Celestron" marked leg of the tripod to point very roughly to the north (no real accuracy at all necessary) with the mount arm on the eastern side of the mount. Make sure the power cord is placed in the arm socket by routing it in an anticlockwise direction around the mount while you stand looking due south in front of the "Celestron" leg.

Now manually slew the OTA clockwise to Altair's (rough ) position while you remain facing due south.

Set up your time site and choose "Auto Two Star " to align.
As your first star, choose Altair and as instructed, move to where you know it (roughly) to be (actually you should be there already). Press enter and align buttons and then choose Polaris as your second star.

The scope will then automatically go clockwise to Polaris. If the OTA angle and direction for Polaris look about right, press enter and align. You should now have a successful alignment with which to work.

Now make a "GoTo" to Vega. Motiom should be anticlockwise from Polaris. If OK, repeat with M31. Motion should still be anticlockwise. Repeat with Caph. Motion still anticlockwise.

Now to Dubhe on the other side of the meridian. Motion now should be clockwise. A long way around but avoiding cord wrap.

Now to confirm all's working. Select Polaris once again. Motion should be clockwise a few degrees. However, now reselect Caph and the OTA should retrace its steps "the long way around". In this manner although you will need to keep an eye on the cord for long distance slews (in your best interest) you should not incur cord wrap.

Having said all this, and I don't know your set up, but if it doesn't work, reroute the cord in the opposite direction (ie. clockwise round the mount).

Finally and back to those 8 X AAs, if the cord is wrapping (and bear in mind that I'm doing this for real in robot mode by now), I can reverse the cord by taking it out of the socket and replace it without losing power and thus alignment.

Incidentally, which "GoTo Approach" setting suited you best ?

Hope this helps,
Tel

--------------------
Truth is the cubed root of Verbosity.