5SE Goto question

[MarkJ44]

Hi all

Recent addition to the forum and the night sky. Got my first scope at xmas, love it so far but have had my teething problems, mostly with Alignment and Goto. Thanks to advice from Ronin and others i bought a power tank and used it for the first time the other night under a brilliant sky down here, and my new finder turned up as well (my first one died after a few weeks!), so i was ready to go.

Aligned first go, excellent,  i sought out Sirius which was a short distance to the right, and the scope headed left. [removed word].  It then did almost a full circle and landed almost on Sirius (phew!!). I tried two other goto's and same thing, full circle before landing close to the target. Is there anything i can do to avoid it going the long way? Why doesn't it go the short way?

Related question, to further improve alignment and goto performance, what do people think of using a reticle eyepiece during the alignment process, will this assist with accuracy?

All that aside, i love just looking around and Jupiter the other night was brilliant.

This is a great forum, so much knowledge out there.

Cheers

Mark

[wheresthetorch?]

Hi Mark.

Somewhere in the menu there is a 'cord wrap' feature, I think under 'scope set-up'. This prevents the scope from tangling the power cable by travelling more than 360 degrees. Try enabling or disabling this feature - it might help.

[ronin]

I suspect you cannot stop it from going the long way round occasionally.

The scope will very likely have stops built in to the base and the scope cannot go past these so the scope has in effect to "unwind" itself.

They are common on most of these - except for some odd reason the inexpensive Meade ETX, 60+70+80 - they for whatever reason just go round and round.

It may be a choice of the cables on the outside get wrapped up or the ones on the inside get ripped out.

Will say that if the mount has stops and so decides to "unwind", or if it does not and can go round and round then external cables get wrapped up . Either the scope unwinds by a big rotation and wraps up a cable or the scope goes round by small amounts and wraps up the cable. But that cable is going to get wrapped up . If like mine the cables come in at the side relative to the scope it means they are 1/4 wrapped up before you begin.

If you can sit things under the tripod with the cables going up to the scope, even this has problems. But if the scope does not automatically unwind then you must do so by picking objects that cause the same effect.

The software and logic behind endstops and unwinding is good fun. The mount will be in a region for "unwinding" so the preferential movement will not always be what "appears" the obvious.

What I suspect you have seen is:

The scope is "unwound"

Rotates in the direction of the shortest movement.

This takes it to a state of "wound up" before it gets to the position.

So it then stops and rotates the other way, thus maintaining a state of "Unwound"

Would be useful to know where the endstops are and what the software boundries are.

Always check that the scope starts up from what is the "most unwound" position. Might mean you undo all the clutches and slowly rotate the scope into one of the endstops, then slowly rotate to the other one - COUNTING the number of rotations then unwind half the amount. I think the ETX I have takes about 2.5 to 3 rotations from endstop to endstop.

A reticule eyepiece is I think a good idea on a Mak/SCT, the field of view is narrow so better accuracy is a good idea. You might find you need an illuminated reticule in order toi see the cross or circle or whatever, so get one that can have the illumination brightness changed. Aplologies but it all adds to the cost. And an illuminated one means you will need to keep a spare battery or two around.

[Astro Imp]

Before investing in a reticule eyepiece try defocusing the star in the EP, it is considerably easier to judge if a nice big circle is centred than a tiny dot.

[MarkJ44]

Thanks everyone for the advice and Ronin for the detailed explanation, i suspect i have much to learn, but looking forward to it!!

Regards

Mark

[SacRiker]

Glad you like the scope. What eyepieces are you working with?

[MarkJ44]

It came with a 25mm as standard,I have since added a 9mm, but the more I read the more I think I will be adding to that. I will obviously need something mid range, and maybe a reticle ep and I still don't understand enough about barlow's.

Any tips appreciated.

With my very limited knowledge at this time it seems a really good first scope.

Cheers