Problematic HEQ5

[Carole]

I have been having problems at camps for a little while now and never got to the bottom of it.  Missing alignment stars and targets sometimes.  Very frustrating as I waste a lot of time hunting around.

I put the mount back to factory settings a little while ago to see if this would help.
I have been imaging at home for the last couple of nights,  polar aligned using Polemaster, and am finding I can get my first alignment star but dubious I have got the right 2nd star and certainly missed my target and had to slew around to find it.  Still using the handset BTW.

But the interesting thing I noticed is that after the session, the mount is not returning to the correct park position, Dec is about 3/8" away from the marked position.  I wondered whether I had had a funny moment the first night and so on the 2nd night I double double checked I had the mount on the marked home positions in DEC and RA before I started and exactly the same thing happened again.  i.e. couldn't find the 2nd alignment star or target and mount returned to same incorrect Home position. 

Any ideas what might be happening.  I checked the input data on the handset which is correct, but even if I had the date time and location wrong it should surely still return to the correct parking position.

Once I have found my target, I can image and guide OK, it's just really annoying.  I guess I probably didn't notice at camps as I was just anxious to cover everything up in the dark and get to bed.  But this time being at home and not covering it up and having some light in the obsy, I noticed it.

Carole

[The Thing]

Is this just using the handset? If it's not returning to the Park position it sounds like clutches are slipping. If you are using EQMOD there are a load of things to check. Is it in both axes?

[Carole]

It seems to be just in Dec Duncan.

I could next time out try EQmod, though I am no great expert with it.
If its not too technical perhaps you could suggest some things to check. 

What could cause the clutches to slip?  The tightening handles were tightened, maybe I need to do them even tighter.

Carole

[The Thing]

Clutches slip if there is too much grease on the brass drum part of the gear. Doing the the clutches up too tight can distort the brass drum causing tight spots as the axis rotates. Eqmod wouldn't help. I never use the hand controller so don't know what you can do with it except maybe a full reset however that's done.

If it was my mount I would strip it down, clean it and regressed.

[Carole]

OK, well I don't normally put excess tightening on the clutch levers, I recently re-set the handset to factory settings hoping that might sort it. 

I have no engineering skills Duncan, so stripping it down is not an option for me. 

Thanks anyway.

Carole

[NoelC]

Is it belt modded?
Have you adjusted the worm clearance at all?

[The Thing]

OK, well I don't normally put excess tightening on the clutch levers, I recently re-set the handset to factory settings hoping that might sort it. 

I have no engineering skills Duncan, so stripping it down is not an option for me. 
Thanks anyway.
Carole

It's easy Carole, you only need a hex keys, screwdrivers, other tools you already have in your kit box like pliers, tube of lithium grease (bike shop/Halfords) and a couple of hours. This is a link to Astro Baby's definitive guide as used by all HEQ5 owners eventually. I do believe Astro Baby is Gina on SGL, she knows what she's about. It will make a difference. Give it a go, you won't look back. Do the DEC axis as decsribed then decide if you are going to do the RA as well, maybe another time.

[The Thing]

Another thought is cables and intermittent faults. Could be when you slew to some positions the handset cable or power cable looses connection. I added an screw on aircraft style power connector from ebay to my HEQ5 because of this (and to my NEQ6), but you need to be able to solder to make that mod.

[Carole]

Is it belt modded?

No its not

Have you adjusted the worm clearance at all?

Duh, what's that?  As stated no engineering skills, it either works or it doesn't, I never tinker.

This is a link to Astro Baby's definitive guide as used by all HEQ5 owners eventually.

Thanks for the link Duncan, will take a look at it and see if it looks at all feasible.

Carole

[Carole]

Don't think it's a power issue Duncan, I am sure I would know about that either through the guiding, or elsewhere.  In any case I don't use the supplied power cable with the cigarette lighter plug, I bought a regulated power cable that plugs into the mains with it's own 12V adapter from Bern years ago.

Carole

[Carole]

I do believe Astro Baby is Gina on SGL, she knows what she's about

I think you are joking here, but they are definitely two different people and both on SGL.  I have communicated with both of them.  Astrobaby lives somewhere in the Dorking area, and lives up to her name with long nails and varnish, doesn't image and owns Newtonians and is probably in her 40s.  Gina lives in Devon has an electronics assembly background, is a complete nutty professor type and is 75 years old.  But I love reading her posts, what an interesting lady she is.

Carole

[Carole]

Just had a look at Astrobabys tutorial, far too complex for me to tackle, I will end up buggering the whole thing up altogether. 

I tried to repair a car once in my youth and ended up with the part I had fitted flying off and making a hole in the carburettor and costing a great deal more than if I had got someone to do the repair in the first place.  Since then I don't touch anything mechanical.

Carole

[Carole]

Think I might have sussed this out.

I have finally found out what cone error is, and I think I have this problem (yet to be fixed). 

For some months I have been missing my second alignment star and also losing the target after a meridian flip.  Then recently following a thread on SGL, I discovered what cone error is and it explains so much.

So I decided to try only aligning on one star near my target (I thought this would only work with EQMod).  It works brilliantly - star and target bang in the middle every time, so after a meridian flip I now send the the mount back to park and do a new one star align, and hey presto target is bang in the middle.

Also, the mount is now returning to Home position, so I guess all the messing about trying to find the 2nd alignment star and syncing was messing with the Home Position. 

Only took 7 years of imaging.....duh!

Carole

[The Thing]

I have a utility which measures the cone error for you http://www.sharpcap.co.uk/conesharp

You can avoid it by not using a SkyWatcher style dovetail - they have those extra screws either side of the main bolt to allow you to fix cone error as they sort of introduce it by being inadequately engineered. An ADM style/flat plate dovetail will always bolt flat to the tube rings so no error, but you need to change the narrow pants SW puck as well...

[Carole]

Thanks Duncan, I think I have found a tutorial on Astronomy shed for sorting out the cone error which looks simple enough for even me to do (I hope), but I have to do it to 3 different scopes, so will be a little tedious, am waiting for the warmer weather to stand outside and fiddle with it all, but at least I have found a work around that does me for now.

No way am I changing the dovetails and the puck, but the dovetails have adjustment screws on them, I always wondered what they were for.

I'll take a look at the sharpcap software, but knowing me it will be too technical.

Carole