SkySensor 2000 poor alignment issue

[ilife13 (David)]

Matthew
Cancel that last request, I should have the direction buttons pressed before powering up. I have reset and re-entered all information.

David

[g__day (Matthew)]

Okay

Now do suggest you do a few tests as described where its convenient, can be inside. Fire up your astronomy program Stellarium and choose say the Moon as alignment target one.

Align on the Moon
Goto Mars which is only a few degrees West - see what it does!
Goto Saturn - which is about 20 degrees East of the Moon
Goto M68 - which is about 15 degrees SW of the Moon
Goto M104 - which is a South and West of the Moon about 5 degrees
Goto Acturus - which is about 20 degrees due North of the Moon

Note your offsets using your hand controllers X/Y or RA/DEC settings - is it traveling the correct magnitude and in the correct direction?

Cheers,

Matthew

[ilife13 (David)]

Matthew
Yesterday (daylight indoors) I attempted some of your suggestions and the results are:
I chose the Moon as a first reference and the scope slewed to point South instead of North (although the elevation was roughly correct). I then chose Vega as a second reference and the movement from the Moon would have been roughly correct.
On a separate start-up (after switching of and re-setting to the start position) I chose Antares and although the scope slew in the right direction it was still 40+ deg out. I did several shut downs and start ups and something stranger happened. On every second start-up, as soon as I pressed "enter" after being prompted to set the scope horizontal in the start position it immediately slewed clockwise at full speed on the Dec motor. The scope slewed about 40-45 Deg before it stopped and if I pressed the stop button during this unprompted slew, it would stop for a couple of seconds and then immediately start again.
I use a battery pack which I am sure is fine but I will check it as I can't afford to leave anything out. I do not have a cable to operate the scope from my computer but I think I should buy one to eliminate that as a possible solution.
I also reset the gears from + to - as you have indicated they should be negative for the southern hemisphere but the motors definitely run the wrong way. This was done after the scope slewed South instead of North for the Moon. When I did this, the scope did slew to the North as it should but it pointed below the horizon. Remember that other reference stars did slew in the right direction with the gears set to positive. There seems to be very little consistency if not random in slewing to various objects. Although the hand controller displays the positions of these reference stars and the Moon correctly (same as Stellarium) everything is extremely mixed up.
One thing to remember is that this mount was working fine initially but after several months of poor/cloudy weather and me being away overseas, when I came to use it the next time I took it to the country for dark skies only to find that the battery in the hand controller had died. As it was only one night I didn't spend much time trying to reset it. I ordered a new battery (which was the correct one) and was fitted to the controller (also done correctly, I am confident) and it hasn't worked since then.

I will do some more hopefully tonight and give you more answers to your questions and suggested procedures.
PS. I have taken a couple of photo's of my set-up but I don't know how to add them to this post.
PPS I have checked to make sure Latitude and Longitude are set and in the correct order.
PPSS I tried the pointing West set up to start but it is no better.

Best Regards
David

[ilife13 (David)]

Matthew
Further test results below. Starts with Formalhault as it is pretty much due East (same as scope start point). In each case the SS2K hand control displayed coordinates matched those on Stellarium but pointing accuracy deteriorated as it slewed from East to West to North moving less and less each time and in fact only getting as far as South for Altair which is actually North. Slewing was consistent (consistently poor) as I returned to the same reference points.

Formalhault
Appr slew position/Actual Approx Alt.Az/Actual Alt.Az
East / East +22Deg / +48Deg
Achernar
South East / South East +13Deg / +26Deg
Rigel Kent
SSE / SW +22Deg / +34Deg
Saturn
South / West +32Deg / +26Deg
Vega
SSW / NNW +44Deg / +17Deg
Altair
South / North +35Deg / +49Deg
The next set are repeated a short time later to check consistency.
Formalhault
Appr slew position/Actual Approx Alt.Az/Actual Alt.Az
East / East +25Deg / +51Deg
Achernar
South East / South East +16Deg / +29Deg
Rigel Kent
SSE / SW +25Deg / +32Deg
Saturn
South / West +30Deg / +22Deg
Vega
SSW / NNW +44Deg / +16Deg
Altair
South / North +38Deg / +49Deg

David

[ilife13 (David)]

Matthew
I managed to find the instructions on uploading images.

[g__day (Matthew)]

Okay - some weird behaviour there alright

A few more things to check.

1. How are you powering it - what is the Voltage / amp rating of the source of power to your gear?

2. Can you check the power supply with a Voltmeter - even the $9.95 ones from Jaycar or Dick Smith are fine for this task - do they match rated voltages and ampages - check its not a faulty power cable into the mount causing a voltage drop

3. Are the pins from the SS2K to the mount all fine - none corroded or bent on the hand controller - no lint in the cable messing up a signal?

4. Have you asked if anyone around you has a spare SS2K you can borrow for a night to confirm its the hand controller - not the mount - acting strange?

5. You are dead certain the new battery is of the correct rating, orientated correctly and well soldered to the unit? Did you test it to confirm it was okay before you soldered it into position? Did you use minimum heat and/or heat sinks (i.e. alligator clips) when you unsoldered the old battery and re-soldered the new?

6. Everything fitted together well - and all spacers and insulators were re-inserted when you fitted the SS2K back together after changing battery - i.e. nothing was obviously touching or shorting between the two boards?

I think it might be time to definitely describe this situation to Chris Erickson who moderates the Yahoo Groups SS2K board and ask his views

https://groups.yahoo.com/neo/groups/SkySensor2000/info

and/or

https://groups.yahoo.com/neo/groups/ss2k/info


Will think some more of what else to try next!

[ilife13 (David)]

Matthew
Power supply is a 900amp 12v jump starter. I have a multimeter and will check it tomorrow.
All pins and connections appear fine nothing bent, dirty or corroded.
I will have to check or post another thread to see if anyone has a SS2K hand controller in Perth (a very good idea).
The new battery was correct and I was aware of overheating with soldering/desoldering and made sure the new battery came with tabs as it was available both with and without. I will open it up again and inspect it. I have retained the old battery and will compare them just in case.

Thanks again

David

[Visionoz (Bill)]

Originally Posted by ilife13

Matthew
Power supply is a 900amp 12v jump starter. I have a multimeter and will check it tomorrow.
All pins and connections appear fine nothing bent, dirty or corroded.
I will have to check or post another thread to see if anyone has a SS2K hand controller in Perth (a very good idea).
The new battery was correct and I was aware of overheating with soldering/desoldering and made sure the new battery came with tabs as it was available both with and without. I will open it up again and inspect it. I have retained the old battery and will compare them just in case.

Thanks again

David

David

Ensure that the cables that connect to the motors are indeed correct for the purpose ie; the RA one to the RA motor and the DEC one to the DEC

HTH
Cheers
Bill

[g__day (Matthew)]

David,

Not sure how much power your mount likes - mine specifies to give it at least 12V 2-3amp, I give it 15V and 5 amp through a Lab Power supply plugged into an Online UPS 1500VA -> mains. It will only draw what it needs I am told!

Must read up on your mount some more, as I am more familiar with the Atlux, but the behaviour you have described doesn't fit a pattern I am used to - so its most interesting. I keep asking myself what am I missing that would make sense of all this. As stayed bfore the SS2K is simply a tank - its the most consistent bit of kit I have ever experienced.

Bill's suggestions made me realise I don't know the cabling for your mount so I must review that; the Atlux has all internal cabling - you just supply power and one cable from the SS2K to the mount itself.

Really want to help solve this one!

[ilife13 (David)]

Matthew
Original Battery from the hand controller was Tekcell SB-AA11 3.6V.
Replacement battery is Saft LS14500 3.6V (equivalent according to Battery World).
I tested the original battery and it is absolutely dead. The new battery shows 3.64V. The connections were also tested.
My power pack is a staedy 12.89V.
All plugs checked, made sure the inside of the hand controller was free of debris and nothing touching that could create a short circuit, tested the cable from cigarette lighter Plug to power box on the mount ( the box on the mount sends power to the two motors).
I think I may need to check this box as it may be either faulty or sending intermittent power to the motors.
Although I didn't find anything obvious I reset the scope and tried again and there is no change.

David

[g__day (Matthew)]

David,

So its very consistent - just wrong...

The battery sounds find - and I'm glad to hear you took the right precautions with the soldering!

I forgot to ask - is tracking fine? If you are polar aligned and you get to your target does it keep it centred well? I expect it shouldn't but will not be surprised to hear it does. Tracking is just real time pointing - and your pointing model seems to be confused - for no fault of your own.

I think it is definitely time to see if you can find someone with an SS2K and see if your unity can run their mount correctly and vice-versa - to isolate the fault to cabling, mount or controller.

I don't like that some goto's had wierd track or unrequested slews - that is exceedingly strange and needs to be isolated and resolved.

Slightly beyond my knowledge - if you were to remove the battery completely - I believe the the hand controller still power on and operate correctly once all parameters were re-established. A pain in the arse but could allow you to do more diagnostics.

I would say join SS2K and SkySensor2000 Yahoo Groups and post your questions and the background data shared here with that user base and you will have a few hundred more experience folk on your side. Whilst I also ponder what is next.

Matthew

PS

This is totally wrong - but what the heck - try changing the sign of the Lattitude from negative to positive, restarting the controller so the hemisphere change takes affect and see if gotos are affected in any (hopefully positive) way. Then revert back to -ve lattitude and reset again and see if the behaviour changes.

Playing in my mind are two scenarios - somehow the location data which must be Southern Hemisphere is confused - or there is a incorrect feedback loop somewhere (a short in wiring, dirty voltage or an optical encoder with muck on it). I pondered would flipping the polarity on the Lattitude trip something and get it to reset correctly!

[ilife13 (David)]

Matthew
I will work on the Yahoo groups and let you know. I opened the grey power box that powers the motors and it looks like it has been opened previously. Some dodgy wiring/soldering but the connections were OK. I did change the negative wire as it was joined and soldered with mesh around it for insulation. Very strange and it is only 3 inches long. I changed it to a single wire and resoldered it. Didn't change anything though.
Further test results follow.
Set the OTA's to point South instead of East (due to the fact it doesn't seem to want to go as far round as North). This was done during the day so it was approximate.
First reference star Sirius and it looked very good both direction and altitude.
Second was Regulus and this also looked very promising (I was trying to gradually get to North). Third star was Arcturus which is when it went wrong (it ended up pointing South instead of NNE. Then back to Regulus which again looked good, followed by Jupiter which also looked fairly good.
I then tried both the Moon and Venus. The scope beeped and advised they were too close to the Sun (this was also correct at the time of testing).
I have tried reverting the gears to -ve (even one motor at a time) but the slews are going in the wrong direction.
Because of the poor alignment, I haven't checked the tracking and the last few nights have been raining or overcast.
David

[ilife13 (David)]

Matthew
Just thought I would bring you up to date.
I have registered with Yahoo groups for the SS2K. I had to open a Yahoo account and apply to the SS2K forums which has now been accepted. I have had plenty of input (all appreciated of course) but so far nothing new to report. I tried to get them to read the IIS forums to save some time as you have had so much input and suggestions but I am not sure whether anybody has done so yet. It is amazing the amount of people that are willing to help and give advice. I hope I can return the favour to all of you some day.
Will keep you posted on any results.

David

[g__day (Matthew)]

David,

It's a very helpful group - and I am sure they will ask you to check things I had assumed would be okay - it will just take them a while to get up to speed.

The key summary I would suggest you give them is simply:

1. Everything worked great until a battery change
2. Battery change itself seems fine
3. On re-initialise all parameters appear correct (and can be summarised for them)
4. Pointing seems to be horrendous - and it gets worse in certain quadrants of the sky.

That should give more experienced minds than me something to diagnose from. It should also trigger a check if anyone else has seen similar issues and knows the cause and fix.

Do ask if they know of any SS2K users in your geography!

I expect they will wish you to confirm wiring seems okay and confirm no blown circuitry appears evident anywhere in the hand controller or mounts motors.

They will likely wish to know if tracking after a one star alignment is fine or horrendous.

If diagnosis is very hard to do I would ping Chris Erickson in the Group out of Hawaii to have a look a the unit if he thinks that might help.

Will look for you on those groups and see if I can contribute ideas too!

Matthew

PS

Posted there in the Yahoo forums in your thread for the above summary and my view you have set up the controller correctly.

PPS

Would love you to get a PC cable and see if after a one star set up, would any goto commands from an astro control program suffer the same or different consequences from entering the same goto from the hand controller. I am starting to ponder if your co-ords match an astro programs coords then encoders appear fine, so it may be something exotic interfering with gotos.

If you lock on one star then issue a goto a second star which fails badly - then issue the same goto again once or twice een does the mount move at all or think its already on target? If you then press the ID button on the controller does it search and find your target star or report its a long way off? If it finds your target star in th ID function are its coordinates correct.

I do feel we are still making progress!

[g__day (Matthew)]

Just a brief note on progress, after 49 posts relating to this on the Yahoo Groups page https://groups.yahoo.com/neo/groups/...s/messages/745

Folks are definitely puzzled by pointing worsening significantly as the mount heads West. Trying to determine if its more likely to be the Handcontroller or the mount.

My latest thoughts are on errant gotos run the SS2K ID function to see if thinks it is on target or if it for unknown reasons (incorrect slew limits caused by a location error in Lat or Long) halted the slew early.

Some progress but wish there was another SS2K user around David's location to speed up the process of elimination as to the root cause of the issue.

[ilife13 (David)]

Matthew
I have been out of action for a while but have spent half the day on this nightmare of a mount.
I believe the problem is two-fold.
Firstly, a man from the Yahoo groups indicated he had some similar issues when he changed the internal battery. As the battery is such a tight fit he found that a solder point was touching the body of the battery and he had to insulate the battery from it. A couple of weeks ago I pulled the hand controller apart and put 3 layers of masking tape over the battery as I did remember not getting the new battery as snug as the old one. As there was some very strange behaviour with the mount I determined it must be the hand controller. I opened it up once more and removed the masking tape. When I held it up to the light, there was a tiny pin hole in it. I had kept the old battery and compared them and found that the positive "bubble" on the new one was about one millimetre bigger than the old one and hence this was stopping the battery from sitting flat within the circuit board. I removed the battery and filed the circuit board to accommodate the the extra millimetre and re-soldered it. I know the filing thing sounds dangerous but it really was necessary to fit the new battery and I was super careful. This has stopped the strange behaviour I was experiencing but the inaccurate slewing continued.
Stage 2 was to remove the motors as the scope was still stopping well short of the targets and the further the slew the worse it got. What I found was that the declination motor gear had 25 teeth and the drive gear had 50 teeth but the right ascention motor gear had 50 teeth and its drive gear had 100 teeth. Although the ratio is consistent at 2:1 I am sure this cannot be correct. My manual tells me +36x144 for each motor which is a 4:1 ratio. Obviously at 2:1 the scope will travel twice as far for each slew.
Am I right?

[g__day (Matthew)]

David,

The battery placement and resolution news is good to hear - I didn't know the battery size was so critical, nor that this type of battery was variable in its dimensions.

The gearing sounds absolutely bizarre and could easily account for what you are experiencing. I think you need to check with others users of the same mount what numbers of teeth their gears have. Having to set your RA ratio to +72x144 would be do-able. But I would be trying to work out did the factory ship it this way or did a previous user do something strange!

If you find all other users have a different gear ratio to you - then you can either try and purchase the correct set of gears for RA or adjust the gearing ratio in the SS2K.

That takes the cake for the most unusual problem I have ever heard!

Matthew

[ilife13 (David)]

Thanks Matthew, perhaps I'm not that stupid after all. I was beginning to think I was going to be highly embarrassed over a silly "rookie" error.
I will try and find the previous owner and ask some questions regarding the gearing.

David

[ilife13 (David)]

Thank you to everybody who helped me with this and a very special thank you to Matthew who spent a lot of time and brain power on it.
I believe the problem is now resolved. The battery was only part of the problem with a pin point short to the battery casing and the fact that the gears are non standard. Rather than the 36x144 ratio as indicated in the user manual it turns out my gear ratio is 36x288. I have only done some indoor daylight testing this morning but it looks very promising and the scope now slews to all parts of the sky and appears accurate. Fingers crossed for a clear night tonight. I will post on the real time testing as soon as it is complete.

David

[g__day (Matthew)]

David,

Glad its almost resolved. The SS2K does allow one to put their own gears into a mount - but this is the first time I've ever heard of one doing so - and a battery reset would mean you would need to know the non default gear ratios for everything to work.

Fingers crossed now - but it feels like you are heading out of the woods now!

Matt