Help with slewing and tracking issue CPC 800 XLT

[proflight2000]

Hi all

I am hoping to tax the minds here from anyone who may have any ideas as to an issue I have at the moment. I am using my CPC 800, when I align with stars on the 3 star alignment I get the all ok message, as soon as I ask it to slew to somewhere it starts moving then basically goes to some other direction and continues to slew elsewhere. This is happening when I do a two star and a solar (planet alignment with Jupiter) all the power seems fine and I can hear nothing sordid coming from the motors. I have set up the handset with my correct longitude and latitude etc and am basically pulling my hair out (what's left of it) any ideas anyone?

Thanks

Terry

[AstroJOE]

I notice you say you have input the longitude and latitude into the handset. Do you not have the GPS version of the mount? If so you shouldn't need to do this. Correct me if I'm wrong but didn't I see an earlier post from you where you were asking about updating the firmware on your handset? If so I wonder whether you may have made the same mistake as I once did by selecting the wrong mount from the menu when downloading the firmware to the handset? It defaults to the CGEM.mount rather than the CPC mount so you have to manually change it yourself.

Apologies if I'm mixing you up with someone else..... But if it was you all you need to do is redo the download process and then manually adjust the mount to the CPC version just before holding down the two buttons on the handset.

Let me know if you need any more help

James

[proflight2000]

I downloaded the CPC nexstar version of the software James, I double checked it before I let it begin, version 4.21. On the GPS, I have turned it off as it gives me nothing more than I can input myself. I have double checked all the numbers so to speak and they are all ok.

[AstroJOE]

I downloaded the CPC nexstar version of the software James, I double checked it before I let it begin, version 4.21. On the GPS, I have turned it off as it gives me nothing more than I can input myself. I have double checked all the numbers so to speak and they are all ok.[/q. uote]

Fair enough its not that then. Have you double checked which time zone you are using? I have never alligned my CPC1100 using lattitude and longitude method by my old Skywatche r Synscan mount wouldn't allign once because I was using the wrong time zone and the daylight saving was wrong. Not sure if this applies on the Celestron mount as well? Only other things I can think of are your mount might be operating in EQ mode rather than Alt\Az? Or possibly the power source is playing up causing the slewing to do funny things. What are you running your set up off and what cable have you got?

[proflight2000]

I have double checked the time zone and being in the UK I have input it as UTC. I am going to factory set the handset later then go through the menus to make sure it is all as it should be, especially the Alt/Az as you mentioned. Hopefully there will be a few clear stars out there later for me to check it all again. I don't think there is anything wrong with the scope itself as it does everything thats on the tin in respect of movement etc, I think it is something with the handset, well I hope anyway. Thanks James I will let you know how it goes as I am now down to the last few things. Oh just to say, I am running the power direct from the mains supply, I was using a tank which was pulling power all ok, but it did the same with a straight power supply as well.

[AstroJOE]

They are pretty solidly made, I only ever use 2 star alignment with the GPS switched on and it's usually pretty much spot on. I try to use stars which are as far apart as possible to align from to get as accurate a triangulation point as possible which seems to help. If I don't then the object I'm looking for tends to end up towards the edge of the FOV in my 40mm e/p...but always within the FOV. I'm guessing your scope is ending up nowhere near the place you want it to rather than just a bit off though?

Good luck, hope you manage to sort it out soon!

[proflight2000]

The alignment side of it is all ok, well according to the handset that is, the issue arises when I tell the handset to slew somewhere, it basically just starts moving, then bypasses the area I chose and carries on until it reaches where it thinks something is. I can't see if it is a motor board problem as the general set up seems to work, but like anything you have to rely on everything working together. Not sure where I could take this scope for a check up so to speak or whether any dealers do fixes, but I will try a few more things first before i head in that direction.

[knobby]

Just to appease my strange thought process :-). If say you used Pollux as one if the alignment stars... When you finish alignment what happens if you tell it to slew to... Pollux?

[proflight2000]

The easiest way to explain Knobby is that I carried out a three star alignment, all was done as required and at the end the handset advised all alignment was ok. I then told the handset to slew to Polaris, it began to move and basically turned towards Polaris, and then continued upwards pointing at 180 degrees, at that point i stopped it. When I did another alignment, again with a successful outcome, I told the handset to slew to Jupiter, it started slewing then went roughly 15 degrees east of Jupiter and again at that point i turned it off. It just goes to different locations to where the slew was requested.

[PeterCPC]

I had exactly the same issue that you describe. Mine started when I changed power supply from mains to a Tracer battery. When I got rid of the Tracer, no more problems and it works fine on mains or a power tank. I wonder, therefore, if it is some power supply issue as these scopes are very fussy about the power. Is it possible to try another mains adapter or a Power Tank?

Good luck.

Peter

[alanjgreen]

Hi Terry,

Is the CPC800 new or few years old? I ask because v4.21 sounds like sofrware for the old version hand controller.

My CPC is around year old, handset is labelled "nexstar+" and the software is 5.14

Not saying this is your issue, but something to check?

Alan

[proflight2000]

Hi guys, with the power supply I used both a tank and a direct mains supply with different plugs and it still does the same thing. On the Nexstar bit, I have the old version 4 handset as the scope is the older one, the original nexstar version was a 4, I just upgraded it to the 4.21. baffling indeed.

[knobby]

How about the pin on the power connector... Mount end, some people have to open up the tiny 2 pronged center pin slightly to make a reliable contact

[proflight2000]

Ok, i have done all the changes that I can think of, tonight i did a three star alignment and the handset advised it was successful, then as soon as i told it to go to jupiter it started slewing the the scope headed north around 15 degree of jupiter, i then did a two star alignment, again successful, i then asked it to take me to the M42 and it went east around 30 degrees of the M42. I am totally baffled now as i cannot fathom what else to do. Does anyone know of a UK celestron repair place at all, or at worse, could it be as stupid as having to add a plus or minus anywhere. Thanks for all the help so far, i did split the pin knobby but still the same ;-(

[proflight2000]

and just to add, i am wondering if the scope is for some reason looking at the opposite side of the sky as I was at Betelguese and told it to go to the M42 which is just below and it went to the other side of the sky, just to see i told it to go from where it was to beteguese and it moved upwards as if it was around the right place but in the wrong part of the sky. mmmmmmm

[brantuk]

What other equipment do you have connected to the CPC when you run the scope? Particularly electronic items like dew controller and dew bands?

[proflight2000]

Nothing bran, its just the scope, the eyepiece and the power supply, i was funny enough about to order goodies for it when this started, so i am holding back for the moment.

[ronin]

What is the data that you are supplying?

As in write it all down here on a  post.

The timezone would I think be 0 or 00, you sais UTC.

Check the mount type, my Meade seems to default to an equitorial not an Alt/Az after a reset.

[proflight2000]

The system gives a timezone across the board Ronan from -10 in the states to + numbers to the east. the UK is set up as UTC (Basically GMT) the onboard GPS shows the correct long/lat and the correct time.

[brantuk]

Hmmmm... It's got  me thinking...... Usually this kind of behaviour is a power problem 9 out of 10 times. When I added dew control and mains transformer it started pointing erratically - but I solved that by reverting to battery pack. Are you positive the power lead is in firmly both ends? Sometimes a loose plug or socket is the culprit - same for the handset.

You could try setting slew limits to 10 degrees above the horizon and switch on the cord wrap function - dunno if it'll help but it at least won't point downwards and will stay within 180 degs every time it moves. Do you have any electronics nearby your observing site (eg pylons or electrical sub station)? Even underground electrical fields can disturb it.

David Hinds may be able to recommend somewhere you can get it checked over - or try Simon at Widescreen Center who is bound to know someone. Meantime I'll watch the thread and think on......

[proflight2000]

I have no issues bran with the power supply, I am coming via the 12v adaptor direct from my power socket to the scope and I have split the pin as well for a better fit. There are no pylons etc in my main area, the same thing happens when i use a power tank as well that is fully charged. The tracking etc all works ok as I had betelguese in the mid of the eyepiece for over half an hour. Could anything like backlash etc affect anything? i did a factory reset on the handset and then put back things as they should be but no change sadly. Or could it be an issue with something inside the scope, its just baffling me right now.

[brantuk]

Yes I'm baffled too - you've pretty much answered all the questions previously asked. Maybe it's in settings? I use GMT and set daylight saving. I ensure date is in the correct order (US style mmddyy), I also make sure it's in alt/az mode, and check I'm west of Greenwich and have the correct time set.

Then I pop it outside and switch on and leave 20 mins for satellite lock (it needs three to go over) - which also serves as part of cool down time. Then I do a two or three star align (sometimes only 1 star) and it never fails. Assuming you have all that correct then it may benefit from a service if still not working right.....

[brantuk]

Oh - you could set backlash to zero so you have a start point for debugging.....

[proflight2000]

thanks bran, ill give all that a go in a sec and see what happens.

[AstroJOE]

Just a thought but have you checked to make sure the Azimuth and Altitude locking knob is fully tightened? Found this paragraph in the user manual....

Adjusting the Clutches

The CPC has a dual axis clutch system. This allows you to move the telescope manually even when the telescope is not powered on.
However, both clutches need to be tightened down for the telescope to be aligned for "goto" use. Any manual movement of the
telescope will invalidate your telescope's alignment.