CPC tracking question

[AlistairHowie]

I was out playing with my newly returned from David Hinds CPC 1100 in between the clouds tonight, but had a bit of a problem with goto and tracking. I successfully did the sky align with three bright objects, choosing the moon as one of them.

The moon tracked just fine, but when I did GOTO Jupiter, the scope missed it completely and pointed near vertical. I manually slewed back down 20 or so degrees to Jupiter, but then it wasn't successfully tracked.

So ... two questions ....

Once I have successfully aligned the scope and received the match confirmed wording and all is fine, will the scope start tracking even if it is not aimed at a star, or does it have to be pointed at a specific star for tracking to work (assuming tracking switched on in the menu)? I suspect it has to be pointed at a star, which might explain why it didn't track if it didn't think it was pointing at Jupiter in the first place. Or to put the question another way, once successfully aligned, if I manually slew to a star, will the cpc automatically keep tracking it once I release the direction buttons?

And secondly, any thoughts on why it was so far out with Jupiter? I've read the manual and so know all the tips about slewing direction to minimise backlash, choosing stars far apart, not in a straight line, etc. I'm presuming that if my gps time and location are all accurate, the CPC can't mistake some stars for others and report successful alignment, can it? Seems very unlikely it would get a match in error?

All thoughts appreciated. Many thanks

[Capricorn]

I wouldn't use the moon for alignment.

It does not follow the normal track and I doubt if the software is able to successfully determine anything accurate from it.

Use stars that is what the scope's are intended for and stars tend to be much more predictable.

Say this becasue when people often post of problems they often use planets and in this case the moon to perform the alignment with. If you consiider that at some time planets like Jupiter. Saturn and Mars will stop and go "backwards" it seems risky to consider using them.

The CPC doesn't align the stars you do, if you have said that the CPC is pointed at a star and the scope can from the encoder information determine a set of parameters to operate with then iit will say it has aligned.

[Space Bat]

As above - you either do solar sys align - and align to the moon...etc or you do star aligns....you get it all confused if trying to combine

[AlistairHowie]

Good advice, thank you. It is ironic, though, that the manual talks of being able to use planets and/or stars for alignment interchangeably, when clearly the reported wisdom of folk on SGL is to the contrary. Oh well.

Can I just clarify the second part of my question... assuming my alignment is fine, at what point does the scope start tracking? If I manually slew to a star, will that be tracked automatically? Or do I have to use the Identify command first so it knows where it's looking? Or do I have to realign the scope based on what I'm looking at to get it to track?

I know it tracks automatically using GOTO, but I guess what I'm asking is can it track when manually starhopping? I was kind of hoping that after alignment, the scope would know where it was pointing and would automatically start tracking... but my experience of manually searching out Jupiter last night and discovering it wasn't tracking suggests otherwise.

Thanks again.

[Psychobilly]

When your using the moon did you align on the Center of the whole disc or just the visible part?

I suppose the controller firmware can compensate slightly ...

Peter..

[redfox1971]

I always do a 2staralign and have no problems with the tracking and the star i goto choosen with the menu is always in my 32m eyepiece,I have my cpc800 on fixed wedge so choose eq north align,two star align,then when finnished for the night i put scope into hibernate mode till next time,then when switch on select a star and then sync on it and it tracks fine again.Did your gps show correct time?,mine in the past dosent always pick up the correct time and so i switch off,on till it picks up correct gps time.

[AlistairHowie]

I centred on the whole moon, not just the visible part. Usually aligning on stars, GOTO and tracking have been spot on. I'm happy to put last night down to some unknown glitch, happy to align on stars in the future.

But does anyone have input to my second question re tracking outside of GOTO?

Thanks again.

[brantuk]

If you are all aligned and gps locked - you can move to another object with the arrow keys and it will track from wherever you stop. It' also knows where you are at any time cos it records how far the motors have moved. So you can then goto somewhere else.

The only time it loses position is if you unlock the clutches and slew around manually.

[AlistairHowie]

Marvellous, thanks Kim. So once aligned it will always track as long as the clutches stay tightened, so basically it is always ticking away showing it's tracking once aligned. It must not have been properly aligned last night even though it reported as such.

[brantuk]

No Probs - if you think about it you wouldn't be able to center up in the finder and eyepiece using the arrows if it didn't keep a record of movements. One thing I sometimes forget is to change the tracking rate when I move from planets back to dso's. Or between EQ and Alt/Az when using the wedge.

The times I thought there was a problem and all along it was pilot error lol