[sheeny (Al)]

Oh Matt! I hear ya mate! Major frustration! Let me just try to address each point in turn...

Originally Posted by g__day

Well I'm up to day four with this my first GoTo mount. Accuracy is variable and lacking - at present its like daylight saving has confused things and its pointing an hour behind where everything currently is or something, plus more pointing errors.

I have found with mine (prior to fitting the GPS module) that despite setting the time accurately (as wellas location, etc) the drive was always behind in RA. The amount it was "behind" varied, and since fitting the GPS module, this error has gone, sine the drive is always up to date (time?) from the GPS signal. I suspect the drive does not start the clock when you enter the time, but after you have completed your alignment. Other than that, my drive is reasonably accurate... provided you put accurat info into it. Its the old GIGO problem (garbage in, garbage out).

Originally Posted by g__day

Just some initial observations about the mount and manual.

1. The mount arrives with the Alignment peg placed between two legs rather than over one, against Celestron's advice - increasing its turning moment and chance of making a nasty whoopsie all the more likely.

Hmmm. I have my alignment peg between the legs, as delivered. I have not had a problem with this. Given the location of the counterweight and scope this should be the most stable position. I could see that with some OTAs it might be necessary to move the peg to the other side to avoid a crash between the OTA and the tripod leg, but otherwise I would be concerned about it.

Originally Posted by g__day

2. The manual probably should suggest the following:

• Understand where 20 or so most prominent alignment guidestars are, else if the set up GoTo is wrong you will not have the knowledge to align the scope to the correct stars
• realise the design we choose means the dec motor can often knock into the RA motor housing - possibly stuffing up alignment? whenever you get to close to Alpha Centuari.
• in fact about a third to half my GoTo attempts failed outright to complete due to the motors colliding, is this a dud design like a car that can go forwards or back, right in either direction but left only in reverse? I'm wondering if this lack of clearance is simply a fatal design flaw doomed to kill half the GoTos you could issue.
• the scope doesn't understand this last point, and if there are two options to get to a new Goto point - bet your bottom dollar that it chooses the one that causes Dec motor housing to have a clunk and stop rather than take the obstruction free route

This is a worry... If the housings are clashing I suggest either the drive is faulty, or the alignment marks are not properly aligned during the start up alignment procedure, or the RA and Azimuth limits in the drive are not set. They should be set from the factory but can be changed.

Originally Posted by g__day

• same with the the 90 degree prisms hitting the tripod leg on some viewing angles cause of the travel route it favours

Are you talking about your star diagonal? What OTA are you using? I can't imagine this with my C8.

Originally Posted by g__day

3. If you point to an incorrect wrong star as one of your three alignment stars you can't really undo, you have to re-boot and start from scratch again.

Actually it lets you correct 2 out of 3... but I share your frustration with this one!

Originally Posted by g__day

4. About 50% of the time on goto first alignment star it points below the horizon which is just plain wierd!

Way below? A reasonable amount of time the drive will try to find a star that theoretically visible but it might be below your local horizon. If it's pointing below horizontal, though, something is wrong. Either the alignment marks not aligned during the start up alignment procedure, the database filter is disabled, etc.

Originally Posted by g__day

5. Accuracy - well its about three finger knuckles behind where it should be on Spica and Jupiter.

Yup! This, I believe is a timing issue which the GPS module fixes.

Originally Posted by g__day

6. Quick align on Jupiter then move teh scope and search for Jupiter again fails. With a small move doesn't the mount is unable to find Jupiter - the one alignment star that you choose 30 seconds earlier.

In a Quick align, the sky is just modelled from the time and location data you enter. It doesn't take any notice of where the scope is pointing... so it still goes to where it thinks Jupiter is.

Originally Posted by g__day

7. The manual has no trouble shooting section

8. The manual has no first use diagnostic to give feedback on how to check your scope is functioning correctly (no benchmark diagnostic tests)

So right now I don't know if its a lemon, operator error and/or a setup fault

Here I go again - attempt 8 tongiht at a alignment that is accurate enough to then get within even the 8 * 30 finderscope for Jupiter.

Any help or suggestions would be greatly appreciated guys. I had such high hopes and desires and now I am left feeling very flat. Simply follwoing all directions to the best of my ability is producing very mediocre results at best.

PS

Test 10 - some better luck, changed the location from Google Earths GPS coordinates of my backyard to just the manufacturer defined Sydney and suddenly GoTo is a whole lot better.

What was the difference? The difference in position should be small, but obviously something about the way you've entered the data must be different???

Originally Posted by g__day

This time Jupiter was in the wide angle scope about halfway in. Still though half my GoTos fail with one of the motors hitting some the other.

PPS

Can anyone else here who uses a CG5 mount validate or refute my worries? Set up properly does it Goto things quite accurately?

Definitely more accurately than you are describing!

The accuracy is only as good as the alignment and data entered. If your initial alignment is out by a couple of degrees (you won't neccessarily do any better by compass) then everything is out by a couple of degrees until you drift align.

The biggest inherent accuracy issue I have found with my CG-5 is the timing issue, which the GPS module fixes. Prior to the GPS I would set the time accurately, but I suspect the clock in the drive didn't start running till after the alignment procedure was finished. So if it took 20 minutes to muck about with the alignment (and maybe a collimation as well) then the scope is out 5 degrees in RA.

Since I have installed the GPS, the goto is reasonably accurate. The night before last for instance, I did a rough align only (compass alignment of tripod followed by 3 star auto align) and it slewed to about a dozen different DSO's and everytime the DSO was well within the FOV of a 30mm EP in the scope. I changed to a 13mm Nagler and some were inside the FOV and some were just outside. If I had bothered to drift align, I would expect all objects to be inside the FOV of the 13mm Nagler.[/quote]

Originally Posted by g__day

Cn it be commanded so the GoTo without briusing its self most of the time?

I dunno what's happening here. Only once I've had this issue, and I didn't get to the bottom of it. I switched it off before it did any damage, so then I couldn't see what data it had wrong in it to make it do what it did. In my experience this just isn't an issue in normal operation. You could muck about with the RA and Dec limits in the drive, but I think you'll find that too limiting. I suspect something is not right to be causing the crashes. Have you sought advice from the dealer you bought the scope from?

Originally Posted by g__day

Many thanks guys,

Matt