SW AZ EQ6 GT pointing accuracy problem

[astrozabi]

Dear Astro friends,

 

Hope everybody doing well.

 

My friend has SW AZ EQ6 GT mount and SW ESPRIT 120 telescope which were laying couple of years as he was building Observatory.

Recently he decided to turn it ON.

 

Mount is well leveled

Polar aligned using PoleMaster

Balanced well

Connected to central electrical network 220V (power adapter gives 12V / 5A output)

All settings after turning mount ON are as they should be: time, date, coordinates etc.

Mount control using SynScan controller.

 

During 1 or 2 or 3 start alignment telescope pointing almost to the start choose in SynScan controller (only some small corrections needed to get start 100% centered in Telescope eyepiece and telescope it self).

In the end of this process, SynScan shows: Alignment is successful.

 

After that we choose an Object (we choose start and planets) where to GoTo. And every time it miss the target 10-20 Degrees.  It seems like mount points the target (Object), stops, wait a second and then moves further and as a result 10-20 Degree deviation.

.

We mentioned during 1 or 2 or 3 start alignment LED on the mount doesn't blink, but it start blinking time by time (not always) when mount is slewing in GoTo process. We monitored Voltage which dropped to 10.7V during GoTo.

We replaced power adapter-  Mount LED on mount stopped blinking. Voltage also didn't drop below 11V even on 9th speed. (only mount is connected. no cameras, guides, heating etc)

But problem was still present.

 

What we did else:

- Setting Factory reset

- Use of other SynScan controller

- As I told above we tried 1 star, 2 start, 3 star alignments, everything is perfect during this processes, but not good at all when try to point to any Object using GoTo.

- Tried Auxiliary encoders ON and OFF

- Tried Synconizing Encoders function which is mentioned in Part VIII (8.11) of the manual to SynScan controller.

- Tried to use over EqMod bypassing SynScan controller - same story

 

In the past, this mount was used only in the "field"  taking power from Car battery through 220V Inverter. but then there were also connected: laptop, heating, DSLR, guiding camera to the same Car battery.

 

May it be that "brain" inside mount is making mistake or it might be mechanical problem? If so, why during alignment everything is perfect.

 

May be I missed something to mention, but seems that we tried everything we know. Looking forward for your advises.

 

Thank you for feedback and clear skies to everybody

[2STAR]

Try Cloudy Nights if no success here

eric

[Deflavio]

 

On 30/09/2020 at 23:48, astrozabi said:

After that we choose an Object (we choose start and planets) where to GoTo. And every time it miss the target 10-20 Degrees.  It seems like mount points the target (Object), stops, wait a second and then moves further and as a result 10-20 Degree deviation.

.

We mentioned during 1 or 2 or 3 start alignment LED on the mount doesn't blink, but it start blinking time by time (not always) when mount is slewing in GoTo process. We monitored Voltage which dropped to 10.7V during GoTo.

We replaced power adapter-  Mount LED on mount stopped blinking. Voltage also didn't drop below 11V even on 9th speed. (only mount is connected. no cameras, guides, heating etc)

When you say "it seems like the mount points, stops, waits and then moves" does the noise from the mount motors also stops, changes in intensity or stays the same? I'm just checking if some of your gear is slipping, maybe two years without use may have loosened something in your gears.

Other possibility, what is the voltage range for this mount? You may want to make sure you are not just close to the limit.

I suggest to post in the equipment/mount section. I'm sure you will get more answers.  

 

Flavio

Edited October 3, 2020 by Deflavio

[Ouroboros]

I’ve been following this on Cloudy Nights.  It’s a bit of a weird one isn’t it?   My mount behaves strangely when the voltage drops below a certain minimum amount. So I’d make sure the supply voltage and amps are as specified in the manual. Even then it’s a bit odd because why should the alignment work exactly but subsequent slewing doesn’t? Unless perhaps the mount draws more current by slewing faster to an object than it does during alignment. 

Edited October 3, 2020 by Ouroboros

[Aramcheck]

You say the problem also existed using EQMod. Have you tried using Astro Photography Tool to platesolve an image & sync the mount? On my SW AZ EQ6 GT I found that after a 1-2 star align, slewing to a target was usually off by some margin (but nowhere near 10-20 deg). (I've subsequently ditched the handset & star align & just rely on APT & platesolving, unless needed for visual use.)

Platesolving an image, would at least quantify the scale of the error & whether it lies in RA/Dec. It'd be interesting to see if the error is consistent for different slews to the same target or random...

BTW - After selecting a target, my mount will slew to the object & then make a small slow speed adjustment. I normally do a rough focus, slew to a bright star and then platesolve with APT & do a fine focus. The mount position is then synced to APT & I find after slewing to a target, the object is usually within the camera's field of view & requires only minor adjustments.

I presume there are no leads causing any drag or snagging issues?

Cheers
Ivor

[MrFreeze]

Have you tried running it from the car battery lately? As the mount requires 12V at 3A, I  would suspect that your 5A power supply is maybe not up to the job. Especially as you say the voltage dropped to 11V on what should be only 60% of the rated PSU current. Many of the cheap chinese manufactured PSUs  are simply not capable of supplying their full rated output - I have a couple of 10A supplies and they certainly can't supply 10A for more than about 15 seconds before they trip out 😠. A car battery can supply a huge current (100s of amps)  as the current draw from starter motors is enormous.

David

[AstroPhil]

It's definitely a power issue: the blinking LED is the 'low voltage' warning on the Az-Eq-6 (I have one). When slewing the current increases substantially - lowering the voltage - and so you'd need a decent PSU for use at 12v (mine is 10A) as MrFreeze says. Even better, these mounts can be supplied with up to 16v: I use a 15v supply and in this case a 2.5A is easily enough. Even better, a higher voltage has lower transmission losses. When you used a battery (13v+ fully charged) this is why it worked better.

P.

[Owmuchonomy]

A Flashing LED on this mount is indicative of a voltage drop somewhere in the supply.  It would seem the problem is intermittent so I would thoroughly check the connections, cables and PSU.  Do both axes rotate freely by hand when the clutch is disengaged?