Fed up with the SynScan GOTO. Updated (Issue Solved)

[PlanetGazer]

I was hesitant to write this earlier, but I wanted to try all possible ways to get my new SkyWatcher 250P GOTO allgined, but to no avail.

I have followed the instruction manuals of both the synscan and SW, and managed to get the message "alignment successful" multiple times on the handset or the app. The closest I got when I tried to dial a different star was a 20 to 25 degrees off on the azimth axis. Most times it's off by a margin on both axes.

I have tried aligning around 30 times on more than 5 diffrenet occasions, different locations as well. I end up ignoring the thing and switch to navigating manually as the eager friends want to observe instantly, but we ran out of objectes and the planets are not close anymore, so I figured it's time to get deeper DSO's and sort out the GOTO.

Here is what I do:

• I level the scope to the zero reading on top of the base

• I make sure the base is level with a spirit level I bought recently

• I point the scope northish, but latley I bought compass to pinpoint north

• I plug all equipments in and then switch on the power from a lead acid battery

• I enter the date ( US fromat, month before day 😕 )

• enter correct time zone obviously

• the coordinates in the format of E 000 00 , N 00 00 

• As for  elevation I use "my  elevation" app, not sure if it's accurate. Does this entry have to be that accurate?

• I tried both brightest star and the 2 star align methods on the handset (which seems to be the same thing apart from the brightest method having an extra menu asking for which direction you are pointing at)

I even used the synscan app and the synscan pro, and tried the 3 star align method. The app uses location and enters all data automatically

•I use the top and right arrows as the last press before centring the star in the eyepiece as  recommended by the manual

 

These are the steps I follow when I align , is there anythung I missed? Your kind help is much appreciated.

 

Update: issue solved, check the reply in the second page

 

Edited October 26, 2019 by PlanetGazer

[PlanetGazer]

Other extra info:

• One time I tried the 3 star align method, the first star to align was capella, the scope slew to capella, exactly, from the first time! But by the time I completed the alignment, the scope was misaligned with the other stars

• There was a foam ring covering the gears between the two wooden layers at the base (glued), it was there the whole time, however I took it apart at the last session. I tried to align after, but no luck. Didn't know the gears were exposed! 

• Here is what I suspect the problem is, but I could be wrong:

• In one of the sessions, I noticed that when the base is level when measured with a spirit bubble, the scope (OTA) is not level, when it's set at zero reading. I would have to move it down minus one of the zero to make it level

• could the gears/morirs be faulty?

• backlash issues? Uncharted waters for me 

[Anthonyexmouth]

i dont know about the correct setup for a dob but if it has to be setup pointing north make sure nothing is throwing the compass off. any metal or underground cable could potentially give a reading thats way off. 

[PlanetGazer]

7 minutes ago, Anthonyexmouth said:

i dont know about the correct setup for a dob but if it has to be setup pointing north make sure nothing is throwing the compass off. any metal or underground cable could potentially give a reading thats way off. 

I'm sure it's north in this case, as I know the area well, I only use the compass to point with more accuracy. 

Thanks for the tip

[Stargazer33]

I'm not familiar with your 'scope or goto system, but are the alt/az clutches tightened, if it has them?

I would think that the foam ring you removed was there for a reason, unless it was packing to stop parts from knocking together during shipping. Is there anything in the setup instructions/manual about removing packing from that area?

[Geoff Barnes]

A couple of things, 

Leave the foam ring in place, I think it's to keep dust etc. out.

Don't align to magnetic north as shown by the compass, align to true north.

Even when the goto misses its target by a large margin, once you have centred your target by manually pressing the handset buttons, leave it tracking that object for a few minutes and then send it off to another target, it should then be a lot closer to its intended target.

I've had all sorts of similar issues with my Dob, and to be honest still do occasionally, but usually it gets reasonably accurate results once it has been tracking something for a few minutes, it then seems to know where things are.

[johninderby]

Just a thought. How are you powering the dob? Insufficient power can cause alignment problems particularily as when slewing during alignment when it can draw more amps than you would expect.

Edited September 28, 2019 by johninderby

[masjstovel]

I had the exact same problem as you and the problem was my Power supply as @johninderby mentions above. I used a supply with too low amps and bought a new one with 2.5 A and it worked perfectly.

 

Other thoughts:
You start from parked position?

Have you calibrated your polarscope? So that your mount is not pointing in the wrong direction because the polarscope is off?

Lastly, it may be obvious and i'm sure you do it, but just to check since i dont find it in your steplist: You balance your scope with the setup you're about to use? And i don't mean to be rude, but you do actually look through the polarscope and align polaris in the right position in the given time? 

I am a newbie and i missed some "captain obvious" points myself my first times so just checking. I would definately try my first tip if everything else is in order - that did it for me.

Edited September 29, 2019 by masjstovel

[PlanetGazer]

8 hours ago, Geoff Barnes said:

A couple of things, 

Leave the foam ring in place, I think it's to keep dust etc. out.

Don't align to magnetic north as shown by the compass, align to true north.

Even when the goto misses its target by a large margin, once you have centred your target by manually pressing the handset buttons, leave it tracking that object for a few minutes and then send it off to another target, it should then be a lot closer to its intended target.

I've had all sorts of similar issues with my Dob, and to be honest still do occasionally, but usually it gets reasonably accurate results once it has been tracking something for a few minutes, it then seems to know where things are.

I was doubting that the foam ring is there for protection, though it's not a reliable material and won't last in place with glue only. Do all SW dobs come like this?!

 

I will have to try this next time, thanks for the help!

 

9 hours ago, Stargazer33 said:

I'm not familiar with your 'scope or goto system, but are the alt/az clutches tightened, if it has them?

I would think that the foam ring you removed was there for a reason, unless it was packing to stop parts from knocking together during shipping. Is there anything in the setup instructions/manual about removing packing from that area?

the dob has no clutches, once you point it at something it will stay still unlike non dob mounts

[Geoff Barnes]

2 hours ago, PlanetGazer said:

Do all SW dobs come like this?!

All the ones I've seen lately seem to have it. It doesn't interfere with anything and never comes adrift, but you could take it out if it bothers you.

Your Dob must have clutch handles on the side of the base and on the bottom if it's a goto model, they all do.

Edited September 29, 2019 by Geoff Barnes

[PEMS]

You must have clutches. You release the clutches when you manually move the scope then you tighten them for the motors and gears to engage to drive the main scope.

 

Guess that is the problem therefore. You need to find and set the clutches as appropriate. Since you can move the scope at present to center the alignment stars it would read that the clutches are more or less off and so the motors and gears are not driving the OTA correctly. Slight slippage.

[johninderby]

There isn’t a clutch release on the Synscan dobs. You can adjust the clutches though.but requires taking things apart. Click on the box below to show the file.

Edited September 29, 2019 by johninderby

[PlanetGazer]

8 hours ago, johninderby said:

Just a thought. How are you powering the dob? Insufficient power can cause alignment problems particularily as when slewing during alignment when it can draw more amps than you would expect.

I use a lead acid battery which is 12V & 7Ah, I check the voltage before starting each session using the option on the handset. Currently it's 12.3 V. Below is a picture of the battery (I charge it by connecting it to the car's battery for a few minutes, engine running of course). Is the handset accurate in measuring the voltage? should I get a Voltmeter to accurately measure it?

 

 

8 hours ago, masjstovel said:

I had the exact same problem as you and the problem was my Power supply as @johninderby mentions above. I used a supply with too low amps and bought a new one with 2.5 A and it worked perfectly.

 

Other thoughts:
You start from parked position?

Have you calibrated your polarscope? So that your mount is not pointing in the wrong direction because the polarscope is off?

 

The battery used is 7Ah, that should be more than what is required. I'm sure that I reset the park option, and have done a factory rest as well. and there is no polar scope on a dobsonian. it's an alt/azm mount.

 

Quote

Lastly, it may be obvious and i'm sure you do it, but just to check since i dont find it in your steplist: You balance your scope with the setup you're about to use? And i don't mean to be rude, but you do actually look through the polarscope and align polaris in the right position in the given time? 

I am a newbie and i missed some "captain obvious" points myself my first times so just checking. I would definately try my first tip if everything else is in order - that did it for me.

Not at all, thanks for your help. Also there is no counterweights on Dobs.

[Cornelius Varley]

15 minutes ago, PlanetGazer said:

I use a lead acid battery which is 12V & 7Ah, I check the voltage before starting each session using the option on the handset. Currently it's 12.3 V. Below is a picture of the battery (I charge it by connecting it to the car's battery for a few minutes, engine running of course). Is the handset accurate in measuring the voltage? should I get a Voltmeter to accurately measure it?

Charging the battery through a car battery doesn't seem like a reliable method to me.

[johninderby]

You definately need a proper battery chrager.

Found the following on battery charge.

”Resting fully charged 12-volt batteries are around 12.8-12.9 volts, and flat dead ones are at 12.0 volts, so 12.4 volts on a resting battery means it's about 50% charged.”

Edited September 29, 2019 by johninderby

[wookie1965]

https://www.skywatcherusa.com/pages/support-center

Download or read through the manual pertaining to your scope here.

I have just had a quick read through you can point to roughly north for autotracking but if you want to use it manually it says point to a bright star and go from there it does explain how you may have more luck this way.

[nigelg]

Quote

Have you set Day Light Savings to yes.

 

 

[PlanetGazer]

Just now, Cornelius Varley said:

Charging the battery through a car battery doesn't seem like a reliable method to me.

Well I checked the voltage before and after, and it does increase, a five minutes charge increased it from 11.7 V to to 12.2 V , this is based on the handset reading. I could charge it at a regular plug (AC), but would have to order a special charging cable.

According to the the Synscan Manual, the requirement is  10 to 15 V and 1 Amp. I remember reading that it requires 12 V and 2 Amp in another manual, but I guess the difference is little, in which both cases is covered by 7Ah by the battery.

[Anthonyexmouth]

2 minutes ago, PlanetGazer said:

Well I checked the voltage before and after, and it does increase, a five minutes charge increased it from 11.7 V to to 12.2 V , this is based on the handset reading. I could charge it at a regular plug (AC), but would have to order a special charging cable.

According to the the Synscan Manual, the requirement is  10 to 15 V and 1 Amp. I remember reading that it requires 12 V and 2 Amp in another manual, but I guess the difference is little, in which both cases is covered by 7Ah by the battery.

the 7Ah refers to the capacity, not the current. 

charging mismatched and differing state of charge batteries on the same alternator isn't really a great idea

[PlanetGazer]

1 hour ago, Geoff Barnes said:

All the ones I've seen lately seem to have it. It doesn't interfere with anything and never comes adrift, but you could take it out if it bothers you.

Your Dob must have clutch handles either side of the base if it's a goto model, they all do.

Well I was in a dilemma since I received the scope whether to keep it or take it, but the frustration made take. I regret taking it apart. I will have to find an alternative. regarding the clutches, they are embedded inside the box yes.

[PlanetGazer]

1 hour ago, johninderby said:

There isn’t a clutch release on the Synscan dobs. You can adjust the clutches though.but requires taking things apart. Click on the box below to show the file.

what would make the clutches slip other than heavy weight or cold temperatures? I did use a heavy 5mm eyepiece X-Cel, but was not using the heavy finder with it, only a light red dot finder. Temperatures are high since I received the scope. The scope is new anyways, received it in early August.

[Cornelius Varley]

17 minutes ago, PlanetGazer said:

Well I checked the voltage before and after, and it does increase, a five minutes charge increased it from 11.7 V to to 12.2 V , this is based on the handset reading. I could charge it at a regular plug (AC), but would have to order a special charging cable.

According to the the Synscan Manual, the requirement is  10 to 15 V and 1 Amp. I remember reading that it requires 12 V and 2 Amp in another manual, but I guess the difference is little, in which both cases is covered by 7Ah by the battery.

A battery reading of 11.7v would suggest a battery that was not in a heathy state. A good battery, fully charged, should read about 13.5v-13.8v.

[alan potts]

As Peter pointed out, every problem I ever had with either the HEQ 5 Pro or my AZ EQ 6 were because of battery, I now use mains and never have a problem. Until now I have said that.

Alan

[PlanetGazer]

31 minutes ago, johninderby said:

You definately need a proper battery chrager.

Found the following on battery charge.

”Resting fully charged 12-volt batteries are around 12.8-12.9 volts, and flat dead ones are at 12.0 volts, so 12.4 volts on a resting battery means it's about 50% charged.”

Oh!  well thanks for that, I will have to try this next time! I will confirm this after my next session

30 minutes ago, nigelg said:

 

Daylight saving is set to no all times, local time zone doesn't use Daylight saving. All data entry shouldn't be the problem, as I have tried using the Synscan app which enters all data automatically once you allow it to connect to the web and allow location on before the start of linking the app to the scope.

[PlanetGazer]

47 minutes ago, wookie1965 said:

https://www.skywatcherusa.com/pages/support-center

Download or read through the manual pertaining to your scope here.

I have just had a quick read through you can point to roughly north for autotracking but if you want to use it manually it says point to a bright star and go from there it does explain how you may have more luck this way.

yep, it's the same as the one I have. My scope came with the CollapsibleGoToDobsonian manual, and a synscan manual, both are similar regarding alignment.

53 minutes ago, Anthonyexmouth said:

the 7Ah refers to the capacity, not the current. 

charging mismatched and differing state of charge batteries on the same alternator isn't really a great idea

 

39 minutes ago, Cornelius Varley said:

A battery reading of 11.7v would suggest a battery that was not in a heathy state. A good battery, fully charged, should read about 13.5v-13.8v.

Noted, thanks for the heads up.

 

31 minutes ago, alan potts said:

As Peter pointed out, every problem I ever had with either the HEQ 5 Pro or my AZ EQ 6 were because of battery, I now use mains and never have a problem. Until now I have said that.

Alan

Reading all the feedback, I can conclude that I will have to test it on a main (AC) power source, and see if it works (that would be me asking my friend to bring his car that have an AC plug). If it works then, I would have to find a permanent working solution for my battery and charger, as I don't have an observing site with an AC power available.

 

Thanks all for the contribution, I will update this topic after my next session.

 

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