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msacco

Synscan - can't manage to star align successfully

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2 minutes ago, Paul M said:

I'm baffled then! There is no indoor method of testing actual star alignment.  Once the 1st star is accepted the mount should just move the prescribed angular distances to the next object unless that object. Synscan drives the motors until the encoders arrive at the correct spot, so unless that object is in entirely the wrong place...., which makes me think of issues with your location and or time data. That was my motivation for getting the GPS mouse, remove a layer of potential errors on my part! :)

Well I'm really lost, as I watched many many tutorials and wrote every small step that might be relevant. I made sure that date/location/everything else is set properly, and still..it doesn't work. I'm probably making a stupid mistake, but where 😕

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Apart from any other problems you might be having, I was a little bit worried that you are using a 2x Barlow and  3.6mm eyepiece for alignment because the field of view would be very small. When I do alignment I normally use a 25mm eyepiece  on it`s own to give a decent field of view to allow for any discrepancies 

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8 minutes ago, Phil Fargaze said:

Apart from any other problems you might be having, I was a little bit worried that you are using a 2x Barlow and  3.6mm eyepiece for alignment because the field of view would be very small. When I do alignment I normally use a 25mm eyepiece  on it`s own to give a decent field of view to allow for any discrepancies 

But should it actually make a difference? Good or bad is one thing, bad being completely off doesn't seem to be related to it isn't it?

Also, if I center an object using small eyepiece, my sense is saying that if I'll switch back to 25mm for example, it should still be dead center.

For example:

image.png.bc0661f5bec1f05396e22eb4fe859ad9.png 

Isn't that the case?

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I would do the entire alignment process with just the 25mm eyepiece.

And only IF that works introduce trailing the alignment process with fins tuning alignment on the second and third star using a 10mm eyepiece.

A barlow and/or the 3.6 is I feel asking too much.

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Have you tried doing a factory reset ?

It solved a similar issue for me, when my HEQ5 would suddenly point in completely hopeless directions, no matter how many times I did the alignments.  The factory setting option is available through the setup menu.  You'll have to input your location data etc. again afterwards.

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A factory reset sounds like the best course of action.. I use a 20mm EP but do have an old 12mm EP with cross hairs if I need it!

Good luck

Ron

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Nobody nearby that can swap handsets to cancel out a faulty one?

I had similar issues with the XX14g, but it turned out to be the balance. I had is so well balanced that the slop in the gears was the issue. I made it front heavy and problem was gone.

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9 hours ago, msacco said:

Thanks for the detailed reply, unfortunately I'm doing all of that and more I believe.

I do perform an accurate polar alignment(spot on, or dot on in this case), I do 3 star align using 2x barlow and 3.6mm eyepiece(which from what I understand is incredibly not necessary), I also do exactly as you say, I only unclutch to the first star align and then the clutches remain locked.

The thing is after selecting the first star, the second star is way off, and so is the third star.

I really can't figure what I'm doing wrong. I've watched dozens of tutorials, read dozens of related articles, and still I can't seem to get it working.

The most annoying thing is that I actually have to go star gazing just to try that and fail. It's not like I'm not having fun with just manual(using the synscan still) gazing, but I just think I can achieve much more.

I'll ask again, does anyone have an idea how can I test my GOTO in my room?

Totally agree :)

The WiFi suggestion was mearly to see if a goto could be performed in the bedroom with you seeing it track to the alignment star on skysafari. You may have a malfunction on the handset. 

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10 hours ago, happy-kat said:

I would do the entire alignment process with just the 25mm eyepiece.

And only IF that works introduce trailing the alignment process with fins tuning alignment on the second and third star using a 10mm eyepiece.

A barlow and/or the 3.6 is I feel asking too much.

But once again, what difference should it make?

9 hours ago, Erling G-P said:

Have you tried doing a factory reset ?

It solved a similar issue for me, when my HEQ5 would suddenly point in completely hopeless directions, no matter how many times I did the alignments.  The factory setting option is available through the setup menu.  You'll have to input your location data etc. again afterwards.

As I wrote before, yes I have :)

9 hours ago, Ronclarke said:

A factory reset sounds like the best course of action.. I use a 20mm EP but do have an old 12mm EP with cross hairs if I need it!

Good luck

Ron

Doesn't work unfortunately.

2 hours ago, Ledge1962 said:

Nobody nearby that can swap handsets to cancel out a faulty one?

I had similar issues with the XX14g, but it turned out to be the balance. I had is so well balanced that the slop in the gears was the issue. I made it front heavy and problem was gone.

Not really...but I can try.

2 hours ago, Nigella Bryant said:

The WiFi suggestion was mearly to see if a goto could be performed in the bedroom with you seeing it track to the alignment star on skysafari. You may have a malfunction on the handset. 

Yeah of course, it's just not something that's going to happen anytime soon :)

 

Any other suggestions? Thanks.

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Could be one of the encoders is not counting ticks correctly. 

Indoors you could try slewing 360 degrees without scope and weights attached, the handset should report the same Ra or Dec at start and finish. 

Using the setting circle should be accurate enough if your error is large like you report. 

Michael 

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OK, a possibly daft notion, but what eyepieces are you using?  My system is different to your it's on a Dobsonian base, but the movement of the scope still relies on motors.  If find the weight of the telescope all important.  For setting up I find the use of the lightest eyepieces is necessary - even to the point of using the small Plossls and even the finderscope that the scope was supplied with.   I find if I load the telescope with a big heavy EP esp. if this is on top of adding in a big heavy optical finder and a red-dot finder on an extension bar that is gets so heavy the motors can't successfully drive it.  Esp. in the up and down axis.  Mostly the horizontal axis moves OK, but the up and down axis is often out.  The tube starts to move, but often finishes a good-bit lower than the intended target if I have too much weight on one end.   This is even the case when moving between targets when I again find it pays to take out the EP's between moves esp. if I've got the heavier one out to use.  I have never played with your type of telescope, but if you are out of ideas can I suggest that you do all you can to lighten the load on the far ends of the telescope and maybe just revert back to exactly what the manufacturer supplied on the assumption that you might be playing with different finders and esp. different EP's it might just be worth trying.

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Hi msacco.  You can do some useful testing indoors.

When I started testing my diy Onstep Goto system the slews were way out, with the scope ( a 200p on an EQ3-2) sometimes pointing at the ground or threatening to collide with the tripod.

Since it can sometimes be several weeks between clear nights in the UK I had to test the mount indoors to solve the problem.

You will need a compass to estimate the Azimuth of the scope & some sort of angle gauge to estimate Altitude. I used a school protractor. You do not need to strive for great accuracy. If you can estimate the Alt & Az  to plus or minus a few degrees you will be able to distinguish between slews that are probably correct & those that are obviously wrong.

You do not even have to mount the scope. I used a cardboard tube that came in a roll of kitchen paper towels to represent the scope, attached to the saddle by two rubber bands. I marked one end as the aperture. This means you can let the Synscan slew wherever it wants without worrying about your scope hitting the tripod.

Do some slews to different targets & estimate the Alt & Az pointing errors.  You can also use the setting circles to estimate the RA & Dec errors directly.  Hopefully you will discover some pattern in the errors which will point to the cause.

In my case I found the RA was about 15 degrees out (I hour), which forced me to accept that there must be an error in the time settings. Of course I had checked these settings many times but eventually I realised that I had misunderstood the way Onstep handles GMT/Daylight Saving Time/Time Zone and had input the wrong information.

Good luck!

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17 minutes ago, lenscap said:

Onstep handles GMT/Daylight Saving Time/Time Zone and had input the wrong information.

I wondered if this was the issue, but the OP said they used Synscaninit and the data it contained so the values should be correct.  I used Synscaninit too and amongst the things I have done wrong is to not feed in the leading zeros if the values and orders of magnitude than the input mask available, i.e. for 32 degrees to input 032 and not just 32 other it can go in as 320 when you don't want it to.  I've also forgotten to put in minus signs for west and I guess South if you are in the southern hemisphere.  I've also forgotten to change the year and to remember that the date doesn't automatically increment during the days the thing is switched off.  In other words synscaninit 2.0 is good, but clearly not idiot proof!

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8 hours ago, msacco said:

But once again, what difference should it make

You are having problems, in the process of elimination I would do an alignment with just the 25mm.

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Would you all agree that if the first alignment star is in the ballpark after the auto slew to it, then location, date, and time are probably correct? 

Michael 

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1 hour ago, michael8554 said:

Would you all agree that if the first alignment star is in the ballpark after the auto slew to it, then location, date, and time are probably correct? 

Possibly, but only if you are 100% certain which star it is in the sky that you think you should be landing on - this was also a big issue of mine.  I didn't know the sky well enough to be 100% certain which named star on the electronic handset was the star in the sky.  In particular I had a real problem with Polaris - it isn't as bright as I ever expected it to be and neither is it a 100% dead straight line off of the plough.  It is, however, a double star, but it isn't as clear a double as some are, but this can help on a clear night to know you are on it.  It is also in a direction I have light pollution with and to begin with I was never 100% sure which star it was to align on.  This never helped with my alignment issues.   If the telescope hasn't slewed properly, but gets pretty close to a fairly bright star, perhaps there is a tendency to think that was the star it was aiming at and to then settle and therefore 'educate' the scope that it is on the correct location when it might not be.  So it is really important that you know without error which start the telescope is aiming for.  Taking out a mobile phone with the Stellarium app. on can help, because as you select a star on the computer you can then use Stellarium on your mobile phone to confirm where it is in the sky and therefore when you correct the telescope to the first selected location you can be quite certain you have the star correct.

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On 16/06/2019 at 12:31, msacco said:

Aiming to the ground around 30 cm's away from the target :)

Looks like a similar situation here: 

But I couldn't really understand what exactly the issue was(see Cloudwatcher and high25 replies).

The problem/solution was this: 

You know the scope dove tail on the mount has to be at right angles to the actual mount so you can see through the polar scope to do your polar alignment . Well, on one occasion I forgot to return it to the proper position after attaching the scope and before using the hand set. I got a result similar to that which you have described.

Does that make sense?

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3 hours ago, happy-kat said:

You are having problems, in the process of elimination I would do an alignment with just the 25mm.

Well I've already done that in the past, it didn't really help. I do understand that we need to try difference things, but this doesn't make much sense to me :)

Thanks anyway!

2 hours ago, JOC said:

Possibly, but only if you are 100% certain which star it is in the sky that you think you should be landing on - this was also a big issue of mine.  I didn't know the sky well enough to be 100% certain which named star on the electronic handset was the star in the sky.  In particular I had a real problem with Polaris - it isn't as bright as I ever expected it to be and neither is it a 100% dead straight line off of the plough.  It is, however, a double star, but it isn't as clear a double as some are, but this can help on a clear night to know you are on it.  It is also in a direction I have light pollution with and to begin with I was never 100% sure which star it was to align on.  This never helped with my alignment issues.   If the telescope hasn't slewed properly, but gets pretty close to a fairly bright star, perhaps there is a tendency to think that was the star it was aiming at and to then settle and therefore 'educate' the scope that it is on the correct location when it might not be.  So it is really important that you know without error which start the telescope is aiming for.  Taking out a mobile phone with the Stellarium app. on can help, because as you select a star on the computer you can then use Stellarium on your mobile phone to confirm where it is in the sky and therefore when you correct the telescope to the first selected location you can be quite certain you have the star correct.

Well I can say that I'm relatively familiar enough with what I'm looking for, and also using apps such as stellarium makes it pretty easy to locate what star I'm looking at.

1 hour ago, Mark Raishbrook said:

The problem/solution was this: 

You know the scope dove tail on the mount has to be at right angles to the actual mount so you can see through the polar scope to do your polar alignment . Well, on one occasion I forgot to return it to the proper position after attaching the scope and before using the hand set. I got a result similar to that which you have described.

Does that make sense?

I guess not, but what I might've understood from this is:

You have your telescope set up in the home position, then you perform polar align, and before he got it back to the home position he started using the synscan?

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I wonder whether the OP has made the same error as I did. I entered the date as 'dd/mm/yyyy' rather than rather than the illogical 'mm/dd/yyyy' US format that Synscan requires. I was lucky that the mount slewed to an area that had no bright stars when I accepted its offer of Vega and so I knew something was awry. On checking with Stellarium, Vega was just below the horizon at the time. However, if had been a bright star in the EP, I'd probably have assumed that was Vega, aligned with that and possibly ended up with a situation similar to the OP.

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4 minutes ago, Geoff_L said:

I wonder whether the OP has made the same error as I did. I entered the date as 'dd/mm/yyyy' rather than rather than the illogical 'mm/dd/yyyy' US format that Synscan requires. I was lucky that the mount slewed to an area that had no bright stars when I accepted its offer of Vega and so I knew something was awry. On checking with Stellarium, Vega was just below the horizon at the time. However, if had been a bright star in the EP, I'd probably have assumed that was Vega, aligned with that and possibly ended up with a situation similar to the OP.

Unfortunately that's not the case 😕

I set up everything exactly as displayed to me in the 'synscaninit' app, and also making sure that everything actually matches, my synscan is not even getting to the point of slewing near a star, so even thought it's fairly easy to detect most stars by their color, I'm not even getting a wrong star to begin with :)

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Is there anything on the OP's scope that could be installed backwards?

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If it was my Dob I would still be up for something to be slipping with the motor.  I.e.the system counts the necessary number of clicks, but the scope has moved wrongly perhaps due uneven weight, or maybe it gets hooked up on something by a trapped cord or power cable and can't move any further?  

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I've also had issues with my Synscan but the Alt/Az version and I'll just describe what seems to have worked for me. I also had issues where it seemed like it would work for 10 minutes and then start slewing in the wrong direction like it had the hemisphere confused. Forgive me if any of this has been said but first thing I did was factory reset the handset. this made no difference, next step was I updated the firmware on the handset this seemed to have partially solved the issues.

There was still something a little off and as I don't have an official power supply and being reluctant to buy one, I tried a few different ones I had ensuring they were tip positive and found one which outputs 12.2V consistently. Since then, albeit only used a few times due to the weather it has been working absolutely fine. I can't see anywhere you've stated what power supply you use but forgive me if I missed it as I've experienced some very erratic behaviour with incorrect power supplies. Hopefully this may help and I hope you solve it soon!

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2 hours ago, msacco said:

I guess not, but what I might've understood from this is:

You have your telescope set up in the home position, then you perform polar align, and before he got it back to the home position he started using the synscan?

Yes, that's what meant. He did a polar align (dovetail aligned E/W so you can use the polar scope), then put the telescope on the mount but left it in the E/W position when using the hand controller. That wouldn't explain it being pointed down at the ground, though.

There are two other possible solutions in an SGL thread from 2009 (see below). The first only applies if you installed your own GoTo kit on a non-GoTo mount and connected the RA and Dec cables the wrong way round. The second is possibly the most likely cause: a software issue.  You may have the latest driver, but that doesn't mean the driver software is properly installed. It may not have downloaded correctly (data loss) and/or the memory section it's living in may be damaged. If a few bytes of code are corrupt or missing, the handset may appear to function properly but could get messed up when certain functions are run.

 

Edited by Mark Raishbrook

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7 hours ago, Mark Raishbrook said:

Yes, that's what meant. He did a polar align (dovetail aligned E/W so you can use the polar scope), then put the telescope on the mount but left it in the E/W position when using the hand controller. That wouldn't explain it being pointed down at the ground, though.

There are two other possible solutions in an SGL thread from 2009 (see below). The first only applies if you installed your own GoTo kit on a non-GoTo mount and connected the RA and Dec cables the wrong way round. The second is possibly the most likely cause: a software issue.  You may have the latest driver, but that doesn't mean the driver software is properly installed. It may not have downloaded correctly (data loss) and/or the memory section it's living in may be damaged. If a few bytes of code are corrupt or missing, the handset may appear to function properly but could get messed up when certain functions are run.

 

I don't think it can be the case for me as well, as I'm not using the home position to star align since I can simply move to the first star manually, so I wouldn't expect it to be accurate on first align.

I actually bought my mount and scope second hand, pretty sure he bought the mount with the GOTO.

As for a software issue, well that first happened to me when I got it, so then I thought about updating the firmware because of that, and it had the same result, so I'm not really sure if that's a firmware issue, but could still be a software issue somehow.

I'll try getting in touch with someone that might be able to help me with that.

7 hours ago, Pullock said:

I've also had issues with my Synscan but the Alt/Az version and I'll just describe what seems to have worked for me. I also had issues where it seemed like it would work for 10 minutes and then start slewing in the wrong direction like it had the hemisphere confused. Forgive me if any of this has been said but first thing I did was factory reset the handset. this made no difference, next step was I updated the firmware on the handset this seemed to have partially solved the issues.

There was still something a little off and as I don't have an official power supply and being reluctant to buy one, I tried a few different ones I had ensuring they were tip positive and found one which outputs 12.2V consistently. Since then, albeit only used a few times due to the weather it has been working absolutely fine. I can't see anywhere you've stated what power supply you use but forgive me if I missed it as I've experienced some very erratic behaviour with incorrect power supplies. Hopefully this may help and I hope you solve it soon!

The issue with that, is that in my case it's completely off, which is not something I belive balancing or anything similar could cause at that level.

Edited by msacco

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