Got big alignment problems using OnStep and NINA...someone please help!

[dazzystar]

Hi All,

As can be seen from the pics (which I've named after their respective Dec setting in NINA) my OTA is not pointing correctly. I'm using NINA and my location details in the ASCOM driver appear to be correct. Can anyone advise what's going on please?

The first picture should be pointing to 45d0m0s, the second to polaris (ish) which is the home position and the last picture 5d0m0s.

Many thanks
Daz

Edited March 11, 2022 by dazzystar

[adyj1]

Daz, is this new kit or stuff you've had working before but has started playing up? 

[dazzystar]

This is all new. 

[dazzystar]

Could it be something to do with alignment in software? I mean all I've done is roughly put the scope pointing to NCP and then within NINA asked it to slew to a coordinate. I surely must have to tell it where it's pointing to initially or train it somehow?

[Anne S]

You need to do a star alignment before you try slewing to anything. In Nina you'll platesolve to achieve this. You need to be under the stars to do it though. As to the numbers being wrong have you set your home position accurately? Most mounts don't have any marks on the axes so it will be approximate until you've aligned the mount to something. If you hen slew to the home position you'll be able to mark it.

[scotty38]

If your location is set up correctly and the scope and mount are pointing more or less North and you ask NINA to slew to an object it should go, more or less, to that object. It won't be perfect but that's where plate solving comes in. However, it will, or should, be near enough to test. I do it all the time to test meridian flips etc etc.

[adyj1]

1 hour ago, Anne S said:

You need to do a star alignment before you try slewing to anything

This isn't quite right - when you connect to EQMOD it *will* have a co-ordinate for the mount (normally the default park position of polaris) which you can check in the EQMOD driver software. If you ask it to slew to an object, as @scotty38 says, the mount will slew to where it thinks that location is. It won't be accurate (that's what alignment is for), but it will be approximate. If the mount slews off in a different direction altogether then there is something other than alignment going awry.

@dazzystar does the mount slew in the correct direction when you press the N/S/E/W buttons in the EQMOD software? The fact it is moving is good, you need to work out whether it is moving in the right direction (can be done inside) and then whether it is slewing at the correct rate (probably a night-time thing; from one known point does it over- or under-slew to a second location).  If it isn't moving in the right direction you need to make sure location and time are accurate. If they are, then I'd look at the ONSTEP configuration to check you've set everything correctly there. Try to use just the EQMOD software and leave NINA out of the equation for now...

Ady

 

[dazzystar]

30 minutes ago, adyj1 said:

This isn't quite right - when you connect to EQMOD it *will* have a co-ordinate for the mount (normally the default park position of polaris) which you can check in the EQMOD driver software. If you ask it to slew to an object, as @scotty38 says, the mount will slew to where it thinks that location is. It won't be accurate (that's what alignment is for), but it will be approximate. If the mount slews off in a different direction altogether then there is something other than alignment going awry.

@dazzystar does the mount slew in the correct direction when you press the N/S/E/W buttons in the EQMOD software? The fact it is moving is good, you need to work out whether it is moving in the right direction (can be done inside) and then whether it is slewing at the correct rate (probably a night-time thing; from one known point does it over- or under-slew to a second location).  If it isn't moving in the right direction you need to make sure location and time are accurate. If they are, then I'd look at the ONSTEP configuration to check you've set everything correctly there. Try to use just the EQMOD software and leave NINA out of the equation for now...

Ady

 

Thanks Ady. OnStep isn't compatible with EQMOD I'm afraid so I have to use the OnStep ASCOM driver. I'll play around more this evening but something isn't right.

[jacko61]

You don't have a custom 'Park' position set by any chance?  In EQmod I've set my own park position to have the scope horizontal so I can shut the roof. When I start up the mount (eq8r-pro) the handset asks if I want to slew to home - this is the standard 'near polaris' position and sometimes if I forget to synchronise this in eqmod, a slew will end up around 90 degrees out. 

Graeme

[Anne S]

1 hour ago, adyj1 said:

This isn't quite right - when you connect to EQMOD it *will* have a co-ordinate for the mount (normally the default park position of polaris) which you can check in the EQMOD driver software. If you ask it to slew to an object, as @scotty38 says, the mount will slew to where it thinks that location is. It won't be accurate (that's what alignment is for), but it will be approximate. If the mount slews off in a different direction altogether then there is something other than alignment going awry

 

I understood that it was new equipment. It's being pointed roughly. My thought was that the mount didn't know the exact home position. Hence the discrepancy.

[dazzystar]

53 minutes ago, Anne S said:

I understood that it was new equipment. It's being pointed roughly. My thought was that the mount didn't know the exact home position. Hence the discrepancy.

Yes Anne. You may be correct but I don't know how to tell OnStep what's home and what's not, etc. yet. This may be the reason for the problem but unlikely I'm afraid.

[Anne S]

Maybe OnStep assumes that the mount is in the correct position when you start it up. As I said above, you won't know how accurate that is until you've been able to synchronise the mount with your software. Then they will agree.

At starparties the gotos on the first night after setup can be way off. Once I'm synced with my software and parked the mount, gotos are extremely accurate next time out. You need to be under the stars. You can then mark the home position. I used a strip of insulating tape for a while till it fell off!

 

[michael8554]

19 hours ago, dazzystar said:

The first picture should be pointing to 45d0m0s, the second to 5d0m0s and the last picture is pointing to polaris

Have you got the order wrong ?

Image 3, Polaris, is pointing roughly 20 degrees above horizontal, but Polaris is currently roughly 50 degrees above the horizon when pointing north.

However Image 2, 5degrees, is pointing 50 degrees above horizontal.

Image 1 isn't pointing north or south so impossible to tell if it's pointing anywhere near 45 degrees.

Those were Dec not Alt figures ?

Michael

[dazzystar]

Thanks Michael. I've edited the post giving the correct image order.

[dazzystar]

I discovered a slight error in the software which has now been corrected in OnStep. Can I assume that if I slew to say 45d0m0s I should see the scope go to roughly 45 degrees in the air?

[michael8554]

Yes in Alt, but not necessarily in Dec - which do you mean ?

Dec 45d pointing south would be 85d above horizontal.

Dec 45d pointing north would be almost horizontal.

Michael

[dazzystar]

Now I'm getting more confused Michael. Dec to me is altitude where 0d is horizon level 90d is above my head / zenith. 45d is in the middle. Where am I going wrong cause at the moment things are really starting to pee me off!

[City9Town0]

Dazzy... Dec is an angular 'altitude'; however the zero and ninety degrees are not horizon and overhead..... 90 degrees is not overhead... it is 'close to' polaris... To avoid being 'peed off' even a little wikipedia or google might help. Relax, read and re-read...

Edited March 11, 2022 by City9Town0

[dazzystar]

It's not just that to be fair. Nothing is going right with this OnStep and I'm on the brink of giving up the whole project to be honest.

[adyj1]

I would still try to see if the movement of the motors matches the movement displayed through the software. Apologies for not spotting you didn't use eqmod, but in this case you do need something like nina; connect the mount in nina and use the slew controls in the equipment/telescope screen to move the mount and see what ascom is reporting to nina, compared with what you are observing the mount itself is actually doing. 

[fozzybear]

Motor direction of motion is correct?

Move Declination a little (10 or 20 deg.) left and right of the home position (NCP/SCP) and watching from behind the mount see if the telescope movement matches the screen.  Reverse Axis2 if it goes the wrong way.

Once that is working do a goto to a point half way up in the sky but not too far in home position (40 degrees away or so.)  If it points down toward the ground RA needs to be reversed.

you have setup NINA with correct co-ordinates for your location and the time is correct