Synscan and the 'Home" setting

[sophiecentaur]

Polar alignment and setting the mount correctly seem to work OK on my s/h NEQ6 Pro. But when I try for star alignment I sometimes get Alignment Failed and a message about RA 45degrees . Other times, the first star that I choose for alignment is way off where the mount seems to think it is. 

When I look on Utilities Show Position, I get a random pair of values. I am assuming that I need to use the handset to a known position and then mechanically put the mount to that physical  position. Of course, I tried using the handset to achieve the usual Home Settings but I just chase my tail as, near the pole, the control just seem to chase themselves. It would be helpful if someone could tell me I am along the right lines and what position to use to get it set up right. 

It's amazing that the procedures for polar alignment and mount alignment  (using a level and the two scales on the axes) are to be found all over the place but I can't seem to find a solution to this particular problem. Weird, when you think that every EQ mount should really be set correctly. Or...... is mine broken?

[Owmuchonomy]

I’m not entirely sure I follow all the issues but to go back to basics. First, before switching on set up your mount and scope in the Home position so mount set at the latitude for your location pointing North and with the counterweight bar pointing at the ground. Your scope should now roughly be pointing at Polaris. Switch on Synscan and enter the correct coordinates for your location and the correct time and date in mm.dd.yyyy format.  Choose 2 star align and choose your first star. The mount should move to put your scope close to your target. Use the handset movement controls to centre the star in your EP. Choose the second star and the mount should put your scope pretty close to that. Adjust using the handset controls to centre it in your EP and you should be successful.  If it is a long way off on your first star it is likely the data you entered in the handset at the beginning is in the wrong format.

[Ronclarke]

I should check your inputs, accurate Lat and Long ,accurate time (check its +1hr for BST) and as said before mm-dd-yyyy . Pick easy to see stars, Vega and Arcturus at the moment, let us know how you get on?

 

Cheers

Ron

[sophiecentaur]

3 hours ago, Owmuchonomy said:

I’m not entirely sure I follow all the issues but to go back to basics. First, before switching on set up your mount and scope in the Home position so mount set at the latitude for your location pointing North and with the counterweight bar pointing at the ground. Your scope should now roughly be pointing at Polaris. Switch on Synscan and enter the correct coordinates for your location and the correct time and date in mm.dd.yyyy format.  Choose 2 star align and choose your first star. The mount should move to put your scope close to your target. Use the handset movement controls to centre the star in your EP. Choose the second star and the mount should put your scope pretty close to that. Adjust using the handset controls to centre it in your EP and you should be successful.  If it is a long way off on your first star it is likely the data you entered in the handset at the beginning is in the wrong format.

 

2 hours ago, Ronclarke said:

I should check your inputs, accurate Lat and Long ,accurate time (check its +1hr for BST) and as said before mm-dd-yyyy . Pick easy to see stars, Vega and Arcturus at the moment, let us know how you get on?

 

Cheers

Ron

Thanks for the replies. 

I would have expected that the show position , when the mount goes to Home , would be an appropriate pair of coordinates - something like  Dec = 90 (?) RA (00:00(?)) . That's assuming it's been turned on with the mount  set to the pole and N direction.  It's confusing me and I wonder whether there's something wrong with my basics or with the mount hardware/software.  Is it wrong to expect the home co ordinates to start off at the same basic (origin) values at switch on?  Why is this not described as a basic part of setting up a mount?

Two or three star alignment often seems to work well enough to use GoTo but other times it is totally wrong. 

I have the right location co ordinates as far as I can tell and the time and date. You cannot get the date format wrong way round because one field (the month) won't allow higher numbers than 12). Also, there are times when it goes straight to very near the first chosen alignment star.

[sophiecentaur]

Thinking about this again, surely when you switch on, the mount has no memory so it has to assume it's in the home position and Show Position should start at the Origin and not some random (apparently) value. This would explain why no one seems to have the problem that I'm experiencing.

[Owmuchonomy]

It does have some memory, for example it will show the last date you used it when you switch on and the last coordinates you used and probably the last position you had your scope in if you didn't use the 'Park to home position' when you last used it.  If you ask it to 'Park' to 'Home' when you have finished it will slew the scope back to the home position then it will say 'Position Saved' and ask you to power down.  Obviously, this function is only useful if you are NOT moving your kit between sessions like me in my obsy.

[sophiecentaur]

6 hours ago, Owmuchonomy said:

It does have some memory, for example it will show the last date you used it when you switch on and the last coordinates you used and probably the last position you had your scope in if you didn't use the 'Park to home position' when you last used it.  If you ask it to 'Park' to 'Home' when you have finished it will slew the scope back to the home position then it will say 'Position Saved' and ask you to power down.  Obviously, this function is only useful if you are NOT moving your kit between sessions like me in my obsy.

My basic question is about what position does the mount think it is in when it's in the home position? Does the software manage to cope with the transformation of all its astronomical data to an apparently totally arbitrary origin? Also, a related question is what does NPE mean?

[Owmuchonomy]

I’m sorry but I don’t understand the question or the reason behind it. Maybe somebody else will answer it.

[ngwillym]

I was always under the impression the the 'Home' or starting position before switching on was with weights down and scope pointing north? Or am I missing the point?

[Cornelius Varley]

15 hours ago, sophiecentaur said:

My basic question is about what position does the mount think it is in when it's in the home position? Does the software manage to cope with the transformation of all its astronomical data to an apparently totally arbitrary origin? Also, a related question is what does NPE mean?

The mount expects to start in the normal home position ie telescope pointing at the celestial pole and counterweight bar pointing downwards. From this position the handset can determine the approximate position of the first alignment star based upon the date, time and location coordinates. Use the handset or unlock the clutches and manually moving the telescope onto the first star and then pressing enter to accept the alignment. The handset now has an accurate start point to locate the 2nd star.

[stash_old]

25 minutes ago, Cornelius Varley said:

The mount expects to start in the normal home position ie telescope pointing at the celestial pole and counterweight bar pointing downwards. From this position the handset can determine the approximate position of the first alignment star based upon the date, time and location coordinates. Use the handset or unlock the clutches and manually moving the telescope onto the first star and then pressing enter to accept the alignment. The handset now has an accurate start point to locate the 2nd star.

If you want proof of the Peter's true statement then attach CDC or Stallarium etc (if you can) before you start alignment and this will show you where the mount thinks its currently pointing at-remeber to select "Track Scope" in CDC.

Although it is possible to have the scope pointing ,from the initial start up position, to a another position than the Celestial Pole - but that's using the "Hibernate at current position".

[sophiecentaur]

5 hours ago, stash_old said:

If you want proof of the Peter's true statement then attach CDC or Stallarium etc (if you can) before you start alignment and this will show you where the mount thinks its currently pointing at-remeber to select "Track Scope" in CDC.

Although it is possible to have the scope pointing ,from the initial start up position, to a another position than the Celestial Pole - but that's using the "Hibernate at current position".

I totally agree with this and other things that have been written. If it were true for my mount, would you not expect it to tell me it is looking at or near the NCP when it's in its home position? The only ways for this to happen would be for power off to set the recorded Position to NCP (or some chosen preset) or to have a manual way to set the Home position to NCP. Neither option seems to appear in the Synscan literature or to be discussed anywhere.

I don't need Stellarium, handy though it is, to Show the Position; it's available on the handset. (I have already had a problem getting my head round how Stellarium can possibly know where I'm pointing if the mount doesn't reset its origin.)

Either way, it has to be an issue yet no one seems to see the significance. I can understand how people may not want to get involved with yet another layer of things but I cannot imagine that mounts can be intelligent enough to  handle a constantly changing Origin for the pointing. 

I would love for someone to see what I am wingeing about and to reassure me it's OK.

[Paul M]

For the home position to mean anything the mount has to be parked there from a known position.

So you're all set, polar alignment complete, 2 or 3 star alignment complete. This means that the mount is mechanically aligned with Earth's axis and Synscan, the "brain" knows how the mount is aligned with the sky.

At the end of your session you can park the mount in the home position and then power it down. Next time you use the mount Synscan can use elapsed time since last use to go directly from the home position to any selected object without any further alignments being required, provided that the mount hasn't been disturbed in the interim.

If you pack up between sessions and can't be certain that the axis encoders and/or polar alignment haven't moved then the home position is effectively meaningless. 

Rack-o-the-eye manual parking in a home position like pose isn't much use either.

[ngwillym]

On 14/05/2018 at 18:28, sophiecentaur said:

Polar alignment and setting the mount correctly seem to work OK on my s/h NEQ6 Pro. But when I try for star alignment I sometimes get Alignment Failed and a message about RA 45degrees . Other times, the first star that I choose for alignment is way off where the mount seems to think it is. 

When I look on Utilities Show Position, I get a random pair of values. I am assuming that I need to use the handset to a known position and then mechanically put the mount to that physical  position. Of course, I tried using the handset to achieve the usual Home Settings but I just chase my tail as, near the pole, the control just seem to chase themselves. It would be helpful if someone could tell me I am along the right lines and what position to use to get it set up right. 

It's amazing that the procedures for polar alignment and mount alignment  (using a level and the two scales on the axes) are to be found all over the place but I can't seem to find a solution to this particular problem. Weird, when you think that every EQ mount should really be set correctly. Or...... is mine broken?

When you say 'mechanically put the mount....' do you mean you move the scope using the hand controller up/down/left/right buttons, or do you physically unlock the RA & Dec clutches and moves the scope? If the latter, the as far as I know, this type of mount doesn't have secondary encoders to cope with manual movement. You have to move the scope to the alignment stars by using the hand controller only.

[sophiecentaur]

3 hours ago, ngwillym said:

When you say 'mechanically put the mount....' do you mean you move the scope using the hand controller

I mean loose the clutches and move the mount to that position by hand. So the number I set into the position memory and the actual mount position should agree. Logically, when it's told to go to the Park position, the Show Position should be NCP plus or minus a little bit.

PS I can't seem to get the four direction pads to get to NCP directly. They all interact in a way that I am sure they shouldn't but RA can be 'anything' at the Pole. The crosstalk between the two pairs of pads makes no sense to me at all.

[Ronclarke]

Note that, wherever you are in the sky left, right, up and down will move the scope in different directions. You have to be looking in the eyepiece or guide scope to see which way it moves! NEVER loose the clutches and move your scope, it will get totally lost. If this happens, park the scope, power off THEN move the mount to it's home position manually. That's the only way!

 

Ron

[stash_old]

3 hours ago, Ronclarke said:

Note that, wherever you are in the sky left, right, up and down will move the scope in different directions. You have to be looking in the eyepiece or guide scope to see which way it moves! NEVER loose the clutches and move your scope, it will get totally lost. If this happens, park the scope, power off THEN move the mount to it's home position manually. That's the only way!

 

Ron

Thats not totally true Ron - if you have AZEQ5/6 8 and I believe some of the newer models all have "smart" encoders that  note you are moving the scope manually and record the RA/DEC accordingly. This can then be "over ridden" by syncing an objects position so that the software recalculates coordinates. But agreed with the NEQ6 your statement is 100% true.  Just as someone has also stated that the manual starting position is critical so that it  agrees(within reason) with the "handsets"(software or hardware version) starting position so that the software can move the mount to where it thinks the object should be - all things being equal. But its far from perfect and not ,IMHO, 100% accurate/reliable due to many factors e.g. motors working 100%,no broken encoders etc etc.

To be honest while I have every sympathy with sophiecentaur I think its being unrealistic to expect 100% accuracy every time - there are too many variables,especially mechanical, which can and do introduce errors especially over long slews. Even in my fixed set up there is no way I can be dead centre on an object every time even if I have not done anything to the set up since I used it last maybe there is something wrong with my set up :-)

IMHO moving away from the handset to software improved my set ups (fixed or grab and go) but I would be the first to acknowledge Sky Watchers manuals are some what lacking in detail. Electronic Polar alignment , if possible in your location, is another god send and saves on back backs/necks. Also the use of Platesolving helped me no end especially as I do remote observing. 

In the end it maybe in this case there is a problem which he/she can live with or needs looking at - but finding the problem especially an intermittent one could be a nightmare and with the number of clear nights limited may not be worth it IMO.

Good luck and I hope you  ,Sophiecentaur , find a solution to your problem.

[dph1nm]

On 14/05/2018 at 22:43, sophiecentaur said:

I would have expected that the show position , when the mount goes to Home , would be an appropriate pair of coordinates - something like  Dec = 90 (?) RA (00:00(?)) .

"Home" is not necessarily RA=0 - I suspect in practice it should be more like the current sidereal time. However, when you first power on the mount it has not done an alignment, so I am not sure whether you would expect "show position" to return anything useful (I have never looked). It is also not necessary to start from the exact home position (or to be level) - you can just unclamp the axes and move manually to the first star (by doing this you are, in effect, refining your home position and clock time). Don't do this with subsequent stars in a 2 or 3 star alignment though! The real question is why are your star alignments failing - a 1-star alignment should never fail, so I assume you are talking about 2 or 3 star alignments. With the original firmware in my HEQ5 (3.2 something I think) 3-star alignments would often fail for no apparent reason, but this seemed to be fixed with the later firmware updates. I think to get a 2-star alignment to fail you would either have to have your polar alignment, or some of the initial handset settings, wrong, or to have aligned on one or more wrong stars (or to have some mechanical/software fault of course).

NigelM

[ngwillym]

@stashold - only the EQ8 has the 'dual encoders' to allow the mount to be moved by hand and remember the position.

@sophie centaur - moving the mount by hand - unlocking the cluthces on the axes will cause the sysnscan to lose any idea of what position it is in.

 

The process should be:-

i)set the scope with the mount set with weights down and pointing to the north with the scope also pointing north , with the latitude scale reading approximately to your latitude.

ii)perform a polar alignment, only by loosening the bolts holding the mount to move the whole kit east/west, and/or by adjusting the latitude with the latitude adjuster - DON'T unlock the axes, or move the scope with the handset.

iii) perform a 2 star or 3 star alignment via the handset.

iv) once this has succeeded, yoy can then use the handset (and only the handset) to move to other objects in the sky - either by using the handset's built in catalogue or typing the RA & Dec directly in to the handset, or even, using the up/down/right/left buttons to move to an object or to star hop from one object to another.

v) When you've finished for the night use the handset to park the scope to 'home'

 

Hope this helps

Neil

 

 

[Cornelius Varley]

42 minutes ago, ngwillym said:

 moving the mount by hand - unlocking the cluthces on the axes will cause the sysnscan to lose any idea of what position it is in.

This is only true after the mount has completed the first star alignment. Before that the clutches can be unlocked and the mount slewed by hand to centre on the first alignment star. The handset now has an accurate starting point. Before that it is more like guesswork based upon date, time and location. 

[Cornelius Varley]

39 minutes ago, ngwillym said:

only the EQ8 has the 'dual encoders' to allow the mount to be moved by hand and remember the position.

The AZ EQ6 GT and AZ EQ5 GT also have dual encoders.

[stash_old]

57 minutes ago, ngwillym said:

@stashold - only the EQ8 has the 'dual encoders' to allow the mount to be moved by hand and remember the position

Sorry that's not true - I have  AZEQ6GT and I can confirm it has dual encoders -  as Peter also confirms.

[ngwillym]

24 minutes ago, stash_old said:

Sorry that's not true - I have  AZEQ6GT and I can confirm it has dual encoders -  as Peter also confirms.

Thanks for that - good to know - I've not follwoed the skywatcher mounts developments.

 

Makes my process a bit obsolete.

Neil

[ngwillym]

Apologies - I was confusing the OPs NEQ6 with the other mounts mentioned - i;m still sure the the NEQ6 does not have dual encoders and therefore cannot be moved by hand and have the syscan handset know where it is.

 

@cornelius - excuse me if I have got this wrong, but the EQ6 (and therefore I assume the NEQ6) manual, page 9 last paragraph  states:- (I paraphrase)

(Sysncan Only) - don't move the mount manually, or you will have to re-home the scope and redo the star alignment). And i think I see where the confusion occurs - in 'Easy Tracking' Mode, yes you can move the scope manually, but only manually to one or more objects - the hand controller will not know where the scope is actually pointing and so cannot be used for Goto - each object to be observed has to be found manually - but you can use the up/down/left/right keys to move the csope. To use the goto function of synscan, you must perform a full feature initialization. I'm still guessing but I think the OP begins in 'easy tracking mode' moves the mount manually to the object and later tried to use the handset to move to other objects?

 

[sophiecentaur]

I don't find it hard work to polar align or to set the mount up with clutches released and using a level in the normal way to do the initial setting up. This is really not the issue. Whatever the accuracy of any alignment process, if I turn off the power then the mount cannot be sure what I have been doing with the clutches (they could even be left disengaged). Does it not have to assume it is starting from Home and that the display when I Show Position should show NCP co ordinates? It is a very simple question which I'm sure can be answered in isolation from all the other alignment questions. If, at the Home Position, the show position gives a value that's nothing remotely like the NCP, how can the mount have a chance of pointing any where near the first star in the star alignment process? Any other system for measuring anything at all, starts with the origin being set to a 'zero' position. This is true for a stop watch, a barometer or an oscilloscope so why doesn't this seem to apply on my mount?

Also, why does no one else seem to have experienced (or considered) this sort of issue?

 

Some of the posts above seem to imply that, even with the clutched disengaged, there are additional encoders that measure the position. That is even more confusing.