Skywatcher goto issue, advice please.

[StormAurora]

I have only used the goto once and as much as I enjoyed looking at DSO s there doesn't seem to be a function to view constellations. It has named stars but apart from about 25 stars i don't know their names or what constellations they are in.

I really wanted to look at Corona Borealis but couldn't use the goto to observe. When I moved it there using the keypad, it wouldn't find my next object via the goto system. I ended up turning it off and resetting the whole system about 6 times!.

Also when i sent it to M81 , it was right on the edge of the field of view, so i moved it into the center and then when I went to the next target it was way off! It was actually very frustrating, although it did find some things I've never seen before and seemed to track well.

Anyone using one of these, got any tips please.

Cheers, clear skies ?

[vitruvian]

Im pretty new to this myself. Did you polar align it and star align it during setup? I find that if I do that its pretty accurate.

[happy-kat]

Please include what mount you are using because eq and altaz differ.

[Knighty2112]

Yes, please state which Skywatcher mount you are using please. Skywatcher mounts don't have a Constellation feature like some of the Celestron Goto mounts have. Best thing to do is buy a good star atlas book or an app for a tablet or phone that has a good list of stars with their Bayer designations (i.e. alpha Leonis, beta Cygni etc) and also their proper names  (i.e. Regulus, Albireo etc). This will help you with using the Goto in this respect. You may also want to use a 20 or 25mm eyepiece to get the objects in view better. No Goto will get the object exactly in the centre of view, but with careful setting up and correct EP size you should get most things in the eyepiece field of view (FOV). 

[Conrad Edwards]

I would also ask how you are powering the mount? Batteries or a power pack?

Or how much backlash/wear is in the gears, and whether any are worn.

Your mount should really get a target in the finderscope at worst.

[ronin]

Do not expect a mount/goto to really have constellations in them. A constellation is simply too big. If you asked it for Leo where does it point the scope? At Denebola, at Regulus, at Algieba, at Ras Elased Australis ? There is 30 degrees between Denebola (Leo rear) and Ras Elased Australis (Leo's nose) in horizontal movement alone.  So where does it point the scope? If it picks the primary, Regulus, then again you have a star in view as you are not going to have the constellation in view.

Your best option is likely to be to find out the name or designation of eeach of the primary stars of the constellations. Even that can be a bit suspect.

The primary star of CrB is Alphecca, but from SS5 it looks like even if you have a 1 degree view through the scope then the only thing in view is Alphecca as CrB is about 3 to 4 degrees in size.

 

[Knighty2112]

18 minutes ago, ronin said:

Do not expect a mount/goto to really have constellations in them. A constellation is simply too big. If you asked it for Leo where does it point the scope? At Denebola, at Regulus, at Algieba, at Ras Elased Australis ? There is 30 degrees between Denebola (Leo rear) and Ras Elased Australis (Leo's nose) in horizontal movement alone.  So where does it point the scope? If it picks the primary, Regulus, then again you have a star in view as you are not going to have the constellation in view.

Your best option is likely to be to find out the name or designation of eeach of the primary stars of the constellations. Even that can be a bit suspect.

The primary star of CrB is Alphecca, but from SS5 it looks like even if you have a 1 degree view through the scope then the only thing in view is Alphecca as CrB is about 3 to 4 degrees in size.

 

The Celestron Nexstar 6/8SE Goto mount I have has a Constellation feature where you can select a specific Constellation, then it will give a list of some of the main stars, DSO's, double stars etc in that particular constellation. This as far as I am aware is only available on the Celestron range of Goto mounts. 

[StormAurora]

I have the  eq3 pro mount. It is brand new. 

I had a Meade goto many years ago and I'm sure it had the constellation option. It came up with a list of objects within each constellation that you could view.

My issue is that if I move the object within the fov, it seems to lose it's positioning and the next target is not in the fov. 

It is polar aligned and powered with a battery pack. 

It also kept bashing into the motor system for the goto or the tripod leg and then I had to keep resetting it all from the beginning. So i had to avoid any objects that weren't directly above me. A bit of a nightmare actually.

Why isn't it simple ?

Thanks for your replies so far.

[ronin]

10 hours ago, Knighty2112 said:

The Celestron Nexstar 6/8SE Goto mount I have has a Constellation feature where you can select a specific Constellation, then it will give a list of some of the main stars, DSO's, double stars etc in that particular constellation. This as far as I am aware is only available on the Celestron range of Goto mounts. 

So I presume they are not going to a "constellation" but telling you initially what is in a constellation so that you can then select one of the objects and so goto that object. Not how I read it - tend to read things literally.

I have never considered that approach, seems as easy to do a bit of work and determine what is in a constellation first, then request that object from the scope data - assumes it is in it. For all I have a couple of goto's I tend to use them to go to an object I define or have decided previously is what I want to observe. Also gives me something to do waiting for clouds to clear.

This seems a area where having a laptop/notebook/tablet and planetarium software seems the more appropriate, rather then a handset. So you can see the constellation and then expand to see the objects, then select as necessary or required. More complication and cost however.

Cannot help on the not going to the next target, I can half see a problem concerning the software and how it seems to operate. However not having a Skywatcher it is guesswork There seems to be presumptions made that are a bit invalid. The main one being that the goto has gone to the target accurately, then any movement you make to centre the target it counts as a change of position, not as centering of the target. Should be easy to "fix" in software if it is not there.

There is a "sync" feature, well I believe there is, whereby you tell it to gotp a star, you centre it then, if I recall right, hold down Esc for a couple of seconds, follow whatever is asked and it then "resets" the scope to the RA+Dec of that star. That way it has a "new" defined position from which to operate. Basically movement and goto errors build up and occasionally you need to reduce or get rid of them.

Concerning it hitting bits of itself I would expect there to be an elevation limit you can set so that it will not go (by itself) above that evelation.

Battery pack(?) - if AA's then you are likely to need new ones every time you use it. The mount really dislikes anything resembling low voltage. Do not use rechareables as these are 1.2v not 1.5v. So if you were expecting 12v you would be giving it 9.6v.

It is more a case of learning all the assorted foibles and idiosyncrasies of the mounts more then not being easy. Although you have to remember that the "computing" power in a handset actually very small and limited. Smartphones and PC's have led us to expect a lot more then a handset can deliver.

[Knighty2112]

2 hours ago, ronin said:

So I presume they are not going to a "constellation" but telling you initially what is in a constellation so that you can then select one of the objects and so goto that object. Not how I read it - tend to read things literally.

Yes. Correct. 

[Knighty2112]

I have both a Celestron Nexstar 6/8SE AZ Goto mount, and Skywatcher Discovery AZ Goto mount also. I find that the Celestron Goto is more accurate and can cope with movement around the whole sky much better than the Skywarcher Goto, which does suffer from more problems getting the objects in view more especially when in a different area of sky. Saying that though it also depends on the eyepiece and magnification you are using too. I use an 18mm EP on my 4SE Mak which works great on the Celestron Goto and always has the object in the FOV even if not in the centre of it. If I use the same scope and EP on the Skywatcher Goto mount then I would soon loose sight of objects in the EP once I start to select them in different areas of the sky, and would have to use a wider FOV with a 25+mm EP to get the objects anywhere inside the FOV.

[StormAurora]

Thank you both for your replies.

I think I was expecting too much. Been spoilt with the old Meade system which was excellent. I am using a Celestron 25mm eyepiece on initial setup, then using the live view on my camera. 

I appreciate the tip  about esc helping fix the targeting error, I will be giving that a try. I use a power pack, Skywatcher, not batteries, old fashioned phrases lol.

I think I will use the mount manually to observe things other than DSO s, seems easier.

Cheers guys ?

[Yearofthegoat]

I have an HEQ5 mount with Synscan and I find everything depends upon how good the alignment is. If I do a 3-star alignment followed by a polar alignment (all via the handset), then the Synscan puts objects almost smack in the centre of the FOV every time. I might do a nudge or two with the arrow keys but generally it's very good. Even if I do a large slew to find something 'manually' it'll still go to the next object without issue.

Conversely, if I do a 1-star or 2-star alignment or omit the polar alignment things aren't as accurate.

To decide what to lookat I've used the Turn Left at Orion book, but also my laptop with Stellarium running. I sometimes take them outside with me, and I've also used my phone with the SkyView app to choose stars within constellations; I then just do a named star find in the Synscan handset. The SkyView app is particularly useful as it lets me hold the phone up to the sky so I can see the constellations next to the app's map (being still a n00b).

I hope you get it sorted - I don't think doing 'off piste' viewing should really upset the alignment and tracking too much, so maybe double check the clutches are set tight, do a 3-star alignment and then a polar alignment etc.?

[StormAurora]

Hi yearofthegoat,

Thanks for your reply. I usually do the polar alignment before I turn on the synscan. Then I carry out the two star alignment but it's always way off. I move it manually to the first star and center it using the keypad, then it tends to get the second star in the fov. 

I am familiar with most of the constellations, luckily. 

I do find it quite frustrating to be honest and end up spending more time resetting it all than imaging! ?

I'm hoping I will get used to it over the coming months.

Thanks again.

[newbie alert]

Not familiar with your mount etc but it does sound like a power/connection issue...

 

[Cosmic Geoff]

It might help if you work though this FAQ of GoTo issues.  The mounts generally work fine when set up with care but it is easy to miss some little 'gotcha'.

 

 

[Yearofthegoat]

Does your mount let you do a 3 star alignment followed by a polar alignment, both via the handset? I started doing that mostly to avoid the contortions to get a good look through the polarscope, but as aforementioned I find it is pretty accurate. It sounds like you know your stuff better than I do. It's not perhaps the dreaded American date format issue? As Cosmic Geoff suggests, work through the GoTo FAQ.

The things I often forget are 1) leveling the tripod head and 2) pointing the N leg north (true north not magnetic north, I think that's right?). Then making sure the time is accurate. These days I mostly use my phone (maybe not the best way, a GPS may well be better).

Only other thing I can think of is how well the rig is balanced, my mount complains if it's wildly off - like when I forget the second counterbalance weight (that sounds totally inept but in my defence I can get away with one disc right at the end of the bar or two really close to the mount).

Am sure you'll get it sorted. Perhaps if you know someone who can pop round that would help - second pair of eyes and all that? Good luck.

[StormAurora]

I have read the FAQ thread and manual and as far as I can see, I'm doing everything correctly. I first line up N leg, then make sure mount is level. I only have the mount and tripod at this point. I then use polarscope to place Polaris where it should be for the time I'm setting up.

Then i put the counterweights on and the ota. Then i balance the tube, then I recheck Polaris is still in the correct position. Then i make sure tube is in home position. Then i start the synscan, enter time, date etc and do a 2 star alignment.

Usually the first star is way off, so i move it to the star manually, center it and then when it goes to the second star it is usually pretty much on target. 

Then off i go. However if the object isn't in the center of the fov, after the alignment and I move it to the center with the keypad, the next object I send it to is not in fov! It's so frustrating. 

I appreciate your help and advice very much. All the best.

[happy-kat]

As a thought don't use polaris as one of your alignment stars.

[Cornelius Varley]

7 hours ago, StormAurora said:

I have read the FAQ thread and manual and as far as I can see, I'm doing everything correctly. I first line up N leg, then make sure mount is level. I only have the mount and tripod at this point. I then use polarscope to place Polaris where it should be for the time I'm setting up.

Then i put the counterweights on and the ota. Then i balance the tube, then I recheck Polaris is still in the correct position. Then i make sure tube is in home position. Then i start the synscan, enter time, date etc and do a 2 star alignment.

Usually the first star is way off, so i move it to the star manually, center it and then when it goes to the second star it is usually pretty much on target. 

Then off i go. However if the object isn't in the center of the fov, after the alignment and I move it to the center with the keypad, the next object I send it to is not in fov! It's so frustrating. 

I appreciate your help and advice very much. All the best.

I think I see the problem. If you go to an object and then have to manually re-centre after the slew the handset now believes it is pointing the mount at somewhere close to the initial target, but not the actual target. If you now slew to another target the handset will send the mount to the location of the new target based upon the original stopping point, not from where you manually corrected. If you use the PAE utility on the handset it should help to improve the accuracy of the second target slew.
 

[Yearofthegoat]

Sounds like that might be it. Just one other thing is I polar align with the scope and weights on the mount already, just out of the way, i.e. horizontal. I have to have them on to do a handset polar alignment anyway, so now that's part of my setup routine.

Whether I remember it all is another matter

[tooth_dr]

Is there any way to tell the mount you are now centred on an object. I think my Meade LXD75 mount allowed this.

[Cosmic Geoff]

8 hours ago, StormAurora said:

Then i put the counterweights on and the ota. Then i balance the tube, then I recheck Polaris is still in the correct position. Then i make sure tube is in home position. Then i start the synscan, enter time, date etc and do a 2 star alignment.

I'm not familiar with this version of GoTo, but having read through your posts I suspect you may be over-complicating things. The mount software, if I understand correctly how these things work, doesn't care whether the mount is mechanically polar aligned or not. The alt-azimuth versions work fine without being polar aligned (!) and also will do a three star align even if the mount is a bit tilted. I also suspect that "home position" is a red herring and only applies to observatory mounted instruments, i.e. the whole thing is bolted down to a pier and if the scope is set to a "home position" against index marks on the mount, you have some confidence that the home position actually means something in terms of minutes of arc.

By contrast, with my Starsense, I set it out at the start of the session pointing horizontally at roughly the same azimuth (at right angles to the house wall) each time, so that it goes and plates the same areas of sky it did at the start of the previous session.

So, if you set up your mount mechanically, then start the 2-star alignment by driving to the first star with the up/down & left/right buttons, not by any auto-aiming, fine tune the aim and then selecting the second star by name and then fine tune the aim again, with a bit of luck you may find it has set up properly.

[StormAurora]

Thanks for your help everyone. I'll let you know how it goes next time.

[Cornelius Varley]

6 hours ago, Cosmic Geoff said:

I'm not familiar with this version of GoTo, but having read through your posts I suspect you may be over-complicating things. The mount software, if I understand correctly how these things work, doesn't care whether the mount is mechanically polar aligned or not. The alt-azimuth versions work fine without being polar aligned (!) and also will do a three star align even if the mount is a bit tilted. I also suspect that "home position" is a red herring and only applies to observatory mounted instruments, i.e. the whole thing is bolted down to a pier and if the scope is set to a "home position" against index marks on the mount, you have some confidence that the home position actually means something in terms of minutes of arc.

By contrast, with my Starsense, I set it out at the start of the session pointing horizontally at roughly the same azimuth (at right angles to the house wall) each time, so that it goes and plates the same areas of sky it did at the start of the previous session.

So, if you set up your mount mechanically, then start the 2-star alignment by driving to the first star with the up/down & left/right buttons, not by any auto-aiming, fine tune the aim and then selecting the second star by name and then fine tune the aim again, with a bit of luck you may find it has set up properly.

The az mount is a little different to the eq version. AZ mounts don't require polar aligning because the mount tracks an object across the sky using both motors. The eq mount only requires one motor to track because the RA axis is aligned to the NCP (polar aligned). If an eq mount is not polar aligned an object will eventually drift out of the FOV. The method of star alignment is also different. The az mount doesn't require a fixed home position, so the first star is always manually found, it will then find the second star from this position. The eq mount, on the other hand, always starts from a known position (home) so the handset roughly knows where the first star is based upon the location/date/time.