Need help to speed up alignment time

[RobertI]

Sorry for length of post but would appreciate some advice....

I’m looking to speed up my setup time for EAA/Video astronomy. My setup is currently a RC6 with a Lodestar camera + reducer on a CG5. I have a finder with a webcam attached giving a FOV of around 3 degrees and I use this for helping with alignment.

A typical setup routine for my equipment is:

1. Set up scope, camera, etc and connect to laptop in house

2. Polar align mount manually (polar scope) – this bit is no problem takes about 1 minute

3. Go into house and do four star alignment remotely – I use the laptop running NexRemote software to control mount and webcamFinder to roughly align each star and Lodestar to accurately align.

Step 3 is the problem for me as sometimes the initial slew to the alignment stars is way off and out of the FOV of the webcam finder. Not sure why but have never been able to get this consistent. This creates a problem as I need to go to the scope and look through an additional finder to pick up the alignment star…and take the laptop with me to control the mount to bring it into the FOV. When it works it is great and only takes 5 minutes, but all too often it takes a lot longer when doing it remotely.

I’m looking for something faster and more consistent.

The options I am looking at are:

1. Starsense. I gather this works well and is accurate even with a small chip camera like the Lodestar. Would totally automate alignment which is great.  But it’s £350 for the CG5 as a very expensive cable is required for it to work. Also I will not be able to use NexRemote software and will have to start using Stellarium or CDC which I guess is no biggy. The Also if the Starsense does not work accurately enough, it’s been money down the drain.

2. A QHY camera or similar with a wide angle CCTV lens to replace the webcam. Gives a 45 degree FOV and can be had for £200. Does not automate the alignment process, but it ensures that I always find the alignment star in the FOV so at least I have consistency. Other advantages are that it can be used during an observing session to remotely do ‘synch’ to a nearby star to help with accurate alignment. I can’t see how this can be done with Starsense with a remote setup.   

Other considerations are that I would one day like to upgrade to a nice quiet Skywatcher mount – I always worry about the coffee grinder CG5 waking the neighbours. I would have to flog the Starsense if I did this.

What do people think would be my best route to improving my set up times? Any thoughts appreciated. 

Thanks!

[bottletopburly]

Could use the polar align in sharpcap to make pA more accurate ,or maybe you have cone error too ,

[ronin]

Suppose you have checked but to some extent this reads that the finder with wbcam is not too well aligned to the main scope.

The other question is when you say " sometimes the initial slew to the alignment stars is way off" is it the first star that the scope slews to ? If so I could expect this. The scope will have no correction to apply on the first slew so all the movement is defined by the start position and any error in that puts the first star in or out of view. It is not until the first star is centered and the scope told this (press Enter I assume) that the software can start to determine the corrections that it needs to apply. These corrections are then applied and refined on the slew to the next star.

The other somewhat maybe irrelevant factor is that a field of 3 degree is actually a field of +/- 1.5 degrees. If the star is 2 degrees off of the center it will not be in view.

[mikeyj1]

+1 on Ronin's start position error, that was always my issue on alignment to start with.  Cone error was next (so +1 on that  ) then polarscope alignment and accurate PA

[RobertI]

Thanks for the suggestions @bottletopburly, @ronin and @mikeyj1, yes @ronin its the first slew that is usually the problem, but I have had problems with the second star on one or two occasions, I'm pretty certain the finder is spot on as it is in the centre of the camera FOV when centred, and I'm prety sure my PA is good as it tracks accurately for 60second exposures when aligned. So i guess my follow on question is whether it is worth experimeting with slighly offset start positions and see which one results in a more accurate first star. If this works does it mean that if I chose another first star, that will be in the right position too? Presumably this is where cone error plays a part?

Is it worth me experimenting, bearing in mind I might not get a good start position every time, or should I just bite the bullet and go for one of the suggested solutions? Or something else? I have been fairly happy woth the webcam finder solution, it just has a restricted FOV. But starsense sounds rather nice too. But then again not spending anything appeals! 

[StevieDvd]

The first star alignment is the trickiest as the system needs to have a known start position.  If you were to do a manual first star alignment at the scope (assuming here for the sake of discussion that PA and location settings, date/time etc are correct) then you can tell the system to go to the park position. If you switched off and started again at that position the first goto should be spot on.  More expensive mounts do have a designated park position that can be gone to but you the rest of us have to mark it manually somehow and that can be difficult to do exact enough for the mount.

If I can put that in simpler words, when you do the above the mount knows 2 positions accurately. If you start from your own park it only knows one and assumes you have set it to the park position it expects.

 

 

 

[Owmuchonomy]

I would just swap 2 and 3 over in your setup routine. For me that bit is back to front.  Then I would run a second star alignment on the side of the meridian I am imaging.

[iapa]

The following steps can be used to do the alignment steps without starsense. 

Following the normal steps to select alignment star, use the controller to slew to star of choice.

Then, using astrotortilla and stellarium select the same alignment star, and platesolve to centre star in field of view, hit the relevant button (don't remember which :() and just enter for the 'rough' alignment, and align for the 'fine' alignment - with my eyesight I am not going ot get closer to centre of view using an eyepiece that astrotortilla and stellarium will using plate solving.

repeat for another couple of stars. Takes, oh, 5-10 minutes tops. I've found it easier that using eyepieces, and faster.

[RobertI]

1 hour ago, StevieDvd said:

The first star alignment is the trickiest as the system needs to have a known start position.  If you were to do a manual first star alignment at the scope (assuming here for the sake of discussion that PA and location settings, date/time etc are correct) then you can tell the system to go to the park position. If you switched off and started again at that position the first goto should be spot on.  More expensive mounts do have a designated park position that can be gone to but you the rest of us have to mark it manually somehow and that can be difficult to do exact enough for the mount.

If I can put that in simpler words, when you do the above the mount knows 2 positions accurately. If you start from your own park it only knows one and assumes you have set it to the park position it expects.

 

 

 

Ok that's an interesting thought. So i could do the first star manually by squinting up the finder. One problem is once i use the handcontroller i cannot use nexremote anymore, but switching off and again could get round that problem as long as it retain positional information. Not sure.

58 minutes ago, Owmuchonomy said:

I would just swap 2 and 3 over in your setup routine. For me that bit is back to front.  Then I would run a second star alignment on the side of the meridian I am imaging.

Not sure quite sure what you mean? How can i do PA after alignment, unless I use ASPA? And why would I if my PA is ok? Unless i'm being dim which is more than likely!  

18 minutes ago, iapa said:

The following steps can be used to do the alignment steps without starsense. 

Following the normal steps to select alignment star, use the controller to slew to star of choice.

Then, using astrotortilla and stellarium select the same alignment star, and platesolve to centre star in field of view, hit the relevant button (don't remember which :() and just enter for the 'rough' alignment, and align for the 'fine' alignment - with my eyesight I am not going ot get closer to centre of view using an eyepiece that astrotortilla and stellarium will using plate solving.

repeat for another couple of stars. Takes, oh, 5-10 minutes tops. I've found it easier that using eyepieces, and faster.

So i beleive what you are proposing Is that I use the main Lodestar camera (i dont think the webcam camera is sensitive enough to pick up more tha one bright start in the FOV) to platesolve and roughly centre the stars during alignment rather than manually pressing the buttons on Nexremote (which is effectively a soft handcontroller)? So that way I don't need an electronic finder at all? The Lodestar FOV is only 30' accross - will this make platesolving a too slow? Sounds great though, is it really that simple? If I platesolve, do I need to align the scope at all, can I just platesolve each every goto instead?

[michael8554]

Hi Rob

Do you need the webcam finder for your EAA?

If not do your 4 Star alignment with a normal finder and a reticule eyepiece parfocal with the Lodestar.

Then swap in your Lodestar and plug in NexRemote cable from remote PC to handset.

Michael

[iapa]

11 hours ago, RobertI said:

So i beleive what you are proposing Is that I use the main Lodestar camera (i dont think the webcam camera is sensitive enough to pick up more tha one bright start in the FOV) to platesolve and roughly centre the stars during alignment rather than manually pressing the buttons on Nexremote (which is effectively a soft handcontroller)? So that way I don't need an electronic finder at all? The Lodestar FOV is only 30' accross - will this make platesolving a too slow? Sounds great though, is it really that simple? If I platesolve, do I need to align the scope at all, can I just platesolve each every goto instead?

Tools: Astrotortilla, Stellarium, Stellarium scope, Celestron mount, Starsense (optional), Polemaster (optical), OTA, imaging camera.

Astrotortilla can use ASCOM driven cameras to take the image.

StellariumScope allows you to control the mount from Stellarium (Ctrl-1 to slew, Ctrl-3 to cancel, Ctrl-5 to cancel - I thing are the three options. You can add the mount using a plug-in within Stellarium - I personally found StellariumScope easier to set up. The plug-in will provide a slew option, but no option to stop slewing.

I think these steps will do the job. About 10-15 minutes once you get into the flow.

During the day align guide scope to imaging scope and rough focus the cameras - I am fortunate in that there is a cooling tower around 6 miles away with a red navigation light on it that I can use. Sometimes the steam obscures the light, in which case there is a hill with a gorse bush about 3 miles away as an alternative. 

1. Once dark, polar align the mount, twice. Polemaster makes this a 4-5 minute job. A mount that hasn't been moved since the last session would not really need this step.
2. Its probably a good idea to set the home position in Nexremote at this point.
3. Make sure the mount is at it's home position and do a quick align. That allows Stellarium to get the mount's current position. If you have a Starsense follow the auto align process instead, and skip to 6 to add alignment stars.
4. follow the steps on the Nextremote to do an alignment. Each time it says to find a star, select t one form the list and let the mount slew. Select that same star in Stellarium, then use Astrotortilla to take an image with the imaging camera, and platesolve which will then direct stellarium to slew to bring the selected point in the FOV. Astrotortilla will automatically refine this a couple of times until the star is about 0.1' off centre. (The 0.1' is a user setting, this is the minimum value)
5. follow the steps on the HC to accept the coarse and fine alignment (enter and align) DO NOT USE THE HC TO MOVE THE MOUNT just accept the position 
6. repeat 3 and 4 until alignment process is complete.
7. Add some calibration stars, again using Stellarium select a calibration star and slew using Stellarium. Plate solve again and Astrotortilla will the target in the centre. Press align to add the calibration star. DO NOT USE THE HC TO MOVE THE MOUNT. Follow the button pushes to add the calibration star.
8. That's you aligned.

Re your last point. You can set limits within Astrotortilla to stop if looking at all of the reference plates across the whole sky. Excellent tutorial: Tutorial (Imaging): Setting up and Using AstroTortilla for Plate Solving ...

 

 

[RobertI]

7 hours ago, iapa said:

Tools: Astrotortilla, Stellarium, Stellarium scope, Celestron mount, Starsense (optional), Polemaster (optical), OTA, imaging camera.

Astrotortilla can use ASCOM driven cameras to take the image.

StellariumScope allows you to control the mount from Stellarium (Ctrl-1 to slew, Ctrl-3 to cancel, Ctrl-5 to cancel - I thing are the three options. You can add the mount using a plug-in within Stellarium - I personally found StellariumScope easier to set up. The plug-in will provide a slew option, but no option to stop slewing.

I think these steps will do the job. About 10-15 minutes once you get into the flow.

During the day align guide scope to imaging scope and rough focus the cameras - I am fortunate in that there is a cooling tower around 6 miles away with a red navigation light on it that I can use. Sometimes the steam obscures the light, in which case there is a hill with a gorse bush about 3 miles away as an alternative. 

1. Once dark, polar align the mount, twice. Polemaster makes this a 4-5 minute job. A mount that hasn't been moved since the last session would not really need this step.
2. Its probably a good idea to set the home position in Nexremote at this point.
3. Make sure the mount is at it's home position and do a quick align. That allows Stellarium to get the mount's current position. If you have a Starsense follow the auto align process instead, and skip to 6 to add alignment stars.
4. follow the steps on the Nextremote to do an alignment. Each time it says to find a star, select t one form the list and let the mount slew. Select that same star in Stellarium, then use Astrotortilla to take an image with the imaging camera, and platesolve which will then direct stellarium to slew to bring the selected point in the FOV. Astrotortilla will automatically refine this a couple of times until the star is about 0.1' off centre. (The 0.1' is a user setting, this is the minimum value)
5. follow the steps on the HC to accept the coarse and fine alignment (enter and align) DO NOT USE THE HC TO MOVE THE MOUNT just accept the position 
6. repeat 3 and 4 until alignment process is complete.
7. Add some calibration stars, again using Stellarium select a calibration star and slew using Stellarium. Plate solve again and Astrotortilla will the target in the centre. Press align to add the calibration star. DO NOT USE THE HC TO MOVE THE MOUNT. Follow the button pushes to add the calibration star.
8. That's you aligned.

Re your last point. You can set limits within Astrotortilla to stop if looking at all of the reference plates across the whole sky. Excellent tutorial: Tutorial (Imaging): Setting up and Using AstroTortilla for Plate Solving ...

 

 

Many thanks for taking the time explain the steps, much appreciated. I will definitely give this a go, nothing to lose really as there is no cost.  I believe the Lodestar has an Ascom driver so that should be ok. hopefully the tutorial should fill in the gaps. I'll let you know how it goes. Thanks again. 

[iapa]

2 hours ago, RobertI said:

Many thanks for taking the time explain the steps, much appreciated. I will definitely give this a go, nothing to lose really as there is no cost.  I believe the Lodestar has an Ascom driver so that should be ok. hopefully the tutorial should fill in the gaps. I'll let you know how it goes. Thanks again. 

NP

 

gimme shout it it doesn't work - i will have missed something out

[noah4x4]

If all else fails, I can recommend StarSense.  Once calibrated and (optional) ten additional star alignments added (both are once only steps) I enjoy incredibly accurate GoTos after its use during alignment. I have one with each of my scopes. Costly, yes, but it saves me hours of valuable time during set-up.

Even a Polar Align on a wedge now takes me no more than five minutes, but the manual is awful. If anybody needs help with this technology, don't hesitate to contact me.  I now have a fully documented set of instructions for polar/wedge alignment with Starsense ( e.g. that includes the critical steps omitted in the instruction manual!).

[RobertI]

41 minutes ago, noah4x4 said:

If all else fails, I can recommend StarSense.  Once calibrated and (optional) ten additional star alignments added (both are once only steps) I enjoy incredibly accurate GoTos after its use during alignment. I have one with each of my scopes. Costly, yes, but it saves me hours of valuable time during set-up.

Even a Polar Align on a wedge now takes me no more than five minutes, but the manual is awful. If anybody needs help with this technology, don't hesitate to contact me.  I now have a fully documented set of instructions for polar/wedge alignment with Starsense ( e.g. that includes the critical steps omitted in the instruction manual!).

Thanks @noah4x4 I have heard nothing but good things about Starsense, it sounds like a lovely piece of kit. I'm behind the curve somewhat when it comes to astro technology.  Believe it or not after 35 years of observing (on and off) I  got my first goto mount only 3 years ago, a venerable CG5 (aka Advanced GT) so I guess I am the opposite of an 'early adopter' of technology. i think the Starsense has proved itself by now though!