Syncing scope to the real world. Need some help.

[Andy56]

Hi,

Father Christmas brought me  a HEQ5 for Christmas.

After Christmas I set it up indoors and got ASCOM/EQMOD/Stellarium all linked. I already have APT PHP2 and Stellarium linked. so that was all working. I have a direct cable from the PC to the HEQ5

So on Tuesday I set it up in the garden while it was light. That's a WO ZS61/600d (astro modified)/guidescope + laptop.

I had forgotten to refocus the polar scope to infinity after checking the graticule alignment on a nearby (10m) roof so when I looked for Polaris I could not find it. Unlike my Star Adventurer which is always quite easy. Also the default setting of the led was very high and I had to reconnect the hand control to reduce it.

So I gave up on this and ensured that the polar axis was aligned as well as possible.

I had read that a crude polar alignment can be overcome by tracking. Not ideal but OK for a first attempt so I tried to do an alignment. ( and it was getting cold)

So this is where I need some advice or clarification.

Slewing to Jupiter using Stellarium did not put it on sensor and I found looking at the camera screen and moving the scope using the PC very difficult, same with Vega and after doing the alignment it could not find M31 or M45  but it found NGC7000 very well, relatively close to Vega.

I have read that you can use plate solving to align the scope. Ie instead of moving the scope to the star you tell the app (Stellarium, APT) where it's pointing.

Have I understood this correctly?

Can this be done through APT alone? and is there a walk though.

The best I've read is from Padraic M

Quote

"I plate solve in APT, Sync to the mount, and send the coordinates to Stellarium. Check Stellarium to see how I'm aligned. Worked perfectly as expected with M57 and M13 - as below."

This seems to indicated that I could use this for alignment by pointing the scope to a starry region of the sky, plate solve, Sync and show in Stellarium for confirmation. If I do this for three points will this give me a good alignment?

 

Cheers

Andy

 

 

 

Edited January 6, 2022 by Andy56
Grammar

[malc-c]

Hi Andy,

The advantage of EQMOD is that you can add multiple sync points which improves the accuracy of gotos.  I have the advantage of a fixed installation in an observatory so I can be up and imaging in 10-15 minutes as a result.  However this is of no real advantage in a mobile set up which is moved between sessions so it is better if all previous align points are cleared from EQMOD.  I would then chose a star in the North, one in the west and one in the east, forming a triangle that has the chosen target within the triangle formed by these three points.  Once you get each align point centred, select the option to sync ( I used CdC but there will be a similar right click and sync option in Stellarium) which creates a record in EQMOD (effectively doing the same three star alignment as done with a handset).  Having done this, EQMOD should be able to calculate any error in polar alignment when applying a slew to a target in that triangle and place the target in the field of view of a wide field eyepiece or camera.  If you have plate solved to do your PA then the accuracy should be even greater. 

[The Lazy Astronomer]

I don't use APT (NINA all the way for me!), but I imagine the process is broadly similar:

1. Polar align (via prefered method)

2. Use Stellarium to locate a target

3. Import target coordinates from Stellarium into NINA

4. Command mount to slew to the target

5. Plate solve to centre target in frame

No need for any additional alignments - just use Stellarium to find targets, and repeat the process from step 3 when you want to move to another target.

Further info for plate solving in APT can be found in the manual: https://www.astrophotography.app/usersguide/pointcraft_and_plate_solving.htm?ms=AAAA&q=UGxhdGUgc29sdmU%3D&st=MQ%3D%3D&sct=MA%3D%3D&mw=MzIw

Edited January 6, 2022 by The Lazy Astronomer
Slight rewording

[adyj1]

I used to do the 3-point star alignment, but once I got platesolving working in APT I just used goto++ and the mount zeros in accurately on a per-target basis (the equivalent is 'slew and sync' in NINA).

I found ASTAP head and shoulders above the rest in terms of platesolving software. If you follow an old tutorial, you may find platesolve2 is used - choose ASTAP every time 😉

  

[ONIKKINEN]

Platesolving all the way, there are no real reasons to do manual align points or star alignment if you have PC control of the mount.

There are some who claim platesolving is bad but just ignore those comments, they are stuck in the ways of the old.

Star aligning is dead, long live platesolve!

[Andy56]

Hi,

Many thanks for your responses.

So it seems plate solving is the way, ie let the software find out where the telescope is pointing instead of pointing the telescope to a particular star.

I have familiarity with APT and plate solving and clicking "Show" so that Stellarium will show where I'm pointing. 

Now, how do I do it for alignment? When I read the manuals is seems to require some familiarity that I don't have.

So, in APT

              Do I point the telescope south and plate solve in APT.

             Then click "Show" and Stellarium should show me where I'm pointing.

             Then, in Stellarium,  use the "Slew Telescope To" dialogue box and hit sync.

OR

             Do I point the telescope south and plate solve in APT.

             Then click "Sync" in the "Point Craft" dialogue box.

Then repeat for East and West.

 

Will this give me the GoTo alignment I need?

Just a little more help and a warm clear night will be great. Not much chance at the moment though.

 

Many thanks

Andy

 

 

[Budgie1]

I use Cartes Du Ceil (CDC) instead of Stellarium but I assume the routine is similar.

• Once focused, I use CDC to choose my target and slew to it.
• In APT I take an image of where the scope is now pointing.
• Now open Point Craft & pick the object the scope should be point at and ask it to "Solve". If it doesn't solve then click "Blind" and it will ignore the target reference and try to do a blind solve.
• Once Point Craft has solved the image, click "Sync" and APT tells CDC where it's actually looking.
• Now choose your target in the "Centre FOV at position" part of the Point Craft menu and click the "GoTo++" button and Point Craft will centre your target in the field of view.

No need to do any star alignment or alignment South, East or West. Plate solving make this operation redundant.

I hope that helps.

Edited January 6, 2022 by Budgie1
Spelling

[adyj1]

I don't think it is either APT or Stellarium/CDC that is recording where the mount is pointing - they are reading where it is pointing from the eqmod driver (if you are using that software - its the mount control software that records the position) 

You use (say) APT to do a 'sync' that tells the driver where the mount is pointed and any software that is connected - maybe CDC - will automatically update when it reads it from the eqmod driver. You can also sync the other way from planetarium software to mount. If you really wanted to you could manually enter co-ordinates and press 'sync' and that would update it (and any other software you had connected to it via ASCOM).

If you've got platesolve working in APT you really should be using Goto++, which works like this;

- start from a position where the mount has some idea of where it is pointing (at the beginning of the session this is usually the parked position, but could easily be after imaging a different platesolved target)

- enter the target co-ordinates in APT (either from the APT object list, or sending the co-ords from the planetarium software)

- select Goto++ and tell APT to slew. APT will then think the mount is pointing directly at the target, but it won't because you haven't aligned yet 😉

  the Goto++ will;

     - slew to where it thinks the target is (especially on the first slew this is likely to be way out, but doesn't matter)

     - take a picure and platesolve it

     - sync the mount to the platesolved co-ordinate - (likely be slightly different to where it thought it was pointing)

     - repeat

The three steps are repeated if needed (to a max of 5 goes normally) with each slew getting closer and closer to the target (and hopefully bang on).

This process is particularly useful for multi-session imaging.

HTH

Ady

 

NB - this is from memory as I've now switched to NINA, so apologies if the buttons/functions have slightly different names  

 

  

Edited January 6, 2022 by adyj1
Changed to try not be eqmod-specific

[Andy56]

Thanks guys I'm getting an understanding now.

So with the setup I have, GoTo++ in APT is the quickest way and removes the need to align an object in the centre of the sensor 3 times, which is the major problem I had.

This will also tell ASCOM which then acts as a server for other clients eg Stellarium.

So if I wanted to do a full alignment (although possibly not needed) I guess I would use GoTo++ on 3 objects and then it should be fully aligned. This just to answer my original objective.

Can't wait for the next clear night!!  

Cheers

Andy

 

 

Edited January 7, 2022 by Andy56
Removed superfluous sentence

[adyj1]

18 minutes ago, Andy56 said:

So if I wanted to do a full alignment (although possibly not needed) I guess I would use GoTo++ on 3 objects and then it should be fully aligned.

You would only do multi-star alignment if you can't do plate-solving.

This would normally be because;

a) you don't have a computer controlling your astrophotography session, or

b) you're doing visual. 

Hth

Ady

[ollypenrice]

On 06/01/2022 at 15:16, ONIKKINEN said:

Platesolving all the way, there are no real reasons to do manual align points or star alignment if you have PC control of the mount.

There are some who claim platesolving is bad but just ignore those comments, they are stuck in the ways of the old.

Star aligning is dead, long live platesolve!

🤣  That would be me. 🤣

In fact I don't think it's bad, I think it's good unless it causes the plate solver to disconnect their brain and throw it in the garden pond, as it sometimes does. We've seen people post images of some bit of random sky and say, 'I can't see M51 in this image even though I spent four hours collecting data on it,' or,  'I used plate solving to shoot these two mosaic panels but the software refuses to join them,' when it is perfectly obvious that they don't overlap, whatever the plate solution tells them.

Plate solving is fine but inevitably it introduces an extra piece of software, sometimes two. Sometimes there are eight rigs imaging at my place and what goes wrong most frequently? Software. And in second place? Software. So use it by all means but don't waste time faffing around getting it to work under a nice clear sky.

Olly

[adyj1]

I hear what you're saying about software problems, @ollypenrice but surely there's a lot of time-saving that comes from a working platesolves solution... Mind you, I do also recognise the need to listen to experience 👍.

What is your workflow for framing a faint DSO without plate-solving? 

[ollypenrice]

Just now, adyj1 said:

I hear what you're saying about software problems, @ollypenrice but surely there's a lot of time-saving that comes from a working platesolves solution... Mind you, I do also recognise the need to listen to experience 👍.

What is your workflow for framing a faint DSO without plate-solving? 

I just put its name into my Argonavis handset and hit GoTo. And there it is, gone to!  However, I then look around the borders of the image on the lookout for an attractive composition so far as field stars are concerned, or how a nebula sits within the frame. Any photograph intended to be good to look at needs a favourable framing in this way.  I always want to avoid a half-included bright star on an edge, for instance.  If the target is Ha dominated, as many are, then I'll try to frame up to include a contrasting blue star when possible. This stops the image from looking as if it has been wrongly colour balanced in favour of red. (Peter Shah's recent Helix used such a star to great effect, I thought.)

In order to re-frame quickly on a subsequent night I'll bring up the screen reticule and note the position of a reference star relative to some obvious point on the reticule.  (You can actually save three star positions in the capture program but I can never remember how to do it and since re-framing is a non-problem I just do it this way.

If my target isn't in the handset's database (unusual) I drive to it using the mount's digital setting circles and, again, make a note of the co-ordinates I've finally chosen.

My main mount is not ASCOM compliant so plate solving isn't an option. I could change it for something else but, in ten years, it has never dropped a sub. Would you change it???

😁lly

[malc-c]

It was commented that undertaking a star alignment, regardless of the set up being mobile or fixed in an observatory was old school and now obsolete, but I have to agree with Olly.  I've never plate solved other then when using Sharpcap to align the mount.  Having alignment points in EQMOD means for me that any goto in the visible area of sky from the observatory results in the target being in the field of view of the camera.  My set up is basic - a 400D canon DSLR on the main scope, a QHY5 on the finder and I use CdC to select the target, EQMOD to drive the mount, APT just to run the sequence to take the images, and PHD2 for guiding....but it works, and I can be up and running taking subs within 20 minutes of opening the observatory.

When it was set up, ten year ago, this was fairly much the norm.  These days, so many applications have evolved to overlap others (NINA / APT etc) and cater for the newer trends that often they introduce just one more step to go wrong, and take longer to debug any issues as often they all now tend to overlap and do the same functions as others.

[david_taurus83]

Hi Andy. This tutorial is a couple of years old now but I believe the layout in APT is still the same so should get you up and running.

https://stargazerslounge.com/topic/334568-setting-up-platesolving-in-astrophotography-tool-apt/

I use NINA mostly now as its a bit more advanced, probably a bit bloated with features if I'm being honest but APT is the better platform if your using a DSLR as its far better supported. 

[adyj1]

2 hours ago, ollypenrice said:

I just put its name into my Argonavis handset and hit GoTo. And there it is, gone to! 

Not familiar with Argo Navis but it must be heaps better than my eq5 😉 . I always had to do small tweaks after the goto, needing me to take exposures and adjust, which all took time. With platesolving it is much quicker than me and also more accurate 😁 

I can understand that the better the kit the less the computer correction would be needed. 

[ONIKKINEN]

4 hours ago, ollypenrice said:

🤣  That would be me. 🤣

In fact I don't think it's bad, I think it's good unless it causes the plate solver to disconnect their brain and throw it in the garden pond, as it sometimes does. We've seen people post images of some bit of random sky and say, 'I can't see M51 in this image even though I spent four hours collecting data on it,' or,  'I used plate solving to shoot these two mosaic panels but the software refuses to join them,' when it is perfectly obvious that they don't overlap, whatever the plate solution tells them.

Plate solving is fine but inevitably it introduces an extra piece of software, sometimes two. Sometimes there are eight rigs imaging at my place and what goes wrong most frequently? Software. And in second place? Software. So use it by all means but don't waste time faffing around getting it to work under a nice clear sky.

Olly

Might be you 😁.

We definitely agree on the brain part, but i think this issue also exists without platesolving. Just as well one could do 3 star alignment perfectly, slew to target and go to sleep and wake up the next day to unusable frames, in fact i think this is more likely without platesolving since you are just using your eyes to determine whether or not you have the target framed. If its an obscure/dim target with poorly defined edges and hard to recognize features its very likely you will end up missing and failing. I have a running project where i am shooting IFN that is only visible after about 2 hours of integration and there isn't even a hint of this structure in a single sub so i could never frame it properly without platesolving. Also this area of the sky has few defining features that could be used as pointers so not helpful to just eyeball these things. I had the camera at an angle of 82 degrees instead of 90 on the first session, so no i will have to check every time that the platesolver does indeed report the 82 degrees and once it does im all set and the framing can not fail. I think platesolving is 90% solutions to problems and 10% possible added problems with software (which will definitely happen at one point). If one follows what the platesolver is doing and understand the parameters that must be set for it to do what you want, it will end up saving about an hour per session and almost never cause problems.

@ollypenrice @malc-c This talk about Argonavis control systems and permanent observatories is a solution to most problems, including this one. If the setup is made of premium parts (Argonavis is in the Mesu?) and permanently placed then the align points would be faster and better as it introduces no extra spanners in the works. This way also every night works the same, as the mount is fixed in an observatory and not moved each night so the alignment points do not have to be remade.

For most users though who set up and tear down each night, or at the very least carry the mount in one go already assembled from a shed/from indoors will absolutely find platesolving a blessing and a solution to many problems including the one OP is having.

1 hour ago, adyj1 said:

Not familiar with Argo Navis but it must be heaps better than my eq5 😉 . I always had to do small tweaks after the goto, needing me to take exposures and adjust, which all took time. With platesolving it is much quicker than me and also more accurate 😁 

I can understand that the better the kit the less the computer correction would be needed. 

Same was with my EQM35, i could do 3 star alignment perfectly with a star exactly centered on my DSLR crosshairs and still have a +/-10 arcminute deviation from where its supposed to point, which would be easily enough to ruin most targets. That would be because the pointing accuracy of Synscan mounts are quoted as 6 arcminutes at best.

[ollypenrice]

29 minutes ago, ONIKKINEN said:

Might be you 😁.

We definitely agree on the brain part, but i think this issue also exists without platesolving. Just as well one could do 3 star alignment perfectly, slew to target and go to sleep and wake up the next day to unusable frames, in fact i think this is more likely without platesolving since you are just using your eyes to determine whether or not you have the target framed. If its an obscure/dim target with poorly defined edges and hard to recognize features its very likely you will end up missing and failing. I have a running project where i am shooting IFN that is only visible after about 2 hours of integration and there isn't even a hint of this structure in a single sub so i could never frame it properly without platesolving. Also this area of the sky has few defining features that could be used as pointers so not helpful to just eyeball these things. I had the camera at an angle of 82 degrees instead of 90 on the first session, so no i will have to check every time that the platesolver does indeed report the 82 degrees and once it does im all set and the framing can not fail. I think platesolving is 90% solutions to problems and 10% possible added problems with software (which will definitely happen at one point). If one follows what the platesolver is doing and understand the parameters that must be set for it to do what you want, it will end up saving about an hour per session and almost never cause problems.

@ollypenrice @malc-c This talk about Argonavis control systems and permanent observatories is a solution to most problems, including this one. If the setup is made of premium parts (Argonavis is in the Mesu?) and permanently placed then the align points would be faster and better as it introduces no extra spanners in the works. This way also every night works the same, as the mount is fixed in an observatory and not moved each night so the alignment points do not have to be remade.

For most users though who set up and tear down each night, or at the very least carry the mount in one go already assembled from a shed/from indoors will absolutely find platesolving a blessing and a solution to many problems including the one OP is having.

Same was with my EQM35, i could do 3 star alignment perfectly with a star exactly centered on my DSLR crosshairs and still have a +/-10 arcminute deviation from where its supposed to point, which would be easily enough to ruin most targets. That would be because the pointing accuracy of Synscan mounts are quoted as 6 arcminutes at best.

 Fair points!

Olly

[ollypenrice]

2 hours ago, adyj1 said:

Not familiar with Argo Navis but it must be heaps better than my eq5 😉 . I always had to do small tweaks after the goto, needing me to take exposures and adjust, which all took time. With platesolving it is much quicker than me and also more accurate 😁 

I can understand that the better the kit the less the computer correction would be needed. 

I don't think the Mesu/Argonavis is astonishingly accurate. It is astonishingly consistent, certainly. But will you take a set of exposures based only on the plate solution given by your software? This would be unthinkable for me. I  want to see what the whole frame looks like, get a feel for what's going on in the picture. That's how Tom and I decided there was more to IC 59 and 63 than was usually imaged and produced our 'Breaking Wave' image. We thought, 'Hang on, what's going on at the bottom of this frame? Does the nebulosity stop there? Let's nudge the mount down a bit and have another look.'

https://www.astrobin.com/full/295716/B/

Olly

 

[adyj1]

4 hours ago, ollypenrice said:

I don't think the Mesu/Argonavis is astonishingly accurate. It is astonishingly consistent, certainly. But will you take a set of exposures based only on the plate solution given by your software? This would be unthinkable for me. I  want to see what the whole frame looks like, get a feel for what's going on in the picture. That's how Tom and I decided there was more to IC 59 and 63 than was usually imaged and produced our 'Breaking Wave' image. We thought, 'Hang on, what's going on at the bottom of this frame? Does the nebulosity stop there? Let's nudge the mount down a bit and have another look.'

https://www.astrobin.com/full/295716/B/

Olly

 

I can see why you don't use platesolves, olly - you are well out my league.

Down here with the beginner astrophotographers platesolve can be a lifesaver... 😛

[ollypenrice]

7 hours ago, adyj1 said:

I can see why you don't use platesolves, olly - you are well out my league.

Down here with the beginner astrophotographers platesolve can be a lifesaver... 😛

I do use them on a co-owned robotic rig but I wouldn't want to frame up just based on a plate solution.

Olly

[PeterCPC]

I'm with Olly on this. I always star align and normally plate solving is an unnessary step. However, I use APT and have used it's platesolving on occassion but it doesn't always work I find. Last time out I was imaging IC405 and looked to be spot on but thought that I would check with pointcraft only to be told that platesolving failed. I was spot on anyway. I would be interested to hear what settings people are using for ATP live view for platesolving to work.

[adyj1]

3 hours ago, PeterCPC said:

I would be interested to hear what settings people are using for ATP live view for platesolving to work

Which platesolving software are you using? (I assume you've set the correct focal length in APT?) 

[PeterCPC]

3 minutes ago, adyj1 said:

Which platesolving software are you using? (I assume you've set the correct focal length in APT?) 

Yes. I have another thread on this now. Thanks.