SGPro 4.4 - Plate Solving Overhaul - Sequence Generator - Main Sequence Software (sequencegeneratorpro.com)




The Chain Solver is really more of a concept than an actual plate solver. The easiest way to think about it is as a simple group of solvers where it will attempt to solve by using one of its constituent solvers and will stop when it has success. The Chain Solver maintains a prioritization of its “internal” solvers and will always attempt to solve in that same order. Of course, you can easily customize this order just by dragging the solvers around in the list until they match your preferences. In addition to solver precedence, you can also use multiple instances of the same solver where each instance uses the same solver application but carries different settings. Lastly, it is important to understand that every equipment profile carries its own unique Chain Solver. In other words, as an example, one equipment profile may configure Pinpoint to use UCAC catalogs and another may use Atlas and switching between them will not clobber any kind of “global” notion of a Pinpoint config.


Let’s look at a Chain Solver setup where we want to, for all solves, attempt with the following solvers: Pinpoint (with Atlas), Pinpoint (with GSC), PlateSolve3 (with Kepler) and, finally, if all of those fail, by using ANSVR:



A checkmark means the solver is active in the chain and, of course, if it’s not checked, the Chain Solver will not use it.


Let’s take a closer look at the Chain Solver list (located in the Control Panel and also in the Equipment Profile Manager):


Configuration and Reordering the Chain


Reordering the chain is super simple. You can either grab the “gripper” icon in each row and drag the solver to wherever you’d like it in the solver order (the arrow points to the “gripper” icon):



Or you can right-click it to choose from several reordering options like “move to top”, “move up”, etc.




Identifying Blind Solvers


It is useful to easily understand what solvers function in a “blind” capacity. A blind solver is nothing more than a solver that does not require any "hint" data in order to produce a solve. This functionality, of course, comes at the cost of time. Blind solvers are typically much slower than non-blind solvers. In any case, it is often a good idea to place these solvers at or near the end of your chain. Each solver has an eyeball icon. If the icon is disabled (gray), it means that the solver is NOT a blind solver and will require accurate hints to succeed. If the icon is not gray, then, of course, the solver is blind (but hints may still be valuable):




What is that little “pin” icon?


It serves to notify you that the plate solver supports “click solving” (for any image solve an arbitrary x,y location). At this moment, we have been able to coerce all solvers to function as viable click solvers.



Solver Status (and Troubleshooting)


For all the plate solvers SGPro supports, there are essentially 2 different classifications of errors that prevent use of a solver in the chain:


Not installed / bad install errors: The plate solver is simply not installed or, it is installed, but is currently unusable (missing files, servers down, etc)

Server install is OK, but SGPro thinks your solver doesn’t know where to find its required catalogs / indices.

Here is what it looks like when one of the supported solvers has an install error:



You’ll notice several identifying features here. The solver itself will have a red border (ignore picture… UI not final), an “X” icon and red text that reads “not installed”. Hovering over the text or icon reveals a tooltip with more information specific to that solver:



And finally, if you actually click the item or right-click it and choose “Download PlateSolve3” you’ll be transported directly to PlaneWave’s site. This has been implemented for all supported solvers.




Cloning Solvers


Some solvers support the notion of “cloning”. This is an advanced feature that, in most cases, can safely be ignored. In the case that you need it though, here it is… What’s it do? It essentially allows you to use the same solver in the list multiple times, but use each instance configured in a different way. An example might include using the same solver in the list twice, but each instance is configured to use a different catalog. Any setting available to a solver can be used and set in a different way between clones. Here is an example of the Pinpoint solver and it’s clone where each uses a different catalog. The top one, named “Atlas” (you can name clones whatever you want) will be used first and then, if that fails, the Chain Solver will move on to using Pinpoint with the GSC catalog (note that this configuration is non-sensical, but serves to illustrate an easy-to-comprehend example).



tip: Hovering the mouse over the solver will reveal its underlying type (in this case Pinpoint).



The Image Preview Context Menu


Changes are afoot here… both in terms of new features and modifications that help support the notion of the new Chain Solver. First let’s cover changes to existing functionality. For many years, SGPro has allowed you to attempt to plate solve almost any image you can see on-screen. This can be done by right-clicking anywhere on the image and simply choose “Plate Solve”. This functionality is certainly still present and is just as easy to use. That said, there are a couple of key differences to be aware of here.



The Plate Solve Image Option


  • Clicking the “Plate Solve” options will now invoke the solve using the Chain Solver (see above)
  • Underneath the “Plate Solve” option you’ll find a new that reads “Plate Solve (using specific solver)”



This option does exactly what you think it does and allows you bypass the Chain Solver and choose to solve immediately with the chosen solver. If a solver is not active in the chain (checked), it will not appear in the menu here.



The Center Here Option


This option has very similar changes to the above Plate Solve option. The top-level “Center Here” option will attempt to center the telescope using the Chain Solver and, alternatively, you can choose to bypass the Chain Solver and center the telescope using any currently active solver within the chain.


The Plate Solve at Mouse Cursor Option


This option functions almost exactly like its “Plate Solve” sibling (discussed above), but with one key difference. Instead of solving at image center, this option will solve the image at the coordinates used to invoke the context menu. Other than that, it has the same optional behavior that allows use of the Chain Solver or any of the individual solvers that comprise its chain.


Solving and Centering Options


In addition to the Chain Solver configuration, this tab is used to house settings and action that allow you to automatically center on a reference frame (see below).   This comes in quite handy when you need to image the same target over multiple nights or when re-centering after a meridian flip.  Once your plate solving setup is complete it is literally as simply as clicking a single button to get your target back in near exact position.




Solve and Sync


The phrase "Solve and Sync" refers to a series of actions designed to synchronize your telescope with the reality of it current location. This process involves:


  • Capturing a frame at the desired exposure length
  • Plate solving that frame 
  • Relaying the results of that plate solve to your telescope such that it knows where you are currently pointed


The two options here are very similar and only differ in the types of plate solvers they use during the solve and sync process.


The Normal Sync


Captures and then plate solves an image.  If the solve is successful the telescope is synced to the solved location.  This is useful if you have your target framed exactly as you would like.  Clicking this action will show a menu (see screenshot below) that allows you to choose the underlying plate solver(s) to use during the sync event. If you chose the Chain Solver, the solve and sync process will use the plate solvers you currently have selected in your Chain Solver. Alternatively, you may choose to engage just a single plate solver if you'd like to override the Chain Solver's default behavior.



The Blind Sync


Same as "Solve and Sync" above but uses a blind solve of your current position.  This is useful to get your scope back on track for remote operation when you can't center a known star. Clicking this action will show a menu (see screenshot above) that allows you to choose the underlying blind plate solver(s) to use during the sync event. If you chose the Chain Solver, the solve and sync process will use the plate solvers you currently have selected, staring with the first blind solver in your Chain Solver. Alternatively, you may choose to engage just a single blind plate solver if you'd like to override the Chain Solver's default behavior.


Options and Configuration


  • Solver Options and Actions: this information is used to solve images captured with your camera.  The data entered here is also used to populate FITS headers in saved images:
    • Bin/ISO: Specifies the binning or ISO at which plate solve frames should be acquired.  
    • Exposure: Time in seconds to expose the image at the designated binning.

    • Solve and Sync Blind: Same as "Solve and Sync" above but uses the Astrometry.NET Web API to do a blind solve of your current position.  This is useful to get your scope back on track for remote operation when you can't center a known star.  However this method does require Internet access.  Upon a successful solve the dialog box above will also appear and allow you to set the coordinates for one of your targets if you would like. Clicking this action will show a menu that allows you to choose the underlying blind plate solver(s) to use during the sync event. If you chose the Chain Solver, the solve and sync process will use the plate solvers you currently have selected, staring with the first blind solver in your Chain Solver. Alternatively, you may choose to engage just a single blind plate solver if you'd like to override the Chain Solver's default behavior.

               


  • Scope Centering:  This section contains options which relate to centering the telescope when using plate solving.  Such activities include Meridian Flip and Auto Center
    • Center on selected target reference: Invokes Auto Center for the selected target.
    • Attempt to center X times until error is less than Y pixels: Setting the "times" and "pixel" values here specifies how the Auto Center and Meridian Flip behave when attempting to get the scope back on target.  You can set a higher attempt count if your mount has some slack in the gears.  Also depending on your setup you may want higher or lower accuracy and to change that you can set the "pixels" variable.  
    • Rotator error: The centering process can also attempt to rotate your camera until a particular sky angle (east of north) is achieved.  If you wish for your sky angle to be 90 degrees east of north, you can set a tolerance for rotational error here.  If your specified error is 2 degrees SGPro will allow 88 - 92 degrees.  If you wish to have the SGPro automatically rotate your camera, you will need a mechanical rotator.  Even if you don't have a mechanical rotator, you can still use the "manual rotator" to get your camera oriented the way you want.  To make sure rotation occurs during centering, go to the target settings dialog and check the "Rotate to" option.
    • Use Filter: This will use the selected filter for each plate solve image that is acquired.  If you want to use the current filter use this value unchecked.