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Plate Solving

Plate solving is a great way to determine where your scope is pointing at exactly in the sky and an important aspect for fast and easy framing. Essentially what it does is taking a shot with your camera, extract the stars and tries to triangulate the current position based on an internal sky atlas of the plate solver.

To utilize the full potential of plate solving it is required that your mount and camera are both connected to N.I.N.A..

It is required that your camera and telescope settings in the equipment settings are set correctly. The two important aspects are Camera Pixel Size for the camera and Focal Length for the telescope.

N.I.N.A. allows you to use the three most popular external plate solvers, each of which has its own benefits and drawbacks. Those plate solvers are Astrometry.Net, Local Astrometry and PlateSolve 2.

General Plate Solving

To plate solve an image you need to capture an image and use the Plate solve current image button in the image panel. This will start the procedure of plate solving your image with the Plate Solver as set in the plate solving settings. Should that plate solve attempt fail the mechanism will try to use the Blind Solver to solve the image.

Before being able to plate solve you need to configure the settings, primary solver and blind solver.

Should it happen that both plate solving mechanisms fail please verify that your image is somewhat in focus and if necessary change the exposure time or filter for that single image.

To apply the plate solving you need to enable the options Sync and if you want to, Reslew to target in the plate solving panel. The former will synchronize your mounts location to the location that the plate solver has determined you’re at. The latter will reslew your mount to the location where it was supposed to be in the first place.

This allows you to skip the whole star alignment process at your mounts start-up.

Plate Solving is also utilized in the Automated Meridian Flip to recenter your image after a flip has been performed. This is essential for a hands-off experience of N.I.N.A..

Our recommendation is to set up all Plate Solvers to have a backup should one plate solver not work as expected in the field.

ASTAP

ASTAP, the Astrometric STAcking Program, astrometric solver and FITS viewer is a powerful standalon platesolve application which can be downloaded on the ASTAP homepage
To work properly you also need to download one set of index files, which can also be found on that website.

Benefits

  • Fast
  • Reliable
  • Capable of fast blind solves even when the mount is far off target
  • No Internet connection required

Drawbacks

  • None

Recommendation

This solver is recommended for both primary and blind solver.

Astrometry.net Plate Solver

The Astrometry.net plate solver will utilize the internet page Astrometry.Net to plate solve an image. It requires registration on astrometry.net to get an API key that you need to enter in the settings.

Benefits

  • Reliable when the mounts location is unknown or far off
  • Does not need to know the cameras pixel size or telescopes focal length

Drawbacks

  • Requires an internet connection
  • Slow

Recommendation

  • Primary Solver: not recommended
  • Blind Solver: recommended when an internet connection is available

Local Astrometry Plate Solver

The local Astrometry plate solver needs to be installed separately. It requires download of index files which can be installed through N.I.N.A. as well to get the required index files that you need for your combination of focal length and pixel size. See plate solving settings.

Benefits

  • Adequately fast when the mounts location is unknown or far off
  • Fast when the mounts location is close
  • Does not need an internet connection to work

Drawbacks

  • Download of the correct index files is crucial for the plate solving performance
  • Can pick up hot pixels as stars (especially an issue with DSLR)
  • Most installer bundles for windows work on rather outdated versions

Recommendation

  • Primary Solver: not recommended
  • Blind Solver: not recommended

PlateSolve 2

PlateSolve 2 is a standalone executable which can be downloaded from the PlateSolve 2 home page. It requires the download of at least one catalogue of stars so it can properly work. You need to start the executable once standalone and set the catalog location of the catalog that you want to use. Both the APM or UCAC3 catalogues will work just fine, but it is recommended to download both of them should you encounter issues with any one of them.

Benefits

  • Very fast when the mounts location is close to the target
  • Does not need an internet connection to work

Drawbacks

  • Slow when the mounts location is far off and the focal length of the scope is long

Recommendation

  • Primary Solver: recommended
  • Blind Solver: not recommended (not possible)
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