Astap Plate Solver Download
Manuela
Plate solving is a method used to determine exactly where the telescope is pointing in the sky by comparing the star field in an image to a database of star positions. Upon matching the image's stars, the plate solving application returns the right ascension (RA) and declination (Dec) of the center of the image. N.I.N.A. understands this output, and may be used to synchronise the mount to that coordinate. This gives the mount a very accurate notion of where it is pointing in space, making subsequent slews very precise.
Plate solving requires that your camera and telescope settings are correct. The two important settings are the camera's sensor pixel size and the focal length of the telescope. N.I.N.A. will usually be able to detect the sensor's pixel size, but the user will need to inform the software of the effective focal length of the optical path. This includes the focal length of the telescope itself and any focal length-affecting devices such as reducers, telecompressors, or barlows.
To manual trigger plate solve of an image you need to use the Plate Solving tool in the image panel.There clicking on the play button a new image will be captured and solved based on the given parameters.Should the solve attempt fail, N.I.N.A. will prompt if the Blind Solver should be used to solve the image.The reason for this is that while most plate solving software is quite good, none are infallible.Where one fails to solve a given image, another might succeed.Thus, the Blind Solver acts as a back up method.
In the event that both the Primary and Blind plate solving applications fail to produce a result, please verify that your image is in focus and, if necessary, increase the exposure time or change the filter type to allow more stars to be adequately exposed.
Furthermore the last failure is stored in %LOCALAPPDATA%\NINA\PlateSolver\Failed to analyze why it failed
To apply the plate solving results to your mount, you need to enable the Sync option and, if desired, the Reslew To Target option in the Plate Solving panel.The former will synchronize your mount's notion of its pointing position to the position that the plate solver has determined is it pointed.The latter option will make N.I.N.A. slew your mount to the location where it was supposed to be in the first place.This allows skipping the star alignment process that is typically done during a mount's start-up process.For a precise centering with a given error margin use the "Repeat until error
Plate solving is also utilized in the Sequencer to center on a given target and Automated Meridian Flip feature to recenter the scope after a flip occurred. Here plate solving will be triggered automatically and the parameters are used from the Plate Solving Options.This is essential for a hands-off operation of N.I.N.A. and it is recommended that the application is set up to have a blind solver, should the preferred primary plate solver not work as expected.
In order for plate solving to work properly a couple of important parameters have to be set as precise as possible. When these deviate to some degree from the real world hardware, platesolving software will have a hard time solving the image or even fail all the time.
If you are unsure about the effective focal length, you can use nova.astrometry.net to validate your real focal length. Upload a non binned image of a target that used your current setup. Once the image is solved the "Pixel Scale" is displayed. You can extract the focal length now by using the formula
"Focal Length = (Camera Pixel Size / Pixel Scale) * 206.26"
N.I.N.A. supports the most popular plate solving software suites available, each of which has its own benefits and drawbacks. The following is a list of support plate solving software and their general characteristics.
The ASTAP (Astrometric STAcking Program) astrometric solver and FITS file viewer is a powerful standalone plate solve application. It is downloaded and installed in two parts - the application itself, and its star database.
N.I.N.A. can upload the image to the API servers of Astrometry.Net for them to plate solve it. This requires the user to register for an account on Astrometry.Net and generate an API key that is then entered into the plate solve settings for Astrometry.Net.
The local Astrometry.Net plate solver needs to be installed separately.It requires download of index files which can be installed through N.I.N.A., as well as the required index files that you need for your combination of focal length and pixel size. See plate solving settings.
PlateSolve2 is a standalone executable which can be downloaded from Planewave's PlateSolve2 downloads 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 fine, but it is recommended to download both of them should you encounter issues with either one of them.
Nina has kindly been selected to add the new PlateSolve3 program to its arsenal of platesolvers, courtesy of Dave Rowe.PlateSolve3 is a standalone executable which has been improved to work with longer focal lengths and smaller FOVs with fewer stars.This download has the necessary catalogues already added. Just unpack it into a directory of your choosing and point to it in Nina platesolving options.
You need to start the executable once standalone and select File - Configure directory.
Set the GaiaDr2 location to the 'UD Catalog' directory in the unpacked PlateSolve3.80 directory.
Then set the UCAC4 location to the 'Kepler' directory in the same unpacked directory.You will also need to set your location in View - Parameters
I ran across this and decided to do some testing using the Observatory rig and two of my travel rigs. I loaded an image I had, M74, and preformed plate solving using both the ANSVR and ASTAP. On my two travel rigs they are both running the older ASTAP version while on the Observatory system is running the newer version of ASTAP.
On the travel rigs both the ANSVR and ASTAP angles always agreed. However, on the Observatory rig, running the latest ASTAP version, the ASTAP was always approximately 180 degrees different. I did this on several images and the ASTAP solve was always different by approximately 180 degrees from the ANSVR solves. Sometimes the angle showed a negative value.
This difference between the ANSVR solve and new ASTAP solve might be the reason my rotator was confused. One time ASTAP told the rotator to go to one place then the next solve, if the blind solver kicked in, ANSVR told it to go to the opposite place.
For problematic images, probably Astrometry.net is the best. For short exposures of a few seconds taken in twilight, ASTAP and PlateSolve2 have a a very similar performance. The star detection routine in ASTAP is robust.
I you happy with the performance, rename astap.exe to PlateSolve2.exe and place it in the users directory to substitute PlateSolve2. Add the 290 files of the G17 star catalog in the same directory. Activity will be show by a small tray icon only. Confidence will be reported as 999 indicating ASTAP is reporting.
Note that:
The internal astrometric solver works best with raw unstretched and sharp images of sufficient resolution where stars can be very faint. Heavily stretched, very long exposures or photo shopped images are problematic. It requires minimum about 30 stars in the image. Images containing of a few hundred stars are ideal. For star rich images it reduce the detection limit to limit the number of stars. This will only work for unstretched images.
well this is not entirely true, at least for astrometry.net. it compiles on cygwin and under macosx and linux just fine. no virtual machine is required, unless you are counting cygwin as a virtual environment.
I did. For Windows to get Astrometry.net running you will need Cygwin or the Win10 64 bit Linux sub-system. Both Astrotortilla and ANSVR use the same old Astronomy.net v0.38 somebody managed to compile long time ago. In the Win64 special Linux sub-system it is possible to install a later version of Astrometry.net See my guideline:
I think in the long term, it would be wise to add in SGP an option to use the command line of Astrometry.net so it would be able to access a local up to date Astrometry.net in a Win10 64 bit Linux sub-system. But they should also try ASTAP
I just like to add how this all started. Originally ASTAP started as a stacking program (and still is) and I used Platesolve2 to get an astrometrical solutions to stack images. The accuracy of PlateSolve2 was not satisfactory for stacking, so I added access to Astrometry.net. That worked fine but slow. Then I developed a star matching routine for stacking which worked much faster and the need for Astrometry.net was limited for Mosaic building where star matching no longer works.
Still impressed by plate solving capabilities of Astrometry.net and PlateSolve2, and having star matching for stacking working, I decided in the spring of 2018 to try to develop my own solving routines.
Reducing to the brightest stars only will result in increasing solving speed but increased risk of missing the solution.Above result show that blind solving with brute force can give excellent results.
Reducing to the brightest stars only will result in increased solving speed but an increased risk of missing the solution. Above result show that blind solving with brute force can give excellent results.
IMPORTANT, previous version of ASTAP had bug which only occured for DSLR cameras. ASTAP looked only to the initial start position in the FITS header of the input file and not to the start position given by SGP in the PlateSolve2 command line. This resulted in long solving times. This has been fixed in ASTAP version 0.9.127 just released.
I have been using ASTAP in SGP for quite some time now and I can confirm that it works very well. Fast and accurate.
The tweak (renaming astap to ps2) works as expected.
I can recommend this option strongly.