NOVA 120 Pointing model user manual
15
When the “
OK
” button is pressed the software matches the star catalog and stars from the image and after some
seconds the next form is displayed, saying that plate solving went fine.
104 stars have been found in this case. This is just a 10s exposure from a 400 mm F/3.5 telescope binned 2x2 image and
turned out to be sufficient. In this case field of view is 1°25’
Select “
Polynomial degree (plate solving)
” from 2 to 4. Then click “
compute
”. The image is calibrated and this has
worked out fine in this case.
Sometime plate solving might not work, and here it a list and proposed solutions
Cause of failure
Solution
Focal length no set correctly
Change focal length, do trial and tests
The center coordinates are not good
Refine them; be sure to get the right one. They do not
need to be accurate.
All sky plate solving can help retrieving these coordinates
Star size (FWHM) too big. When star FWHM exceeds 15 to
20 pixels, it might not work.
Use binning to reduce star FWHM size. Be sure to be
properly focused
Too few stars
Increase exposure time, or/and binning
A combination of failures above will result in failure, they do not compensate, so go step by step.
Failure to achieve PRISM’s plate solving will result in pointing model failure, so this is a mandatory step and need to
work out!
