astrosatch But how can platesolve be possible if there are trailed stars?
Trailed stars cannot be plate solved. (I missed the part where you had earlier mentioned that you have trailed stars.) You need to make sure that your mount is tracking sidereal rate correctly, and tracking is turned on before taking a plate. Tracking on most reasonable mount is automatically turned on after a GOTO command is given to the mount. But check it to be sure.
Check the tracking without ASIAIR connected to a mount. With tracking turned on, you should never see star trailing with a 10 second exposure unless your mount is not tracking or has the wrong rate. Many older mounts have a way to tweak the clocks, but newer mounts with crystal oscillators can usually hold reasonable tracking, unless something has gone wrong.
If all else fails, use the ASIAIR's autoguiding to keep the guide star in its position. That should stop trailing, If the guide plate is stable but the main camera star is not stable and if you are sure your mounts's clock is good, you have flexure between the mount and your optical train, although it is hard to imagine a flexure that causes star trailing with a 5 second exposure.
How on earth can people with FL 2000mm+ plate solve if I can't with 800mm?
Because ASIAIR is capable of plate solving long focal lengths as long as the sensor is large enough so that the plate size is larger than 0.2º on both dimensions. And they do not have trailed stars.
Again, stars need to be a tack sharp pinpoint. A sufficiently elongated object with not be registered as a star. Plate solving needs asterisms of stars to solve for their aggregate location in the sky -- no stars, no asterisms, and therefore no plate solution.
Chen
