SharpCap Forums

Hi,
I have gone through all the troubleshooting tips and still cannot get polar alignment in a reasonable time. THe other night it took nearly 45 minutes. It starts quickly so obviously is within the required 5 deg of Polaris but doesn't advance after turning the tube for ~ 90 deg although enough stars seem to be in use. It says I am to check exposure time and gain but any change doesn't make a difference.
My camera is a Lodestar X2 and a QHYCCD mini scope with a focal length of 130 mm. The usual exposure time is ~ 4 sec. Please can you give me any advice as for the best frame rate? I suppose a maximum framerate is nonsense if the exposure time is 4 seconds. I tried anything from maximum to 1 frame in 4 sec - I'm a bit frustrated.
Best regards,
cruxaustralis1976

Hi,

depending on your initial pointing and how well/badly the guide scope is lined up with the mount axis, the field of view can change quite a bit when you rotate through 90 degrees. It might be that you just end up in an area of sky that is poor in stars by bad luck. It's even possible that the rotation takes the field of view outside the SharpCap 5 degree zone (if the guider is aligned poorly).

My recommendations would be :

Use a plate solve tool (Astrotortilla etc) or upload an image from each direction to nova.astrometry.net to check where you are pointing and if you have wandered to the edge or outside the 5 degree zone.

Try starting in the rotated position - in the start position you only need *one* frame to solve to proceed. In the second position you need many frames to solve reliably during the adjustment, so if it is reliable one way and not the other then use that to your advantage.

If still no joy then send a frame captured in each orientation to me for further testing.

thanks,

Robin

Hi Robin, sorry for the late reply and thanks for your advice! I will try next time. I just wonder what has gone awry as in the past it was done so quickly. The tripod sits on well marked spots on the concrete slabs so the orientation has not changed for years.
Cheers,
Cruxaustralis

Hi,

yes, working out what has changed will be tricky, but a saved image has a chance of helping. It could just be that you hit a very poor patch of sky (very few stars) by sheer bad luck, causing the plate solving to have trouble.

cheers,

Robin

Or like me check that something isn't getting in the way when you drop the scope 90 degrees - in my case the top of an Apple tree.
Greg