SGP has trouble solving near Ra of Zero

I’ve been running some tests and came up with an interesting problem. I set a position of 0 Ra. The solve seemed to give a Ra of -23.999 hrs and the error was reported as something like 763,000 pixels, 359.99 degrees.

What’s happening is the wrap around of the angle at 0 to 360 degrees, 0 to 24 hours etc. The difference between a Ra of -23.999 and 0 is 0.001, not practically 24.

I can work round this by not choosing 0 as a Ra but if there’s an object there it may be more difficult.


Thanks for the heads up. We’ll add some better checking here.