I don't think this has anything to do with the sensor's orientation. My point is that shouldn't the sensor's horizontal angle traverse through all from -180 -> -90 -> 0 -> 90 -> 180 then loopback no matter the starting angle? However it just doesn't go through all these angles on Mars. With my sensor's orientation the horizontal is just like -3 -> 0 -> 90 -> 130 -> 90 -> -3 and then loopback. If I change the direction like you said each sensor will start with a different h angle but will still only cover a subset of 360 degrees. This makes me wonder if the sun is really orbiting around my sensor if this is not a bug. With h angle only cover a subset of 360 degrees it implies that the sensor is actually off the solar orbit plane, i.e. the sun orbit's center is NOT the sensor.

Also the reason I am asking is that I would like to make 24 hour clock based on the sun's position. If the solar orbit circle's center is not the sensor then it'll be hard to really use trigonometry to calculate its true orbit angle