Camera group error relating to the `is_set` attribute

[fergusL]

I have observed similar errors occurring intermittently, which can shutdown POCS states. The logs shown below occurred during the day when POCS was waiting for sunset (at 4:16pm local time, sunset was at ~5:15pm). This is significant bug as it can cause POCS to randomly shutdown.

S 06-29 06:15:39.308 Unit says: Entering taking_darks state from the starting state.
S 06-29 06:15:39.952 Unit says: Taking bias frames.
I 06-29 06:15:40.049 Moving telescope to park position for dark observation.
W 06-29 06:15:42.330 Ignoring weather safety for BiasObservation.
I 06-29 06:15:42.926 Starting observation block for BiasObservation
I 06-29 06:15:42.930 fine focus required because we haven't focused yet.
I 06-29 06:15:43.166 Taking observation BiasObservation for CameraGroup with 9 cameras.
I 06-29 06:15:49.878 Observation status: {'current_exp': 1, 'exp_set_size': 5}
I 06-29 06:15:49.880 fine focus required because we haven't focused yet.
I 06-29 06:15:50.102 Taking observation BiasObservation for CameraGroup with 9 cameras.
I 06-29 06:15:56.865 Observation status: {'current_exp': 2, 'exp_set_size': 5}
I 06-29 06:15:56.867 fine focus required because we haven't focused yet.
I 06-29 06:15:57.103 Taking observation BiasObservation for CameraGroup with 9 cameras.
E 06-29 06:15:57.416 PanError: Attempt to start exposure on 192.168.80.200 (1919420013090900) with Birger Focuser & ZWO Filter Wheel with ZWO Filter Wheel while not ready.
E 06-29 06:15:57.419 PanError('Attempt to start exposure on 192.168.80.200 (1919420013090900) with Birger Focuser & ZWO Filter Wheel with ZWO Filter Wheel while not ready.')
C 06-29 06:16:00.060 Problem going from 'taking_darks' to 'starting', exiting loop [AttributeError("'NoneType' object has no attribute 'is_set'")]
I 06-29 06:16:00.065 Parking the telescope before stopping states.
S 06-29 06:16:00.081 Unit says: Entering starting state from the taking_darks state.
S 06-29 06:16:02.292 Unit says: Parking Huntsman.
I 06-29 06:16:02.299 Setting new observation to None
S 06-29 06:16:02.324 Unit says: I'm takin' it on home and then parking.
S 06-29 06:16:02.444 Unit says: Finished with the parking state. The next state is parked.
S 06-29 06:16:02.453 Unit says: Entering parked state from the parking state.
S 06-29 06:16:03.162 Unit says: I'm parked now. Phew.
S 06-29 06:16:03.165 Unit says: Finished with the parked state. The next state is housekeeping.
S 06-29 06:16:03.168 Stopping POCS states

[fergusL]

Not sure if this is related to the bug or just a coincidence but this error occurred again this evening with the same jetson/camera

I 07-04 06:15:18.601 Starting observation block for BiasObservation
I 07-04 06:15:18.604 fine focus required because we haven't focused yet.
I 07-04 06:15:18.833 Taking observation BiasObservation for CameraGroup with 8 cameras.
I 07-04 06:15:24.705 Observation status: {'current_exp': 1, 'exp_set_size': 5}
I 07-04 06:15:24.707 fine focus required because we haven't focused yet.
I 07-04 06:15:24.933 Taking observation BiasObservation for CameraGroup with 8 cameras.
I 07-04 06:15:31.430 Observation status: {'current_exp': 2, 'exp_set_size': 5}
I 07-04 06:15:31.432 fine focus required because we haven't focused yet.
I 07-04 06:15:31.649 Taking observation BiasObservation for CameraGroup with 8 cameras.
E 07-04 06:15:31.988 PanError: Attempt to start exposure on 192.168.80.200 (1919420013090900) with Birger Focuser & ZWO Filter Wheel with ZWO Filter Wheel while not ready.
E 07-04 06:15:31.990 PanError('Attempt to start exposure on 192.168.80.200 (1919420013090900) with Birger Focuser & ZWO Filter Wheel with ZWO Filter Wheel while not ready.')
C 07-04 06:15:34.957 Problem going from 'taking_darks' to 'starting', exiting loop [AttributeError("'NoneType' object has no attribute 'is_set'")]

[fergusL]

This issue still occurs but changes have been made to allow pocs to continue after the error occurs, so it no longer interrupts pocs states