Thanks for the info on smartphone battery life, using a planetarium program. Good to know.
As for the CP4 versus CP3, the CP4 might be a bit more accurate and run coordinate conversions a lot faster.
I was told that unlike the old CP3, which calculated all coordinate conversions using “integer mode” trig and arithmetic, the CP4 has a modern high speed microprocessor actually using extended precision “floating point” for its values. Thus, it is faster, more precise and accurate.
However, I don’t know how much improvement would be apparent in continuously running coordinate conversion, since the incremental changes in sky positions are so minute and slowly varying anyway. But, it is nice to have a modern fast processor, with room to add more future firmware functionality in the CP4, compared to an out-dated, memory limited, microwave oven control level of chip :-)
Either controller, CP3 or CP4 are excellent in design and performance – I would say without competition - and my trusty old CP3 will never be sold, and always be my backup in case the CP4 goes in for repairs again. My expectations for better performance and expanded future upgradability in the spiffy new CP4 product, were my deciding factors.