Since I don't use a warm room, I would still like to monitor the temp & humidity inside the observatory. Reason for this is to set the exhaust fan to kick in at certain temp or humidity range. Could I use the use a BMP180 code in the weather tab to show it on the weather control panel instead of the thermomstat panel?  Temperature(outside) Humidity(outside) and Temperature (Inside) ditto for the humidity?
Thanks
Nino

Yes, that's the kind of thing those functions are for.

The BMP180 is temperature and pressure only though so I guess you intend to use a BME280?

I purchased the items on your list(Stellar Journey) from ali express, they started arriving last thursday,  I had some bme280's sitting around so I had used those for the outside sensor.  The bmp180 and the si7021 arrived today. I added the si7021 code to the temperature tab, will wire it up hopefully tomorrow. I also have the rain sensor as the TSL237 and MLX9061.  Just have to figure out how to mount them in my sensor "birdhouse".  I had a DS1302 RTC laying around, but I ordered the DS3234 without a battery, thought I could find it locally, but no.  I have to order one from amazon or go to Batteries Plus.   
Thanks again
nino