Gina

Looks a nice dome.

So that's a plan to connect the Nano to the Uno (or Mega is I run out of pins on the Uno) next is to connect from the house. Two types of comms link, cable or WiFi and I would prefer the latter as one reason for buying the AP was for WiFi in the observatory. Must check that first.

The actual DS18B20 sends 12 bits of data so I shall have to check if the MS 5 bits (used by DS18B20 as sign) can be accessed separately. If not I'll be limited to 12 bits and may need to do more data processing in the Nano.

Actually, the wind data could be sent as just one byte viz. 0-15 wind direction and 0-15 wind speed on Beaufort scale but with two bytes I have the luxury of a whole byte for each or counting as a word of 16bits, I could use 9 bits for wind direction in degrees and 7 bits for wind speed in mph 0-127.

The library emulates a DS18B20 which sends 2 bytes so I can easily encode the data for wind direction and speed.

More info LINK

Found this :- OneWireArduinoSlave ?

Yes, one of the things I was thinking. Now if the Nano could behave as a 1-wire slave... But I could use a 1-wire device as an interface I think.

I guess I could "use a sledgehammer to crack a nut" and use a computer in the observatory and connect both Arduinos by USB then connect to that using TeamViewer but I'm sure there's a better way.

Looked into doing away with the mast-top Nano and using long wires to the master Arduino but the wind vane direction chip uses SPI which has a very limited range, quoted as a few inches or a foot or two at best, so that's out. Also, looked further into serial but without line drivers and receivers, that's very limited too. This is getting silly!! Maybe out-of-the-box thinking required.

Been reading about I2C for connecting two Arduinos and there's a problem with the cable length. The limit appears to be less than 2m and the remote Arduino is up on the top of my 5m mast. The cable can come out of the mast tube at above 1.5m above ground but that's still far too much. So that's I2C out of the frame Serial has been suggested as another way of connecting two Arduinos but the serial lines on the remote Nano are connected to the USB-serial chip. I can't find information on disconnecting the serial chip so that I cam use the Tx and Rx lines independently of the chip. I guess I could use a 4-5m USB cable but...

If I were starting again I would probably go for the RPi rather than Arduino but with almost all the hardware built and the code written, I'll probably stick with the Arduinos. My WiFi should work but as I already have gigabit Ethernet available in my observatory, I think I'll use that. OTOH if the Arduinos prove too awkward the RPi is an alternative.

Cloud and rain forecast for tonight - that's because I expect to be ready for testing outdoors, of course!!

Cloudy tonight so no stars to test on.

I see the current Ethernet shields for the Arduino do have pass through connections so it may be possible to stack both the Ethernet shield and the data logger shields on the main Arduino Uno or Mega. I'm currently using a Uno but have a feeling it won't have enough I/O ports. Fortunately the shields fit both Uno and Mega. The data from the wind instruments could be carried by a serial stream over two or three lines (including Gnd) and, in fact, I gather you can connect two Arduinos via I2C or serial.

Made and attached the focus motor bracket and now printing a new focus gear as the spacing has changed. This project has gone even more in the direction of "make it up as I go along", I haven't decided what the case will look like yet ?

I think it's pretty much settled down at just over 10°C so I think that concludes testing for now and I can aim to get the ASC up together enough to test outdoors tonight - probably hung on the guttering outside the living room window. If it isn't raining!!!

Nearly down to 10°C now. The current arrangement allows almost unobstructed airflow over the fins whereas before the table was below it so even though spaced away a bit would still have impeded the airflow a bit. This won't arise when mounted out of doors and the nighttime temperature will be lower than the 20°C ambient indoors. Initial thoughts are that the cooling is better than when using the pipe as heatsink/cooler. Should be, there's an enormous increase in surface area. Hopefully, I should get rid of the annoying hot pixels when imaging the stars. I have a couple of ideas if it isn't good enough. I could cut a hole in the observatory wall beside the ASC and fit an extractor fan to blow cool air from inside the observatory over the cooler. Or I might have another look at water cooling - I have about 4" above the position of the water block for a reservoir. I already have a fan assisted radiator and plenty of plastic tubing that I used in my cooled DSLR experiments some years ago.

Gradually creeping down - now back to 11°C.

Initial camera temperature 12°C (crept up a bit from previous reading) and now leaving the rig running with repetitive 10s exposures and everything the same except for the orientation of the cooler.

The camera temperature seems to have settled down to about 11°C with continuous 10s exposures so I've turned the rig to give what should be better cooling.

Camera thermal insulation and clamping plate completed and fitted. Now testing again. It will be some time before I can post results because this thermal process is extremely slow.

Yes, obsy roof is all fine and I used the mini guttering attached to the ROR with the down pipe running into a full size down pipe and spout, arranged so that when closed the water from the roof runs down into the 4" spout. When the roof is open it shouldn't be raining ? The guttering on the warm room roof is full size as it collects water off the warm room roof and half the ROR.

Ah well, if you're a whiz at glass fibre construction that's a different matter. I've done some glass fibre work many decades ago but that was tiny compared with a full sized dome.

I don't think they had the contact adhesive when I bought my EPDM but no doubt other makes of contact adhesive would have done.