PAN008: Macquarie University, Australia

PAN008

2019-05-11T14:00:00Z

PAN008 was originally up at the observatory here at Macquarie University using the original iEQ45 Pro mount that the PANOPTES team had replaced on PAN001. We removed it from PAN001 because of bad tracking problems with the idea that maybe it could be saved with PAN008.

It couldn’t.

PAN008 as reborn on 2019-05-11T14:00:00Z:

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PAN008 has a few key differences from the baseline design, namely in that it is using two Raspberry Pis for control (one in the control box, one in the camera box), as well as a slimmed down power control. The primary goal with using the Raspberry Pis is to save money.

Here are key differences as well as work to be done:

Pier

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It was hard for me to source the 80160 aluminium extrusions but the 4040 (that is 40mm x 40mm) were easy to find and cheap. In fact, the solid versions were only a dollar more per 500mm (~$34 AUD = ~$24 USD). It was only slightly more money to have the M8 tapping done while they were cutting so I went ahead and ordered them that way.

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I had the two plates machined at the shop here on campus. I don’t have the bill yet but should be pretty cheap. I told them to use spare parts so the bottom plate is 12.5 mm thick and 250mm square. The top plate is 20 mm thick and 120mm on the side, which exactly matches the diameter of the iEQ30 Pro.

I screwed up on the iEQ30 Pro measurements and was 1mm off for the M6 screws, so you see an additional set of the smaller holes in the picture. I plan to widen out the counterbore on the center hole as it can then double for use with the CEM25 that will become PAN009.

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I haven’t yet drilled the holes in the bottom plate to attach to this to anything as I’m not sure where it will go or what is the best size. For now I will use this pier mostly while testing and was a temporary pier until PAN008 can go back up on the large pier at the observatory (it’s under construction until Sept.).

Control Box

The full details of the Raspberry Pi with instructions need to be written up but here is the control box with parts:

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You can see the power items in the upper left, with the 12V battery being the big black box. There is a UPS that handles the main input and battery charging/failover, with this mains being supplied by a big friendly plastic switch. The raspberry pi 3 B+ is in the lower right and the Infineon (with Arduino Uno under it) power control is the red thing with all the red and black power wires coming out if it.

There is also a raspberry pi cam attached to an hdmi cable that is being fed outside the box. I plan to use it for some kind of cool all sky or infrared cam.

Camera Box

Inside the camera box is a raspberry pi and a small custom board that is used to distribute the power. There is 12V that comes to the camera box and this board has 2x the 8v voltage regulators that feed the camera as well a UBEC 12v to 5V 3A regulator, which is great. It’s designed for LiPo batteries (and drones and RC cars), but work perfectly in dropping down the voltage while also giving at least 2.5A needed for the Pi. You could build your own but why waste the time. These give off almost no heat. They do have a bright annoying green led.

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(I’ll replace this with a better picture tomorrow)

The raspberry pi, in addition to actually connecting to the cameras, also has an AutomationHat on top of it, which allows for easy power cycling of each camera. It still remains to be done to make this “easy” switching integrated with pocs and the whole system but it’s already in python so should be easier.

Still need to add back the accelerometer and the temperature and humidity for the camera box. PAN008 previously had the SenseHat in the camera box, which also had a camera attached. To keep things simple I will probably had a whole new Pi to the camera box which does have this SenseHat and a camera, which gives me all the sensors in the camera box and keeps it a little separate from the taking of the pictures. I have a secret hope in the future to use the pi cam as an autoguider in which case this Pi could also run that (one day maybe).

Weatherproofing

Still in the middle of weatherproofing but I did have some of the lens caps printed that PAN010 made. PAN008 gets red. :). They are being sealed with sugru although unfortunately ran out of red sugru half way so need to way.

Because these should be facing down for any rain anyway, the main goal with the printed covers and sugru for PAN008 will be to keep bugs and spiders out.

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Similarly sealing off other joints with some of the colored sugru, which is fun.

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Mount

Not really different, but more back to the original. :wink: Because the two raspberry pis can communicate wirelessly, there is no need to run a thick usb cable through the mount axis. Originally both power and communications ran inside the mount but eventually the USB got pinched on PAN001. Simply because I don’t like the wires coming out the front of the box, but also because the polar scope isn’t of use to me in the southern hemisphere, PAN008 continues to have the 12V wires run inside the mount.

This does mean that I needed to remove the polar scope, but since PAN008 is in the southern hemisphere the polar scope doesn’t do much good anyway.

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Here I also drilled out a small hole on the provided cap so it can be sealed a bit better. This allows me to spool wire inside the cap, which is easier to pull on (if needed) from the twisting axis.

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One thing I have done is attached connectors at each point so that, for instance, I don’t have to thread and unthread a really long wire through the mount every time. Having a whole series of connectors is a a bit annoying for a permanent install and will require extra weatherproofing of cables, but it’s nice for testing and moving it around lab.

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Future Work

  • Finish weatherproofing.
  • Finish rpi docker software integration.
  • Add sensors back to camera box.
  • New name?
  • Probably a lot more. :slight_smile:

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I reckon the Obs will be ready by late July, but great to see it back ready to go.

Also, you forgot to mention … Needs Input!

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Nice progress Wilfred! Great to see a unit with a different build philosophy.

In regards to the iEQ45Pro, is it cactus? Or is there hope for it?

Back on sky soon! Testing out some of the polar alignment routines. Observatory still under construction so can’t set things up permanently yet, but PAN008 is almost all ready to go!

I still need to do some final weatherproofing, so ignore the plastic wrap, but nice to get the first Southern Hemisphere unit back on sky! Not a bad Southern Cross image from my cell phone.

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