Project:
Nikon D800 for astrophotography ?

Contents:

1. Nikon D800 overview
2. Adapter Nikon to Pentax 645
3. Lid, Dove tail, Tube ring
4. Focuser mechanism, driver
5. Off-axis guide camera
6. Computer module and DC/DC converter
7. DC/DC general triple converters
8. Main bracket
9. Wiring & USB-HUB
10. Test with Windows and APT
11. First Light
12. Balance system
13. Nikon vs Canon, Pentax FA vs Pentax
14. Tilt adjuster
15. KStars/INDI setup for Nikon
16. To be continued

Note:
I take no responsibility or liability for what are written here, you use the information on your own risk!

6: Computer module and DC/DC converter

I have used both APT in PC Windows and KStars Linux system. Windows is easier to understand, Linux can use a simplier computer. I built this setup to take both system. But I start with Linux system because I have a Raspberry Pi5 left over.

The Raspberry Pi5 computer needs 5 Volt and 5 Ampere. It need a power supply that can deliver that power. I used a similar DC/DC converter to an earlier project. This one will be built in the same enclosure as the Raspberry and direct connect to the 40 pin terminal, not the USB-C port. The USB-C cable protrude far away from the chassi and the risk of damage is high.

Raspberry Pi5:

The Raspberry Pi5 looks almost the same as the older Pi4, but the cooler is different. I use the 4GB version which I think will be enough, much cheaper and only this was available.

Enclosure:

The Raspberry Pi5 will be placed on the upper part. The hooks grab the cooler's chassi. In the lower part will the DC/DC converter be placed. 8 to 24 Volt input and 5 Volt at maximum 5 Ampere output.

This is how it looks like when 3D-printed.

The hooks grab the cooler on the back side.

Later a lid will push the Raspberry in place and lock it. Now I can direct connect the power to the 40 pin terminal. No longer a protruding USB-C cable on the side. A screw terminal for the incoming power, later another one for 5 volt output to some extra device.

With the lid mounted it lock the Raspberry in place. The lid also protect the power cables that goes between the Raspberry's 40 pin terminal and the DC converter.