SpaceCat Update: PowerBox Solution

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Starting to pick up from where I left off at the beginning of July. Still have to decide on where to mount the Pegasus Astro Pocket PowerBox Advance. I’m not happy with the L-bracket solution I came up with as an alternative to the PPBAdvance hanging off the tail end of the dovetail bar. With the L-bracket, its position partially blocks the airflow for the QHY268C cooling exhaust vents.



The plan is to install a Synta-style dovetail bar on the bottom of the PPBAdvance using the BuckeyeStargazer mounting bracket. Then with it mounted on the dovetail handle, install a USB 3.0 hub and finder shoe for the guide scope, which can be mounted on top with the Pegasus Astro top plate for the PPBAdvance. Might also try mounting the environment sensor to the front or back face of the PPBAdvance.

To use both brackets, the BuckeyeStargazer mounting bracket needs to be modified slightly for it to be compatible with the PPBAdvance top plate. Two of the mounting tabs on the BuckeyeStargazer mounting bracket overlap the mounting holes for the Pegasus Astro top plate, and need to be sheered off in order to mount both brackets to the PPBAdvance.




Still need to wire everything up through the PPBAdvance, and try to power it up. Going to need at least a 12V10A power supply. I’m still a little concerned about the power requirements. Although it’s likely I won’t be running all the devices at full power at the same time. So the demand should still be within the limits of the power supply.

Power connections should be mapped as follows:

Data connections should be mapped as follows:

  • Pocket PowerBox Advance Gen2 (USB 3.0 Type-B)
    • USB 2.0 Port 1 (unused, provides up to 3A of current)
    • USB 2.0 Port 2 (unused)
    • USB 3.0 Port 3 – QHY268C Main Camera (USB 3.0 Type-B)
    • USB 3.0 Port 4 – Sabrent 7-Port USB 3.0 Hub (USB 3.0 Type-B)
      • Player One Mars-M (IMX290) Guide Camera (USB 3.0 Type-B)
      • DSD AF3 Autofocuser (USB 2.0 Micro-B)
      • DSD FR1 Field Rotator (USB 2.0 Micro-B)
      • DSD FP1 Flap Panel (USB 2.0 Micro-B)
    • EXT Port (RJ12) – Environmental Sensor (hardwired)

Assuming extreme conditions, the QHY268C and dew heater strips can draw up to 3.25A of current combined. Estimating 1A maximum current draw from the Sabrent USB hub (5V × (900mA + (3 × 500mA)) / 12V). The focuser, flap panel, and field rotator will likely only be used one at a time with 1A maximum current draw from each. Total max current can then be estimated to be ~5.25A with the average potentially being about half that depending on environmental conditions and the set point temperature of the camera sensor.

Note that the above power consumption estimate does not include the mount or computer. Those will need to be powered separately from the PPBAdvance. Also, Pegasus Astro notes that a typical backyard astrophotography setup typically demands a range of 5-7 Amps for efficient operation.

Continues in SpaceCat Update: Assembled for Testing.

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