My First Light with the QHY5 (aka PL1M)

My PL1M Autoguider: A Budget Star Finder with a Quirky Side

I’ve been using my PL1M autoguiding camera (a QHY5 model rebranded for the French market) for over two months now. Before picking it up, I spent a good deal of time weighing my options, particularly between this model and the DMK-21 USB. The price difference (around €100) ultimately tipped the scales in favor of the PL1M. This camera is imported and distributed in France by M42Optic, a niche company that’s carved out its place in our country’s somewhat exclusive amateur astronomy scene. It boasts a 1/3-inch monochrome CCD sensor (larger than the DMK-21’s) and comes with an integrated ST4-compatible autoguiding interface.

For a long time, I’d been on the hunt for an autoguiding camera sensitive enough to snag a guide star regardless of where I was pointing in the sky, without having to manually adjust my guidescope. This was a critical requirement for operating my observatory remotely. I put the camera through its paces on both a C11 at F/10 (2800mm focal length) and a 50mm refractor. In both scenarios, the camera consistently found a star, even in the most star-sparse regions, with exposures under 4 seconds, provided the gain was cranked up high enough. I use Guidemaster software to manage the camera and handle the autoguiding, and I’ve got no complaints there – it works like a charm.

The camera supports 2x2 binning mode, which boosts its sensitivity by a factor of four. However, this mode isn’t recommended for guiding, as it also divides your tracking precision by the same amount! I typically use it to quickly locate a guide star on screen before switching back to 1x1 binning for precise tracking.

Initially, I ran into some major headaches with this camera. It would systematically freeze my entire USB chain after just a few minutes of use: my mount controlled by EQMod, imaging software… it was a complete disaster, especially when trying to control things remotely! I quickly realized that connecting the PL1M via a USB switch to my main PC was a recipe for trouble. So, I decided to add an extra PC, dedicated solely to autoguiding, with the PL1M as its only connected peripheral. The result? Full nights of tracking without a single crash!

Overall, I’m extremely happy with this budget-friendly camera. Since I’ve never had the chance to test a DMK-21, I unfortunately can’t offer a direct comparison between the two models.