17th June. SharpCap & ZWO woes.

Monday 17th: Sunny and I spent almost the entire day in the observatory trying to capture a prom. No matter what I did my efforts proved stubbornly pointless. I captured videos, worked on them and then deleted them and my resulting stills. Apart from my continuing lack of skill with the stacking software the seeing wasn't really very good. The overlaying ripple was back. I even tried FireCapture and it provided no advantage over SharpCap.

Thursday 20th: A helpful contact has suggested I check the effect of my laptop PS [power supply] on the surface "ripple" I am seeing on my laptop screen when imaging with SharpCap. Without the laptop being present I checked the potential of the mounting which had been tickling my fingertips and lighting a neon, test screwdriver. It showed a 60VAC potential relative to the big stepladder nearby when the AWR's 12V 7A power supply was active. The ladder is not earthed but sits on rubber feet.

I bonded the mounting to the stepladder but can still feel a potential on certain parts of the mounting and OTAs. Presumably these parts are isolated by the bearings or the felt lined, tube rings. An imaging test with SharpCap, with and without the laptop PS being connected, might prove interesting.

I have now attached crimped spades to the two green cables trailing from the AWR motor drive plugs. These are now slipped over the green terminal on the AWR Drive-box. An earthing cable, to a ground spike, will be tried on the green terminal next. My observatory is fed with a two core, extension cable to a 2-pin socket. So is not yet earthed. Reversing the 2-pin plug has no effect on the 60VAC potential on the mounting.

A quick check before dinner showed no difference on the SharpCap screen when I detached the laptop's PS. Rather unexpectedly the active screen area of the laptop showed a ground glass screen effect on the focused image. Almost as if the screen were greasy.

The sun had set so I attached the ZWO 120 MC to the 90mm Vixen to focus on some distant trees at 400 yards. I come from a generation where ground glass screens were the norm on most cameras, including SLRs.

The image above right shows the full screen if the laptop photographed with my Lumix TZ7. The image left is a cropped close up [macro] of the active area in SharpCap. The "ground glass" filtered texture is more easily seen and explodes into small crosses when enlarged.

Click on any image for an enlargement.