CCD Notes July 25-26, 2005 Connelly's Springs, NC. Radio Astronomy, sort of. Messier 13. Click the image for a 1024-pixel version. Exposure: 90 minutes (30 x 3 min exposures; dark subtracted, no flats). Optics: Astro-Physics 5-inch F6 refractor @ F4.5. Camera: SBIG ST2000XM w/ST237 guiding chip (chip temp: -15C). Filter: Clear, IR-blocking. Mount: Losmandy G11. Guiding, camera control, image stacking, alignment & calibration: Maxim 4.10. 16-bit response curve tailored for web display in Photoshop CS2. Remote computer control: Access Remote PC. OK, it's a nice enough M13, but what's really special about it? It's first light for a wifi-controlled observing setup I've been hammering together for a week or two. This is the cobbled up parabolic antenna I'm using to beam wireless signals into the backyard. It links this Linksys router to the internal 802.11b wifi connection in a small notebook computer. The parabolic reflector is mounted so that the router's stock antenna stands at the focus of the reflector. Out in the yard, the notebook computer runs a shareware remote PC application that lets me operate it (and with it all the telescope and camera drivers it hosts) from the comfort of my office. No wires, no musquitors. This is the larger parabolic antenna I'm using to grab a clean signal from a cell tower about 2.2 miles south of here. This and the smaller antenna above are made from aluminum flashing screwed to parabolic curves cut and sanded from pieces of plywood. The WWAN reflector has a strip of oak mounted in front of its focus so that an accessory WWAN antenna sold for window-mounting can be held with Velcro near the focus of the reflector. It all feeds a Novatel V620 wireless modem. How well does this work? The notebook computer can't find a network at the observing site without the parabolic reflector on the Linksys router. It connects solidly, at full speed, with the reflector aimed right. The WWAN connection goes from 30% signal strength to 51-54% with the reflector (whatever those numbers mean). The bottom line is that I'm getting 150-200kbps uncompressed up- and downlinks to the Internet and 11 Mbps into the backyard. Read about these do-it-yourself antennae here: Free Antennas Dot Com. I'm still taking data while I write and post these notes. I want an hour of data before I start messing with the image. Maybe more. I'll post the finished image up above tomorrow. I could use that water cooling I've been writing about -- it's 78F and 83% humidity out there -- but I figured there were enough new things going on tonight that I could do without that added excitement. The camera is holding -15C at 85-90% cooling capacity. A bigger issue is that I haven't got RoboFocus to run right with the new computer, but that too will yield. Stay tuned... <=Previous Next=>