I would like to put up an all sky camera, to monitor and record meteors, fireballs and any other naked-eye visible phenomenon.
But I am the classic penny pinching astronomer. The cheapest low-end all sky cameras I found online cost $400, and the high end is more than $2000. Some still require additional components to connect to a computer. So I’m looking for a way to do all sky observing on the cheap.
The obvious criteria would include:
- Low cost (Astronomy penny pincher, duh)
- A view from horizon to horizon, or nearly so. Let’s say 160 degrees minimum view.
- Weatherproof, sturdy enough to leave outside all the time
- Easy to construct – common components
- Good light sensitivity – hopefully to view to magnitude 5 or 6
One popular trick long used has been to point the camera down onto a a convex mirror, or a polished chrome hubcap to get a fisheye view of the sky, horizon to horizon in all directions, or nearly so. This would certainly work, though it strikes me that you’d have to keep the mirror or hubcap clean, taking windex to it every few days at a minimum. I was hoping for a direct sky view, perhaps through an acrylic dome or a lens that can be exposed to the sky, to the sun and left out all the time.
My first thought was to use a webcam. Advantages are that they're cheap, and plug directly into a USB port with no additional interfaces required. If I were to use a CCTV camera, I’d have to convert the analog video signal from the camera to some sort of storable, analyzable digital signal. This is done with a video capture card for your computer, or a USB dongle that turns the analog video into digital signals the computer can record and analyze. They’re cheap enough, so this is certainly a viable option, not off the table.
Some web searches turned up, of course, some really cool stuff. There are networks of all sky cameras (www.allsky.com) and plenty of networked live and recorded cameras. NASA has a network at (http://cams.seti.org/easyCAMS.html ). All it takes to participate is about $700 in equipment, plus a dedicated computer with two external hard drives. On the plus side, their software is free, and they’re doing some amazing science with this low end stuff.
There are also a few websites where helpful fellow amateur astronomers have posted instructions for how they built their all sky cameras. For example, Chris Peterson’s Cloudbait Observatory site, (http://www.cloudbait.com/projects/allskycamera.html) or Michael Morris’ very workable DIY effort (http://stargazerslounge.com/topic/159282-another-diy-all-sky-camera/),
It also seems this topic was covered in a Minnesota Astronomical Society meeting in Nov 2011. (http://freemars.org/mnfan/MAS/2011-11-Nov-Meeting/). One photo I love is http://freemars.org/mnfan/MAS/2011-11-Nov-Meeting/2011-11-03-044.jpg which appeals to my inner penny pincher astronomer.
The best example of what I was shooting for, however, was from the Oak Grove Observatory website at (http://www.oakgroveobservatory.com/diy_allsky.shtml ). Here are instructions for how to build an all-sky camera using webcam for about $30. Now we’re talking about some serious penny pinching. This camera fits into a piece of PVC pipe, a front-door viewer peeks out the top, and one USB cable trails out the bottom. It’s weather proof, rugged as heck, and if you can keep the USB run short, very penny-pinching.
Sadly, the camera he used, the Quickcam 4000 Pro is no longer available so cheaply. I found one for $40 used. And the follow on cameras aren’t as light sensitive. Oak Grove notes that the Quickcam 3000 and QC zoom will also work but you may have trouble with the drivers. These cameras can be found fairly cheaply on Amazon.
One key point I will emphasize is the need for a webcam with focusing threads. If the camera is a fixed-focus, you will not be able to adjust to get the image in focus. An auto-focus webcam will not work for this purpose.
Capture software is another post. I’m still working on this. It seems there are several dedicated meteor detection programs available, as well as motion detection and capture programs like SupervisionCam available for free.
So far I've had limited success. The resolution of the low end cameras is poor, and the light sensitivity is low, even those that have very low lux ratings. Also some are rated 0 lux, but assume you'll have some sort of infrared lighting.
I did succeed in modifying a 'dummy' security camera dome to take a camera. The plastic dome and base cost $4. I had to purchase a 50 foot extension camera cable, which cost $8 and had two wires, one with BNC ends and one for power. The power cable fit, but the BNC required an adapter, BNC to RCA. That was another $4.
Still experimenting. Photos to follow.
