Morning twilight fireball - 19 Feb 10 - 06:36am

30 Jan 2010 Fireballs

These two clips are compressed down from 47.5 and 170Mb each. The quality has necessarily suffered a bit!

New PC Hardware

I have upgraded the capture PC to a 2.4GHz box that I rescued off a skip. After hosing out the insides and replacing the PSU, which had gone futt, it works perfectly. The postage on the new (second hand) PSU cost more than the PSU itself - a bargain!

New Capture Software

I've been using HandiAVI to watch the sky and capture bolide and meteor events, and it has worked well up to a point. The problem with HandiAVI is that it can not discriminate between the bright flash of a meteor and a bright cloud moving across the sky. The result was that although it would successfully capture meteors and bolides burning up in the atmosphere... it also recorded Gigabytes of nice fluffy clouds drifting across the night sky. Not ideal.

So... out with the excrable HandiAVI and in (on a trial basis) with SonotoCo's UFO-Capture and UFO-Analyse suite. I've been running this since the beginning of 2010 and so far, so good. UFO-Capture seems to do an excellent job of ignoring clouds and aircraft... though I notice that it also seems to ignore every Iridium flare, which makes me wonder if it's missing some meteor/bolide events. Some fine tuning is in order, me thinks. The only down-side I see with the new software is that after 30 days you have to cough up around €150 for a single-user licence. Needs must, I guess.

Frame Grabber Upgrade

Unhappy with the results I was getting with the Hauppauge WinTV cards I had, I picked up a Canopus ADVC110 audio/video converter box. The Canopus box is capable of delivering much higher resolution (720 x 480 @ 30fps) than the Hauppauge card's miserable 352 x 288. The difference in image quality was immediately and strikingly obvious - a big improvement!

The Sentinel camera feeds in a composite video NTSC signal to the Canopus which converts it on the fly and outputs the video stream to the PC/laptop via a 1394-FireWire connection. My laptop already has firewire but none of my desktop PCs had it so I picked up a four port PCI FireWire card on eBay for around $8 + postage.

Here's how the sky looks using the Hauppauge frame grabber:

and here's how it looks with the Canopus ADVC110 box:

If a fireball or other transient event is captured, a section of the avi movie can be run through Registax, aligned and stacked for a cleaner all-sky image:

Using a planetarium program, like TheSky6, an all-sky view of the heavens can be generated to identify bright stars, constellations and planets visible at the time of the bolide capture or transient event.

Then using PaintShop Pro or another similar graphics package, the cleaned up image from the camera and the image from TheSky can be overlaid on each other as separate layers. By altering the opacity of the top layer it is possible to see TheSky6 image nicely blending in to the real sky image from the camera.

Using TheSky6 all-sky map also helps to identify and eliminate hot pixels in the camera that might otherwise be mistaken for bright stars.

Frame Grabber Resolution Problems

I am using a Hauppauge WinTV GO Plus card as a frame grabber. Unfortunately this card is only capable of half PAL resolution at best (according to Hauppauge) so I am not getting the best resolution that the camera is capable of.

Here's an example of what my setup is achieving with the Hauppauge card:

Above: Night time image with nearly full moon.

and here's what the camera is capable of:


The image above is from a similar HB-710E camera setup at the University of Saskatoon. As you can see there is much less noise and much better resolution! Me thinks the Hauppauge card is destined for the bin!

The Ochra South Observatory

Visit The Ochra North Observatory here.

The Ochra South Observatory consists of a Sandia Bolide Detection Camera and propriatry Sentinel software running under Linux. I am deeply grateful to Dr. Richard Spalding of Sandia National Laboratories USA for providing the camera and software free of charge.

The camera unit itself is a Sony HB-710E super low lux (0.0005 lux) 1/2" B&W 768x494 pixel CCD with a Rainbow L163VDC4P fisheye lens with a 180 degree field of view. The camera assembly is mounted in a 6" diameter heavy duty plastic pipe with a clear perspex dome. The camera housing also contains a power supply, a thermostatically controlled heating element and fan to prevent the perspex dome fogging up. With the addition of a couple of plywood flanges the camera unit can be mounted inside a disused chimney pot with power and signal cables running down the flue to the room below.

NB - these photos are by Jeff Brower of his Sentinel camera in BC... as I forgot to take any shots of mine before putting it up on the roof! However, mine is exactly the same

A Hauppauge WinTV Go Plus PCI card is used as a frame grabber to convert the analogue camera signal into a digital image. The original Sentinel software package that came with the Sandia Bolide Detection Camera runs under Linux, and although it works, it has its limitations. It requires a dedicated Linux box to monitor the camera, and at present is unable to compress the captured movie files. This results in the hard disk filling up very quickly with multi-megabyte and occasionally gigabyte files.

I am experementing with using a Windows based package called HandiAVI which is capable of capturing both meteor/bolide events and time-lapse movies simultaneously from the same camera input. This can be very useful if, like me, you wish to monitor local light pollution and sky glow as well as capture bolide events at the same time. I am working closely with the developer of HandiAVI to improve the functionality of the software. I am running HandiAVI on an old Pentium II laptop under Windows 2000, which is more power efficient than running it on a desktop PC.

The laptop is used solely as a capture device, with a Hauppauge WinTV USB device to create standard avi movie files, which are compressed on the fly by HandiAVI. Each morning the resulting avi file for the previous night is downloaded onto my main laptop via the houses' internal network and analysed using another function of HandiAVI. Bolide events can be analysed frame by frame to examint the exact time and point of appearance, direction and duration.

The resulting AVI video files are then grabbed, via the internal house network, onto my main laptop for analysis and storage. With this setup it should be possible to capture not just bright fireballs and bolides, but also dimmer shooting stars, Iridium flares, the ISS/Shuttle and any other transitory phenomena in the sky. Time lapse photography is also possible, and I hope to also adapt the bolide camera to detect cloud cover, sky glow from light pollution and general sky conditions.

Getting the camera into the chimney pot was a life threatening experience! With a precipitous drop on either side, I had to shimmy along the ridge tiles on my very tall roof, risking serious damage to the Crown Jewels! The north side of the roof was slick with moisture and algae making a fall totally unstoppable if I slipped! Scary monsters!!

I will post up interesting bolide events on this site as I capture them.

Watch this space!