A while back I tried using an imaging source camera to detect meteors. It's never been designed for this and it turned out to be be pretty much useless compared to the trusty 902's.
However on the SonotaCo forum one of the well know continental observers Matej Korec posted about tests done with a QHY guiding camera. These show some promise although there are driver issues. If these can be resolved at £200 it could be a useful tool!
I'm keen to move to a smaller pixel size to try and improve my spectroscopic resolution but this comes at surface area/quantum efficiency cost.
Has anyone else tried different cameras for video type observing?
It may be worth speaking to Dominic Ford at the BAA Meeting in Birmingham this weekend (hopefully he'll be there) ... I had an email from him a few weeks ago regarding some cameras that he has tried in back-to-back tests with the Watec 902 series cameras. Pixel size will be comparable to the Watecs though (if they are any good) the price is attractive.
What is the requirements for a camera to use for spectroscopy Bill? What minimum frame rate or exposure do you need to use or can you use sensup and longer exposures? I understand the need for sensitivity and a good resolution, but when the pixels get smaller, the resolution may be better, but the camera is generally less sensitivity for the same size chip. There are many cams out there with good resolution and very usable with long integration times for deep space objects, but they fail miserably for meteor work at 25fps.
The requirements? To have both tiny pixels and huge pixels at the same time! ;-) I built a ccd camera in the mid 90's and as soon as you start assembling the components you realise everything is a compromise between competeing parameters. Especially if you start trying to tweak it. From my experience, 10-15 fps with the small corresponding increase in exposure time but with the smaller pixel size MIGHT be a step in the right direction. Matej's example videos do show promise. The perseid fireball I captured 3 years ago is the only event I've seen where I'd like to have had a higher frame rate to capture a really fast change in spectrum. Everything else has been fairly sedate (so far!). I might cough up and get one to experiment with myself. No doubt these things will come up on Saturday. Looking forward to the meeting.
I have a QHY5L-II-M camera that I've been using this year to obtain differential photometry of PHEMUs (Mutual PHEnomena of the Jovian satellites' eclipses and occultations.)
It uses a 1/3rd-inch format CMOS sensor with 14-bit (I think) digital output via USB cable. I use FireCapture software. Its maximum pixel setting is 1280x1024.
It came bundled with a C/CS-mount adaptor ring and a couple of 1/3d-inch format lenses, a 1.25mm fish-eye lens and an 8mm f/1.0 lens as well as other accessories. With the adaptor ring it takes my other video lenses, such as 12mm f/1.2.
I haven't had any joy yet getting it to talk to UFO Capture, but I'll look into it this summer. As SonotaCo mentioned, the appropriate drivers are required.
In UFO Capture I then selected this native QHY WDM video option, chose the Intel IYUV codec, read in the PF640x480N.ufi then set the exposure time to 40ms and maximum gain.
The UFO Capture Preview screen only refreshes once a minute or so using this driver and camera. (I used FireCapture to focus the lens and to align on Vega.)
UFO Capture locked up occasionally, although I managed to record a test video using the camera's 1/3rd-inch 8mm f/1.0 lens. The lim mag didn't go very deep, but see the attached pic from a recording of Vega rising.
I'm quite happy using my Watecs for meteor work, but this has been an interesting exercise. More tests needed.
Hi, Thanks for the info. I get the feeling it might not be a viable option to use UFO for this particular camera. Running it at even lower resolution seems to defeat the purpose! The strategy descibed by the Polish Fireball Network guys may be the best bet at the moment. For my purposes it might very well have some advantages but the 910 will take some beating for ease of use and overall performance!
My QHY5 arrived and it a blinding epiphany It occured to me we might be looking at this from the wrong angle. The native WDM driver will be outputting whatever it's outputting in a size that UFO capture will not be looking for. I think that's whats hanging it up. The driver is conflicting with the max input of the normal version. That might well be complete nonsense as I'm not a computing expert.
BUT UFO capture HD does have these pixel counts. Downloaded the HD trial, set up the camera and viola! It picks up the camera, plays the video feed and records and replays seemingly OK. However the preview seems a bit "jumpy" and the slow frame rate is really obvious in the playback. My laser pointer in the garden was really hopping around frame to frame.
I'll need to have a play with UFO HD and see how it behaves. It's got potential so roll on the Perseids when it starts to get dark again :-)
Yep, the hefty license fee is a bit of a deterrant but those 30 minutes soon evaporate. This might be indicating other driver problems or just a slow drive, I don't know, but it takes a good minute to go from a standing start to detecting. If it's timing from the off then time is disappearing, also it takes ~15 seconds to go from recording back to detecting, again more time when the clock is running. I'm probably close to the limit already in just an hour of basic tests. The other issue is that even ~ 12 - 15 fps the playback seems to be fixed at 25fps so the playback looks seriously speeded up. There may be settings for this but I haven't got that far yet! Under the "set" button the qhy camera controls for gain and exposure appear and can be adjusted so if it produces a comparable star field to the 910 then I will be very impressed but we'll see....
With a clean installation (XP SP3) on an old dell 780 (3Gnz, dual core) I can get 15fps to run normally (-ish) with UFO HD. (Must be close to chop off!) It does seem to have a need for particular operations to be done in a particular order though, not quite turn-key like the PAL video systems. By way of an experiment I stuck the trusty 12mm f1.2 onto the qhy5. attached the 830g/mm grating and used a compact flourescent lamp as the source.
This is the result.
It's a bit chunky due to using a 25mm mirror to reflect the light into the camera so it's a very wide source. The effective resolution is therefore very low in this example. However the dispersion measured across the length of wavelength span is down to 0.6nm/pix. This is where it starts to get a bit more interesting.
By way of a comparison this is a picture I dragged off of the the net.
Good to see the laws of physics in action, the spectra are more or less identical, mercury is mercury anywhere!