Camera test
| WAT-902H2 Ultimate | KPC-350BH PC164C | KPC-650BH PC164-EX |
|
|---|---|---|---|
| Signal Format | CCIR | EIA | EIA |
| Image sensor | 1/2" B/W EXview HAD CCD | 1/3" B/W Sony Super HAD exView CCD | 1/3" B/W Sony Hi Res Super HAD exView CCD |
| Type de capteur | ICX254AL | ICX258AL | |
| Pixels effectif | 752(H) x 582(V) 440k | 510(H) x 492(V) 250k | 768(H) x 494(V) 380k |
| Unit cell size | 8.6µm(H) x 8.3 µm(V) | 9.6µm (H) × 7.5µm (V) | 6.35µm (H) × 7.4µm (V) |
| Horizontal resolution (TVL) | 570 TVL | 420 TVL | 600 TVL |
| Sensitivity | 0.0001 lux | 0.0003 lux | 0.003 lux |
| Electronic Shutter | 1/50 | 1/60 | 1/60 |
The data above come from technical referencesWAT-902H2 Ultimate , KPC-350BH et KPC-650BH
I check this web site for KT&C and supercircuits camera http://www.prc68.com/I/KPC350.shtml
You have all the details on the Watec 902H2 and a comparison with the Watec 120N on this excellent web sitehttp://www.kolumbus.fi/oh5iy/astro/Ccd.html
I made the video recordings one after another by a clear night, no moon, far from lighting pollution.
Cameras were mount by Fujinon YV2.7x2.9LR4D-SA2L lens.
-VariFocal Length (mm) 2.9 ~ 8(2.7x).
-Maximum iris aperture F0.95
The field of view for each around 45°, corresponding to a focal length of 8 mm sensor 1/2" and 6 mm sensor 1/3"
For the recording I use USB Dazzle DVC90 video capture device and UFOCapture software (which is very useful even in a simple registration)
- PAL (CCIR for black and white) the maximum recording resolution is 720(H) x 576(V). Notice it gives a distorted analogic video (video in 5/4 bent into 4/3).So we record it in 704 (H) x 528 (V) but we loose a little bite resolution or after resize it in 768 x 576.
Video format is 25 fps
- NTSC (EAI for black and white) the maximum recording resolution is 720(H) x 480(V). Video is also distorded. So it can directly records in 640 x 480 which is very correct with the KPC-350BH (or PC164C) or after resize the video in 720 x 540.
The rate for NTSC is 29.97 fps
Detail on UFOCapture guide (heading: Step 7 Previewing test)
Sensitivity
Capture Settings:
(The Watec ellectronics settings are Gamma OFF and AGC Lo to have a signal noise ratio comparable to KT&C)
How you can see, the limit stellar magnitude is the same for the three selected images: 3.8. It's not really good to estimate the sensitivity of the cameras. Par contre sur les films on voit que la WATEC 902H2U et la KPC-350BH sont au coude à coude et la KPC650BH en deça des deux autres. However on the films we see WATEC 902H2U and KPC-350BH are neck and neck and KPC650BH below two other.
Here the difference of sensitivity is more visible. For example, a few degrees below Alkaid, we note stars are not visible with the KPC-650BH while they are for the other two cameras.
By comparing composite image WATEC 902H2U-and KPC-350BH, we can see that magnitude limit of visible stars is the same. We might think a slight edge in brightness for the KPC-350BH, but my view,it's due to lower resolution which makes the stars appear less ad hoc on integrated image, therefore more visible.
Movies: 5 seconds of each record, not encoded, in native format. (Although the files are compressed in zip, they are heavy)
First KPC-650BH, on the internet some sellers posting a sensitivity 0.0003lux and others 0.003lux. Considering the tests, we may conclude that it is less sensitive than the KPC-350BH and I suspect a 0 voluntary to lure buyers...
Between WATEC 902H2U and KPC-350BH (PC164C): For me these two cameras have equivalent sensitivity. Of course the Watec have a better image resolution and allows advanced electronic settings, but for meteor detections is it worth the cost to pay 3 times more for a WATEC ($319 vs. $93 for KPC350BH)? (Knowing the CCD with time dead pixels appear...)
Up to you see according to your budget... ;-)
In any case, we can say for better resolution CCIR format is preferable to EIA (NTSC black and white) because NTSC is limited by 480 horizontal resolution while CCIR goes up to 576 pixels. It would be interesting to find KPC-350BH in CCIR format at the same price as EIA format. But I haven't found...