Test of a recent unexpensive CMOS webcam for astronomy :

CMOS is 1280*1024 pixel (not interpolated)

Acquisition Astrosnap-Pro, processing Registax 4


20070204 : Sky was clear but seeing (NE wind, 20 km/h) was very poor... but the next days are going to be cloudy with rain and/or snow !


click on image for original 1280*1024 size.
This is for test, not much attention to éliminate artefacts in Registax 4 multipoint.

LX200 12", F=3m

Attention : some image will have this artefact and should be eliminated before stacking :



click on image for a non resized image (1280*1024 camera format, just a window saved).
The camera was set on "low light" mode (exposure is around .3s)

LX200 12", Televue 3x Barlow, F=9m

Attention : some image will have this artefact and should be eliminated before stacking :

SUN HAlpha (Coronado PST)

click on image for a full size image (1280*1024).

Coronado PST at focal plane, on a photographic pedestrial...

Attention : As guiding is manual and altazimutal, the Sun is moving fast in the field,
screws have to be turned every few seconds and this shows that this camera will give this kind of wave artefacts in similar cases
( frames should be eliminated before processing) :



Tonight's CONCLUSION :

On the plus side,

Sensor is "huge" compared with the famous Philips ToUCam, then FOV is BIG !

Resolution is impressive : true 1280*1024 pixels
This gives very detailled results on bright objects (Sun, Moon...),

There is a native "low light" mode with exposures up to about .3s
which eg. can turn Saturn into a bright but well defined blob when pushing the luminosity and gamma cursors, but can be adjusted also at will :

LX200 12", Televue 3x Barlow, F=9m

In general, there is a lot of efficient controls !
Also, another test should be done later with a better seeing !


On the minus side :

- moving object will give wavy artefacts, also some more or less colorfull lines may appear on some images,
- missing intermediate tones in very low light,
- sensitivy in normal mode is not enough for Hires on planets... Below a single image and a stack of 12 :

- depending on resolution choosen, acquisition speed is limited :
From 30 fps at 640*480, to 5 - 10 fps at full resolution
(in all cases, RGB scheme looks as uncompressed or very little compressed).
- also a powerfull PC is necessary (I got more 2fps than even 5fps in full size mode with AMD at 1.8Ghz!) and stability can be very annoying on slower PCs.