(meteorobs) OT -Question to the UFOCaptureV2. -PAUL PUGH et.al.,

Francisco Ocaña albireo3000 at yahoo.es
Fri Aug 28 13:44:02 EDT 2009


Larry wrote:
> This 
> starting position is excellent for meteor radiants and total meteor counts 
> using the "T" image....but not magnitude. The .avi's are flawless.
Well the UfoAnalyzer tool allows you to determine the magnitude of each 
event. This is not easy because you never have more than 20-30 
references, most of them saturated or undersampled. Remember that most 
of our CCTV cameras have a very tiny dinamic range (30 - 45 dB). If the 
fireball is within this range (it does not saturate), UfoA may be able 
to determine "accurately" its magnitude. However brighter events are 
always wrong estimated.
> (I believe) great care must be excersized on Scintillation Mask and Frame 
> shift settings. Both can cause clipping on leading edges & trailing edges of 
> a meteors weaker ablation. I understand that frame shift value determines 
> how far back in the frames UFO looks in determining a trigger or ending a 
> triggered .avi.... (IF) Head & Tail are short values. I will continue to use 
> 30 (1 second) on both and examine that function more closely later.
30 is ok, but 60 will be too (if you don´t have RAM or HDD 
resctrictions. Stacking 120 frames will give you more reference stars ( 
I think if you double the time you get 0,75 magnitude deeper).
> I will NEVER use Slow Object masking. I need the plane trails and also will 
> not risk losing any part of slower fireballs. Another area of further 
> investigation....
Never say never, jeje. I use plane trails to confirm it works, however 
the slowest ever fireball will be faster than 80% of the planes. I have 
everyday 15-20 planes crossing the field for more than 25 seconds. That 
means 400 seconds or almost 2 Gb of planes.  How do you manage them?
> UFO  uses the same model card without these defects.
And about Frame Grabber Cards... which do you (and other UfoCapture 
users) use? I use a chip USB one, and I want to upgrade to a PCI one. 
Any ideas?



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