Björn said, "If I remember correctly, my five year old Sony Hi-8 has a rating of 0.7 lux in normal mode." The 4 Lux for my camera sounded too high to me too. I got it from the technical specifications. Like Willie said the 0 Lux means that the built in infrared light makes it possible to shoot in total darkness (up to a couple meters anyway). I plan to try to adapt my video camera to my night vision scope. That may get down to magnitude +8 or so. Tom Iowa USA ----- Original Message ----- From: "Björn Gimle" <b_gimle@algonet.se> To: "Tom Wagner" <sciteach@mchsi.com>; <SeeSat-L@satobs.org> Cc: "Astronomer" <Astronomer@yahoogroups.com> Sent: Wednesday, June 04, 2003 4:03 AM Subject: Re: the mag the Sony 4 lux camera is capable of seeing One number doesn't confuse me - Magnitude is 2.5 * 10-LOG(Brightness) Or Brightness = 2.512^Magnitude LOG(100)=2, so 100* = 5 mag 2.5*LOG(16) = 3.01 2.512*2.512*2.512=15.85 But lux ratings do: If I remember correctly, my five year old Sony Hi-8, which my children now use, has a rating of 0.7 lux in normal mode (there is no NightShot) and at max optical zoom (12*?) I got ten stars in the Pleiades, and at least three Jovian moons. Since then, most cameras boast "0 lux"! (<0.5?) An article in S&T Feb-2003 compares Meade Electronic Eyepiece ($70, no lux rating), PC164C ($130, 0.0003 lux), PC165C ($230, 0.05 lux) and StellaCam-EX ($700, 0.005-0.000005!) - and uses different scopes, different subjects and different exposures to compare (!) some results. Rainer Kracht uses an integrating Mintron 12V1C-EX and lens f=75mm f/1.3 to get satellites down to +12. Greg Roberts' 1004x gives him satellites down to +8.3 with 0.003 lux and an 82 mm f/1.6 lens. Several messages on SeeSat-L (and DSat). With 11-inch scope and 0.0003 lux, S&T only got to mag +10 /Björn ----- Original Message ----- From: "Tom Wagner" ... > etc. I did some starlight magnitude tests with my Sony digital video camera > [DCR TRV 340]. Following are the results. > > The lens setting was 50 mm, F 2.4 at 20X magnification. > The imaging device is a 1/6", 460K gross pixels CCD. > The video was actually 290K Pixels. > The minimum illumination capable of being perceived is 4 Lux > Using the so-called "NightShot" mode I could barely see a star that was mag. > +3. > Using the "Super NightShot" mode I could barely see a star that was mag. +6. ... > According to Sony the Super NightShot mode is about 16 times brighter than > straight NightShot. > > Now can someone tell me how 16 times correlates to 3 magnitudes in > brightness? > ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html ----------------------------------------------------------------- To unsubscribe from SeeSat-L, send a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@satobs.org List archived at http://www.satobs.org/seesat/seesatindex.html
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