Video Camera Spectral Sensitivity Issues Hristo Pavlov IOTA, WSAAG, Tangra Observatory IOTA Annual Meeting 2012

All Video Cameras are Different WAT902HWAT120N+ PC164EX Flea3 (ICX414)

NGC 6716

Equipment 14 LX200 ACF + F/3.3 FR Flea3, WAT120N+, WAT920H, PC164EX2 AVer Grabber, VDub, HuffYuv & MPEG4 SLOAN Photometric Filters ADVS

Observing Sessions DateCameraStart UT End UT FilterZenith Angle AtmExt Max m 03 SepWAT120N11:1011:24Clear21°-24°0.01 m 21 SepFlea310:5311:07r'31°-34°0.01 m 21 SepFlea311:0911:20r35°-37°0.01 m 21 SepFlea311:3711:48Clear40°-43°0.02 m 04 OctWAT120N10:5911:14Clear43°-46°0.02 m 04 OctWAT902H11:2011:32Clear47°-50°0.02 m 04 OctPC164EX211:3911:45Clear50°-53°0.02 m

Data Reduction

Magnitude and Colour Fitting Mag = -2.5 * NonLinerityCoeff * Log10(I) + ColourCoeff * CatalogColour + ZeroPoint

g = -2.5*1.012*Log10 (Intensity) * (B-r) / r = -2.5*1.017*Log10 (Intensity) * (B-r) / WAT120N+ (Gamma = OFF) WAT902H (Gamma = OFF) g = -2.5*1.183*Log10 (Intensity) * (B-r) / r = -2.5*1.210*Log10 (Intensity) * (B-r) / g = -2.5*1.034*Log10 (Intensity) * (B-r) / r = -2.5*1.138*Log10 (Intensity) * (B-r) / PC164EX2 g = -2.5*0.928*Log10 (Intensity) * (B-r) / r = -2.5*0.927*Log10 (Intensity) * (B-r) / Flea3 (Gamma = OFF)

g - InstrumentalMag = * (B-V) + ZeroPoint +/ r - InstrumentalMag = * (B-V) + ZeroPoint +/ V - InstrumentalMag = * (B-V) + ZeroPoint +/ U3 - InstrumentalMag = * (B-V) + ZeroPoint +/ WAT120N+ WAT902H g - InstrumentalMag = * (B-V) + ZeroPoint +/ r - InstrumentalMag = * (B-V) + ZeroPoint +/ V - InstrumentalMag = * (B-V) + ZeroPoint +/ U3 - InstrumentalMag = * (B-V) + ZeroPoint +/ g - InstrumentalMag = * (B-V) + ZeroPoint +/ r - InstrumentalMag = * (B-V) + ZeroPoint +/ V - InstrumentalMag = * (B-V) + ZeroPoint +/ U3 - InstrumentalMag = * (B-V) + ZeroPoint +/ PC164EX2 g - InstrumentalMag = * (B-V) + ZeroPoint +/ r - InstrumentalMag = * (B-V) + ZeroPoint +/ V - InstrumentalMag = * (B-V) + ZeroPoint +/ U3 - InstrumentalMag = * (B-V) + ZeroPoint +/ Flea3 (ICX414) ( for B-V < 1.7)

Steve Preston Events

Partial Mag Drops Only – Asteroid Brighter than Mag 13

(774) Armor Occults TYC On 8 Aug 2013 Predicted Drop (1.28 m ) Observed Drop (0.69 m )

(1) Ceres Occults TYC On 04 Jun 2012

Conclusions Camera instrumental magnitudes can be very different than predicted V and R magnitudes To match camera measured magnitudes to V or R calibration is required Transformation colour coefficients can be determined experimentally for your camera and used to convert standard magnitudes to instrumental magnitudes and vice versa

QUESTIONS?