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Using a DSLR to Study Variable Stars. Canon 450D - linear over a magnitude using RAW images with a specific setting. Canon 85 mm fixed lens- can be used to do precise estimates down to magnitude 8 ( undriven ). Canon 200 mm fixed lens-
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Canon 450D - linear over a magnitude using RAW images with a specific setting
Canon 85 mm fixed lens- can be used to do precise estimates down to magnitude 8 ( undriven ).
Canon 200 mm fixed lens- can be used to do precise estimates down to magnitude 10 ( undriven ).
Precision PhotometryEye: +/- 0.1 mStandard DSLR Photometry: +/-0.03mPrecise DSLR Photometry:+/- 0.01m
Precision PhotometryThe right settings for the right signal to noise ratio (SNR -100)
Precision PhotometryEpsilon Aurigae & 85 mm lens:Exposure 5 secs,ISO 200, f5Exposure 5 secs, ISO 200, f4.5Exposure 5 secs:ISO 200. f4.
Precision PhotometryCentered target starsThe effect of windRemote SwitchCareful FocusLong ExposureDark Frames
Standard DSLR Photometry +/- 0.03m ten images analysed
200 mm lens - exposure 3.2 secs, f2.8, ISO 800 images every ten/fifteen minutes
85 mm lens, exp 5 secs, f3.5, ISO 800
Variations of 0.2/0.3 magnitude - a new world of variables
Precision DSLR Photometry +/- 0.01m thirty/ fifty images analysed
Estimates of the 20/2/10JD: 2455248.367Camera Settings with an 85 mm lens: Exposure-5 seconds, ISO 200, f4.5 sets of ten images:Analysed with AIP4WIN v2.1.10(1) 3.776V(2) 3.777V(3) 3.774V(4) 3.769V(5) 3.781VAverage = 3.775V Standard Deviation = 0.004
AIP4WIN - analysis of RAW images
Dark frames Flat Fields
Multi-image deep sky stacking procedure - 30 minutes to analyse 50 images
V Photometry Green Channel Images Transformation Co-efficient
Estimates of the 10/3/10JD: 2455266.327Camera Settings with an 85 mm lens: Exposure-5 seconds, ISO 200, f4.5 sets of ten images:Analysed with AIP4WIN v2.1.10(1) 3.769V(2) 3.760V(3) 3.776V(4) 3.764V(5) 3.758VAverage = 3.765V Standard Deviation = 0.007
DSLR Cameras - not as sensitive as CCD cameras because they are not cooled - but yield just as good results down to mag 10.5 desloughney@blueyonder.co.uk