Using a DSLR to Study Variable Stars
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Transcript of Using a DSLR to Study Variable Stars
Using a DSLR to Study Variable Stars
Canon 450D - linear over a magnitudeusing 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 Photometry
Eye: +/- 0.1 mStandard DSLR Photometry:
+/-0.03mPrecise DSLR Photometry:
+/- 0.01m
Precision Photometry
The 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 Photometry
Centered target starsThe effect of wind
Remote 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
200 mm lens - exposure 2.5 secs, f2.8, 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: 2455248.367
Camera 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) 3.781V
Average = 3.775V Standard Deviation = 0.004
AIP4WIN - analysis ofRAW images
Dark framesFlat Fields
Multi-image deep sky stacking procedure - 30
minutes to analyse 50 images
V PhotometryGreen Channel Images
Transformation Co-efficient
Estimates of the 10/3/10JD: 2455266.327
Camera 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) 3.758V
Average = 3.765V Standard Deviation = 0.007
Deciphering Epsilon Aurigae
Presentation of estimates
DSLR Cameras - not as sensitive as CCD cameras
because they are not cooled -but yield just as good results
down to mag 10.5