- #1
Patrick Watson
- 4
- 0
I am currently capturing and analyzing spectra. My analysis software includes allowances for Doppler shifts resulting from relative radial motion between source and observer, and also Earth’s rotation. Results are accurate .
The basic introduction to the Doppler effect generally starts with waves in water with a static and then a moving wave generator which very clearly shows wave length changes.
Sound waves – similar demonstrations with sirens etc,. – also very clear effect.
When it comes to light I have a ‘blind spot’.
Using the example of an Hα photon (say 6563 Å) emitted from a hydrogen atom (keep it simple - nearby star, ignoring Earth’s rotation).
Situation 1:
No relative radial motion. Photon measured by observer at 6563 Å.
Situation 2:
Source ‘static’, observer moves towards or away from approaching photon. Observer measures blue or red shift.
Situation 3:
Source moves towards ‘static’ observer. Here I need HELP. This photon, once emitted, is traveling at the speed of light – this being independent of the motion of the source. I am currently unable to see how the beginning wavelength would be measured differently by the observer.
Regards,
Patrick.
The basic introduction to the Doppler effect generally starts with waves in water with a static and then a moving wave generator which very clearly shows wave length changes.
Sound waves – similar demonstrations with sirens etc,. – also very clear effect.
When it comes to light I have a ‘blind spot’.
Using the example of an Hα photon (say 6563 Å) emitted from a hydrogen atom (keep it simple - nearby star, ignoring Earth’s rotation).
Situation 1:
No relative radial motion. Photon measured by observer at 6563 Å.
Situation 2:
Source ‘static’, observer moves towards or away from approaching photon. Observer measures blue or red shift.
Situation 3:
Source moves towards ‘static’ observer. Here I need HELP. This photon, once emitted, is traveling at the speed of light – this being independent of the motion of the source. I am currently unable to see how the beginning wavelength would be measured differently by the observer.
Regards,
Patrick.