wpo - Venus in daylight
1999 Oct 15: This set of hi-res spectra taken in about an hour this mid-morning
in full sunlight indicates that spectroscopy is not necessarily confined
to night-time. This is possible because the spectroscopic slit admits a
tiny sample of skylight. The spectrum covers the near IR [top - 'A'-band
head] to violet [bottom H+K lines] with overlaps between the frames. The
strong line in the 5th+6th frames is Ha [C line].
No processing applied except darkframe subtract and auto contrast stretch.
The individual spectra, which occupy only a small horizontal strip across
the imaging chip, were cropped under CCDOPS special 'spectroscopy crop'
option. The resultant file size per spectra is tiny at <20K.
Although purporting to be Venus' spectrum it is largely reflected sunlight
taken in slightly hazy sky conditions which reinforce the earth's atmospheric
oxygen + water-vapour lines mostly in the red/ near IR region. With careful
analysis it should be possible to subtract the lines due to sunlight etc.
[using the Moon's airless spectrum for example as a reference source] to
reveal the subtle lines or 'bands' due to CO2 - carbon dioxide etc. in
Venus' atmosphere. There is much that the amateur can probe with this spectrometer
when attached to regular backyard 'scopes.
return to main spectrometer page..
