Earthshine blog

Earthshine blog

"Earthshine blog"

A blog about a system to determine terrestrial albedo by earthshine observations. Feasible thanks to sheer determination.

More on SKEs

Optical designPosted by Peter Thejll Jan 26, 2013 10:06AM
In this post: http://iloapp.thejll.com/blog/earthshine?Home&post=289
the importance of the SKE for scattered light was discussed. The images shown, though, were not shown fairly - with intensities scaled to comparable levels. I therefore extracted a line across the BBSO image and a line across our image, at right angles to the SKEs, rescaled the intensities, aligned the plots and get this:
The black curve is from our image (whichis a sum of 10 well-exposed images). The red curve shows the cut across a single BBSO image.The BBSO image has only the DS peeking our behind the SKE, while our image has the BS in full view.

We see entirely comparable 'halos'! The BBSO image ha a more pronounced sloping 'tail' onto the black side of the SKE than we do, and more noise. If that sloping tail is 'halo' we had a better system than the BBSO!

What does the above mean? It does NOT mean that we have less 'halo problems' than BBSO does - because the BBSO expose their DS so that the halo from the BS is not allowed to be formed. Yes there is a similar halo from the DS on their images as there is from the BS on our images - but the halo from our BS is very much stronger than their DS halo.

When the BS halo is small - i.e. near New Moon - we have minimal effect of the BS halo.


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