Earthshine blog

Earthshine blog

"Earthshine blog"

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

PSF estimated from Markab compared to Dragonfly paper's

Exploring the PSFPosted by Peter Thejll Mar 15, 2014 09:21AM
In this post below we compared our canonical PSF (raised to various power) to the PSF shown in Figure 6 of the AvD paper.

We have since re-estimated /below) our PSF from radii near 0.1 arc minutes to 13 arcminutes using excellent data from multiple images of the star MARKAB. This PSF is empirical for one specific night and does not need the raising-to-a-power that the canonical one does. We plot it as is on the AvD figur, trying now to re-create the twopanels of that Figure:

Right panel shows our PSF as surface brightness in magnitudes per area.

I'd say our empirical PSF (green line) looks like it is realistically modelled by the canonical one raised to 1.8 and still beats the AvD PSF (the crosses).

We extended our PSF beyond 13 arcminutes by a third order power-law.

We have assumed a few things: AvD speak of normalized flux - we take this to imply that the PSF is divided by its VOLUME, not its area. We assume that calculating the surface brightness involves taking the total flux inside some distance from the peak and dividing it by the area.





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