In a previous life I was a variable star observer, mostly with binoculars. I observed eclipsing binaries, cepheids and long period 'Mira type' stars. One of the techniques that I used often was to compare the surface brightness of the out of focus disks of stars. It should be possible to do the same with the tether. This would not necessarily give the same results as photometric or CCD measurements, but a comparison of the surface brightness of the out of focus tether with the surface brightness of equally out of focus reference star images would probably give reproducible results that would at least be quantified. One pitfall of this method is that it is sensitive to the colors of stars so it would be best to use reference stars that are about the same color as each other, and if possible the tether. To do this right would require that all observers use the same reference star series. I will take a crack at this if I get another look at the tether. Stephen SThompson@esiusa.com