[Aavso-photometry] UBV Photon Counting

[Arne Henden]

Bessell has a U-band prescription that uses a Schott IR blocker,
reasonably effective for CCDs.  We use such a filter here
as CuSO4 is very difficult to work with (tends to break).
   I do a fair amount of U-band work, especially time series
on bright variables, but also calibration work for things
like GRBs.  You can do reasonably well with a CCD, with the
usual constraints of whether your telescope works well at
U and how well you can calibrate out the atmosphere.
Arne

Richard Miles wrote:
> Jeff,
> 
> Your UBV observations of BET PER and write up on your webpage at:
> 
> http://www.hposoft.com/Astro/PEP/algol.html
> 
> is most impressive and very enjoyable to read.  Well done.
> 
> Like you I started EPS AUR observtions in 1982 but unlike you I did not 
> think to keep measuring its out-of-eclipse characteristics ahead of the 
> next (2009) eclipse - nice paper on this.
> 
> I should be getting a filter wheel for my main scope later this year so 
> I shall have to make sure I get a U filter.  However I am very doubtful 
> of its efficacity because unlike the 1P21 phototube, the red leak will 
> really wreck the true U signal when measured by a CCD.  If I remember, 
> the advice was to include a copper sulphate window to block the IR side 
> - now there's a challenge!
> 
> I wonder if anyone else on this list is doing U photometry 
> (successfully) with a CCD camera?
> 
> Richard
> 
> 
> 
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