[Aavso-photometry] UBV Photon Counting

[Jeff Hopkins]

Hello Richard,

I remember you. Good to hear from you. Indeed, it has been a long 
time. I put aside photometry for a while (a decade), but now my kids 
are grown and gone and I'm retired so I have lots of time. I started 
doing photometry again a couple of years ago.

I have tried the analog PMT route, but find the photon counting much 
better. The dead time has not been  a problem. I have done photon 
counting with 1.5 M stars with no problem. I have found it much more 
accurate and easier than the analog route. Maybe I'm just getting 
old, but there is something mystic, a connection with the quantum, 
when sitting there watching the photons come in real time. I'm taking 
the pulse of a distant star system.

I have a fairly complete list of bright variable stars (brighter than 
5 mag). See

http://www.hposoft.com/Astro/PEP/BVS/BVS.html

I recently completed several months of UBV observations of Algol. UBV 
light curves at

http://www.hposoft.com/Astro/PEP/algol.html

I did that mainly for fun, but it was an interesting project. Another 
one I have started on is beta Aurigae.

Dr, Robert Stencil (U of Denver) and I recently presented a poster 
paper on epsilon Aurigae at the recent AAS meeting in San Diego. The 
abstract is at

http://www.aas.org/publications/baas/v36n5/aas205/433.htm

We are gearing up for another epsilon Aurigae campaign. There is also 
interest in a similar star system, EE Cep, but that is 10/11 V mag 
and too faint for the Phoenix skies. It might be a good CCD project, 
but observations should include the U band.

Regarding the U band, there is much information that can be gleaned 
from a star system by observing what happens in the UV band.

I'm trying to get a hold of an SSP-4 photometer to do some J and H 
band work. That should be an interesting project. While not photon 
counting, it is single channel photometry.

I do hope there are still others out there counting photons.

Jeff


At 07:36 -0700 1/19/05, Richard Miles wrote:
>Jeff -  Long time no hear, welcome to the list and good to know that 
>you are well and still operational.
>
>You may be right about UBV photon counting and you the last left. 
>My last PMT observations were back in 1998 or so, the results from 
>which were published in December 2004!
>
>I am keeping my PMT photometers for old-time sake - they are also 
>the best detector for very bright stars, which you never know may be 
>all that's left over in the heavens as targets for we amateurs once 
>the telescopes like Pan-STARRS and LSST start up.  Like you say also 
>about the U-band, that is another avenue that PMTs work well in 
>compared to CCDs.
>
>>  FWIW, I recently has some problems with the tracking on my old 
>>orange C-8 and purchased a new Meade LX-90 just before Christmas 
>>while it was on sale. The LX-90 is a great telescope and I love the 
>>computer control, however when I replace the C-8 with the LX-90 and 
>>did some UBV photometry I was disappointed. The U band reading on 
>>the same star, same air mass under similar skies is about half that 
>>of the C-8.
>
>Could be a combination of things - more absorption by the corrector 
>plate glass, UV transmission suffering if multicoating is optimised 
>for the visible, etc.  Stay with the C-8.  I'm back to using my 
>24-year-old C-11 tube assembly, it's a great scope.
>
>>  I'd be interested in hearing from anyone who is doing UBV photon 
>>counting. I know equipment for that is hard to find, but really 
>>pretty easy to make. I designed and marketed a unit back in the 
>>1980's and have another design I have been toying with.
>>
>
>I remember it well - personally I went for DC amplification rather 
>than photon counting to avoid pulse pile-up problems with bright 
>objects.  The brightest comparison 'star' I once used was Saturn.
>
>Seriously - a key question is whether there could be certain 
>astronomical projects out there, where your UBV photometer has a 
>very distinct advantage over CCDs.  Not sure what the answer is??
>
>Best regards,
>Richard Miles

-- 
Jeff Hopkins
HPO SOFT
http://www.hposoft.com/Astro/astro.html

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