[Aavso-photometry] Chart Generator for EPS AUR

[Jeff Hopkins]

Hi Steve,

Epsilon Aurigae is a 3rd magnitude (V) star and pretty easy to find, 
right next to Capella and at the vertex of the triangle known as the 
kids. Lambda Aurigae is the normal comparison star. While there are 
other stars closer, they are too faint for CCD work in that if you 
stay linear with epsilon the comparison stars will be in the noise. 
For CCD photometry there are two major problems, the brightness and 
wide separation of program and comparison stars.

Bob Buchheim wrote an article for the SAS Vol. 5 Number 3 Newsletter 
titled "Getting Ready for Epsilon Aurigae." He indicated the problem 
with CCD photometry and the brightness of epsilon Aurigae. He 
suggested stopping down the telescope, but that does not solve the 
separation (around 5 degrees) of the program and comparison star.

At HPO we have investigate using a 50mm F/2.0 camera lens on a DSI 
Pro. Preliminary results are very encouraging. Both epsilon and 
lambda Aurigae fit in the image and by defocusing the image a bit 
under sampling is solved. Several nights have produce BVRI data where 
3 sets were 0.01 magnitude or between data spread. I'm in the process 
of writing up the procedure. While this is CCD filter photometry, it 
is very different from CCD photometry of fainter stars.

Of course the star system works best with single channel photometry. 
For more information check
http://www.hposoft.com/Campaign09.html

Jeff


At 18:26 -0700 01/21/2008, Steven Orlando wrote:
>Hello All!
>
>On the homepage, there was a call for data for EPS AUR. However, 
>when I go to  plot a chart I get no photometric start for my FOV.
>
>Anyone have a link to a star chart for this star?
>
>Steve
>_______________________________________________
>
>Aavso-photometry mailing list
>Aavso-photometry at mira.aavso.org
>http://www.aavso.org/mailman/listinfo/aavso-photometry

-- 
Jeff Hopkins
HPO SOFT
Counting Photons
http://www.hposoft.com/Astro/astro.html
Hopkins Phoenix Observatory
7812 West Clayton Drive
Phoenix, Arizona 85033-2439 U.S.A.
(623)849-5889
(623) 247-1190 (Fax)
www.hposoft.com