[Aavso-photometry] DSI Wide

[Jeff Hopkins]

As a follow up I will be attempting some BVRI photometry tonight with 
a DSI Pro (w/filter slide), Mogg adapter and telephoto camera lens.

My goal is to check feasibility of this to get quality data for 
epsilon Aurigae (V - 3.00) and comparison star lambda 5 degrees 
away). Preliminary tests show epsilon and lambda Aurigae easily in 
the same image and around 65,000 counts for epsilon with a 15 second 
exposure (just an IR blocking filter). I am working with Bob Stencel 
to try to set up some techniques for people to do quality photometry 
on epsilon Aurigae before the start of the eclipse in the summer of 
2009, during and after. This is an ideal project for single channel 
photometry (PMT photon counting/analog and solid state, e.g., using 
an SSP-3). Because most now seem to think you  MUST use a CCD and 
since some CCD cameras are very reasonably priced now, a technique 
using the CCD camera would be great.

Tonight I try the BVRI filters with the above arrangement and 
determine exposure times. I plan to get three images with each filter 
and do a SD on the reduced magnitudes to get an idea how well this 
technique works.

I will be posting this project and the results on my web site 
shortly. Wish me luck.

Jeff

At 14:01 -0700 12/22/2007, Keith Robinson wrote:
>Hello All and all the best for the season from England
>
>My interest in the DSI wide was really as a Christmas present for my wife
>who likes doing the pretty picture thing (I'll stick with our 8inch
>Newtonian for photometry). Following Jeff Hopkins advice I've now ordered a
>Mogg adaptor for use with Olympus lenses; my wife has an OM 10 with a
>variety of lenses so it's a case of not having these go to waste.
>
>On removing the nose piece from the DSI Pro the thread on the filter cage is
>indeed Pentax 42mm compatible but yes you do also need an extension tube in
>addition to get the focus.
>
>Anyway hopefully the Mogg adaptor will do the job but it'll have to serve as
>a birthday present instead.
>
>Best regards
>
>Keith

-- 
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
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