[Aavso-photometry] SSP-4 photometer available for loan

[Jeff Hopkins]

Hi Arne,

I think it's great the AAVSO has SSP-4 units to lend. This is an 
exciting area of photometer and before the SSP-4 was well out of 
reach of most smaller observatories.

As you mentioned using the SSP-4 is very different from CCD 
photometry and while somewhat similar even different from my single 
channel photon counting. The software that comes with the unit is 
good once you get to understand it. It does not reduce the data, only 
provides date, time and counts.

The SSP-4 seems ideal for the epsilon Aurigae project as there are 
very little data for the infrared during the eclipse. Continuous 
monitoring out of and during the eclipse may show some most 
interesting data and help decipher what they mysterious gigantic 
secondary object is.

When I purchased my SSP-4 I was determined to use it exclusively for 
epsilon Aurigae. I tried it on my C-8 with very disappointing 
results. While out-of-eclipse epsilon produced somewhat reasonable 
counts the comparison star lambda Aurigae was about the same as the 
sky. I found out later that Optec recommends at least a 10" scope.  I 
purchase a 12" LX200 GPS to use with it. While the counts were much 
better, the signal to noise was still not good for lambda. The system 
produce fair data, but I was not happy with it. I tried it on a 16" 
LX200 and it was much better. My recommendation for using the SSP-4 
on the epsilon Aurigae project is to use at least a 12" aperture with 
14" or 16" or greater preferable. Remember when epsilon goes into 
eclipse the counts will drop dramatically.

Anyone wishing more information on the SSP-4 cans see 
http://www.hposoft.com/Astro/IR.html

Anyone interested in the epsilon Aurigae campaign please drop me an e-mail.

Jeff


At 07:16 -0700 02/17/2008, arne wrote:
>The AAVSO has five Optec SSP-4 near-infrared single-channel photometers
>that we load out to members who want to try something new and different,
>and at the same time support continued monitoring of stars in the NIR.
>
>These photometers look identical to an SSP-3; very compact, simple
>devices.  They come with two filters: J (1.25micron) and H (1.65micron).
>Simple software gets the data into your computer, and the AAVSO HQ
>PEP software can process the raw data for you.  Very simple!
>
>At the same time, the simplicity means that you have to handle this
>device manually.  There is a flip mirror for acquisition and centering
>using an eyepiece; and a two-position filter slide that you have to
>move manually.  In other words, without modification, this is a system
>where you have to be at the telescope.  You cannot work very faint, but
>most Mira and LPV stars are very bright in the NIR, so this means the
>majority of your targets will be red variables.  Like other PEP measurements,
>it will take you 15minutes to an hour per object to acquire one datapoint,
>again not a problem with long period variables, but meaning that you won't
>observe too many stars on any given night.  It is also a device that
>requires photometric skies since you have to physically move the telescope
>to the comp star as this is a single-channel system.  However, you
>don't need good seeing, and light-polluted skies are usually no problem.
>
>However, it is simple to use, and requires very little computer skill to
>operate.  We currently have a varied program of objects, but the primary
>goal was to support the long-term monitoring of Miras that Patricia
>Whitelock was doing from South Africa.  As more professional telescopes
>switch over to NIR array detectors, the brighter stars become more and
>more neglected.  The initial observations targeted a variety of stars
>to see where the systems would be effective, but we will be giving
>a more definitive program for the SSP-4 systems in the near future.
>Also, there will be campaigns like the upcoming epsilon
>Aurigae eclipse, where NIR observations will be extremely important.
>
>These systems are given out on long-term loan to members.  We ask only
>that you use them for AAVSO projects, maybe not every night, but often
>enough that they don't gather dust.  We have two that are available for
>immediate loan: one in the northern hemisphere, and one in the southern
>hemisphere (with priority for Australia).  If you think you might be
>interested in either system, email me privately.  Note that, while I
>say they are loaned to members, you can easily join the AAVSO these days,
>and the price of membership is far less than the US$3000 cost of the SSP-4!
>Arne

-- 
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