Optec SSP- 4

Data Acquisition Software Instructions

Introduction

With the introduction of the SSP- 4 photometer, the J and H infrared bands are now open to amateur photometry at a reasonable cost.

The infrared band begins at about 1.1 micron wavelength. The J filter covers the 1.25 micron band and the H filter the 1.65 micron band.

Figure 1
Spectral Response of J and H Filters

There are many stars that are very bright in the infrared region and of interest photometrically.

Design

The SSP- 4 is similar in external design to the Optec SSP-3 solid state photometer. The internal c components are very different, however. The most significant difference is the detector. In stead of a PIN diode the SSP-4 uses an Hamamatsu G5851 InGaAs photodiode. The InGaAs detector is thermoelectrically cooled to -40C within the detector. This makes cool down very fast as only the small detector needs to be cooled.

Figure 2
Spectral response of the Hamamatsu G5851 InGaAs photodiode

Figure 3
SSP-4 X-Ray Drawing

Operation

The SSP-4 can be operated manually via buttons on the unit and data read out on a four digit LED display. While manual operation takes a bit to get used to, it is not difficult to master. It is recommended that the unit be used with an external computer to take advantage of other features. Using the supplied data acquisition program the user can control the unit and record data automatically. The filter slide is still manual, however. There is no provision for automating changing of the filter. A big advantage o the computer use is the data range is increased significantly. In manual mode the maximum reading is 9999 counts. Using the computer interface the reading can be up to 65000 counts. This increases the dynamic range over six times.

Present Page Version as of 19 December 2006

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