There are very few commercial units available today. Those that are available are expensive. Typically they sell for $2,000 or more with filters. Of course by buying a commercial unit you will be ready to start photometry as soon as you have unpacked and mounted the photometer head.
OPTEC SSP-5 Photometer
Currently Optec, Inc. is the only company offering complete photometers. Figure 5 shows the OPTEC SSP-5 photomultiplier tube photometer. This a self contained unit with 4 digit LED display. It should be noted that the unit is not a photon counting unit, but an analog system that used a voltage-to-frequency converter. The output pulses (from a voltage-to-frequency converter, not pulses directly from the photomultiplier tube) can be interfaced externally. The unit is powered by an external DC power supply using 117VAC or 220 VAC. Base cost is $1,800. To that must be added the cost of the photomultiplier tube and filter slide and set which can raise the price close to $3,000 or more.
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| Figure 5 OPTEC Model SSP-5 Photometer |
OPTEC SSP-7 Photometer
The Model SSP-7 is $9,900 and while it comes with the photomultiplier tube, the filters are extra. The Model SSP-7 has some nice features, e.g., a cooled photomultiplier assembly and headed optic and electronics area. Like the Model SSP-5, the SSP-7 uses an analog output with a voltage-to-frequency converter and is not a photon counting system.
Figure 6 shows a photo of the Model SSP-7 Precision Photometer mounted on Meade 10" LX-200 Schmidt-Cassegrain Telescope.
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| Figure 6 OPTEC Model SSP-7 Photometer |
For more information on these units see http://www.optecinc.com
EMI Gencom STARLIGHT-1
The EMI Gencom STARLIGHT-1 Photon Counting Stellar Photometer comes in two parts, the photometer head and the counter. The photometer head uses an end-window EMI 9924A photomultiplier tube. The head contains an amplifier and pulse conditioner as well as high voltage power supply. This unit is no longer commercially available. Figure 7 show a picture of a STARLIGHT-1.
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| Figure 7 EMI Gencom STARLIGHT-1 Photometer |