SSP-4 Photometer Observation Report and Analysis #4 - Observations

In this report I present my initial observations with the SSP-4 and a 0.25 SCT through 17 June 2003. My observation technique is as follows:

1. Set gain =10, Detector temperature = -40 C, and integration time = 5 seconds. Set dark current greater than 100.
2. Eight observations with J filter of star
3. Three observations of sky with J filter
4. Eight observations with H filter of star
5. Three observations of the sky with H filter.
6. Next star and repeat steps 2-5.

In a typical observation session, each star is measured at least twice in each filter band. Each observation has been reduced with the Henden and Kaitchuck Astronomical Photometry Software For IBM-PC. This software takes into account color differences between the comparison stars and airmass differences.

Table 1 contains my first set of observations with the photometer. Each of the column headings is self explanatory except for the "Est Error" column. The error estimated by taking the standard deviation of the mean. Taking at least two observations per target and using two comparison stars results in at least four estimates of the target magnitude. The standard deviation of the mean of these multiple observations becomes the estimated error. All of the observations in table 1 have been submitted to the AAVSO or ALPO.

Table 1 - J and H Band Observations with the SSP-4

Notes:
1. k_j = 0.09, k_h = 0.07, = -.03, = 0.98
2. One observation per band only
3. k_j = 0.10, k_h = 0.07, = -.03, = 0.98

Table 2 - Catalog Magnitude for Stars in Table 1

Equations for differential photometry

Where

• J = J band magnitude in the standard system
• j = instrumental j band magnitude
• H = H band magnitude in the standard system
• h = instrumental h band magnitude
• k_h = principle extinction coefficient
• k_jh = principle extinction coefficient
• = transformation coefficient
• = transformation coefficient
• ZP_h = zero-point constant
• ZP_jh = zero-point constant
• x subscript denotes the unknown star
• c subscript denotes the comparison star