RPHOT Photometric Reduction Software

An Automated UBVRI Aperture Photometry Data
Acquisition and Reduction Software Package
for PC-Based Observatories

Important note - For 15 years, RPHOT has been exclusively distributed by Optec, Inc. As of Jan 21, 2005 the distribution of RPHOT has been transferred from Optec Inc. to Nolten Software, the designer.

RPHOT 3.0 is a command-line driven package. The data-acquisition module DTAK was designed around the SSP3CARD. The current version of the SSP photometer line connects directly to the serial port and does not use the SSP3CARD. Optec wrote their own data acquisition module- SSPDATAQ - which can be freely downloaded. Go to the Optec site and click on the link to their ftp server, then go to the "software" folder. For legacy users who still have the SSP3CARD version of the Optec photometers, the RPHOT data acquisition module is called DTAK. The RPHOT package still works well in modern WinPC's, with or without DTAK. The user brings up the command line window and executes RPHOT within this window.


RPHOT is the most comprehensive PC-based software package available for acquiring and reducing instrumental or Johnson/Cousins UBVRI photometry data with the SSP-3(A) / SSP-5(A) or any aperture photometer. RPHOT allows observers great flexibility in planning and modifying their nightly observing programs. RPHOT produces optimal reductions even from data containing missing filters or sky measurements, automatically. Virtually any mixture of variable star, asteroid, comet, or lunar occultation photometry can be accommodated, in all filter combinations. Each object can be reduced using either "all sky" or differential photometry methods, resulting in output text files suitable for direct submission for publication. Final plots may be sent to a wide range of supported printers, or to .PCX files suitable for processing with PC Paintbrush compatible software.

RPHOT users can...
* Manually or automatically log date, time, filter, counts, star name, gain scale, integration time, and comments while at the computer/telescope.

* Optec SSP photometer owners can additionally program a wide range of filter cyclings and any integration time from .01 second on up (for occultations), or any integer integration time (for variable stars).

* Edit or delete raw data during data acquisition.

* Optionally streamline data taking by first creating a file of the observing sequence.

* Switch back and forth between "slowmode" (for variable stars, comets, asteroids, etc.) and "fastmode" (for occultations).

* Do up to 400 ("slowmode") or 32000 ("fastmode") consecutive integrations per filter, with optional automated cycling through all filters in a filterset (SSP owners only).

* Plot raw or integrated counts vs. time for occultations, zooming in on the critical moments of the event, then sending the plot to a printer or .PCX file.

* Produce, store, and plot/print/.PCX the regression fits of first and/or second order extinction coefficients and/or transformation coefficients for U, V, U-B, B-V, V-R, and V-I, within minutes of ending observations.

* Produce a file of heliocentric UT dates, times, and standard UBVRI and/or instrumental and "clear" magnitudes and color indices for each object. Each object's file will be appended with succeeding nights of observations.

* Automate the reduction of one or a whole series of data files using command line argument batch files.

* Plot and print a light curve or periodogram of any star in any Johnson or instrumental color or color index, with any time window desired, including "folded" light curves for periodic variables. Also, the user can rapidly try different periods for suspected periodic variables and use optional parabolic fits to solve for the times of minimum / maximum light. Light curves can be least-squares best fit to polynomials up to order 19, or sinusoids.

Basic System Requirements:

* Any PC (not Mac) computer will work. Even the most primitive one still on duty in your backyard observatory. Version 1 was even been tested on the old original ~1980's IBM 8088.

* Wide range of printers supported including HP LaserJet and DeskJet, most 9 and 24 pin dot matrix, and all PostScript printers.

* For automated data acquisition: Optec Model SSP-3A/SSP-5A photometer or Model SSP-3/SSP-5 photometer and SSPCARD. For all other photometers, manual data logging is also possible, into RPHOT-format raw files.

* For all other functions: any photometer. However, raw data must first be put into RPHOT-compatible raw data files. Here is an example. It shows the data log for a session of differential photometry on the eclipsing binary AR Aurigae. Photometry developers who are interested in how to make photometry files in RPHOT format should contact me at the email address at the bottom of this page.

The RPHOT Package Includes:
* A comprehensive 75 page manual describing all RPHOT features, plus appendices showing how RPHOT works.
* All programs required for manual and automated data acquisition, reduction, plotting and printing.
* Drivers for PostScript, dot matrix, laser and ink jet printers, and all standard .PCX file formats.
* A simple shell environment from which the data acquisition and reduction programs may be run.
* Sample data and sample reductions.
* Star catalogs (text files in an easy to understand format) containing UBVRI data and coordinates for:
---- 49 bright B-V = V-R = 0 standard stars,
---- 75 bright first order extinction/transformation standard stars,
---- 42 bright red-blue pairs for second order extinction,
---- 60 bright RS CVn and eclipsing binary stars and their comparison stars.

* Utility programs for...
---- calculating airmass, given coordinates or any star name assigned to an RPHOT star catalog.
---- calculating the Julian Date and decimal given the UT date and time.
---- adding stars to any of the RPHOT star catalogs.
---- producing ephemerides of eclipsing (or other periodic) variables in compact, easy-to-read for, with user defined sun and star altitude observability criteria.
---- performing a graphic Jurkevich period search on any sequence of data in any filter, plotting the Jurkevich index vs. period to the screen, printer, and/or .PCX file.
---- cloning the reduced output files into Julian Date format and trimming out unused filters, for convenient reporting.
---- converting print files into high resolution binary files suitable for later printing, or
for sending directly to your printer or a .PCX file for PC Paintbrush compatible processing.

RPHOT Release 3.0
(c) 1991, 1999 Nolten Software, all rights reserved.

RPHOT is no longer supported or distributed as demand has dried up. Astrometrica is excellent software which is capable of photometric differential photometry.

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