Class Project
The class project involves the reduction of several nights worth of data from the CTIO 0.9m telescope on an X-ray binary: RX J0925.7-4758. You are required to take the data and reduce it using all the steps we have studied in class, understanding why each step needs to be taken, and once reduced, to accurately measure the brightness of the object in question and perform differential photometry to obtain a light curve for the object over the course of the observing run.
Periodic updates will be posted to this page showing example data, for you to compare to your products to make sure you're on the right track and have not made a horrible mistake.
The observations are taken in the filters BVRI. A Tek2048 chip was used, but only the central 1024x1024 was read out using a single amplifier. The gain was 3.0 e-/ADU with a readout noise of 1.5 ADU. Since all the observations are less than 300 seconds in length, the contribution from the dark current may be ignored. There are no dark frames in the calibration filesets.
The photometric observations are relative and are made with respect to the following stars as indicated in the finder image below. Since the practice was differential and not absolute you will find that photometric standards are not taken every night.
| Star | V | B-V | V-R |
|---|---|---|---|
| Comp1 | 16.24 |
+1.23 |
+0.76 |
| Comp2 | 16.06 |
+1.49 |
+0.84 |
| Comp3 | 16.96 |
+2.19 |
+0.87 |
Please note that the images may be reflected vertically from the detector frame to match the North up, East left orientation shown in the finder chart.
The observing logs for the run are available here as a large PDF file (35 MB): Observing Logs.
| Night | File Nos. | Compressed Tarball |
|---|---|---|
| 1 | 2-148 |
File [181 MB] |
| 2 | 149-313 |
File [208 MB] |
| 3 | 314-476 |
File [207 MB] |
| 4 | 477-643 |
File [209 MB] |
| 5* | 644-779 |
File [175 MB] |
| 6* | 964-977 |
File [23 MB] |
| 7 | 978-1147 |
File [227 MB] |
| 8 | 1148-1284 |
File [171 MB] |
Please note that some of the data files for nights 5 and 6 were lost - you will not be able to use those data in your processing and final measurements.
Please also note that the results of these observations have already been published - so you have something to cross-check against:
"The Galactic Supersoft X-Ray Binary RX J0925.7-4758 (MR Velorum)", Schmidtke, P. C.; Cowley, A. P.; Taylor, V. A.; Crampton, David; Hutchings, J. B., 2000, AJ, 120, 935-942 [Link]
and,
"Synoptic Observations of the Supersoft Binary MR Velorum (RX J0925.7-4758): Determination of the Orbital Period", Schmidtke, P. C.; Cowley, A. P., 2001, AJ, 122, 1569-1571 [Link]
You are expected to write up a full report of your data reduction, how your measurements were made, and present your results with errorbars in graphical form. This should look pretty much like the Observations, Reduction and Results sections of a scientific paper. You are not being asked to interpret the results. This report is due in to the Instructor's mailbox in paper form by Fri Dec 1 at 5pm.
A solution to the Project has been worked up by Rolf Jansen and is posted here.
Example Night 1 Calibration Files
These are examples of what your calibration files should look like both cosmetically and numerically - check these against your versions. Note that bad columns and pixels have not been removed or corrected in these versions. Also note the discrete nature of the data in the superbias and the fact that the flats have been renormalized to values close to 1.0.
Super Bias |
B Flat |
V Flat |
R Flat |
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