1. The Reduction and Reporting of Data On Proto-Planetary Nebulae From Two Observatories. By Wesley Cheek With Mr. Wen Lu & Prof. Bruce Hrivnak

2. Outline 1.Background 2.Project goals 3.What is data reduction? 4.What is photometry? 5.Results

3. Proto-Planetary Nebulae Evolved objects, near the end of their lives. Missing link between when a star stops fusion and when it glows as a nebula. Exhibit periodic changes in light intensity and color. Mass loss and periodicity not fully understood.

4. Project this summer Reduce data from the SARA North and South observatories and do photometry on the images. Create light curves from photometric data for each object and begin analysis (look for variation). Post results and information about each object on a password protected website. (Collaborative project)

5. Data reduction? Charge -Couple Devices (CCDs), the primary instrument used in astronomy, have inherent noise. Raw data are oftentimes ‘dirty’ and we would like to clean them up. Calibration images Biases - Approximate the noise from the amplifier electronics. Darks - Approximate noise from thermal electrons. Flats - Attempt to correct for pixel to pixel sensitivity differences.

6. Photometry? Draw two circles around a star, one within the other. One circle records counts from the star while the annulus records the counts from the background. Subtract background from the star. Computer does this for every star in the field and outputs star magnitudes to file.

7. Results Light curves plot intensity versus time. Periods range up to ~200 days. Need more data for better period finding. Next big step is to standardize data from all three locations (including VU) and combine them into big light curves. Website makes data accessible to collaborators.

8. Acknowledgements Indiana Space Grant Consortium National Science Foundation Kitt Peak National Observatory, SARA-N Cerro Tololo International Observatory, SARA-S Valparaiso University Prof. Bruce Hrivnak Mr. Wen Lu