A Blind Search for Variable Stars using an 11-inch RASA and a One-Shot Color Camera
Volume 52 number 1 (2024)
- Nathan Taulelei
- Eltham College, 1660 Main Road, Research, VIC 3095, Australia; natanotau@gmail.com
- Tristan Wood
- Eltham College, 1660 Main Road, Research, VIC 3095, Australia; tristanjtwood@gmail.com
- Andrew Yen
- Eltham College, 1660 Main Road, Research, VIC 3095, Australia; ayen@elthamcollege.vic.edu.au
- Michael Fitzgerald
- Las Cumbres Observatory, 97 Dalton Street, Eltham, VIC, 3095, Australia; psyfitz@gmail.com
- Lindsay van der Pal
- Eltham College, 1660 Main Road, Research, VIC 3095, Australia; lindsay.vanderpal@gmail.com
Abstract
In this paper we report tests of an 11-inch wide field Rowe Ackermann Schmidt Astrograph (RASA), a one-shot color (OSC) imager and data processing semi-autonomously by Astrosource as a variable-hunting system. The success of this test is demonstrated by blind recovery of five known variables in the field, and identification of six more probable variables. The researchers repeatedly imaged and studied a single field of approximately three square degrees (March to June 2021) chosen based on the relative absence of AAVSO database stars within the field. Analysis techniques were developed and applied to process the large quantity of data produced to identify stars exhibiting variability over the time period. Twelve variable stars were identified, six previously known—albeit one with a curious period difference—and five potential, but not confirmed, discoveries (1 likely rotational, 1 likely RRc, 1 likely δ Scuti, and 2 of uncertain types). Some candidate stars were followed-up with further data obtained with a 0.4-m class telescope from Las Cumbres Observatory. The methods developed by this team to find and identify variable stars have proved efficient and productive. The potential discoveries were made on the dim end of the magnitude range (14th–16th), however, the exposure times used in this study were quite short and could reasonably be extended, so future searches will be made with longer exposures to focus on this magnitude range. Recommendations are made for future variable search using a combination of RASAs and OSCs.