AAVSO: American Association of Variable Star Observers

Proposal #109

Proposer (2092) Michael Heald (msheald@hotmail.com) obscode: HMH
Assigned To(3663) Dirk Terrell
Date SubmittedApril 20, 2019

Member Name: Michael A. Heald - HMH
1) Target Star: RR CET, a RRAB star with a period of 0.55302836 days
2) Rationale: A review of the historic light curve suggests low amplitude magnitude changes of 0.03 to 0.05 or less magnitudes (eyeball estimate from light curves) with a frequency of about an hour around the expected baseline. It is likely that something in m y equipment, technique, or reduction process is causing such variability. However, a number of other light curves in the database also show such variability, so it may be an effect related to the small size of the telescopes used or to the effect of the movement of air cells during the observation periods
In any case, CCD data became available in the International Database since 2006. RR CET is well studied in the professional literature. The few light curves I was able to find during my internet search failed to show such low amplitude variability. However, the curves I was able to locate had errors of about 0.03 magnitudes with the Fourier analysis of RR CET's period, so correlation with the International Database is difficult. Additionally, it is possible that low amplitude variations might have been averaged out in the published data. If the position of such putative low amplitude oscillations varied with respect to the major light curve, it might not have been detected by the Fourier analysis since the low amplitude variations would have been averaged out.
3) Plan for Data: Upload to the AAVSO International Database. I will also use this data to compare with past observations. The data will assist me in determining why my data shows such oscillations so that I can improve my photometry in the future. Additionally, if the data shows possible magnitude oscillations, the data will help generate hypotheses for additional observations.
4) I Request Observations be sent to my VPHOT Account.
5) Magnitude Ranges: V Magnitude Range: 9.1 to 10.1.
6) Time Interval of Observations: 90 seconds - to match the frequency of the putative low amplitude variations.
7) Filter Requested: V
8) Exposure Times: 90 seconds in V and taken continuously for a 6.5-hour period. If the S/N is too low to see baseline trends of 0.03 magnitudes, every 2 images can be stacked in order to improve S/N.
9) Start Date: 18:30 PM, 11/21/2019, MST (end of astronomical twilight) till 01:00 AM, 11/22/2019, MST. These times/dates would cover RR CET from about 30 degrees east to 30 degrees west from my location in Las Cruces, NM, and allow me to coordinate my observational data with the BSM observations. These dates would also minimize the chance of poor weather since the "monsoon" season occurs from August till October in the Las Cruces area.

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
RR CET 1.535603 1.34175 10.1–9.1 No


(2092) Michael Heald — March 28, 2023, 9:47 a.m.

Hello! It has been a while, and I thought that the proposal had not been accepted. Might this project still move forward? Best regards. Mike

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