AAVSO: American Association of Variable Star Observers

Proposal #369

Proposer (37004) Mark O'Connell (123juniper@comcast.net) obscode: OMAA
Assigned To(3663) Dirk Terrell
Date SubmittedJune 14, 2023

This is proposal for regular observation of variable star BW Cyg (AUID 000-BDN-302). The existing record of observations for this star consists of only 37 observations made sporadically between 2018 and the 2023. Of these observations, 1 is Visual and 36 are CCD. Only 6 of the CCD observations are transformed. Seventeen of these observations were made by a single observer over a period of 119 days in 2020. This limited sampling does not allow either the nominal period of 171 days nor the nominal variable type, SRB, to be confirmed from the observational record. Moreover, the available observations do not give a clear indication of whether the multiple periods, generally expected of semi-regular variables, can be observed for BW Cyg.

The available observations do show magnitudes within a range of 12 - 13 (V), which are consistent with the nominal range of magnitudes (13 to 15.7 p) cited in VSX. A recent (JD2460102) preliminary observation gave a magnitude of appox. 12.5(V). These magnitudes would be suitable for measurement by instruments of the AAVSOnet BSM. And, the northerly declination (+58:45:53) should be generally observable from AAVSOnet's northerly locations on most dates during the year.

A regular cadence of observation -- 1 set of photometric observations collected every 10 -14 days -- continuing during a total period of approximately 250 days -- could provide a basis for determining the main period(s) that can now be observed. Photometric observations using V, B, and R filters (and I, if available at the selected site) are desirable for building this basic initial record. After such a basic, systematic set of observations, further analysis could indicate whether any more extensive or more detailed observation might yield additional, informative results.

Target RA (H.HH) Dec (D.DD) Magnitude Telescope Observation Frequency Expiration Date Proprietary Term
BW Cyg 20.573211 58.76486 12.0–16.0 BSM_NH2 3 Dec. 20, 2023 No


(3663) Dirk Terrell — June 16, 2023, 2:40 p.m.

Arne suggests a cadence of 3 days to get good resolution for the light curve.

(37004) Mark O'Connell — June 19, 2023, 4:04 p.m.

The cadence in the original proposal was estimated from the (broad) recommendations in:
A specific suggestion from Arne definitely supersedes that -- assuming that the network can accommodate the workload.

(4726) Kenneth Menzies — June 23, 2023, 1:13 a.m.

Committed to NH

Comments on this proposal are closed.