* Astronomy

Observers have misidentified the semiregular variable T CMa over many years due to the use of charts with insufficient detail. A detailed chart is provided to allow for correct identification and it is also suggested T CMa may be non-variable and should be dropped from observing lists.
T CMa is located at R.A. 07h 21m 26s, Dec. –25° 26' 48'' (equinox 2000), and has alternative designations, including CoD –25 4409, CPD–25 2242, and ASAS3 072126-2526.8. It is listed in the General Catalogue of Variable Stars (Kholopov et al. 1985) as a semiregular variable of visual magnitude range 9.5 to 11 and 309-day mean period. No spectral classification is given. This star is found some 28 arcmin NW of the peculiar red variable VY CMa.
It had been observed visually on an occasional basis by the author between 1998 and 2003, showing little variation around a mean magnitude 11.5. Intrigued by this apparent lack of large amplitude variability, a check was made of observations in the AAVSO International Database via the AAVSO Light Curve Generator to look for any long-term regular variability.
This also failed to show any such variation but did reveal other observers were recording T CMa some 2 magnitudes brighter at a mean magnitude near 9.3.

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