BL Tel is a long period eclipsing binary with a period of 778 days. I have taken photometry measurements of the last 3 eclipses. The most recent one was in August. The spectrum also changes significantly during the eclipse as the cooler stars spectrum becomes visible.
Attached is my measurements of the latest eclipse as well as spectra in and out of eclipse.
Terry,
Well done!
The spectra clearly shows the difference in the stars involved in this system.
I honestly don't know why the AAVSO cannot come to terms with the great opportunities spectroscopy can add to their photometric work.
