› Forums › Spectroscopy › Learning to measure eqw of spectral lines › EW estimates in Alpy spectra of VV Cep
![](https://britastro.org/wp-content/uploads/2016/08/picture-3730-1470174999-80x80.png)
I used a crude but simple estimate of the EW of the Hα and Hβ emission lines in the VV Cep spectrum, in order to monitor progress of the current eclipse. I drew a ‘continuum’ by extending a straight line between the turning points at the base of the emission lines. As an example here’s the result I got in BASS with last night’s spectrum:
I realise the approach is not strictly scientific but is repeatable and seems to have given a reasonably comparable set of measurements. Here’s the latest time plot of my EW measurements on my own and others’ Alpy spectra:
The latest episode of Hα brightening seems to have appeared bang on time!
I’d welcome any comments on the approach
Cheers
Hugh