Filters for nova photometry

Tue, 06/20/2017 - 22:16

In a similar manner to the LPV monitoring, novae are equally hard to do with wide-band filters.  After the initial outburst, the nova goes into a "nebular" phase where most of the emission is coming from nebular lines like 500.7 and 656.3nm.  Some filters, like Ic, will continue to fade, while others, like V, stay high for months to years.

You can select an optimal filter set that both has a "continuum" filter unaffected by the emission lines, along with a couple of narrow-band filters to emphasize the lines themselves.  This is poor man's spectroscopy, but if done for long periods and on many novae, has strong potential for unique science.

Ulisse Munari and collaborators wrote a paper about this:


which suggests using the Stromgren b,y filters along with Halpha and [OIII] 500.7 narrow-band filters.  The narrow-band filters are easy to obtain from various vendors like Baader and Astrodon.  Astrodon also used to have Stromgren filters; perhaps he can be convinced to start supplying these again if a group order was made.  I'd think these filters would work for many emission-line targets.

So, if you had a spare CCD camera and telescope, and populated an 8-position wheel with ~3 Wing filters and 4-5 nova filters, you might have an interesting setup that could study lots of stars for a decade or more!