owls-app 0.2

Olin Wilson Legacy Survey

Interactive visualization tool for time-series spectra from the Olin Wilson Legacy Survey (OWLS).

OWLS is monitoring stellar magnetic activity cycles with optical echelle spectra of FGKM stars with the ARC 3.5 m Telescope at Apache Point Observatory (APO).

Getting started

Installation

python -m pip install owls-app

Run the app

To run the interactive tool, run:

owls-app

Multiple sessions

If you already have an instance of solara or owls-app running, you can launch a second one by specifying a different port:

owls-app --port 1234

Details

What is this spectrum viewer?

Meet Specviz (documentation, source) part of the jdaviz interactive data visualization and analysis package developed at the Space Telescope Science Institute. Specviz supports quite advanced workflows that we won’t summarize here – check out their docs at the link above.

What is this time series viewer?

Meet LCviz (documentation, source), a light curve visualization and analysis tool built on jdaviz, developed at the Space Telescope Science Institute. LCviz supports quite advanced workflows that we won’t summarize here – check out their docs at the link above.

How are the echelle orders normalized?

The app will attempt to remove the continuum from each echelle order by dividing out a fifth order polynomial fit to the corresponding order of an ARCES spectrum of the hot subdwarf standard HZ 44 to roughly remove the blaze function, and then dividing by the order’s maximum flux. This normalization method is most imprecise near strong lines in hot star atmospheres. The flux units of the spectrum viewer are thus relative flux.

Can I download these spectra?

Yes! We’re submitting all spectra to MAST as HLSPs, though it may take some time before they’re available on MAST. Reach out to Brett if you’d like them sooner.

Are the spectra saved locally?

When you select a new observation, owls-app will download and cache the spectrum from a collection OWLS FITS files hosted online. The cache is managed using the astropy cache machinery, which will store the files in a hidden directory in your home directory, ~/.owls-app/. The spectra are stored as .fits.gz files, and they are 0.63 MB per spectrum.

To clear the OWLS observations from the cache on your machine, you can call:

from astropy.utils.data import clear_download_cache
clear_download_cache(pkgname='owls-app')  # note that the pkgname is important!

Note: if no package name is specified, this command would delete any files cached by astropy, and you might not want that.