FAQ

1. What wavelength range can this classify over?

   The templates used to classify your spectra are defined over the range 3,650 to 10,200 Angstroms. The process for classifying involves matching on specifically chosen spectral lines which range from 3,925 Angstroms to 10,000 Angstroms. Your spectrum should be defined for at least part of that range, although it need not span the full range and can be defined outside that range. Small wavelength coverage can lead to less accurate radial velocity, metallicity and spectral type estimates however.

2. Why is a template not showing during the eyecheck process?

   The templates were compiled by averaging SDSS DR12 spectra for each spectral and metallicity type. In some cases, not enough spectra existed to provide a template. If you choose a spectral type in the eyecheck program for which a template is not available, nothing will be shown.

3. I'm seeing warnings or errors output on the command line, but PyHammer seems to run fine. What's going on?

   As various packages and modules get updated, certain components of PyHammer may start to generate errors or depreciation warnings. We will try to address these as they occur, but unless PyHammer crashes, you can usually safely ignore these warnings.

4. Why can't I choose to classify my spectra as K8 or K9?

   It is a general consensus (though by no means unanimous, ref. Johnson & Morgan 1953, Keenan & McNeil 1989) that the K8 and K9 stellar types are sufficiently similar to their neighboring spectral types that they need not exist. Instead, the spectral classification jumps from K7 directly to M0. As such, we disallow selecting those spectral types in the eyecheck GUI. Corresondingly, the automatic spectral typing algorithm will not match to a K8 or K9 spectral type.

5. Can I use my own templates?

   Yes. You can choose to replace the templates in the template directory, or else provide your own for the templates which don't exist. Note however, that templates must conform to specific conventions.

   a. In order to be recognized, the filename must take one of three forms: SS.fits, SS_+M.M.fits, SS_+M.M_Dwarf.fits. In these names, SS is the spectral type and subtype (e.g., M5) and +M.M is the [Fe/H] metallicity where you must specify the sign, either positive or negative (0.0 is considered positive) (e.g., +0.0, -0.5, +1.0).

   b. The template itself must be configured such that it is "normalized" to the flux at 8000 Angstroms. In other words, the flux in the template file must be divided by the flux at 8000 Angstroms, making the flux at that wavelength equal to one.

6. My plot size is too large/small! How do I change that?

   This issue is purely a function of your computer and its resolution and settings. The best I can tell you is to go into the code itself and adjust some sizes. The sizes of the GUI components on the left panel will generally remain consistent and shrink to the smallest size possible, so you shouldn't have to adjust that. The plot is where things appear to be oversized on your screen. If you want to adjust this, change the following lines in eyecheck.py. Note that line numbers may change with future commits.

   Line 260:

   self.figure = plt.figure(figsize = (12,6))

   This sets the figure size. Currently set to 12, 6 (as a width, then height). You might want to try 10, 5 or 8, 4.

   Lines 591-593

   ax.set_xlabel(r'$\mathrm{Wavelength\;[\AA]}$', fontsize = 16)
   ax.set_ylabel(r'$\mathrm{Normalized\;Flux}$', fontsize = 16)
   ax.set_title(r'$\mathrm{Template:\;' + templateName + '}$\n$\mathrm{Spectrum:\;' + spectraName.replace('_','\_') + '}$', fontsize = 16)

   The default font size of the axis and title is set here to 16. Try changing this to 12 or 10.

   If the axis labels and plot title are off the edge of the plot window (especially after you adjust things), you can try playing with the spacing on Line 620.

   plt.subplots_adjust(left = 0.075, right = 0.975, top = 0.9, bottom = 0.15)

   This just adds padding around the plot. Increase or decrease as desired.

   The settings we chose were set to look the best on a wide variety of monitors and setups, but obviously we can't fit everything perfectly. Hopefully adjusting these will allow you to achieve the desired size and resolution. Good Luck!