Append does not track metadata-- returns copy of metadata of just one lightcurve

Append does not track metadata-- returns copy of metadata of just one lightcurve

lcf = KeplerLightCurveFile.from_archive(6922244, quarter=4)
lcf2 = KeplerLightCurveFile.from_archive(6922244, quarter=5)

lc = lcf.SAP_FLUX
lc2 = lcf2.SAP_FLUX

lc.channel, lc2.channel
(31, 3)

new_lc = lc_a.append(lc_b)
new_lc.channel
31
'''

Is this behavior desired?

[barentsen]

I suggest the following way forward for this issue:

• Combining lightcurves should always return a generic LightCurve object that does not contain metadata that is specific to e.g. an individual KeplerLightCurve (e.g. channel is not an attribute of LightCurve).
• The combination of lightcurves should be implemented in a robust LichtCurveCollection.stitch() method. The LightCurve.append() method should either be removed, or be a light wrapper around LichtCurveCollection.stitch().

@nksaunders Do you want to look into this as part of #309?

[barentsen]

Just before merging I made a small change to make sure LightCurveCollection could hold multiple lightcurves with the same targetid. I was worried users will be confused if a collection can’t hold any arbitrary combination of LightCurve objects.