LEMONY--a Library of Empirical Medium-resolution spectra by Observations
  with the NAOC Xinglong 2.16\,m and YNAO Gaomeigu 2.4\,m telescopes
  This study expands the coverage and improves the homogeneity of the
distribution of MILES template stars in the parameter space, as well as extends
the wavelength coverage of the template spectra to the far red beyond the
Ca\,{\sc{ii}} triplet. To achieve this we have carried out a major
observational campaign using the OMR long-slit spectrograph mounted on the NAOC
2.16\,m telescope and the YFOSC long-slit spectrograph mounted on the YNAO
2.4\,m telescope. The original sample is based on the MILES library,
supplemented by 918 stars selected from PASTEL database. In total, 822 OMR and
1,324 YFOSC spectra, covering respectively the wavelength ranges
$\lambda\lambda$3800--5180 and $\lambda\lambda$5150--9000, have been collected
and reduced. The spectra have a mean resolution FWHM (full-width at
half-maximum) of $\sim 3.3$\,{\AA} and are wavelength- and flux-calibrated to
an accuracy of $\sim 20$\,km\,s$^{-1}$ and $\sim 5$\,per\,cent, respectively.
The spectra are further corrected for systematic errors in the wavelength
calibration to an accuracy of $\sim 4$\,km\,s$^{-1}$ by cross-correlating with
the theoretical spectra. Almost all the spectra have an average signal to noise
ratio (SNR) better than 100 per pixel. Combined with the MILES spectra, there
are now 1,731, 1,542, 1,324 and 1,273 stars with spectra covering respectively
$\lambda\lambda$3800--5180, $\lambda\lambda$3800--7500,
$\lambda\lambda$5150--9000 and $\lambda\lambda$3800--9000. This paper describes
our template star selection, the observation and data reduction, and presents
the reduced spectra collected hitherto.
