MEGARA is an optical integral field and multiobject fibre based spectrograph for the 10.4m Gran Telescopio CANARIAS that offers medium to high spectral resolutions (FWHM) of R $\simeq$ 6000, 12000, 20000. Commissioned at the telescope in 2017, it started operation as a common-user instrument in 2018. We are creating an instrument-oriented empirical spectral library from MEGARA-GTC stars observations, MEGASTAR, crucial for the correct interpretation of MEGARA data. This piece of work describes the content of the first release of MEGASTAR, formed by the spectra of 414 stars observed with R $\simeq$ 20000 in the spectral intervals from 6420 to 6790 $\r{A}$ and from 8370 to 8885 $\r{A}$, and obtained with a continuum average signal to noise ratio around 260. We describe the release sample, the observations, the data reduction procedure and the MEGASTAR database. Additionally, we include in Appendix A, an atlas with the complete set of 838 spectra of this first release of the MEGASTAR catalogue.

中文翻译：

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MEGARA-GTC 恒星光谱库 (II)。MEGASTAR 首次发布

MEGARA 是用于 10.4m Gran Telescopio CANARIAS 的基于光学积分场和多目标光纤的光谱仪，提供 6000、12000、20000 雷亚尔的中到高光谱分辨率 (FWHM)。2017 年在望远镜上调试，开始运行作为 2018 年的普通用户仪器。我们正在从 MEGARA-GTC 恒星观测创建一个面向仪器的经验光谱库，MEGASTAR，对于正确解释 MEGARA 数据至关重要。这篇作品描述了MEGASTAR第一次发布的内容，由414颗恒星在6420到6790 $\r{A}$和8370到8885 $光谱区间内以R$\simeq$ 20000观测到的光谱形成\r{A}$，并以 260 左右的连续平均信噪比获得。我们描述了释放样本、观察结果、数据缩减程序和 MEGASTAR 数据库。此外，我们在附录 A 中包含了一个地图集，其中包含第一版 MEGASTAR 目录的完整 838 个光谱集。