Using the 2016 Mercury transit of the Sun, we characterize on orbit spatial point spread functions (PSFs) for the Near- (NUV) and Far- (FUV) Ultra-Violet spectrograph channels of NASA’s Interface Region Imaging Spectrograph (IRIS). A semi-blind Richardson–Lucy deconvolution method is used to estimate PSFs for each channel. Corresponding estimates of Modulation Transfer Functions (MTFs) indicate resolution of 2.47 cycles/arcsec in the NUV channel near 2796 Å and 2.55 cycles/arcsec near 2814 Å. In the short (≈1336Å${\approx}\,1336~\mathring{\mathrm{A}}$) and long (≈1394Å${\approx}\,1394~\mathring{\mathrm{A}}$) wavelength FUV channels, our MTFs show pixel-limited resolution (3.0 cycles/arcsec). The PSF estimates perform well under deconvolution, removing or significantly reducing instrument artifacts in the Mercury transit spectra. The usefulness of the PSFs is demonstrated in a case study of an isolated explosive event. PSF estimates and deconvolution routines are provided through a SolarSoft module.

中文翻译：

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界面区域成像摄谱仪点扩散函数的在轨测定

利用 2016 年水星凌日事件，我们描述了 NASA 界面区域成像光谱仪 (IRIS) 的近 (NUV) 和远 (FUV) 紫外光谱仪通道的轨道空间点扩散函数 (PSF)。使用半盲 Richardson-Lucy 反卷积方法来估计每个通道的 PSF。调制传递函数 (MTF) 的相应估计表明，NUV 通道中 2796 Å 附近的分辨率为 2.47 周期/弧秒，2814 Å 附近的分辨率为 2.55 周期/弧秒。短 (≈1336Å${\approx}\,1336~\mathring{\mathrm{A}}$) 和长 (≈1394Å${\approx}\,1394~\mathring{\mathrm{A}}$ ）波长 FUV 通道，我们的 MTF 显示像素有限的分辨率（3.0 周期/角秒）。PSF 估计在反卷积下表现良好，消除或显着减少了水星凌日光谱中的仪器伪影。PSF 的实用性在一个孤立爆炸事件的案例研究中得到了证明。PSF 估计和反卷积例程通过 SolarSoft 模块提供。