The great comet C/1995 O1 (Hale–Bopp) presented a remarkable opportunity to study its long-term brightness over four years. We used 2240 observations published in the International Comet Quarterly from 17 observers during 1995 July to 1999 September to create a secular lightcurve. In order to account for observer differences, we present a novel algorithm to reduce scatter and increase precision in a lightcurve compiled from many sources. It is implemented in a publicly available code, ICQSPLITTER, which uses a self-consistent statistical approach. To first order, the comet’s lightcurve approximates an r ⁻⁴ response for both pre- and postperihelion distances. The preperihelion data are better fit with a fifth-order polynomial with inflection points at 4.0, 2.6, 2.1, and 1.1 au, some of which are associated with physical changes in the coma. Outbursts may have occurred a few days before perihelion and at ∼2.2 and 7.4 au postperihelion. The Afρ values derived from the final magnitudes are consistent with an r ^−1.5 dependence on heliocentric distance and are within a factor of 2–4 of those derived from spectroscopy and narrowband photometry. We present correlation equations for visual magnitudes and CO and H₂O production rates that are consistent with the preperihelion brightness increasing due to CO outgassing until about 2.6–3.0 au from the Sun and then are strongly correlated with H₂O production rates. We also present two generalized correlation equations that may be useful for observation planning and data analysis with the James Webb Space Telescope and other observatories.

伟大的彗星 C/1995 O1 (Hale-Bopp) 提供了一个绝佳的机会来研究其四年来的长期亮度。我们使用了1995 年 7 月至 1999 年 9 月期间 17 位观察者在国际彗星季刊上发表的 2240 次观测结果来创建长期光曲线。为了考虑观察者的差异，我们提出了一种新颖的算法来减少散射并提高从许多来源编译的光曲线的精度。它是在公开可用的代码 ICQSPLITTER 中实现的，该代码使用自洽的统计方法。对于一阶，彗星的光曲线近似于r ^-4对近日点前和近日点后距离的响应。近日点前数据与拐点位于 4.0、2.6、2.1 和 1.1 au 的五阶多项式更吻合，其中一些与彗发的物理变化有关。爆发可能发生在近日点前几天和近日点后~2.2和7.4 au。来自最终星等的Afρ值与依赖于日心距离的r ^-1.5一致，并且在来自光谱学和窄带光度测量的那些值的 2-4 倍之内。我们提出了视觉震级和 CO 和 H _{2 的}相关方程O 生成率与由于 CO 释气而导致的近日点前亮度增加一致，直到距离太阳约 2.6-3.0 au，然后与 H ₂ O 生成率密切相关。我们还提出了两个广义相关方程，它们可能对詹姆斯韦伯太空望远镜和其他天文台的观测计划和数据分析有用。