The satellite company's quarterly report listed orbital data calculated from the J2000 epoch.

這家衛星公司的季報列出了以J2000曆元計算的軌道資料。

Please update the tracking software so all coordinates reference the new epoch by Friday.

請在週五前更新追蹤軟體，讓所有座標都以新的曆元為基準。

During the meeting, the engineer explained why the client's orbit data used an outdated epoch.

會議中，工程師說明了客戶的軌道資料為何使用了過時的曆元。