Any sight can be advanced and used to obtain a "running fix". It may be that the navigator due to weather conditions could only obtain a single sight at dawn. The resulting LOP can then be advanced when, later in the morning, a Sun observation becomes possible. The precision of a running fix depends on the error in distance and course so, naturally, a running fix tends to be less precise than an unqualified fix and the navigator must take into account his confidence in the exactitude of distance and course to estimate the resulting error in the running fix.