Separation measurements

Separation (star-to-star angle) measurements have the following planning considerations:

Neither star needs to be near the meridian, and there is no need to avoid the meridian.
Both stars should be well above the horizon (say 30 degrees) to reduce refraction effects.
Having both stars at about the same altitude helps reduce, but not eliminate, refraction/flexure effects.
Large separation angles require long pitch slews. Shorter separations are more efficient.
Pairs of stars that have similar ras will have their separation largely in dec. When later calculating the delta ra from the separation, these pairs will have very narrow spherical triangles that will not produce very good results. East-west separations are better.
Pairs can be interchanged between the direct and pitch optical paths, and thus can be used to check that the measured separations are the same.
Separations that involve a star that is in the west in the early evening need to be measured immediately to avoid waiting a year.
Roll slews are very slow. Target lists that minimize roll slews are more efficient. This usually means having the primary star in the direct optical path and the secondary star in the pitch path, with the second stars following in roll order.
Software reticles are of no help for separation measures.