Correction can vary, but 10 to 30cc of color correction is typical. For areas of much high pressure sodium pollution, such as is typical near large cities of today, a weak green filter can help. If filters of any type are used, don,t forget the rule of thumb that for every 30cc of filtration doubles the exposure. Slide films of choice are few, but excellent results have been obtained with two types, Kodak Elite 400, and Ektachrome P1600. Both are far less green sensitive than past Ektachromes and Fujichromes of past years, and have recorded details in the blue gas and yellow dust tails very well in recent comets.
Color negatives offer the best selection for high speed films today.
As a benefit from competition among film manufacturers for the fastest color negative films, the astronomer has a wider selection of high speed color negative film than ever before. There are three films in our opinion that have far surpassed the others in fineness of grain and excellent color response for shooting comets. These are Fuji Super G 400 Plus, Super G 800 Plus, and Kodak Pro 400 ppf films. The Fuji 800 speed film is fast, has unusually fine grain and is responsive to both the blue gas and yellow dust tails in comets. The contrast is good, and meets nearly all of the requirements for the ideal comet shooting film.