I am currently making a figure of Union civil war hero captain Hubert Dilger of the horse artillery.
I have been unable to find any reference as to the colour of the saddle blankets used by that arm of service
I know the cavalry had blue bankets with a yellow stripe and it seems logical that the artillery should have blue with a red stripe but I have been unable to confirm that.
Can anybody help?

http://www.militaryhorse.org

This site has some great reference for horse usage, equipment and organization. If they don't have specifically what you're looking for, they do have a wealth of information that I've found very useful in the past.

Also, are you asking about a saddle blanket or an officers schabraque? If I recall correctly (and I could be wrong) but I think the US artillery saddle blanket is red with blue striping along the edge. I'm not sure if the artillery officer's shabraque was like the cavalrys (which was that blue swallow tailed saddle cloth with a yellw stripe along the edge)

Peter, sorry I never got back to you on this one, but life has gone a little haywire. I'll try to hit the books tonight and let you know.

Renarts
I am depicting Dilger in campaign dress with his horse equiped with a McClellan saddle and blanket rather than a shabraque

Peter,
I checked my reference library for that period along with some friends in the NPS who do the Civil War interpretive programs as well as a couple of pretty hard corp re-enactor/scholars/authorities and all my resources show the red blanket with blue edge stripes. The below web link (the only reference I could conveniently reference that would get my point across and is for quick reference only) will show a saddle blanket under the saddle and just use the red blanket with the blue stripes with the crossover patch to the rear of the saddle.

http://www.crchilds.com/id25.htm

Understand too, that this was not set in stone and as materials were shorted they were substituted. The policy may have been the red blanket but it may not necessarily have been what Capt Dilger specifically used. i.e. a good example of this is currently being discussed here in FL by the NPS, their researchers as well as several authorities here in the stated and in Spain regarding the Spanish occupation of Florida and just who exactly was the occupying force and how they were outfitted and uniformed. New information has been found that shows that though the Spanish regulation for army uniforms called for a red waistcoat, stocks of red wool were short and its is possible that many of the sodaltos here did not have red waistcoats. Another hard argument point currently being discussed was whether or not the castillo was garrisoned by army, marines or a combination of both. The cool thing about history is despite what you may know it changes regularly.

Good luck on the project.

Renarts
Thnks very much for your efforts.
A red blanket with blue stripes it is.I appreciate that Dilger may not have used this type of saddle cloth just as he may never have had a dapple grey horse but I fancy the challange of painting the dapples and it should look good with the red blanket.
I will post pictures of the completed project in due course