Organized and managed by Sons of Union Veterans of the Civil War Camp #45, the New England Civil War Museum has an extensive collection of Civil War memorabilia. Their website features just a few items of weaponry and headgear. Their library holds additional material. A quick look at their website shows that, just for Connecticut regiments, they hold several published and unpublished histories, scattered letter collections and more.
Once you get beyond the basics of your ancestor's Civil War service, consider checking with the New England Civil War Museum. They may be able to fill in some details.
You can visit their website at http://www.newenglandcivilwarmuseum.com, write them at firstname.lastname@example.org, contact the museum by phone at 860-870-3563, or write them at 14 Park Place, 2nd Floor, Rockville, Connecticut 06066.