A roster appears to show Julian Ellendorff as second lieutenant of Company H, 42nd New York, at Gettysburg, possibly acting as the regimental adjutant. He was promoted to first lieutenant on August 13, 1863.
https://museum.dmna.ny.gov/application/files/3715/5060/0460/42nd_Infantry_CW_Roster.pdf
Patrick Henry Lennon, the son of Irish immigrants, was first lieutenant of Company H, 42nd New York, at Gettysburg, where he received a serious flesh wound in the right arm on July 3. On February 12, 1864, he was promoted to captain. He was killed on May 12, 1864 at Spotsylvania. An image of Lennon, shown wearing his sword, appeared in Military Images, vol. XXIX, no. 1, July/August 2007.