Passage: In early January 1915, the German naval command became aware that British ships were reconnoitering in the Dogger Bank area.  Admiral Ingenohl was initially reluctant to attempt to destroy these forces, because the I Scouting Group was temporarily weakened while Von der Tann was in drydock for periodic maintenance. Konteradmiral Richard Eckermann, the Chief of Staff of the High Seas Fleet, insisted on the operation, and so Ingenohl relented and ordered Hipper to take his battlecruisers to the Dogger Bank. On 23 January, Hipper sortied, with Seydlitz in the lead, followed by Moltke, Derfflinger, and Blücher, along with the light cruisers Graudenz, Rostock, Stralsund, and Kolberg and 19 torpedo boats from V Flotilla and II and XVIII Half-Flotillas. Graudenz and Stralsund were assigned to the forward screen, while Kolberg and Rostock were assigned to the starboard and port, respectively. Each light cruiser had a half-flotilla of torpedo boats attached.Again, interception and decryption of German wireless signals played an important role. Although they were unaware of the exact plans, the cryptographers of Room 40 deduced that Hipper would be conducting an operation in the Dogger Bank area. To counter it, Beatty's 1st Battlecruiser Squadron, Rear Admiral Archibald Moore's 2nd Battlecruiser Squadron and Commodore William Goodenough's 2nd Light Cruiser Squadron were to rendezvous with Commodore Reginald Tyrwhitt's Harwich Force at 08:00 on 24 January, approximately 30 mi (48 km) north of the Dogger Bank.At 08:14, Kolberg spotted the light cruiser Aurora and several destroyers from the Harwich Force. Aurora challenged Kolberg with a search light, at which point Kolberg attacked Aurora and scored two hits. Aurora returned fire and scored two hits on Kolberg in retaliation. Hipper immediately turned his battlecruisers towards the gunfire, when, almost simultaneously, Stralsund spotted a large amount of smoke to the northwest of her position. This was identified as a number of large British warships steaming towards...

Question: Where was ship Von der Tann in January of 1915?
drydock