Just finished the quest to get the brooch from the dreadnaught the went to talk to Petra.

First and foremost, speak with Petra on the Reef to accept the quest, The Taken War: Petra. To complete this quest, you must head to various planets and take down Taken Champions. As you patrol, you'll eventually see the warning message, "Taken forces are corrupting the area." Once this happens, you will see Taken Lieutenants spawn, followed by a Taken Champion. These events are not easy, so it's best to have a full fire team with you to make sure you can make it through the quest. Taking down the Taken Champion results in obtaining the Reciprocal Rune, which you need for the quest. Repeat these steps twice for each planet until you get the next step in the quest line. The next quest is Wolves of Mars, which you obtain from Variks at the Reef. First you need to kill Fallen pirates across a variety of planets. You shouldn’t have much trouble finding or defeating these enemies once you reach the planets listed in the quest. You should be able to complete the first objective by simply performing a quick, low level strike featuring Fallen enemies. Once you've completed the first task, head to the Rubicon Wastes on Mars. At this point Archon will spawn with a few adds in tow. This is close to where you spawned for the Cerberus Vae strike. Complete the remaining quests you can receive from Variks and that can be completed from the main system screen in the game. With the first two quests down, wait until the reset for the following day, then you can gain access to the next quest. You get the Boolean Gemini Exotic Scout Rifle by completing the quest, Lost and Found. This quest is obtained by speaking to Petra in the Vestian Outpost. Lost and Found is actually very simple. All you need to do is kill 50 Taken and Hive enemies as you patrol the Dreadnaught. The enemies can be found in the Dreadnaught – the Mausoleum, Hall of Souls and Hull Breach. Once that step has been completed, head to the Court of Oryx and do a Tier 1 event until you get "Tech Witch Brooch." Turn in the Brooch, once you are at Rep Level 3, Petra will give you the gun

I have done all that