Sh2-298 or NGC2359, one of the nebulae whose spectrum has been analyzed in this work. Combination of images in the filters B (blue), R (green) and H-alpha (red) obtained with the Wide Field Camera of the Isaac Newton Telescope (INT) of the Isaac Newton Group of telescopes (ING) at the Roque de los Muchachos Observatory (Garafía, La Palma). Credit: Ángel R. López-Sánchez (AAO/MQU) and Sergio Simón-Díaz (IAC).