Cat´s Paw Nebula: Bear Claw Nebula as it is also sometimes called, was discovered 1837 by John Herschel at the Cape of Good Hope (Cape Town). If  imaged in the narrow-band hydrogen Ha spectral line it shows many interesting details otherwise not easily visible. Several very heavy stars, as big as ten times the mass of our sun, are ionizing the hydrogen gas in their neighbourhood, thus emitting light predominently in this spectral line. The nebula is in a distance of 5500 LY from us.