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Published online by Cambridge University Press: 19 July 2016
The star Herschel 36 (Her 36) which ionizes most of the Hourglass nebula has been observed during a lunar occultation as well as by speckle interferometry in the near infrared (NIR). From the lunar occultation data the strip brightness profile has been extracted which shows that in the L′ band Her 36 is extended with a FWHM of 0.45″. Subsequent speckle interferometry revealed 11 sources in a 6′ × 6′ area at a level of 0.15″ resolution. From the comparison of the brightness profile obtained by the occultation and the strip brightness profile synthesized from the speckle image, we conclude that Her 36 is surrounded by a very young infrared cluster.