Director's Discretionary Time (DDT) nights are assigned to new programs in which an urgent observation of an unexpected and timely event of high scientific interest is required or those in which observations are essential for a certain project and cannot wait to be requested by the regular procedure. These nights are also intended for observations that could not be carried out due to technical problems or bad weather. To request DDT nights it is necessary to write a short proposal using the following form:
PI (or collaborator):
Title of the observation proposal:
In case a proposal has been granted in this semester, put the number of nights granted and observed:
Number of DDT nights:
Brief justification:
Observation Instructions:
The DDT proposal must be sent at least one week before the requested observation date and by e-mail to the OSN director (direccion.osn [at] iaa.es).
Publications including observations made during the DDT period should be acknowledged in the text and acknowledgements as follows:
    First page: Based on observations made with the ... telescope at the Observatorio de Sierra Nevada, operated by Instituto de Astrofísica de Andalucía (IAA - CSIC).
    Acknowledgements: We thank the Observatorio de Sierra Nevada for allocation of Director's Discretionary Time to this programme.