Application for Observing Time
at the Calar Alto Telescopes

- General Information -

Spanish open time at the CAHA 2.2- and 3.5-m telescopes

Applications for observing time at the 2.2- and 3.5-m telescopes for the Spring semester 2021
(January 1 through June 30)

The Principal Investigator (PI) of the proposal must be affiliated with a Spanish Institution at the time of submission. Co-investigators (CoIs) from all countries are welcome to participate along with the Spanish PI.

As an ICTS (Spanish Singular Scientific Facility), Calar Alto offers a minimum of 20% of the available observing time. Due to the new status of the observatory, the number of available observing nights for the Spanish community is larger since 2019. For this reason, Calar Alto encourages Spanish PIs to send their proposals and take advantage of the new situation.



October 15, 2020 23:59:59 (CEST)

Earliest date for submission is September 17, 2020

Calar Alto also offers the option to buy observing time at the 3.5-m and 2.2-m telescopes. Interested PIs must submit a proposal following the regular Call for Proposals procedure. Those pay-per-night proposals approved by the TAC will be accepted. In these cases, a separate operation agreement (MoU) between CAHA A.I.E. and the respective user institution shall be signed.
Proposals submitted out of the regular period indicated in the regular Call for Proposals will also be considered and evaluated by the TAC, but their priority will be conditioned by the availability of the schedule of the semester. For further information please contact the CAHA director (director at

1.23-m telescope
For any use of the 1.23-m telescope, a separate operation agreement between CAHA A.I.E. and the respective user institution will be previously signed.
There is no definite deadline for this telescope, but a scientific proposal must be submitted to the CAHA director (director at, and it will be evaluated all year long by an external TAC. Only the best rated proposals for the 1.23 m will receive time on this telescope. Since the 1.23-m telescope with the
DRL camera can be used remotely, experienced observers are welcome to use it from the distance. Yet, for new users, we strongly recommend that the first run is performed in visitor mode for several nights, to gain sufficient experience at the telescope. Limited support will be available (day and night, on a best effort basis) for remote users, considering that larger CAHA telescopes have a higher priority.

Schmidt telescope
The Schmidt telescope (80-cm aperture, 1.2-m mirror) is currently under contract with the European Spatial Agency (ESA), with well-trained observers using it fully remotely, in an automated way, with Python scripts. The only instrument mounted is a 2k CCD (model FLI ProLine 23042, offering a field of view 44'x44' ), property of Deimos Space S.L.U., to do free band imaging. A filter wheel has just been installed to perform multi-band imaging and photometry.

"Based on observations collected at the Centro Astronómico Hispano-Alemán (CAHA) at Calar Alto, operated jointly by Junta de Andalucía and Consejo Superior de Investigaciones Científicas (IAA-CSIC)."
Alternatively, a similar phrasing appearing in the paper acknowledgements is acceptable. Failure to do so may result in penalties being applied by the TAC for future proposal submission from the same PI/Co-I(s).

If you would like to get an email reminder in the future to inform you about the start of the next proposal round, send an email to notice"at" with the subject line "CfP subscribe". In the same way you can unsubscribe from this list with the subject line "CfP unsubscribe".
Please note that a new proposal submission (web-based) system should be available for the Autumn 2021 semester. We'll inform in advance former users by email, and potential new ones through our News web page on Please stay tuned!

Last updated: September 16, 2020