During the first years of operation, the OAJ telescopes and cameras will be mostly devoted to conduct the Javalambre Physics of the Accelerating Universe Astrophysical Survey (J-PAS; started in 2023) and the Javalambre Photometric Local Universe Survey (J-PLUS; since 2016). Both J-PAS and J-PLUS will provide powerful 3D views of the Universe that will be made publicly available to the community as legacy projects.

The OAJ Open Time

The OAJ Open Time is splitted in semesters as given below:

• Semester A: January 1st – June 30th
• Semester B: July 1st – December 31st

JST250

The OAJ regularly offers Open Time with JPCam at the JST250, open to the astronomical community.

• OAJ JST250 Director’s Discretionary Time(OAJ-JST250-DDT), up to 30h/semester. OAJ-JST250-DDT proposals are reserved for testing the feasibility of potential future observing cases of great scientific impact, for the follow-up of objects in which a quick response is key for the scientific return, for astronomical unexpected events, or for high impact science cases for which the JPCam FoV and its filter system are specially suitable to the point that it could hardly be conducted with other accessible infrastructures. OAJ-JST250-DDT proposals are evaluated by an internal committee chaired by the Director of CEFCA.

OAJ-JAST250-DDT proposals can be submitted at any time. Details of the call are available in the CfP document.

Notice that, in addition to the observing time described here, CEFCA also offers Legacy Surveys with the JST250 telescope for up to five years. Details of the Legacy Survey program can be found here. Prior to the Legacy Survey program, CEFCA offered Shared-Risk Programs with the JST250 telescope. These programs were carried out during the 2025B, 2026A, and 2026B semesters.

We hosted a live online session to support users with the CfP details, observing tools, and the proposal submission process. The recorded videos can be found at:

https://youtu.be/JI12v0832lk and https://youtu.be/OPtqa3DXSIE

You can find the presentation in PDF format: here

JAST80

The OAJ regularly offers 80h of Open Time with T80Cam at the JAST80 per semester to the astronomical community. The rest of the available time is devoted to conducting large-sky surveys or Legacy Surveys. In total, more than 25% of the observing time of the JAST80 is offered.

Here only the call for regular observing time is described.

Two different categories of Open Time are defined for the JAST80:

• OAJ JAST80 Regular Programmes (OAJ-JAST80-RPs). OAJ-JAST80-RPs are defined as short observing projects that require no more than 40h/semester. These projects are expected to benefit from the large FoV and/or the unique filter set of the OAJ telescopes. Notice that the only available observing mode is the Target of Opportunity (ToO).
• OAJ JAST80 Director’s Discretionary Time (OAJ-JAST80-DDT), up to 30h/semester. OAJ-JAST80-DDT proposals are reserved for testing the feasibility of potential future observing cases of great scientific impact, for the follow-up of objects in which a quick response is key for the scientific return, for astronomical unexpected events, or for high impact science cases for which the T80Cam FoV and its filter system are specially suitable to the point that it could hardly be conducted with other accessible infrastructures. OAJ-JAST80-DDT proposals are evaluated by an internal committee chaired by the Director of CEFCA.

The average length of the astronomical night at the OAJ is about 8.4h.All the different categories of Open Time are split into the same 1:2:1 ratio of Dark:Gray:Bright time conditions.

In case that the open time allocated for OAJ projects is not awarded completely (either due to a scarcity of proposals or to their unfeasibility and/or low quality), the OAJ-TAC may decide to move this time to any other category with overpressure of high quality proposals. Otherwise, this time will be moved to the OAJ-DDT and the J-PLUS/J-PAS time in the ratio decided by the OAJ-TAC.

Notice that, besides the observing time described here, Legacy Surveys with JAST80 telescope for up to 5 years are offered by CEFCA. You can see the details here.

Calls for open time currently available are indicated below:

Applying Conditions & Submission Instructions for JAST80

The opening and deadlines of the call for proposals for OAJ-RPs for JAST80 in each semester are:

• Semester A – Openning: August 1st; Deadline: September 15th.
• Semester B – Openning: February 1st; Deadline: March 15th.

OAJ-DDT proposals can be requested at any time.

Proposals shall be filled in and submitted following the OAJ Observing Proposal Tool and the instructions available at this website. To access this tool, you must be logged in, for which you must have registered previously at the OAJ website. If you have any problem to log in, please contact us.

Observing at the OAJ

By default, OAJ proposals are executed in queue mode. The visitor mode can be considered upon request depending on the available resources and logistics at the OAJ.

Deliverables and Proprietary Time

The data collected at the OAJ as part of an Open Time proposal will be provided to the contact person indicated in the proposal form, once the observations are concluded and validated by CEFCA.

The delivered data account for:

• Raw scientific data
• Calibration frames (bias, darks, flatfields and spectrophotometric standards)
• Scientific data reduced and photometrically calibrated in a standard way with the specific OAJ pipelines developed by the CEFCA team for each instrument

After a proprietary time of one year, the data will be made public through the OAJ External Data Access Machine.

Acknowledgments

Publications derived or partly based on OAJ observations shall be acknowledged as follows:

“Based on observations made with the (JAST80 and/or JST250) telescope/s at the Observatorio Astrofísico de Javalambre, in Teruel, owned, managed and operated by the Centro de Estudios de Física del Cosmos de Aragón.”

This sentence shall be included as a footnote in the first page of the publication. If this is not possible, it will be included in the Acknowledgment section of the manuscript.

In case of a publication derived from the OAJ DDT, the Acknowledgment section of the manuscript shall include the sentence:

“We thank the Centro de Estudios de Física del Cosmos de Aragón for allocation of Director’s Discretionary Time to this program.”

In case of a publication that makes use of OAJ data reduced by CEFCA with the OAJ pipelines, the Acknowledgment section of the manuscript shall include the sentence:

“We thank the OAJ Data Processing and Archiving Department (DPAD) for reducing and calibrating the OAJ data used in this work, as well as the distribution of the data products through a dedicated web portal.”