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Call 2024A

Call for Proposals to be supported via the Opticon Radionet Pilot (ORP) Trans-National Access programme (Grant Reference Number 101004719) in semester 2024A. The call is open to astronomical teams from any nation.

The call for observing time at OPTICAL telescopes supported by the ORP Trans-National Access programme will close on Sunday 10th September 2023 at 23.59UT exactly. Radio telescopes in the ORP are not included in this call. Please review this note carefully, even if you have used the TNA programme before.

The semester is centred on February 2024 to August 2024, but the semester dates for each telescope varies from January 2024 though to September 2024 to accommodate their normal semesters and maximise scheduling flexibility.

The maximum number of nights available at each facility is given in the table below. If your project can be done at more than one facility indicate in the technical case any alternate choices and note any technical issues such as changes in the time request which would result. It may be possible to move projects between telescopes to match scientific rating and demand.

Requests for multiple telescopes for the same scientific project must be included in a single proposal form. Request for projects with different scientific objectives should be made on separate proposal forms.

Unless noted below, any instrument available to national users of an observatory may be requested. Please consult each observatory web-page for instrument details and policies.

Long term status proposals can now be requested. A proposal can request long term status where the science goals would cover more than one semester. The maximum request for long term status will be 2 semesters, 2024A and 2024B, the remaining semesters supported by the ORP contract. Long term status proposals can use an additional 1 page of justification, split between scientific and technical justification according to the PI's preference. Only one additional page is allowed compared to a single semester proposal. Although the ORP telescopes support long term proposals, they reserve the right to cancel any long term proposal before the end or the requested period at their own discretion.

Projects must be scientifically competitive and will be ranked based on scientific merit and technical feasibility by a special international time allocation committee. The ORP team will attempt to schedule nights allocated by this committee subject to practical constraints on telescope and instrument availability. The oversubscription factor varies considerably between facilities and semesters but, as a guide, on average ~33% of proposals in recent rounds have been awarded time.

Proposals must meet certain rules for formal eligibility concerning team membership. Please pay attention to those rules or your proposal may be rejected without any scientific evaluation. Note that 'The user group leader and the majority of the users must work in a country other than the country(ies) where the installation is located'. Since many national astronomical facilities are located in remote sites we add the restriction that 'The group leader and the majority of the users must work at institutions which are outside the country/ies which operate the telescope'. The interpretation of 'majority' is 50% + 1 user, and the user group leader is a member of the user group. In the case of applicants with significant national infrastructures the proposal must contain an explanation of why the project cannot be executed with comparable national facilities. Please also note there is a prohibition on projects which could be applied for by the PI using national mechanisms open to them to access non-national telescopes. Examples of such mechanisms are guaranteed time due to international agreements or provision of instrumentation and bilateral national time exchanges between specific communities. Submission of similar proposals to national calls for the same instrument/project are strongly discouraged. The ORP process asks for technical support from each observatory and duplicated programmes will be severely disadvantaged. In such cases, please outline clearly why the proposals are different. Note that projects led by, or dominated by, non-EU persons are limited to 20% of the total allocations. If in doubt, contact the ORP representative (details below) for clarification.

Nights available at each Facility in semester 2024A
Facility Nights/hours available Semester Queue Scheduled Time critical observations (e.g. transits) Overrides allowed? Monitoring possible?
Nordic Optical Telescope (ORM, La Palma) 10 Nights 1 Apr 2024 - 30 Sept 2024 Only in scheduled service nights Yes Yes Yes

Notes: Apart from regular visitor mode, the NOT offers (queue) service mode observing and provides a wide range of options for flexible scheduling through Target-of-Opportunity programs and/or monitoring programs on any time-scale (from hours to years).

A complete overview of the instrumentation, with links to dedicated webpages can be found here:

Liverpool Telescope (ORM, La Palma) 50 Hours 1 Jan 2024 - 31 Aug 2024 Yes Yes Yes Yes

Notes: Robotic. Request in hours. The instruments RISE, IO:O, MOPTOP and SPRAT will be available.

TNG Galileo (ORM, La Palma) 10 Nights 1 Apr 2024 - 30 Sept 2024 No Yes Yes Possible with severe limitations

Notes: Service and visitor modes, not queuing. Service time is scheduled on fixed nights so, e.g., seeing requirements do not apply. Objects included in the TNG Protected Target List cannot be requested.

Fractional nights can be requested in 1 hour blocks, assume 9hr per night.

A Long-Term programme on the optical counterparts of gravitational wave events is already running at TNG. Therefore, proposals on this topic will not be accepted.

Monitoring mode is subjected to severe limitations at TNG. The schedule is dominated by long blocks of full-nights belonging to Large Programs dedicated to Exoplanetary Science. Proposals requesting high frequency monitoring of exoplanets or other targets (more than 1 point per week) should clearly specify the ideal and the minimum rate need to get the expected scientific results. To optimize telescope observing time and scientific return in exoplanets observations, time sharing with Large Programs is necessary. A time sharing agreement will be requested after the proposals are accepted.

CAHA 2.2m (Calar Alto) 5 Nights 1 Jan 2024 - 30 June 2024 Yes Yes No Yes
Notes: CAFE, CAFOS and ASTRALUX are available.
CAHA 3.5m (Calar Alto) 10 Nights 1 Jan 2024 - 30 June 2024 Yes Yes* No Yes*

Notes: *only possible with PMAS and CARMENES

From the beginning of 2021 there will be three long-term Legacy programs at the 3.5m: CARMENES (detection, follow-up and characterization of planets around M dwarfs with radial velocities), KOBE (K-dwarfs orbited by habitable exo-planets) and CAVITY (Galaxies inhabiting the loneliest regions of the Universe). The agreements with CAHA protect these three science cases. So we suggest that researchers interested in similar scientific cases contact the observatory staff ( before submitting their proposals, in order to ensure that there will be no conflict with the legacies.

CARMENES, PMAS and Omega 2000 are available.

Anglo-Australian Telescope. (Siding Spring) 10 1 Feb 2024 - 31 July 2024 No Yes* No Yes

Notes: *Please contact the Observatory to discuss your plans before submitting a proposal for time-critical observations and monitoring.

Current instrument availability is listed on the AAT instrument status page. Proposers should review important information for applicants on the "Applying for Observing Time" page after the normal AAT Call for Proposals is released.

All approved OPTICON programs will be supported by local AAT support astronomers. Observers should fill out the Form for Visitors and Remote Observers at least one week before their run starts.

Please refer to the Form for Visitors and Remote Observers for the latest updates on the local restrictions due to COVID.

Telescope Bernard Lyot (Pic du Midi) 80h = 10N 1 Mar 2024 - 31 Aug 2024 based on TAC priority Yes Possible (min 24hr notice) Yes

Notes: Note that all 2024A applications to TBL from non-French astronomers must be made via this ORP call and not via the national French process. In 2023B the first tests on the SPIP infrared spectropolarimeter will be done, and this instrument should also be offered in 2024A to the ORP community.

Observatoire de Haut Provence 1.93m 10 Nights 1 Mar 2024 - 31 Aug 2024 No Yes No Yes

Notes: Note that all 2024A applications to OHP from non-French astronomers must be made via this ORP call and not via the national French process.

A Low-Res (SPRAT design) spectrograph, MISTRAL is now available in visitor mode.

SOPHIE spectrograph imaging CCD will be updated from mid-October until end of November 2023 and will not be available on T193 telescope during this period.

Canada France Hawaii Telescope 4 1 Feb 2024 - 31st July 2024 Yes Possible for high priority proposals Yes Yes subject to instrument availability

Notes: NO visitor mode. Queue scheduled only.
Please pay particular attention to overheads. MegaCam delivers 5h/night, WIRCAM 5h/night, SITELLE 6.5h/night, SPIRou 7h/night, and Espadons 7.5h/night. Useful information on heavily subscribed RA ranges and other scheduling factors can be found on the CFHT Call for Proposals webpage.

SPIRou is now available with 7 hours per night.

Carlos Sanchez Telescope (Obs del Teide, Tenerife) 14 1 Jan 2024 - 30 June 2024 Yes Yes No Yes
Notes: Visitor, service or remote observing modes available.
Aristarchos Telescope (Helmos Observatory, Greece) 20 1 Jan 2024 - 31 March 2024 Yes Yes Yes Yes
Notes: The direct imaging CCD camera and the RISE2 wide-field fast imager will be available for this call.
Las Cumbres Observatory (LCO) 400 (hours) 1 Feb 2024 - 31 July 2024 Yes Yes Yes Yes
Notes: Robotic. Request in hours.

The ORP contract is for time on the LCO 1m network.

Time on the 1m network may be exchanged for 0.4m network time at a ratio of 1:2.

2m time is not offered.

1.0m - SINISTRO Imaging, NRES Spectroscopy

0.4m - SBIG and QHY600 Imaging

Meade 0.4m telescopes with SBIG 6303 cameras are being replaced by
Planewave DeltaRho 0.35m telescopes with QHY600 CMOS cameras.
Information on this is at: Planewave Delta Rho 350 + QHY600 CMOS camera systems

Information on the ongoing LCO Key Projects is available at: LCO Key Projects

ORP proposals that contribute to and collaborate with LCO Key Project teams are encouraged,  but direct competition on a per-target basis is not permitted.  For such proposals, please consult with the relevant Key Project PI.

REM (La Silla, Chile) 300 (hours) 1 Apr 2024 - 30 Sept 2024 Yes Yes Yes Yes

Notes: Robotic. Request in hours. Observations are robotically scheduled, but time constraints and repetition rates can be inserted.

Please see

REM can observe simultaneously in the bands g, r, i, z, (visible) plus one infrared chosen among (z', J, H, Ks).

SALT 50 (hours) 1 May - 31 October 2024 Yes Yes Yes Yes

Notes: Only service observing. Limited pointing envelope due to telescope design. Phase 2 (observing definition) forms will be required from successful applicants.

Only queue-scheduled service mode. Please read their latest Call for Proposals document and use the SALT visibility calculator and the instrument simulators (all of which can be found at to ensure you fully understand the telescope and its pointing envelope and calculate the overheads correctly.

Please include in the technical justification a detailed explanation of the signal-to-noise requirements and how the overheads have been calculated. Please also discuss extra constraints, such as waiting period between observations, time restrictions, weather and Moon requirements etc. in your technical justification.

Phase 2 observing forms will be required from successful applicants.

NIRWALS, SALT’s new IFU-fed NIR spectrograph, is still being commissioned at the time of this Call.  We expect it will be available to users during the semester, but due to the nature of commissioning work, its availability is uncertain.

Facilities not in this list are not offering EU supported observing in this semester, even though they may have done so in the past and may do in the future. Some facilities have policies which allow international users to apply via their regular national proposal process or to specific international time which is not part of the ORP pool. Proposals made to and approved via non-ORP mechanisms will not qualify for travel grant support. Note that the results of the ORP TAC review will be communicated to the national TACs to avoid undesirable duplication.

ORP facility users must ensure that all efforts are made to publish any resulting scientific publications, including data, in accordance with H2020 Open Access Guidelines as stipulated in the Grant Agreement.

Successful proposers will receive travel funds as necessary for them to take up the observing time. This will normally be for a single observer. If travel support for more than one observer is required for clearly demonstrated scientific reasons it will be necessary to get confirmation from the Project Scientist (details below). Please also see the section on Trans-National Access on our Rules for Travel page.

For downstream processing by the individual observatories, successful proposers may be required to complete and submit either Phase 1 (application forms) or Phase 2 (detailed observing request) forms. In this situation the science case will not be re-evaluated. The forms will be used to extract practical information required for the observatory proposal reporting and scheduling databases.

Groups which have had ORP resources from previous semesters will be required to provide reports on previous resource use, project status and publications, etc., as part of any new proposal.

Please note that we adopt the following definitions and you should consider which facilities offer these options when defining your project:

Semester: This is the range of dates over which observations may be requested. It is not the same for each observatory.

Queue Scheduled: Weather and time dependent flexible scheduling to meet observing criteria specified by the user and scientific priority set by the observatory. Usually carried out by staff astronomers. Will not be attempted if specified conditions cannot be met and will not be carried over into future semesters.

Time Critical Observations: Predictable events which require special schedule constraints (eg. Planet transits, asteroid occultations, simultaneous observations with spacecraft)

Overrides: Observations which cannot be scheduled in advance but must be triggered by the PI of the proposal to take precedence over scheduled observing due to nature of a statistically likely but unpredictable event (eg. GRB, Supernova, Comet Outburst). Individual observatory policies may limit the number and frequencies of such triggers. Please check the observatory webpages for details noting that sometimes this mode is referred to by individual observatories as a Target of Opportunity (ToO).

Targets of Opportunity: Completely unexpected and unpredictable events of very high interest resulting from a specific discovery (eg A whole new class of object discovered in a survey, a radio signal or biomarker from an extrasolar planet, discovery of an object predicted to impact Earth). Almost by definition observing time for such projects cannot be scheduled in advance and would normally be allocated via a direct request from the PI to each observatory for director’s discretionary time. Such eventualities are almost impossible to accommodate within the ORP scheduling process. If you plan to request time for such a project, as distinct from the reasonably predictable overrides as defined above, please contact the TNA organiser (details below) first to discuss options and possible triggering scenarios on a case by case basis. For the moment, follow up of gravitational wave events are considered to be in this category as recent examples have been well covered via DDT and pre-existing national ToO/Time Domain Astronomy programmes.

Monitoring: Observations which require a regular cadence (eg SN decay, giant planet weather, comet activity variation with heliocentric distance) but which are not highly date/time specific. May be executed in ‘service mode’ to minimise PI travel.

Service Mode: Observations which are carried out by a local astronomer as part of a classically scheduled operations without flexibility for specific observing constraints. Also known as ‘Delegated visitor mode’. The PI is not expected to provide an observer.

Robotic: Automated telescope or network of telescopes using software to schedule and execute observations according to observatory schedule, weather and priority algorithms without direct human intervention on a nightly basis. Essentially automated queue scheduling without real-time human discretion.

The proposal software, a variant of the NORTHSTAR system already in use at several observatories, is available at the following url: You are required to register for account (only minimal information is required) and you can then create, share and complete your proposal on-line. Note that each Northstar system is unique, you cannot use a Northstar account created for another TAC process (e.g. an ex RADIONET account). Download the latex .cls file and the sample 'case for support' tex file. (NB. Updated version for 2019A onwards) These will provide a template which you should use and contains a summary of what information is suggested for the scientific case. Use this rather than creating your own latex file from scratch.

Proposals using the wrong template, or which have been modified to use smaller fonts or narrow margins, will be disqualified at the TAC meeting.

For general questions about the call, registering with NORTHSTAR and policies, rules and procedures look in our FAQ page and if this does not help you then contact the Optical Trans-National Access coordinator (details below). Note that technical support for the submission software is not provided out-of-hours or on weekends and late applications will not be accepted. Large target lists can be uploaded as a suitably formatted file. In the case of large projects, or those with a large list of possible targets from which only a subset will be observed, upload only a sample of representative targets.

For specific practical information about telescopes/instruments, please contact the local observatory team directly.

Good luck

Dan Dicken (

Optical Transnational Access Lead