Call for proposals

Observations with APEX, the Onsala 20 m telescope, and the Swedish LOFAR station 

(For EVN Call for Proposals, see the Astro VLBI page.)

Proposals are invited for observations with the APEX telescope, the Onsala Space Observatory 20 m telescope, and the Swedish LOFAR station in stand-alone mode, in the observing period April – ​August 2019.

Deadline: Friday 23 November 2018 (23:59:59 UTC)
(If you are considering submitting close to the deadline, please note that support will only be available during normal office hours.)

Proposals for APEX and the Onsala 20 m telescope are to be submitted through the NorthStar system.


APEX, the Atacama Pathfinder EXperiment, is a 12 m diameter submillimetre telescope at 5100 m altitude on Llano Chajnantor in Chile.

The receivers offered in this Call are the heterodyne receivers SEPIA (band 5, 159-211 GHz, and band 9, 600-722 GHz), PI230 (band 6, 200-270 GHz), and FLASH+​345 (band 7, 268-374 GHz), and the bolometer arrays ArTeMiS (350 and 450 μm ) and LABOCA (870 μm).

In general, proposals for Swedish time on APEX must have at least one co-I with a Swedish affiliation; however a maximum of 20% of the observing time will be open to international proposals (i.e. those without a PI or co-I with a Swedish affiliation) - to be scheduled based purely on scientific merit.

More information about APEX proposals.

Onsala 20 m

The Onsala 20 m diameter telescope in Sweden is equipped with receivers for 1850 GHz and 67116 GHz.

Our receivers now provide continuous coverage in the ranges 18-50 and 67-116 GHz with a 4 GHz bandpass. Recent upgrades include the capability to observe both sidebands simultaneously ("2SB") with dual polarisations. This enables e.g. such important lines as CS 2-1 near 98 GHz, and 13CO/C18O near 110 GHz, to be observed at the same time. The lower portion of the 3/4 mm band, 67-87 GHz, enables observations of low-energy or ground state transitions of important deuterated species.

The telescope is open for scientists from all countries.

More information about Onsala 20 m telescope proposals.


The Swedish LOFAR station at Onsala Space Observatory is an array of antennas for the frequency bands 10–90 MHz and 110–240 MHz. It is part of the International LOFAR Telescope (ILT), but is offered here in stand-alone mode.

The Swedish LOFAR station is open for scientists from all countries.

More information about Swedish LOFAR station proposals.




Calls for proposals for single-dish observations with the Onsala 20 m telescope and APEX, and for stand-alone observations with the Swedish LOFAR station in Onsala, are normally issued twice per year, with deadlines in April/May and October. VLBI-observations are handled through a separate proposal procedure (not by Onsala Space Observatory).


Calls for proposals for observations with some other related instruments can be found here:

The European VLBI Network (EVN)
> ALMA Science Portal at ESO
> European Southern Observatory (ESO) - Science Users Information
> Low Frequency Array (LOFAR) 

Note: APEX data can be accessed through the ESO Science Archive APEX Query Form.​​

Published: Fri 30 Aug 2013. Modified: Mon 29 Oct 2018