Observing with GREGOR

The GREGOR observing plan for the first half of 2025: 

→ will be published here in February 2025  ←

GREGOR Observing Time Allocation Procedure

Observing time at GREGOR is allocated by the KIS TAC for the German KIS time, the Spanish TAC for the 20% Spanish time, and the EAST TAC for the 5% of the International Time Programme. More detail on the TAC procedures below. The deadline for proposals for observing campaigns in the first semester of 2025 (Period 2025A) is 24 January 2025. The period for scientific observations is from April until August. 

GREGOR Observing Proposal Template 2025A:

For the German KIS time and the International Time Programme (ITP/CCI) use the following LaTeX template:

LaTeX template            PDF Preview

For questions on the 2025A Observing Campaign please contact Rolf Schlichenmaier via kis_tac@leibniz-kis.de.

The following instrument modes are available in 2025A:

GRIS: The instrument GRegor Infrared Spectrograph can be customised with any of the following setups (CWL=central wavelength):

1. One spectral channel: Any individual wavelength in the range 1.0-1.3 µm or 1.55-1.80 µm. Sampling and spectral ranges depend on the particular wavelength. At a CWL of 15650 Å, the spectral sampling is 40 mÅ and a spectral range of 40 Å
2. Two spectral channels working simultaneously at:
   • CWL 10830  with a spectral sampling of 14.6 mÅ and a spectral range of 14.6 Å
   • CWL 8542  with a spectral sampling of 11.1 mÅ and a spectral range of 11.1 Å
3. Two spectral channels working simultaneously at:
   • CWL 12820  with spectral sampling of 25.6 mÅ and a spectral range of 25.6 Å
   • CWL 8542  with a spectral sampling of 16.3 mÅ and a spectral range of 16.3 Å

In all the options above, polarimetric and spectroscopic modes are available after the successful commissioning campaign in 2024.

In the case of the input to spectrograph, there exist two options:

1. Long slit with a field-of-view of 60 x 0.135 arcsec².
2. Image slicer IFU mode with a slitlet size of 100 microns (sampling of ~0.38 arcsec) and a field-of-view of 3 x 6 arcsec². An interlaced mode also exists that involve two sequential measurements perpendicular to the slitlets separated ~0.19 arcsec (the so-called double-sampling mode)

In both cases, the sampling along the slit/slitlet direction is 0.135 arcsec. 

HiFIplus: The upgraded High-resolution Fast Imager (HiFI+) consists of three camera control computers with two synchronized sCMOS cameras each. HiFI+ offers near-diffraction limited imaging at high cadence in six spectral windows: Ca II H, G-band, blue continuum, broad- and narrow-band H-alpha, and TiO. Dichroic beamsplitters splitting at 650 nm and 740 nm can be selected. With the 650 nm beamsplitter, H alpha is in Slit Jaw of GRIS. With the 740 nm beamsplitter, Halpha and TiO@707nm can be observed with HiFIplus (and is not visible in SlitJaw).

When using the beam splitter of 650 nm it will be available only for the blue channels.

New off-limb AO: GREGOR has a new AO mode (H-alpha-AO) which allows locking the AO off-limb on prominences (if the prominence shape permits). This mode is in comissioning and offered on a shared-risk basis. It allows to use of HiFI+ Hɑ 656 nm narrowband and GRIS He 10830 Å simultaneously with Ca II 8542 Å.

ZIMPOL: In collaboration with IRSOL, high-precision spectropolarimetric observations with the ZIMPOL polarimeter are offered in service mode for projects requiring a short observing time (up to a few hours). Observations are carried out in combination with GRIS (only slit mode), two slit-jaw cameras, and standard AO (H-alpha-AO in testing phase). In combination with the GREGOR Slow Polarization Modulator (GSPM), the ZIMPOL setup is particularly well suited for measuring polarimetric signals with precision and accuracy down to 0.001 %, such as produced in the quiet photosphere near the solar limb by scattering and modified by the Hanle effect. The available spectral range is 4250 Å - 6800 Å, and the spectral window is a few Angstroms (depending on order and wavelength), the polarimetric precision is about 10^-5, the pixel scale is 0.32 arcsec/pixel, the area covered by the camera is 43.6 (±0.4) arcsec, and the slit width 0.26 (±0.02) arcsec (70 µm). Contact Renzo Ramelli:  renzo.ramelli@~@irsol.usi.ch.