Version

Date

Changes

1.0

Apr 29, 2025

Original release.

Activity

Date/Time

Release of Call

April 29, 2025

Proposal Preparation Tool available

(DKIST Proposal Architect Tool)

May 29, 2025

Proposal Submission Window open

April 29, 2025, 07:00 GMT

Proposal Submission Window close

(Proposal Submission Deadline)

May 29, 2025, 23:00 GMT

Proposal Review Window open

June 3, 2025

Proposal Review Window close

October 2025

(depending on the number of proposals submitted)

Announcement of Proposal Selection

(Notification to Proposers)

October 2025

Experiment Generation Window open

(Contact with Proposers)

November 2025

Anticipated Execution Cycle start

(Start of Observing for Cycle 4)

March 2026

Anticipated Execution Cycle end

(End of Observing for Cycle 4)

November 2026

Cycle 4 will offer the following instruments:

• Cryogenic Near-Infrared Spectro-Polarimeter (Cryo-NIRSP)

• Visible Spectro-Polarimeter (ViSP

• Visible Broadband Imager (VBI)

• Diffraction Limited Near-InfraRed Spectropolarimeter (DL-NIRSP)

https://nso.atlassian.net/wiki/spaces/PDOI/pages/3534716929/Visible+Broadband+Imager+VBI?atlOrigin=eyJpIjoiOGNjYjFhYzA0YmZiNDM4NjhiNjFiMGEwYWRmMzBlODgiLCJwIjoiYyJ9

VBI-Blue Filters: Ca II K, G-band, Blue-Continuum, H-Beta.

VBI-Red Filters: H-Alpha, Red-Continuum.

Modes: speckle and/or frame selection on the full (optical) FOV or nominal central (physical) FOV.

• Combination of the filters is constrained by the choice of the observing configuration.

• Proposers are not required to use all available filters.

• The VBI-Red is not available under the FIDO configurations 1a and 1c.

https://nso.atlassian.net/wiki/spaces/PDOI/pages/3534717052/Visible+Spectro-Polarimeter+ViSP?atlOrigin=eyJpIjoiMGQ4NTlhNzMyM2RmNDA1MGJmN2QyODk3ZGJlNzU3MTkiLCJwIjoiYyJ9

Offered Lines: Ca II K 393.4 nm, Ca II H 396.8 nm (includes H I 397 H-Epsilon in the red wing of Ca II H), H I 410.1 nm (H-Delta) New, H I 434.0 nm (H-Gamma) New, Sr I 460.7 nm, H I 486.1 nm (H-Beta), Mg I b2 517.3 nm, Na I D2 589.0 nm and/or Na I D1 589.6 nm (either individually or both lines combined when centered at 589.3 nm), Fe I 525.0 nm, Fe I 557.6 nm New, Fe I 617.3 nm New, Fe I 630.2 nm, H I 656.3 nm (H-Alpha), Fe I 709.0 nm New, Ca II 849.8 nm New, Ca II 854.2 nm , Ca II 866.2 nm New.

Modes: intensity and polarimetry.

Slits: 0.2 arcsec, 0.1 arcsec, and 0.05 arcsec slit widths.

• Combination of spectral lines is constrained by the choice of the observing configuration.

• Proposers are not required to use all three arms of the ViSP. In case not all arms are used, Science Operations will add lines to our discretion for testing purposes. This will not have any impact on Proposers.

• Please be aware that specifically when including the Ca II H and/or K lines in the observation, the frame rate and cadence that the instrument can achieve is reduced (<20 Hz) due to the increased exposure times.

https://nso.atlassian.net/wiki/spaces/PDOI/pages/3534782465/Cryogenic+Near-Infrared+Spectro-Polarimeter+Cryo-NIRSP?atlOrigin=eyJpIjoiMmE2M2RkN2RkNjlmNDE0ODg5NmEyMDAyNGZmNTA2YzEiLCJwIjoiYyJ9

Offered Lines: Fe XIII 1074.7 nm, Fe XIII 1079.8 nm, He I 1083 nm, and Si X 1430 nm (spectroscopy only).

Programs: Two separate predefined programs for spectroscopic or spectropolarimetric observations:

• Coronal (off-limb) program.

• Prominence (and/or coronal rain) program.

New

https://nso.atlassian.net/wiki/spaces/PDOI/pages/3534782610

Offered Lines: Ca II 854 nm (arm1), He I 1083 nm (arm 2), Fe I 1565 nm (arm3).

Modes: intensity or polarimetry in the high-resolution (f/62) and mid-resolution modes (New).

• Combination of spectral lines is constrained by the choice of the observing configuration.

• Ca II 854 nm (arm1) is not available under the FIDO configurations 1a and 1c.

Combining Instruments - Observing Configurations (a.k.a. coude or FIDO Configuration)

Combining the ViSP, VBI Blue and/or Red channels, and the DL-NIRSP will be facilitated through a total of three different configurations of the Facility Instrument Distribution Optics (FIDO).

Please be aware of the following:

• Only one Observing Configuration per Proposal is supported.

• Using the Cryo-NIRSP is independent from these configurations.

• Proposers are not required to combine post-WFC instruments and can choose to request only one instrument in stand-alone mode.

• If Proposers decide to request the ViSP without the VBI, a default VBI configuration will be added by DKIST Science Operations.

• Cycle 4 will not support using the Cryo-NIRSP and post-WFC instrumentation within the same Proposal even if the requested observations are separated out during the day or on consecutive days.

Configuration 1

Config 1a

• ViSP: offered spectral lines < 950 nm: Ca II K 393.4 nm, Ca II H 396.8 nm (includes H I 397 H-Epsilon in the red wing of Ca II H), H I 410.1 nm (H-Delta) New, H I 434.0 nm (H-Gamma) New, Sr I 460.7 nm, H I 486.1 nm (H-Beta), Mg I b2 517.3 nm, Na I D2 589.0 nm and/or Na I D1 589.6 nm (either individually or both lines combined when centered at 589.3 nm), Fe I 525.0 nm, Fe I 557.6 nm New, Fe I 617.3 nm New, Fe I 630.2 nm, H I 656.3 nm (H-Alpha), Fe I 709.0 nm New, Ca II 849.8 nm New, Ca II 854.2 nm , Ca II 866.2 nm New.

• VBI-B: B-Cont only.

• DL-NIRSP: He I 1083 nm (arm 2), Fe I 1565 nm (arm 3).

• VBI-R: No light.

Config 1c

• ViSP: 490 nm < offered spectral lines < 950 nm: Mg I b2 517.3 nm, Na I D2 589.0 nm and/or Na I D1 589.6 nm (either individually or both lines combined when centered at 589.3 nm), Fe I 525.0 nm, Fe I 557.6 nm New, Fe I 617.3 nm New, Fe I 630.2 nm, H I 656.3 nm (H-Alpha), Fe I 709.0 nm New, Ca II 849.8 nm New, Ca II 854.2 nm , Ca II 866.2 nm New.

• VBI-B: Ca II K, G-Band, B-Cont, H-Beta.

• DL-NIRSP: He I 1083 nm (arm 2), Fe I 1565 nm (arm 3).

• VBI-R: No light.

Configuration 3

Config 3c

• ViSP: 490 nm < offered spectral lines < 643 nm: Mg I b2 517.3 nm, Na I D2 589.0 nm and/or Na I D1 589.6 nm (either individually or both lines combined when centered at 589.3 nm), Fe I 525.0 nm, Fe I 557.6 nm New, Fe I 617.3 nm New, Fe I 630.2 nm.

• VBI-B: Ca II K, G-Band, B-Cont, H-Beta.

• VBI-R: H-Alpha, R-Cont.

• DL-NIRSP: Ca II IR 854 nm (arm 1), He I 1083 (arm 2), Fe I 1565 nm (arm 3).

FIDO independent combination

Proposers should be aware that there is a FIDO independent combination that can always be executed only needing some exposure time adjustment for the VBI Blue with minimal impact on summit operations:

• ViSP: Mg I b2 517.3 nm, Fe I 525.0 nm, Fe I 557.6 nm New, Na I D2 589.0 nm and/or Na I D1 589.6 nm (either individually or both lines combined when centered at 589.3 nm), Fe I 617.3 nm New, Fe I 630.2 nm.

• VBI-B: B-Cont filter.

• DL-NIRSP: He I 1083 nm, Fe I 1565 nm.

Telescope

GOS Occulting

(near-limb pointing)

Yes

Limb-Tracking

No

Telescope Mosaicking

No

Pointing Target Types

All pointing targets are allowed and only constrained by individual instruments. Some targets are intrinsically risk-enhanced.

Cryogenic Near-Infrared Spectro-Polarimeter (Cryo-NIRSP)

Off-limb observations and respective targets only:

• Prominence.

• Active corona.

• Quiet corona.

Visible Broadband Imager (VBI), Visible Spectro-Polarimeter (ViSP), and Diffraction Limited Near-InfraRed Spectropolarimeter (DL-NIRSP)

On-disk and at/near-limb observations and respective targets:

• Quiet sun.

• Pore.

• Sunspot.

• Plages

• Filament.

• Coronal hole.

Risk enhanced targets:

• Spicules

Observing Program Types

Standard

Yes

Proposers requesting flare observations are welcome to do so under the standard program type (as before in Cycle 1, 2, and 3).

Special Proposal Types

Thesis enabling

Yes

Coordination (Flare Proposals only)

The DKIST will limit PI-led coordination testing to those Proposers requesting flare observations. The testing will take place during observing windows that do not coincide with Remote Sensing Windows of Solar Orbiter. We will work directly with the highest ranked accepted PI’s per FIDO configuration on the details of the coordination.

Proposers requesting flare observations who are interested in coordinated observations between DKIST, IRIS and/or Hinode need to Create a Request for Coordinated Observations in the Proposal Architect (PA).

Furthermore, we would like to continue gauging the interest in PI-led coordination with IRIS and Hinode for those who are not requesting flare observations. Please use the “Additional Comments” field to inform us about such interest.

Please do not provide any coordination information in the science justification and observing strategy files.

Profile Information

Additional Comments

DKIST would like to continue gauging the interest in PI-led coordination with Iris and Hinode. Those Proposers who are interested are invited to inform of this in the “Additional Comments” section.

Please do not provide any coordination information in the science justification and observing strategy files at this time.

Science Keyword Catalog

Proposers requesting a flare observation are asked to select “flares” in the science keyword catalog.

The science keyword catalog is empty with the exception of the flare keyword! Work in Progress.

Instrument Performance Calculators

(IPC)

Observing Strategy

VBI Instrument Details

Proposers requesting the VBI will be required to provide all specific instrument parameters in the Observing Strategy following the examples provided therein.

DL-NIRSP Instrument Details

Proposers requesting the VBI will be required to provide all specific instrument parameters in the Observing Strategy following the examples provided therein.

Flare observations

Proposers requesting a flare observation do not need to specify or mention a quiet-sun reference observation in the Observing Strategy nor do they need to add such an observation in the Proposal Preparation and Submission Tool's web interface. DKIST Science Operations will add those observations to the experiment in collaboration with accepted Proposers. The length of such additional observations will be limited to about 10 min.

File Upload

VBI, Cryo-NIRSP, DL-NIRSP IPC output file

(IPC = Instrument Performance Calculator)

Proposers are not required to upload a VBI, Cryo-NIRSP, or DL-NIRSP IPC output file.

ViSP IPC output file

Proposers are required to upload a ViSP IPC output file.

• Ca II K 393.32 nm

• G-band 430.52 nm

• Blue Continuum 450.28 nm (B-Cont)

• H-Beta 486.13 nm

• H-Alpha 656.28 nm

• Red Continuum 668.42 nm (R-Cont)

• TiO 705.83 nm

• Fe XI 789.18 nm

Speckle Reconstruction

Yes

Yes

Frame Selection

Yes

Yes

XX out of YY

Yes

Depends on the selection of speckle reconstruction and/or frame selection for a given FIDO configuration.

Yes

Depends on the selection of speckle reconstruction and frame selection for a given FIDO configuration.

FOV

Center (45 arcsec square): Yes

Full Field (2 arcmin square): Yes

Center (69 arcsec square): Yes

Full Field (2 arcmin square): Yes

ROI

No

No

Binning

No

No

Frame Rate

30 Hz (whenever possible)

30 Hz (whenever possible)