What’s New?

• Apr 22, 2026

  • Added notes clarifying the what the spatial coordinates box mean.

• Apr 21, 2026

  • Added note about Dataset Extras.

  • Updated Dataset Details images.

  • Update to the Spectra Axis filter.

• Feb 9, 2026

  • Added descriptive notes around the information contained in the dataset details page.

• Jan 6, 2026

  • Deleted the prior update from Oct 14. Updated the manual to note that the filter for searching by Polarimetric Sensitivity (formerly Accuracy) is not currently available, as explained in the text.

• Oct 14, 2025

  • Updated Section 2.6.8 Polarimetric Accuracy → Polarimetric Sensitivity.

• Aug 28, 2025

  • Updated the manual for some unit corrections in the Portal.

  • Added a section on what to do if you forget to start a personal endpoint while downloading data.

  • Added informational notes about the Fried Parameter.

  • Added informational notes about how the rounding of the Portal displays, which may make it appear that results outside of the filter bounds are being presented.

• Jul 14, 2025

  • Updating the manual for the new Product ID.

    • For each dataset created by an Experiment, a unique ID, known as the Product ID (e.g., L1-JAZXI), is created. The Product ID is a new identifier introduced to address the issue that Dataset IDs are not preserved during reprocessing. The Product ID will remain the same regardless of how many times a dataset is reprocessed. This makes it the ideal ID for sharing datasets with other users. See alsoDKIST Level 1 Data Product IdentifiersPreview.

Table of Contents

The DKIST Data Center Search Portal is one of the main tools for accessing DKIST data. It presents a clear, visual interface to the calibrated DKIST datasets. The Portal enables search, filtering, and download functionality for all public datasets. While the Portal allows searching metadata for all datasets, a user can download datasets only for which they are a PI or Co-I during the exclusive access period. The Portal uses search filters that provide a rich interface for finding datasets of interest, with granularity ranging from individual datasets to all datasets generated for a proposal. In addition, searching using filters such as wavelength or spectral line, spatial coordinates, or whether an observation contains polarization data, allows for broad searches across the entire archive. These filters are key to the Portal's operation and are described in detail below. Lastly, in addition to creating new search filters, another key feature of the Portal is the ability to save filters for reuse, e.g., to find previously searched datasets.

1.1 DKIST Data Products

Datasets from the DKIST instruments are both large and complex. To maximize the scientific return from the data, it is necessary to provide calibrated data products to the user. The Data Center is responsible for calibrating the raw data received from the telescope into Level 1 data products. As raw data is received, it is divided into processing candidates to create a processed dataset. A dataset is roughly defined by the following items:

• Instrument

• Broad wavelength

• Similar instrument parameters

For example, an experiment that uses VBI with observations at Ca II K (393.327 nm) and H-beta (486.139 nm), and DL-NIRSP with observations at Fe XI (789 nm) and Ca II (854.2 nm) would result in 4 datasets. 

Each dataset contains a series of calibrated Level 1-compliant FITS files with image data and attached headers, and provides a single calibrated frame per FITS file. In addition to the calibrated data files, the dataset includes a quality report, a browse movie, and one ASDF file to support the DKIST User Tools and enable more granular data discovery. All of these files are available via the search Portal and the User Tools, along with the datasets.

1.1.1 Level 1 Data

The calibrated (Level 1) datasets consist primarily of FITS files from the same instrument program. The aim of the calibration is to remove as many of the telescope and instrumental effects as possible. Initial calibration codes are based upon those supplied by the Instrument teams. Undoubtedly, calibration upgrades or additional routines will be needed as experience with each instrument is gained. Data users are encouraged to provide feedback to the Data Center on any additional calibration steps they may find necessary to conduct their science. Please see also I found a bug in the DKIST Data Center Calibration Pipeline - now what?Preview

1.1.2 ASDF File

The Advanced Scientific Data Format (ASDF) is a next-generation interchange format for scientific data. Although it can also be used to store image data, the Data Center uses it to store all header information, world coordinate information, and file ordering for all the FITS files in a dataset. The User Tools use this information to present a unified view of the dataset, enable finer-grained filtering of any header field (not possible in the Search Portal), and support selective file downloads.

1.1.3 Browse Movie

To give a user a snapshot of a dataset's data, a browse movie is created for each dataset.

1.1.4 Quality Report

It is vitally important for both the Data Center and the scientists to be confident in the files produced by the calibration process. To this end, a Quality Report is created for each processed dataset. This report details the steps used to create the calibrated dataset and any errors encountered during the process. This could, for example, be a smaller-than-optimal number of dark frames used for averaging during the dark calibration step. In addition, the Quality Report will include information on weather conditions, sky brightness, and seeing, which may help a scientist more easily find datasets or parts of datasets of interest.

1.1.5 Dataset Extras

Following reprocessing of the ViSP data (April 2026), the Data Center has created a new set of data products called dataset extras. All dataset extras are included with a full download of the main dataset and live in a subdirectory called “extra”. The primary purpose of dataset extras is to provide a common context between the user and the DKIST Data Center when discussing issues seen in the L1 data. However, for experienced users, they provide a detailed look at the intermediate calibration products used to create Level 1 data. Additionally, they make it much easier for the DKIST team to monitor trends in various aspects of Telescope operation. A full description of the dataset extras is given at the link:https://docs.dkist.nso.edu/projects/visp/en/stable/dataset_extras.html

1.1.6 Level 2 Data Products

Separate from the Data Center calibration effort, there is an effort to create higher-order data products, such as magnetograms, from the publicly available data. It is envisioned that this effort would regularly create higher-order products for a small number of lines. In the future, these higher-order products will also be available from the Portal.

1.2 Downloading DKIST Data

When dealing with datasets that DKIST will create (on the order of multiple Terabytes), old methods of data transfer like FTP are just not suitable. In addition, because the Data Center has only finite networking resources, it must be able to shape and limit requests to ensure a fair distribution of resources among all data requestors.

Delivering DKIST data to the scientist thus requires a system that:

• will be stateful

• can continue if interrupted without restarting

• can deal with transfers that might last many days and

• guarantees the veracity of the downloaded data 

To provide scientists with the best possible download experience, DKIST DC uses Globus to transfer files to users. (See https://www.globus.org/data-transfer .)

Downloading DKIST data will require a few extra steps, including creating a Globus account and defining an "endpoint" for a user’s data.

An "endpoint" is one of the two file transfer locations – either the source or the destination – between which files can move. Once a resource (server, cluster, storage system, laptop, or other system) is defined as an endpoint, it becomes available to authorized users who can transfer files to or from it. Authorized Users are users (PIs, Co-Is) who are part of the proposal team for which data were collected. Only authorized users can download the data during the exclusive access period.

The DKIST Data Center will be the source endpoint, and the destination endpoint will be a place at a user's institution or research group facility designed for downloading large datasets. It will also be possible to download datasets/subsets to a user’s laptop, but these datasets will be very large. (See also Logging in to Globus below.)

Users can search for datasets without being logged in, but they must authenticate with Globus to download datasets. Note that searches may display datasets that are currently in the exclusive access period. Although metadata is available for these searches, a user cannot download the data unless they are part of the proposal team and only after the exclusive access period has expired.

The primary search mechanism for DKIST data is the search Portal. Figure 1., below, displays the default view when a user accesses the search portal dashboard. By default, the portal displays datasets sorted by Dataset Creation Date, newest first. Note that while datasets may appear in the search, some may be downloadable only by the PIs or Co-Is of the proposal to which the dataset belongs during the exclusive access period.

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Figure 1. Default portal view.

2.1 Search Results

The search Portal uses filters to construct queries that return datasets matching multiple criteria. These search filters appear in the left panel of the Portal. One such filter example is given below, for data taken between 2025/10/31 21:00 and 2025/10/31 23:30 UTC. An in-depth look at the Portal filters is given below.

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Figure 2. Basic experiment execution date-range search in the Portal.

The standard search results are summarized below. As filters are applied, the number of matching datasets is continuously updated. The Portal also shows how many datasets have been processed in total and how many are currently selected for download.

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Figure 3. Summary of results matching the current filter, including those selected for download.

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Figure 4. Results from the filtered data search. Two of the datasets have been added to the search cart.

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Figure 5. Click on the up/down arrows to the right of the proposal description summary to view the full proposal description text. As indicated by the red symbol on the far left of the results summary, this dataset is still within the exclusive access period

Field	Description

Field	Description
Open	Add the dataset to the cart for download via Globus.
Open	Add all the datasets to the cart for download via Globus.
Open	Remove the dataset from the cart.
Open	Remove all the datasets from the cart.
Open	The dataset is in an exclusive access period and is generally not available for download. Log in if you are the PI/Co-I to download the data. See Section 2.3 for more details on exclusive access periods.
Open	Download the ASDF file for this dataset.
Open	Download the Quality Report for this Dataset.
Open	View the browse movie for this dataset.
Proposal ID	This dataset is within the exclusive access period. Click the symbol for more information. If you are the principal investigator for this dataset, you will need to log in to download it.
Product ID	The unique ID for each dataset, which is part of the proposal. See also more on the Product ID.
Description	The unique ID of the dataset. Click on the link for more information about the observations in the dataset. See figures 6-8.
Observation Wavelength	The wavelengths contained within the dataset.
Dataset Creation Date	The date at which the dataset was created after calibration by the Data Center.
Experiment Execution Date	The date on which the experiment was executed. Experiments generate the observations for a dataset as part of a proposal.
Instrument	The instrument that took the dataset

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Figure 6a. Example of part of the details page for each dataset.

The top half of the dataset details pages contains links to download the Movie Preview file, the ASDF file, and the Quality Report. If you are not logged in and the dataset is within its exclusive access period, you will see a red banner indicating that it is not available for download. If you are logged in as the PI or the dataset is publicly available, there will be no exclusive access period banner; instead, there will be a link to add the dataset to the cart, as shown below.

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Figure 6b. Button to add dataset to cart

Additionally, you can play the preview movie in the browser. The full proposal description is provided, along with a link to the code used to calibrate the data.

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Figure 6c. Example of part of the details page for each dataset

Additional information about the dataset is also presented on the details page. The pages also list other datasets from the observing program that created the dataset, as well as all datasets available under the particular proposal. Users are also urged to review the quality report for more information about the conditions observed and any issues that may have arisen during calibration.

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Figure 6d. Example of a dataset that has not been reprocessed

The Product ID is a new ID created to address the problem that Dataset IDs are not preserved across reprocessing. The Product ID will remain the same regardless of how many times a dataset is reprocessed. This makes it the ideal ID for sharing datasets with other users. A new section has been added to the dataset details section (also reflected on the details page for the Product ID) that details the reprocessing of a particular dataset.

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Figure 6e. Example of a dataset that has been reprocessed

The figure above shows an example of a reprocessed dataset. Here, GKCQRP is the new Dataset ID, and KSLNTD is the previous Dataset ID. The Data Center keeps the current and previous datasets available, and also notes the dataset before the previous one, which will have been deleted. Note that you can also use the Dataset ID to search for data, and it will give you almost identical detail pages. From Figure 6d, searching for L1-LKULP (Product ID) and MGOQDS (Dataset ID) accesses the same information.

2.1.1 DKIST Spatial Coordinates

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Figure 6f. Comparison of scan geometry and observation bounding box for two ViSP datasets. The solid line shows the sequence of slit center positions (the scan track), while the dashed rectangle indicates the observation bounding box derived from the minimum and maximum helioprojective coordinates. In both panels, the bounding box is aligned with solar east–west (HPLN) and north–south (HPLT) by construction. However, the scan geometry differs: in the MALODS example (left), the scan proceeds approximately east–west, whereas in the LCQCPP example (right), the scan proceeds nearly north–south. This demonstrates that the bounding box does not encode the orientation of the observation.

 

The spatial coordinates provided with DKIST datasets are expressed in helioprojective coordinates, specifically solar longitude (HPLN) and latitude (HPLT), in units of arcseconds. These coordinates describe positions on the plane of the sky relative to solar disk center, with HPLN aligned east–west and HPLT aligned north–south.

The observation “bounding box” associated with a dataset is an axis-aligned bounding box defined by the minimum and maximum HPLN and HPLT values across all measurements in the dataset. As a result, this box is always aligned with solar east–west and north–south directions. It represents the total spatial extent of the observation but should not be interpreted as a pixel grid, image frame, or individual data product.

For example, ViSP imagest consist of a sequence of slit measurements acquired as the instrument scans across the solar surface. The orientation and direction of this scan (i.e., the observation geometry) are not encoded in the bounding box. In particular, the scan direction and slit orientation may be significantly rotated relative to solar east–west and north–south, even though the bounding box itself remains axis-aligned. To understand the true geometry of the observation, users must examine the sequence of slit positions or the dataset’s WCS information.

2.2 DKIST Dataset Known Issues (Caveats)

 

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Figure 7. The dataset caveats pages.

As the Data Center has completed calibration of the ViSP, Cryo-NIRSP, and DL-NIRSP data, we have worked with NSO scientists and instrument teams to document the issues we are aware of in the processed datasets. These issues have been captured in the DKIST Data Center Archive Help Desk on the DKIST Data Set CaveatsPreviewpage. This page will be continually updated with the latest information on the ViSP and VBI datasets as they are processed.

2.3 Dataset Exclusive Access Periods

DKIST is implementing an exclusive access period for its scheduled observations. PIs will have 6 months from the date the DC makes their data available for analysis before it is made public. For datasets primarily used for a PhD student's thesis work, this term is extended to 12 months. A PI may elect to waive the exclusive access period. Although the data itself is subject to an exclusive access period, the metadata is not. As shown above (Figure 4), results may contain data that is not yet public. For more information, see https://nso.edu/telescopes/dkist-data-access-policy/

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Figure 8. Information about the exclusive access period

 

Clicking the exclusive access icon (see Table 1) will show a user how much longer the data will remain private within that period before becoming public.

2.4 Filtering Search Results

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Figure 9: Default appearance of the portal showing filter options

The primary mechanism for data selection is the construction of filters. Using the filters, a user can search for any number of parameters. Filters are additive. A dataset must match all filter criteria (including negated ones) to be displayed. By default, the search Portal will display the latest available data with no filtering applied. Figure 9 illustrates the default appearance of the Portal, showing the filter options.

These options are broken down into Basic and Advanced search filters and provide the functionality to load previously saved filter combinations. The use and display of the filters are described in detail in the following sections.

Note that there are currently few sanity checks for possible filter values or combinations. It may be entirely possible for the user to specify a filter combination that yields no valid datasets.

Fields that accept multiple values have their parameters OR'd together, while values across parameters are AND'd. These are listed explicitly in the table below.

Parameters that are OR'd, such as Dataset ID, may be added to the filter multiple times to select multiple datasets.

2.4.1 The Filter Bar

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Figure 12: Default filter bar

 

The filter bar displays the current filters in use. If nothing is selected, it will appear as illustrated on the left. Within the filter bar, there are four filter-related options, listed below:

Open	Save Filter. Choose a unique name (max 50 characters) for this filter. This will save the current filter under the provided name.
Open	Load Filter. Select a previously saved filter to load. The drop-down box will list all the filters you have previously saved. (See also Previous Filters)
Open	Share Filter. Will create a URL that you can share with other scientists. This URL will expand to the current filter selection. See Share Current Filter
Open	Clear Filter. This option deletes the current set of filters and reverts to the default search. (Display latest datasets)

Table 2. The Save, Load, Share, and Clear filter options.

Open	The filter bar includes a shortcut that lets users find publicly available datasets.

Table 3. The Display Only Public Datasets shortcut.

When a user adds a filter option, it appears to the right of the Current Filter. In the filter bar example below, the Portal will search for the latest datasets collected with the VBI instrument. Since this filter was loaded from a previously saved one, its name is also displayed.

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Figure 10. Filter bar with date selection

2.4.2 Negating Filters

For certain filters, such as Has a Spectral Axis, adding that filter without a value sets it to false. The search will look for datasets without a spectral axis and will return only VBI or Cryo-NIRSP context imager data. It should be noted that Has a Spectral Axis now has a direct negation value. See Has a Spectral Axis for more details.

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Figure 11. Negating a filter option.

2.5 Basic Search Filters

The “Basic” search filters are intended to be the primary filters for searching DKIST data. They are Publicly Available Data, Proposal ID, Experiment Start Date Range, Dataset Creation Data Range, Instruments, Spectral Line, Spatial and Polarization Observations. These filters are now described in detail.

2.5.1 Publicly Available Data

This filter lets a user toggle their search between all publicly available datasets and those currently in the exclusive access period.

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Figure 12. Select a type of dataset access to filter by

Using the dataset access filter, a user can toggle between publicly available data and data that is still within the exclusive access period. The default (no filter) will search both dataset types. Clicking on ADD ACCESS FILTER adds Dataset Access to a user’s current list of selected filters. Note that you can also select the shortcut on the Filter Bar to enable users to find publicly available datasets.

2.5.2 Proposal ID

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Figure 13. Select data by proposal ID(s)

 

This filter allows you to select datasets with a particular Proposal ID. All observations scheduled with DKIST have a Proposal with a unique ID. Entering a Proposal ID here, e.g., pid_1_50, and all datasets associated with that ID are displayed. To select multiple Proposal IDs, separate them with commas. Attempting to add a new Proposal ID filter when one is already selected will replace the existing selection with the new one. Note that while all metadata is available for searching, a user can download data only for which they are the PI or a Co-I during the exclusive access period. Clicking ADD PROPOSAL ID FILTER adds Proposal ID to the current list of selected filters. A user may add more than one Proposal ID to search for by adding a new search ID and clicking on ADD PROPOSAL ID FILTER again.

2.5.3 Experiment Execution Date Range

This filter limits the results to datasets that intersect the specified Experiment Execution Date Range. This is the date on which the experiment was run at the telescope. DKIST data is available from the earliest to the latest calibrated observation, which may lag the current date considerably, so there can be a substantial difference between the experiment execution time and the dataset creation date (see below). Be aware that a too-wide execution date range may exceed the 1000-dataset selection limit.

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Figure 14. Selecting an experiment execution date range to filter on

2.5.4 Dataset Creation Date Range

This filter limits the results to datasets that intersect the specified Date Range. DKIST data is available from the earliest calibrated observation up until the latest calibrated observation, which may lag the current date considerably. Users should be aware that a too-wide date range may exceed the 1000-dataset selection limit.

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Figure 15. Selecting a dataset creation date range to filter by

Unlike the Experiment Start Date, the Dataset Creation date is determined by when the data is calibrated and published to the Portal. Especially for VBI datasets, this data may lag the Experiment Start Date by a considerable time. It is useful if you want to see the latest data calibrated by the Data Center. Clicking on ADD DATASET CREATION DATE FILTER adds DATASET CREATION DATE RANGE to a user’s current list of selected filters.

2.5.5 Instruments

This filter allows the selection of datasets from one or more of the current DKIST Instruments. This menu is built dynamically so that a user can only choose instruments for which observations have already been taken (Note: VTF will be added in 2026). As more instruments are commissioned and their datasets become available, they will appear in the drop-down menu. Clicking ADD INSTRUMENT FILTER adds Instruments to the user’s current list of selected filters.

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Figure 16. Selecting instruments to filter by

2.5.6 Spectral Line

This filter allows selecting datasets based on one or more spectral lines observed by DKIST instruments. This is provided as a convenience to the user. Wavelength searches are also available. However, for the VBI, VTF, ViSP, and DL-NIRSP instruments, the band-passes in which the instruments observe have already been defined to maximize the scientific return from the instrument. The Spectral Line filter provides an easy way to select these instrument band-passes. For the ViSP instrument, which doesn’t use specific wavebands, a selection of the most common lines has been made. The ViSP line list will be updated as the DC gains more experience with the ViSP wavelengths being searched. For ease of selection, a user can filter by one of the DKIST instruments (i.e., choose Instrument to filter lines) to limit the line selection to that particular instrument. Clicking ADD SPECTRAL FILTER adds a Spectral Line to the user’s current list of selected filters.

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Figure 17. Selecting the passband or line, in this case, from the VBI instrument

See Appendix: Supported Spectral Line Searches for a complete list of the current supported spectral lines.

2.5.7 Spatial

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Figure 18. Select data using a spatial filter

This filter allows you to select datasets using a Spatial Bounding Box. To select a spatial match for datasets, enter the upper and lower corners of a helio-projective Cartesian Spatial Bounding Box in arcseconds.

A user may choose a bounds match such that the datasets Contain the bounding box, Intersect the bounding box, or are Wholly Contained by the defined box. Effective limit for the bounding box is the maximum off-point for the telescope of ~1.5 R_SUN, or -1440” to 1440” in Solar X and -1440” to 1440” in Solar Y. Clicking ADD SPATIAL FILTER allows the user to add a spatial bounding box to the user’s current list of selected filters.

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Figure 19. Illustration of the bounds matches

Figure 19 (to the left) illustrates the available bound matches. The blue rectangle labeled A represents the corners of the observation bounding box. The red rectangles represent the extent of the spatial search bounding box. The red rectangle numbered 1 represents the Wholly Contained match, where the observation bounding box is wholly contained by the spatial search bounding box. The red rectangle numbered 2 represents the Intersects match, where some part of the observation bounding box overlaps the spatial search bounding box. The red rectangle numbered 3 represents the Contains match, where the observation bounding box contains by the spatial search bounding box.

2.5.8 Polarimetric Observations

This filter allows you to select datasets based on whether they contain Polarimetric Observations. All DKIST instruments, except VBI, can observe at different polarization angles. Select Polarimetric Observations Only or Intensity Observations Only to choose between these observations that contain polarimetric data, and those that don’t (Intensity Observations Only). By default (no filter), both observation types (and spectroscopic data) will be selected. Clicking ADD OBSERVATION FILTER allows the user to add Polarization Observations to the user’s current list of selected filters.

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Figure 20. Select polarimetric or intensity data

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Figure 21. Choose Polarization observations or Intensity observations only. If neither is selected, the default is both

 

2.6. Advanced Search Filters

The ‘Advanced’ search filters provide additional options to refine searches for DKIST datasets. They are Investigated by Me, Experiment ID, Dataset ID, Numerical wavelength search (primarily for ViSP), Exposure, Fried Parameter, Polarimetric Accuracy, Target Type, If Data Has a Spectral Axis, Spectral sampling, Temporal Sampling, and Spatial Sampling. These filters allow users to locate datasets more quickly, for example, if a PI knows their Proposal ID or is interested in a specific scientific objective, such as a sunspot (Target type) observed with excellent seeing (Fried parameter).

2.6.1 Investigated By Me

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Figure 22. Select only datasets for which the logged-in user is a PI or Co-I.

This filter quickly allows a principal investigator to find all datasets associated with their login. A user will only see this option if they have logged in via Globus first. Click ADD INVESTIGATED BY ME FILTER to add Investigated By Me to the user’s current list of selected filters.

2.6.2 Experiment ID

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Figure 23. Select data by experiment ID(s)

This filter allows selecting datasets that contain a particular Experiment ID. Experiments are how DKIST turns proposals into scheduled observing plans. A proposal may contain one or more Experiments. Entering an Experiment ID, e.g., eid_1_50, displays all datasets associated with that ID. To select multiple Experiment IDs, separate them with commas. Attempting to add a new Experiment ID filter when you already have one selected will just replace the Experiment ID selection with the new one. Note that while all metadata is available for searching, a user can download data only for which they are the PI or a Co-I during the exclusive access period. Clicking ADD EXPERIMENT ID FILTER adds Experiment ID to the user’s current list of selected filters.

2.6.3 Dataset ID

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Figure 24. Select data by Dataset ID(s)

This filter allows you to select datasets with a specific Dataset ID. For each dataset created by an Experiment, a unique ID, known as the Dataset ID, is assigned. Entering a Dataset ID (e.g., AMJJB) selects a specific dataset. If you add another Dataset ID to the one already selected, then both datasets will be returned. Note that while all metadata is available for searching, a user can download data only for which they are the PI or a Co-I during the exclusive access period. Clicking ADD DATASET ID FILTER adds the Dataset ID to their current list of selected filters. Users are cautioned that Dataset IDs are only used once. In the event of data reprocessing, the Dataset ID will be replaced by a new one. For permanent identifiers to share data with, see Product ID below.

2.6.4 Product ID

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Figure 25. Select data by Product ID(s)

 

This filter allows you to select datasets containing a specific Product ID. For each dataset created by an Experiment, a unique ID, known as the Product ID, is assigned. Entering a Product ID, e.g., L1-JAZXI, selects a particular dataset, in the same way as entering the Dataset ID, LHMMPP,\would. The Product ID is a new ID created to address the problem mentioned above: Dataset IDs are not preserved across reprocessing. The Product ID will remain the same regardless of how many times a dataset is reprocessed. This makes it the ideal ID for sharing datasets with other users. Clicking ADD PRODUCT ID FILTER adds Product ID to the current list of selected filters.

2.6.5 Numerical Wavelength Search (Primarily for ViSP)

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Figure 26. Select datasets based on numerical wavelength search

This filter allows selecting datasets within a specified minimum and maximum Wavelength range. To search on specific wavelengths or wavelength bands, a user enters a minimum and maximum wavelength in nanometers, e.g., 1000nm and 1300nm. Any intersection will match. This is designed to be particularly useful for the ViSP instrument. Clicking ADD WAVELENGTH FILTER adds wavelength range (in nm) to a user’s current list of selected filters. Whereas the other DKIST instruments have predefined wavelength bands defined by instrument filters, ViSP can image the sun in three bands simultaneously across the 380‒900 nm range. To search across multiple wavelength ranges, add multiple min-max wavelength pairs to your search filters. such as shown in the image below.

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Figure 27. Example of searching for multiple wavelengths

2.6.6 Exposure Time

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Figure 28. Select datasets by exposure time in milliseconds

This filter allows selecting datasets based on the minimum and maximum Exposure Times. To filter on Exposure Time, a user enters the minimum and maximum Exposure Times (in milliseconds) to search for datasets. The Exposure times should be common across a dataset. The user may enter either or both of the Exposure bounds. Any intersection will match.

The lower bound will be assumed to be zero if not specified, and the upper bound will be infinite if not specified. Clicking ADD EXPOSURE TIME FILTER adds an exposure time range in seconds to a user’s current list of selected filters.

It may appear that some of the returned results do not match your search criteria. This is due to a rounding limitation in which the portal rounds results to the specified precision for the displayed field, even though the inventory database stores data at full precision.

2.6.7 Fried Parameter

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Figure 29. Select datasets based on seeing conditions (Fried parameter)

There are no Fried Parameter values available for Cryo-NIRSP. As Cryo-NIRSP currently takes all the light for its observations, the AO system is not running, so no Fried Parameter can be provided.

Should you find that a FITS file is missing an ATMOS_R0 keyword for an instrument other than Cryo-NIRSP, it is because the computed r₀ is very likely unreliable. See Missing Fried Parameter Value in DKIST Level 1 FITS FilesPreviewfor more information.

This filter allows you to select datasets based on the Fried Parameter. The Fried Parameter (commonly referred to as r₀) is a measure of the quality of optical transmission through the atmosphere, due to random inhomogeneities in its refractive index. A Fried parameter of 12-15 cm can be considered generally excellent seeing. To filter by atmospheric seeing conditions, a user enters the minimum Fried parameter (worst seeing) in centimeters (the minimum allowed value is 0.1 cm) that they are willing to accept. All datasets with a Fried parameter larger (better seeing) than or equal to the minimum Fried parameter will match. Clicking ADD FRIED FILTER adds the minimum Fried parameter in centimeters to the user’s current list of selected filters.