ObjObsSAP < IVOA

---+ Object Observability Simple Access Protocol

_*Note:* This protocol is formerly known as Object Visibility Simple Access Protocol (ObjVisSAP)._

*Current status:* [[https://www.ivoa.net/documents/ObjVisSAP/20200514/index.html][WD-1.0]]

*GitHub repository:* [[https://github.com/ivoa-std/ObjObsSAP]]

---++ Abstract

The Object Observability Simple Access Protocol (ObjObsSAP) is an IVOA Data Access protocol which defines the standard for retrieving object constraint-free observability time intervals through a uniform interface within the VO framework for given object coordinates to be observed by a given Astronomical Observatory. The ObjObsSAP services can be registered in an IVOA Registry of Resources using the VOResource, Extension standard, having a unique ResourceIdentifier in the registry. The ObjObsSAP interface is meant to be reasonably simple to be implemented by service providers. A basic query will be done introducing a set of sky coordinates and a given time period (optional). The service returns a list of constraint-free observability time intervals formatted as VOTable. Thus, an implementation of the service may support additional search parameters (some of which may be custom to that particular service) to more finely control the selection of the observability periods. The specification also describes how the search on extra parameters has to be done.

---++ Implementations

_This list of implementations is mostly inspired from the ESA page [[https://www.cosmos.esa.int/web/vovisobs_protocols][vovisobs_protocols]]._

_*Legend:* %GREEN% *&#x1F592;* %ENDCOLOR% = up-to-date with the last version of WD-1.0_
---+++ Services

   * %GREEN% *&#x1F592;* %ENDCOLOR% JoshuaFraustro 's example implementation based on FastAPI ( [[https://github.com/jwfraustro/fastapi-objobssap][GitHub]])
      * Access URL: [[https://vo-labs.dev/objobssap/api/query][<span data-mce-mark="1">https://vo-labs.dev/objobssap/api/query</span>]]
      * Validation result: %GREEN%<em>Compliant (A++) </em>%ENDCOLOR%[2025-10-13] [ [[https://registry.euro-vo.org/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=https://vo-labs.dev/objobssap/api/query?][test URL]]]
   * <p>The [[https://www.cosmos.esa.int/web/integral][INTEGRAL]] gamma-ray Observatory: Visibility and Observation Locator</p>
      * <p>Access URL: [[http://integral.esa.int/isocweb/tvp.html][<span data-mce-mark="1">http://integral.esa.int/isocweb/tvp.html</span>]]</p>
      * Validation result: %ORANGE%Partially Compliant (C--)%ENDCOLOR% [2025-09-17] [ [[https://registry.euro-vo.org/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=http://integral.esa.int/isocweb/tvp.html?][test URL]]]
         * Details: the server just answers something but no XML/VOTable answer in any case ; nothing is really compliant
   * <p> [[https://www.cosmos.esa.int/web/xmm-newton/home][XMM-Newton]]: Visibility and Observation Locator</p>
      * <p>Access URL: [[http://xmmvisibility.esac.esa.int/vischecker/ServVISC][<span data-mce-mark="1">http://xmmvisibility.esac.esa.int/vischecker/ServVISC</span>]]</p>
      * Validation result: %RED%Not Compliant (E) %ENDCOLOR%[2025-10-17] [ [[https://registry.euro-vo.org/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=http://xmmvisibility.esac.esa.int/vischecker/ServVISC?][test URL]]]
         * Details: !NullPointerException for any request (former parameters s_ra and s_dec expected)
   * <p>The [[https://www.cosmos.esa.int/web/gaia][GAIA]] mission: Visibility (displaying scanning patterns)</p>
      * <p>Access URL: [[https://gaia.esac.esa.int/gost/ObjVisSAP/gaiaobjvisap][<span data-mce-mark="1">https://gaia.esac.esa.int/gost/ObjVisSAP/gaiaobjvisap</span>]]</p>
      * Validation result: %RED%Not Compliant (E)%ENDCOLOR% [2025-10-17] [ [[https://registry.euro-vo.org/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=https://gaia.esac.esa.int/gost/ObjVisSAP/gaiaobjvisap?][test URL]]]
         * Details: !NullPointerException for any request (former parameters s_ra and s_dec expected)
   * <p>The [[http://cxc.harvard.edu/][Chandra X-ray Observatory]] (CXO): Visibility and Observation Locator (under development)</p>
      * <p>Access URL: [[http://integral.esa.int/interest//api/visibilities/chandra][<span data-mce-mark="1">http://integral.esa.int/interest//api/visibilities/chandra</span>]]</p>
      * Validation result: %RED% *Service Unavailable* (Proxy Error - HTTP-502)%ENDCOLOR% [2025-10-17]
   * <p>The [[http://www.hxmt.org/index.php/enhome][Insight-HXMT]] (Hard X-ray Modulation Telescope) has developed a visibility interface based on these protocols. Currently only accounting for Sun and Moon. The effects of Earth and South Atlantic Anomaly (SAA) will be included in the next version</p>
      * <p>Access URL: [[http://integral.esa.int/interest//api/visibilities/insight-xmt][<span data-mce-mark="1">http://integral.esa.int/interest//api/visibilities/insight-xmt</span>]]</p>
      * Validation result: %RED% *Service Unavailable* (Proxy Error - HTTP-502) %ENDCOLOR%[2025-10-17]
   * <p> [[http://www.not.iac.es/][Nordical Optical Telescope (NOT)]] - basic geometrical visibility service</p>
      * <p>Access URL: [[http://integral.esa.int/interest//api/visibilities/not][<span data-mce-mark="1">http://integral.esa.int/interest//api/visibilities/not</span>]]</p>
      * Validation result: %RED% *Service Unavailable* (Proxy Error - HTTP-502)%ENDCOLOR% [2025-10-17]
   * <p>Swift ( [[https://github.com/Swift-SOT/swift-vo][GitHub]]):</p>
      * <p>Access URL: [[https://www.swift.psu.edu/vo/objobssap/query][<span data-mce-mark="1">https://www.swift.psu.edu/vo/objobssap/query</span>]]</p>
         * Validation result: <span class="WYSIWYG_COLOR" data-mce-mark="1" style="color: orangered;">Partially Compliant (C--)</span> [2025-10-17] [ [[https://registry.euro-vo.org/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=https://www.swift.psu.edu/vo/objobssap/query?][test URL]]]
         * <span style="background-color: transparent;">Details:</span>
         * 
            * <span style="background-color: transparent;">incorrect MIME-Type (`<span class="WYSIWYG_TT">application/xml</span>` instead of `<span class="WYSIWYG_TT">application/x-votable+xml</span>`)</span>
            * <span style="background-color: transparent;">fields `<span class="WYSIWYG_TT">t_observability</span>` and `<span class="WYSIWYG_TT">t_validity</span>` are missing</span>
      * <p>Access URL: [[http://integral.esa.int/interest//api/visibilities/swift][<span data-mce-mark="1">http://integral.esa.int/interest//api/visibilities/swift</span>]]</p>
         * Validation result: %RED%Not Compliant (E) (Proxy Error - HTTP-502)%ENDCOLOR% [2025-10-17] [ [[https://registry.euro-vo.org/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=http://integral.esa.int/interest//api/visibilities/swift?][test URL]]]
   * <p>The [[https://www.nustar.caltech.edu/][NuSTAR mission]] provides their [[http://www.srl.caltech.edu/NuSTAR_Public/NuSTAROperationSite/Schedule.php][schedule]] in a VO-compliant format as [[http://www.srl.caltech.edu/NuSTAR_Public/NuSTAROperationSite/][csv]] files but do not provide an URL query service</p>
      * _Possibly inactive_
---+++ Clients
   * Web client [[http://integral.esa.int/toby/][TOBY]]

---+++ Validators
   * [[https://registry.euro-vo.org/evor/#home][Euro-VO Registry]] validator:
      * Website: https://registry.euro-vo.org/evor/#newstandalonevalidation
      * Direct access URL: [[https://registry.euro-vo.org/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=https://emellega.github.io/object-observability-mock/]] _(url attribute to replace by the access URL of the service to test)_ [[https://evor-int.esac.esa.int/evor/eurovoweb/validation?type=ObjObsSAP1.0&url=https://emellega.github.io/object-observability-mock/][<br />]]
      * GitHub repository: [[https://github.com/emellega/object-observability-mock][<span data-mce-mark="1">https://github.com/emellega/object-observability-mock</span>]]

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This topic: IVOA > WebHome > IvoaTCG > TCG-TC-20240927 > ObjObsSAP
Topic revision: r6 - 2025-10-17 - GregoryMantelet