########### Annotations ########### Annotations are glyphs displayed on top of images to depict the presence of known sky objects, like galaxies, bright stars and so on. They come from catalogues but can only be displayed on images for which we know which part of the sky they represent, images that have been **plate solved** and contain the world coordinate system (WCS) information in their header, so only FITS or Astro-TIFF files. .. figure:: ../_images/annotations/example.png :alt: example :class: with-shadow :width: 100% View of full annotated image Plate solving, can be done within Siril in the :menuselection:`Image Information --> Image Plate Solver...` entry, or using external tools like `astrometry.net `__ or `ASTAP `__. .. figure:: ../_images/annotations/plate_solved_gui.png :alt: plate solved GUI :class: with-shadow :width: 100% Buttons for annotations When a plate solved image is loaded in Siril, you can see the sky coordinates for the pixel under the mouse pointer displayed at the bottom right corner and the buttons related to annotations become available. The first button toggles on or off object annotations, the second the celestial grid and the compass. ******************* Types of catalogues ******************* Siril comes with a predefined list of catalogues for annotations: * Messier catalogue (M) * New General Catalogue (NGC) * Index Catalogue (IC) * Lynds Catalogue of Dark Nebulae (LdN) * Sharpless Catalogue (Sh2) * Star Catalogue (3661 of the brightest stars) In addition, 2 *user defined catalogues* can be used: * User DeepSky Objects Catalogue * User Solar System Objects Catalogue ******************** Catalogue management ******************** Both these catalogues can be enabled/disabled for display in the :menuselection:`Preferences menu --> Astrometry` :ref:`tab `. A slider on the right side, allows you to easily navigate across the catalogue list. .. figure:: ../_images/annotations/cat-manage_view.png :alt: Catalogue management :class: with-shadow :width: 100% Catalogue management in Preferences/Astrometry The two *user defined catalogues* can also be purged (ie deleted) via the appropriate buttons. The *user catalogues* (DSO, SSO or extra catalogues) are stored in the user settings directory and can be easily modified. Their location depends on the operating system: * for *Unix-based* OS they will be in ``~/.config/siril/catalogue`` * on *Windows* they are in ``%LOCALAPPDATA%\siril\catalogue``. The position of the compass on the image can be adjusted from the preferences too. .. _Local_Catalog: These annotation catalogues are for display purposes only. They are not used in astrometry or photometry tools, contrary to the star catalogues like NOMAD, which can now be :ref:`installed locally ` too. .. figure:: ../_images/annotations/bottom.png :alt: Bottom :class: with-shadow Local Catalogue (NOMAD) setup ************************** Searching for a new object ************************** When the name of an object in the image is known (if not, see the `Inverse Search`_ section), it is possible to add it to annotations: * with the image loaded and plate solved, type :kbd:`Ctrl` + :kbd:`Shift` + :kbd:`/` or :guilabel:`Search` in the pop-up menu (right click). A small search dialog will appear. In it, object names can be entered, then pressing :guilabel:`Enter` will send an online request to SIMBAD (for a star of Deep Sky Object) to get the coordinates of an object with such a name. If found, and not already in any catalogue, the object will be added to the *Deep Sky user Catalogue*. The items of this catalogue are displayed in *ORANGE* while the objects from the predefined catalogues are displayed in *GREEN*. .. figure:: ../_images/annotations/user_dso.png :alt: User DSO :class: with-shadow :width: 100% Deep sky objects from user and predefined catalogues From Siril version 1.2, we can now search for solar system objects too, using the `Miriade ephemcc `__ service. This is done by prefixing the name of the object to be searched by some keyword representing the type of object: ``a:`` for asteroids, ``c:`` for comets, ``p:`` for planets. Since they are moving objects, they can be added several times, and the request is done for the date of observation of the currently loaded image. The date is associated to the name in the *user Solar System Catalogue*. The items of this catalogue are displayed in *YELLOW*. Examples of valid inputs (not case sensitive): * ``HD 86574`` or ``HD86574`` are both valid for this star * ``c:67p`` or ``c:C/2017 T2`` are valid forms for comets * ``a:1`` and ``a:ceres`` are both valid for *(1) Ceres* * ``a:2000 BY4`` is valid for *103516 2000 BY4* * ``p:4`` or ``p:mars`` for Mars ****************************************************************** Filling a Solar System user Catalogue: which SSO is in this field? ****************************************************************** To answer the question *Is there any solar system object in my image?*, a special function does a request to an online server of the IMCCE too (`SkyBoT `__) and displays the results in the console and in the image. * with the image loaded and plate solved, right click/``Solar System Objects``, or in the command line you can use the ``solsys`` function. It displays in *RED* all the Solar System objects in the field of view (if any are known and found of course). Objects magnitudes and equatorial coordinates for the image date are printed in the console. These red annotations will be erased as soon as the ``Show Objects names`` button is toggled. .. figure:: ../_images/annotations/solsys.png :alt: Solar Sytem Result :class: with-shadow :width: 100% Result of a Search Solar System process However, you may want to save any particular item in the User Solar System Objects Catalogue. It can be done by using the ``Search`` command for a solar system object as previously described. This way, the saved item is diplayed in *YELLOW* and will be displayed in any image that has this field of view by enabling the annotations. .. figure:: ../_images/annotations/solsys_and_search.png :alt: Solar System :class: with-shadow :width: 100% View with predefined/DSO/SSO .. note:: Newly discovered objects, or some fast moving objects, will have their position misaligned with the image. This is often the case for comets for example, which can be an arcminute off. This happens because the orbital parameters of the object are not very well known or that they have not been updated recently in the system. If you are looking for an alternate computation of the coordinates of the known objects of the field, you might query manually the `JPL Small Body identification tool `_. .. _Inverse Search: **************************************** The inverse search: what is this object? **************************************** Especially useful for photometry works, it is possible to identify a star or other objects in the image by drawing a selection around them, right clicking to bring up the context menu, and selecting the :guilabel:`PSF` entry. This will open the PSF window, and if it’s a star it will display the Gaussian fit parameters, but it will also display a Web link at the bottom left of the window: opening it will bring you to the `SIMBAD page `__ for the coordinates of the object and in many cases will give you the name of the object. SIMBAD doesn’t have all known objects, but the coordinates from the page can still be used as a starting point to look for the object in other online catalogues, for example `Gaia DR3 (VizieR) `__. **************** Extra catalogues **************** Sometimes, users create their own catalogues, we can try to link them here to help everybody. They are *user catalogues*, so installing them requires either replacing the current user catalogue, or by manually merging their lines into a new file. List of known user catalogues: * Variable stars, extracted from `GCVS `__ 5.1, discussed `here in French `__, (:download:`file link `).