{"id":3787,"date":"2025-09-18T12:57:12","date_gmt":"2025-09-18T10:57:12","guid":{"rendered":"https:\/\/montsec.ieec.cat\/?page_id=3787"},"modified":"2025-09-18T12:57:16","modified_gmt":"2025-09-18T10:57:16","slug":"tjo","status":"publish","type":"page","link":"https:\/\/montsec.ieec.cat\/en\/astronomy\/tjo\/","title":{"rendered":"Joan Or\u00f3 Telescope (TJO)"},"content":{"rendered":"

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Astronomy<\/a> | Joan Or\u00f3 Telescope<\/strong><\/span><\/h1>\n

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Joan Or\u00f3 Telescope<\/span><\/span><\/h2>\n

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The Joan Or\u00f3 Telescope<\/strong> is managed by the IEEC and is currently the largest telescope in Catalonia.<\/span><\/em><\/h3>\n

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It has a primary mirror of 0.8 metres and an F\/9.6 Ritchey-Chr\u00e9tien optical system. The Joan Or\u00f3 Telescope (TJO) was built by Optical Mechanics Inc. (OMI) and is equipped with a 6.15 metre automatic dome manufactured by Baader Planetarium GmbH.<\/span><\/p>\n

The telescope is named in honour of the biochemist Joan Or\u00f3 i Florensa, one of the most relevant scientists related to the study of the origin of life. In the midst of Franco’s era, Joan Or\u00f3 emigrated from Lleida to the United States to work on the research on Darwin’s theories and to answer some fundamental questions: who we are and where we come from. He worked at NASA and participated in the arrival of the first man on the Moon and in the exploration of the planet Mars. On returning to Catalonia, during the 1990s, Joan Or\u00f3 and the foundation that bears his name were the main promoters of the project to build an astronomical observatory in the Montsec area.<\/span><\/p>\n

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Research<\/h2>\n

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The TJO is a multi-purpose astronomical telescope<\/strong> and, as such, it carries out a wide variety of observations related to different scientific cases.<\/span><\/p>\n

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Instrumentation<\/h2>\n

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The TJO is equipped with two instruments: an imaging camera<\/strong> (LAIA) and a medium resolution spectrograph<\/strong> (ARES). It also has a second imaging camera (MEIA2) as a backup camera.<\/span><\/p>\n

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Joan Or\u00f3 Telescope<\/p>\n

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Research<\/p>\n

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The TJO is a multi-purpose astronomical telescope and, as such, it carries out a wide variety of observations related to different scientific cases. Given its size, the main application of the TJO are the time-series astronomical observations, where high cadence or continuity are the main requirements.\u00a0<\/span><\/p>\n

Its main advantage is the flexibility of the operating modes, allowing the monitoring of objects for long periods of time, as well as the fast reaction capacity (potentially less than a minute).<\/span><\/p>\n

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Given these characteristics, the scientific cases of the TJO include:<\/strong><\/span><\/h3>\n

 <\/p>\n

    \n
  • Exoplanets research<\/b> (characterising and tracking known planets with transits or selected searches of individual objects).<\/span><\/li>\n
  • Eclipsing binaries<\/b> (to understand the structure and characteristics of stars).<\/span><\/li>\n
  • Pulsating variables<\/b> (to study stellar interiors).<\/span><\/li>\n
  • Evolved variable stars<\/b> (giants and supergiants).<\/span><\/li>\n
  • Stellar activity<\/b> (to understand the magnetic dynamo system and characterise the behaviour of activity phenomena).<\/span><\/li>\n
  • Variability of active galactic nuclei<\/b> (related to accretion and matter ejection phenomena).<\/span><\/li>\n
  • Solar System objects<\/b> (tracking asteroids, NEOs or comets).<\/span><\/li>\n
  • Supernovae<\/b> (with the ability to observe them from the first moments).<\/span><\/li>\n
  • X-ray binaries<\/b> (rotational variability, accretion phenomena and radial velocity curves).<\/span><\/li>\n
  • Novae<\/b> (being able to collect data from the early stages).<\/span><\/li>\n
  • Optical counterparts of gamma-ray bursts<\/b> (GRBs).<\/span><\/li>\n
  • Any <\/span>transient astronomical phenomenon<\/b> in general.<\/span><\/li>\n<\/ul>\n

    The mentioned scientific cases require considerable flexibility in the planning of the nights, together with the ability of the system to react quickly to the alerts of observations of GRBs, supernovae, or other similar phenomena. Participation in robotic telescope networks implies the ability to make continuous observations. Similarly, the TJO can be used as a follow-up telescope complementary with space missions or other ground-based telescopes that require astrometric or photometric measurements. The TJO offers open time to the astronomical community through competitive proposals reviewed by a time allocation committee.<\/span><\/p>\n

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    Joan Or\u00f3 Telescope<\/p>\n

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    Instrumentation<\/p>\n

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    The TJO is equipped with two instruments: an imaging camera (LAIA) and a medium resolution spectrograph (ARES). It also has a second imaging camera (MEIA2) as a backup camera.<\/span><\/p>\n

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    LAIA<\/strong><\/h3>\n

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    The <\/span>LAIA <\/b>instrument<\/strong> (Large Area Imager for Astronomy) <\/b>is the optical imaging camera of the TJO, operational since December 2018. It consists of two components: the CCD camera and the filter wheel. <\/span><\/p>\n

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    CCD camera<\/p>\n

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    The CCD camera is an Andor iKon XL with a 4k\u00d74k back-illuminated sensor:<\/strong><\/p>\n

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    R\u00a0<\/span>Model:<\/strong> CCD230-84
    R\u00a0<\/span>Manufacturer of the sensor:<\/strong> e2v
    R\u00a0<\/span>Sensor type:<\/strong> back-illuminated
    R\u00a0<\/span>Coating:<\/strong> BV
    R\u00a0<\/span>Number of pixels:<\/strong> 4096 \u00d7<\/span> 4096
    R\u00a0<\/span>Pixel size:<\/strong> 15 \u00d7 15 um (0.4 x 0.4 arcsec at the TJO)<\/span>
    R\u00a0<\/span>FOV at the TJO:<\/strong> 30 arcmin
    R\u00a0<\/span>Sensor size:<\/strong> 61.4 \u00d7<\/span> 61.4 mm
    R\u00a0<\/span>Quantum efficiency:<\/strong> >90% from 500 to 650 nm; >50% in all the range from 400 to 850 nm<\/span>
    R\u00a0<\/span>Typical working temperature:<\/strong> -50\u00baC
    R\u00a0<\/span>Dark current:<\/strong> <0.01 e-\/pixel\/sec at -50\u00baC<\/span>
    R\u00a0<\/span>Readout noise:<\/strong> <9e- RMS a 1 MHz
    R\u00a0<\/span>Redout channels:<\/strong> 4
    R\u00a0<\/span>Non-linearity:<\/strong> <1%
    R\u00a0<\/span>Readout time:<\/strong><\/span><\/strong> 8 sec<\/p>\n

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    Filter wheel<\/p>\n

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    The filter wheel is physically attached to the telescope, behind the primary mirror mount. It can accommodate up to 12 3-inch filters<\/strong> that are positioned on the optical axis of the telescope using the rotating filter wheel. There are currently 5 Johnson-Cousins photometric filters installed (manufactured by Custom Scientific): <\/span>U<\/b>,<\/span> B<\/b>,<\/span> V<\/b>,<\/span> Rc <\/b>and <\/span>Ic<\/b>; 4 Sloan Digital Sky Survey photometric filters (manufactured by Asahi Spectra): <\/span>g<\/b>,<\/span> r<\/b>,<\/span> i<\/b>,<\/span> z<\/b>; and an <\/span>H-alpha<\/b> filter (Asahi Spectra).<\/span><\/p>\n

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    Vignetting<\/p>\n

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    LAIA is designed to cover the entire field of the TJO focal plane. With its 4096 \u00d7 4096 pixels, LAIA can cover a field of 27.3 \u00d7 27.3 arc minutes<\/strong>. On the other hand, the focal plane covers a circular field of 30 minutes of arc. This causes the edges of the LAIA images to be vignetting. Additionally, the ARES pick-off mirror is also seen in the LAIA field of view with vignetting at the northern end of the field. As a result, the LAIA images will look similar to the one shown to the right.<\/span><\/p>\n

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    Standard calibration procedure<\/p>\n

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    The TJO control system is designed to periodically execute the acquisition of calibration images, including bias, darks and flats:<\/strong><\/p>\n

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    R\u00a0<\/span>Bias: <\/strong>They are usually taken in multiples of 5 before the start and at the end of each night. Observers are given a minimum of 10 bias images.<\/span><\/p>\n

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    R\u00a0<\/span>Darks:<\/strong> They are obtained just before or after the bias images. The exposure time of the dark images will correspond to the maximum exposure time of the night science images.<\/span><\/p>\n

    [\/et_pb_text][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

    R\u00a0 <\/span>Sky flats: <\/strong>These are routinely taken at the beginning and end of the night under suitable sky lighting conditions. When sky conditions do not permit, observers are provided with the most recent flat images available.<\/span><\/p>\n

    [\/et_pb_text][et_pb_divider color=”#406fda” _builder_version=”4.18.0″ _module_preset=”default” z_index=”1″ width=”33.3%” custom_margin=”1px|90px|-18px|0px|false|false” custom_margin_tablet=”|0px|||false|false” custom_margin_phone=”|3px||5px|false|false” custom_margin_last_edited=”on|phone” custom_padding=”5px|24px|0px|0px|false|false” locked=”off” global_colors_info=”{}”][\/et_pb_divider][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ module_id=”ares” _builder_version=”4.18.1″ _module_preset=”default” custom_padding=”0px||||false|false” global_colors_info=”{}”][et_pb_row _builder_version=”4.18.1″ _module_preset=”default” custom_margin=”0px|auto|10px|auto|false|false” custom_padding=”0px||0px||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.18.0″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” text_font_size=”32px” text_line_height=”1em” header_text_color=”#1a1140″ custom_margin=”-2px|||||” text_font_size_tablet=”32px” text_font_size_phone=”26px” text_font_size_last_edited=”on|phone” global_colors_info=”{}”]<\/p>\n

    ARES<\/strong><\/h3>\n

    [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.18.1″ _module_preset=”default” custom_padding=”0px||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

    The ARES instrument (Astronomical mid-REsolution Spectrograph)<\/strong> is a fibre spectrograph installed in a dedicated room on the ground floor of the TJO building. ARES allows the observation of bright stars with a resolution of R=12000 in two spectral windows centred at 512 nm and 656 nm.<\/span><\/p>\n

    ARES is designed by Fractal SLNE. It allows performing medium resolution spectroscopy with the following characteristics:<\/span><\/p>\n

    [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_3,1_3,1_3″ _builder_version=”4.18.1″ _module_preset=”default” custom_margin=”1px||||false|false” custom_padding=”0px||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”1_3″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

    Limiting magnitude:<\/strong> S\/N=10 for V=13 mag in 1-hour exposure time
    Global transmissivity:<\/strong> >10%
    Spectral resolution:<\/strong> R=12000
    Two spectral windows:<\/strong> green (from 405 to 530 nm), red (from 630 to 673 nm)<\/p>\n

    [\/et_pb_text][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

    In order to achieve a high global transmissivity (>10%) two telescopes (manufactured by Takahashi)<\/strong> and two VPHs in Littrow configuration are used.<\/span><\/p>\n

    [\/et_pb_text][\/et_pb_column][et_pb_column type=”1_3″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_image src=”https:\/\/montsec.ieec.cat\/wp-content\/uploads\/2022\/11\/instrument4-2.webp” alt=”instrument4″ title_text=”instrument4″ _builder_version=”4.18.1″ _module_preset=”default” width=”115%” global_colors_info=”{}”][\/et_pb_image][\/et_pb_column][et_pb_column type=”1_3″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_image src=”https:\/\/montsec.ieec.cat\/wp-content\/uploads\/2022\/11\/instrument3.webp” alt=”instrument3″ title_text=”instrument3″ _builder_version=”4.18.1″ _module_preset=”default” width=”100%” global_colors_info=”{}”][\/et_pb_image][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_2,1_2″ _builder_version=”4.18.1″ _module_preset=”default” min_height=”204.5px” custom_margin=”0px||0px||false|false” custom_padding=”11px||0px||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_image src=”https:\/\/montsec.ieec.cat\/wp-content\/uploads\/2022\/11\/instruments6.webp” alt=”instruments6″ title_text=”instruments6″ align=”right” _builder_version=”4.18.1″ _module_preset=”default” width=”100%” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][\/et_pb_image][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” text_font=”Source Sans Pro|700|||||||” text_text_color=”#406fda” text_font_size=”22px” global_colors_info=”{}”]<\/p>\n

    VPHs<\/p>\n

    [\/et_pb_text][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” locked=”off” global_colors_info=”{}”]<\/p>\n

    The dispersion system of the ARES spectrograph<\/strong> is composed of two VPHs developed by Wasatch Photonics<\/strong>, providing the two spectral windows and maintaining a high transmissivity. Both VPHs are mounted on a rail (prepared to accommodate an additional one) which allows a quick change between them.<\/span><\/p>\n

    [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_2,1_2″ _builder_version=”4.18.1″ _module_preset=”default” min_height=”341.5px” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” text_font=”Source Sans Pro|700|||||||” text_text_color=”#406fda” text_font_size=”22px” global_colors_info=”{}”]<\/p>\n

    CCD camera<\/p>\n

    [\/et_pb_text][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” locked=”off” global_colors_info=”{}”]The CCD detector used by ARES is an Andor Newton DU940P CCD camera with the following characteristics:[\/et_pb_text][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” width=”100%” custom_margin=”0px|0px|0px|0px|false|false” custom_padding=”0px|0px|0px|0px|false|false” locked=”off” global_colors_info=”{}”]<\/p>\n

    R\u00a0<\/span>Sensor type: <\/strong>BV- back-illuminated, optimised for VIS
    R\u00a0<\/span>Number of pixels: <\/strong><\/strong>2048 \u00d7<\/span> 512
    R\u00a0<\/span>Pixel size: <\/strong><\/strong><\/strong>13.5 \u00d7<\/span> 13.5 um
    R\u00a0<\/span>Sensor size: <\/strong><\/strong><\/strong><\/strong>26.7 \u00d7<\/span> 6.9 mm
    R\u00a0<\/span>Minimum working temperature: <\/strong><\/strong><\/strong><\/strong><\/strong>-100\u00baC
    R\u00a0<\/span>Readout noise: <\/strong><\/strong><\/strong><\/strong><\/strong><\/strong>2.8 e-
    R\u00a0<\/span>Dark current: <\/strong><\/strong><\/strong><\/strong><\/strong><\/strong><\/strong>0.0002 e-\/pixel\/s
    R\u00a0<\/span>Linearity: <\/strong><\/strong><\/strong><\/strong><\/strong><\/strong><\/strong><\/strong>better than 99%<\/p>\n

    [\/et_pb_text][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_image src=”https:\/\/montsec.ieec.cat\/wp-content\/uploads\/2022\/11\/instrument5-1.webp” alt=”instrument5″ title_text=”instrument5″ align=”right” _builder_version=”4.18.1″ _module_preset=”default” width=”100%” custom_margin=”||0px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”][\/et_pb_image][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.18.1″ _module_preset=”default” custom_margin=”8px||||false|false” custom_padding=”0px||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” text_font=”Source Sans Pro|700|||||||” text_text_color=”#406fda” text_font_size=”22px” custom_margin=”5px||||false|false” locked=”off” global_colors_info=”{}”]Spectra with simultaneous calibration[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_2,1_2″ _builder_version=”4.18.1″ _module_preset=”default” custom_margin=”0px||||false|false” custom_padding=”0px||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”]ARES is equipped with three fibres, providing 3 simultaneous spectra in each exposure. One of the fibres is centred on the stellar-type object of interest, another is used in order to obtain the spectrum of the sky background, and the third fibre, positioned between the other two, can be used both to obtain flats of a calibration lamp or to obtain calibration arcs in wavelength. The observer can choose which type of calibration spectrum will be inserted into the image when defining the configuration of the observations. [\/et_pb_text][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” custom_padding=”0px||||false|false” global_colors_info=”{}”]Below are two examples, one showing the two sky fibres illuminated, and the other with a star centred on a sky fibre and a simultaneous calibration arc.[\/et_pb_text][et_pb_image src=”https:\/\/montsec.ieec.cat\/wp-content\/uploads\/2022\/11\/instruments7.webp” alt=”instruments7″ title_text=”instruments7″ _builder_version=”4.18.1″ _module_preset=”default” locked=”off” global_colors_info=”{}”][\/et_pb_image][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.18.1″ _module_preset=”default” custom_margin=”0px||||false|false” custom_padding=”0px||||false|false” locked=”off” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” text_font=”Source Sans Pro|700|||||||” text_text_color=”#406fda” text_font_size=”22px” custom_margin=”5px||||false|false” locked=”off” global_colors_info=”{}”]Standard calibration procedure[\/et_pb_text][et_pb_text _builder_version=”4.18.1″ _module_preset=”default” global_colors_info=”{}”]Apart from the calibration of the spectrum obtained simultaneously with the images, the TJO control system is designed to periodically obtain the calibration images, including bias, darks and spectroscopic flats:[\/et_pb_text][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”0px||25px||false|false” custom_padding=”||0px||false|false” global_colors_info=”{}”]<\/p>\n

    R <\/span> Bias:<\/strong> They are usually taken in multiples of 5 before the start and at the end of each night. Observers are given a minimum of 10 bias images.<\/p>\n

    [\/et_pb_text][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” custom_margin=”||25px||false|false” global_colors_info=”{}”]<\/p>\n

    R<\/span> Darks:<\/strong> They are obtained just before or after the bias images. The exposure time of the dark images will correspond to the maximum exposure time of the night science images.<\/p>\n

    [\/et_pb_text][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}”]<\/p>\n

    R<\/span> Spectroscopic flats:<\/strong> The optimal calibration strategy for ARES is still under evaluation. The main purpose of spectroscopic flats is to trace the position of the spectrum and correct the intra-pixel response. For this reason, 4 options can be studied: direct illumination of the CCD, dome flats, illumination of the fibres with LEDs, and standard stars. The solution that provides the optimal result will be used for the spectra images delivered to the observers.<\/p>\n

    [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section]<\/p>\n","protected":false},"excerpt":{"rendered":"

    Astronomy | Joan Or\u00f3 TelescopeJoan Or\u00f3 TelescopeThe Joan Or\u00f3 Telescope is managed by the IEEC and is currently the largest telescope in Catalonia.It has a primary mirror of 0.8 metres and an F\/9.6 Ritchey-Chr\u00e9tien optical system. The Joan Or\u00f3 Telescope (TJO) was built by Optical Mechanics Inc. (OMI) and is equipped with a 6.15 metre […]<\/p>\n","protected":false},"author":5,"featured_media":0,"parent":3776,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_et_pb_use_builder":"on","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"class_list":["post-3787","page","type-page","status-publish","hentry"],"yoast_head":"\nJoan Or\u00f3 Telescope (TJO) - Observatori del Montsec<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/montsec.ieec.cat\/en\/astronomy\/tjo\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Joan Or\u00f3 Telescope (TJO) - Observatori del Montsec\" \/>\n<meta property=\"og:description\" content=\"Astronomy | Joan Or\u00f3 TelescopeJoan Or\u00f3 TelescopeThe Joan Or\u00f3 Telescope is managed by the IEEC and is currently the largest telescope in Catalonia.It has a primary mirror of 0.8 metres and an F\/9.6 Ritchey-Chr\u00e9tien optical system. 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