{"id":10922,"date":"2022-07-12T08:46:06","date_gmt":"2022-07-12T04:16:06","guid":{"rendered":"https:\/\/ino.org.ir\/?page_id=10922"},"modified":"2026-06-09T14:39:59","modified_gmt":"2026-06-09T10:09:59","slug":"for-astronomers","status":"publish","type":"page","link":"https:\/\/ino.org.ir\/en\/for-astronomers\/","title":{"rendered":"for astronomers"},"content":{"rendered":"<section class=\"l-section wpb_row us_custom_bfd15b4e height_medium\" id=\"ino340-telescope\"><div class=\"l-section-h i-cf\"><div class=\"g-cols vc_row via_flex valign_top type_default stacking_default\"><div class=\"vc_col-sm-12 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"wpb_text_column us_custom_93995a29\"><div class=\"wpb_wrapper\"><h4>The INO340 Telescope<\/h4>\n<p dir=\"ltr\"><strong>Overview:<\/strong><\/p>\n<p dir=\"ltr\">The INO340 is a 3.4-m Ritchey\u2013Chr\u00e9tien Cassegrain telescope operated by the Iranian National Observatory. Its primary mirror is made of ceramic ZERODUR\u00ae, with an optical diameter of 3300 mm, a thickness of 180 mm \u00b1 10 mm, and a mass of ~4000 kg. The mirror has a focal ratio of f\/1.49, a central hole of 700 mm, and a surface roughness of &lt;2 nm RMS. The secondary mirror, also made of ZERODUR\u00ae, is convex with an optical diameter of 582.4 mm, a thickness of 90 mm at the center, and a mass of ~60 kg. The Cassegrain focus provides a final focal ratio of f\/11.24. The telescope optical design delivers an unvignetted field of view of up to 20 arcminutes, while the currently installed KEPLER KL4040 camera provides a usable imaging field of 3\u00d73 arcminutes, which can be increased to 6.6 \u00d7 6.6 arcminutes using a focal reducer. Three bent Cassegrain ports are available, each with a field of view of 8 arcminutes. All foci are equipped with instrument rotators and autoguiders, and acquisition cameras are available for field verification. The telescope operates over a wavelength range of 325\u20132500 nm, with an entrance pupil located on the primary and a back focal distance of 1670 mm. The telescope is mounted on an altitude\u2013azimuth structure and is normally operated by staff: observers submit proposals, and the INO observing team conducts the observations and provides the data for download. Occasional on-site observing may be arranged under special circumstances, with visitors accompanied by the observing team.<\/p>\n<\/div><\/div><div class=\"w-tabs us_custom_eb849559 layout_hor style_trendy switch_click has_scrolling\" style=\"--sections-title-size:1em\"><div class=\"w-tabs-list items_6 align_none\" style=\"font-weight:600;\"><div class=\"w-tabs-list-h\"><a class=\"w-tabs-item active\" aria-controls=\"content-f410\" href=\"javascript:void(0);\"><span class=\"w-tabs-item-title\">The Optics<\/span><\/a><a class=\"w-tabs-item\" aria-controls=\"content-udf7\" href=\"javascript:void(0);\"><span class=\"w-tabs-item-title\">The Mounting<\/span><\/a><a class=\"w-tabs-item\" aria-controls=\"content-ke00\" href=\"javascript:void(0);\"><span class=\"w-tabs-item-title\">Instruments<\/span><\/a><a class=\"w-tabs-item\" aria-controls=\"content-r774\" href=\"javascript:void(0);\"><span class=\"w-tabs-item-title\">Object Visibility Checker<\/span><\/a><a class=\"w-tabs-item\" aria-controls=\"content-zfc8\" href=\"javascript:void(0);\"><span class=\"w-tabs-item-title\">Signal To Noise Calculator<\/span><\/a><a class=\"w-tabs-item\" aria-controls=\"content-vb62\" href=\"javascript:void(0);\"><span class=\"w-tabs-item-title\">Applying for Telescope Time<\/span><\/a><\/div><\/div><div class=\"w-tabs-sections titles-align_none icon_chevron cpos_right\"><div class=\"w-tabs-section active\" id=\"f410\"><button aria-controls=\"content-f410\" class=\"w-tabs-section-header active\"><div class=\"w-tabs-section-title\">The Optics<\/div><div class=\"w-tabs-section-control\"><\/div><\/button><div  class=\"w-tabs-section-content\" id=\"content-f410\" aria-expanded=\"true\"><div class=\"w-tabs-section-content-h i-cf\"><div class=\"g-cols wpb_row via_flex valign_top type_default stacking_default\"><div class=\"vc_col-sm-6 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"wpb_text_column us_custom_f03ee871\"><div class=\"wpb_wrapper\"><div dir=\"ltr\" style=\"text-align: left;\">\n<p>The optical system of the INO340 is a Ritchey\u2013Chr\u00e9tien Cassegrain with a hyperboloidal primary and a convex hyperboloidal secondary mirror, optimized to deliver high image quality over a wide field of view. The primary mirror has a diameter of 3.4 m and a focal ratio of f\/1.49, giving a final system focal ratio of f\/11.24 at the Cassegrain focus. The entrance pupil is located on the primary mirror, and the system provides a back focal distance of 1670 mm.<\/p>\n<p>The telescope operates over a wavelength range from 325 nm to 2500 nm, enabling observations from the near-ultraviolet to the near-infrared. At the main Cassegrain focus, the optical design provides an unvignetted field of view of 20 arc min, well corrected for off-axis aberrations. In addition to the main focus, three bent foci are provided, each offering a field of view of 8 arc min, allowing flexible instrument mounting and operation.<\/p>\n<p>The mirrors are fabricated from ZERODUR\u00ae\ufe0f ceramic, providing excellent thermal and mechanical stability due to its negligible coefficient of thermal expansion. The optical surfaces are polished to a micro-roughness below 2 nm RMS, ensuring high throughput and image quality across the full spectral range. Active support and positioning systems are employed to maintain the mirror figures and alignment during telescope operation, compensating for gravitational and thermal deformations.<\/p>\n<p>The scale at the Cassegrain focus is 0.18526 mm per arc sec, corresponding to a plate scale well matched to modern imaging and spectroscopic instrumentation. The optical design of INO340 delivers a compact, high-performance system, combining wide-field capability, broad wavelength coverage, and excellent image quality for a wide range of astronomical applications.<\/p>\n<p>Optical characteristics of INO340 foci<\/p>\n<table>\n<tbody>\n<tr>\n<td><\/td>\n<td><strong>Cassegrain Focus<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>Focal length (mm)<\/strong><\/td>\n<td><strong>~ 38212<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>Focal ratio<\/strong><\/td>\n<td><strong>f\/11.24<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>Unvignetted Field diameter (arcmin)<\/strong><\/td>\n<td><strong>20<\/strong><\/td>\n<\/tr>\n<tr>\n<td><strong>Scale (arcsec\/mm)<\/strong><\/td>\n<td><strong>5.398<\/strong><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-11555\" src=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/optics1-300x217.png\" alt=\"\" width=\"494\" height=\"357\" srcset=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/optics1-300x217.png 300w, https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/optics1.png 478w\" sizes=\"(max-width: 494px) 100vw, 494px\" \/><\/p>\n<p>Spot diagram for a flat focal surface at the nominal cassegrain focus of the INO340 telescope showing images produced on axis and at 3, 4.5 and 6 Arcminutes (units are \u00b5m).<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-11557\" src=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/optics2-300x103.png\" alt=\"\" width=\"588\" height=\"202\" srcset=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/optics2-300x103.png 300w, https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/optics2-600x205.png 600w, https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/optics2.png 614w\" sizes=\"(max-width: 588px) 100vw, 588px\" \/><\/p>\n<p>On axis image images produced at the cassegrain focus of the INO340 telescope when focus is moved from the nominal position by the amounts shown on top of each image (units are \u00b5m).<\/p>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div><div class=\"vc_col-sm-6 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"w-image align_none\"><div class=\"w-image-h\"><img loading=\"lazy\" decoding=\"async\" width=\"722\" height=\"525\" src=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2022\/07\/allscicase2.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2022\/07\/allscicase2.jpg 722w, https:\/\/ino.org.ir\/wp-content\/uploads\/2022\/07\/allscicase2-300x218.jpg 300w, https:\/\/ino.org.ir\/wp-content\/uploads\/2022\/07\/allscicase2-600x436.jpg 600w\" sizes=\"(max-width: 722px) 100vw, 722px\" \/><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><div class=\"w-tabs-section\" id=\"udf7\"><button aria-controls=\"content-udf7\" class=\"w-tabs-section-header\"><div class=\"w-tabs-section-title\">The Mounting<\/div><div class=\"w-tabs-section-control\"><\/div><\/button><div  class=\"w-tabs-section-content\" id=\"content-udf7\" aria-expanded=\"false\"><div class=\"w-tabs-section-content-h i-cf\"><div class=\"g-cols wpb_row via_flex valign_top type_default stacking_default\"><div class=\"vc_col-sm-6 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"wpb_text_column us_custom_f03ee871\"><div class=\"wpb_wrapper\"><p style=\"text-align: justify;\">The INO340 telescope is mounted on an altitude\u2013azimuth and is controlled by the INOCS system, which drives the main hour-angle and declination axes, the Cassegrain instrument rotator, the focus, and the dome. The observer interacts with the telescope via a dedicated software interface from the control room, which allows entering target properties, pointing, exposure times, and filter selection, then starting the observation automatically. Adjustments to telescope tracking can be made automatically by the telescope control system.<\/p>\n<p dir=\"ltr\" style=\"text-align: left;\">The INO340 operational range is:<\/p>\n<ul dir=\"ltr\" style=\"text-align: left;\">\n<li>Zenith distance &lt; 68\u00b0<\/li>\n<li>&#8211; 6 h &lt; hour angle &lt; + 6 h<\/li>\n<li>Declination &gt; -30\u00b0<\/li>\n<\/ul>\n<p dir=\"ltr\" style=\"text-align: left;\">Pointing accuracy is 3 arcseconds. Tracking precision (assisted) of 0.2 arcseconds over a 10-minute interval. Blind offsets are typically accurate to 3 arcseconds.<\/p>\n<\/div><\/div><\/div><\/div><\/div><div class=\"vc_col-sm-6 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"w-image align_none\"><div class=\"w-image-h\"><img loading=\"lazy\" decoding=\"async\" width=\"2560\" height=\"2424\" src=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2024\/04\/\u062a\u0644\u0633\u06a9\u0648\u067e2-scaled.jpg\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2024\/04\/\u062a\u0644\u0633\u06a9\u0648\u067e2-scaled.jpg 2560w, https:\/\/ino.org.ir\/wp-content\/uploads\/2024\/04\/\u062a\u0644\u0633\u06a9\u0648\u067e2-300x284.jpg 300w, https:\/\/ino.org.ir\/wp-content\/uploads\/2024\/04\/\u062a\u0644\u0633\u06a9\u0648\u067e2-1024x970.jpg 1024w, https:\/\/ino.org.ir\/wp-content\/uploads\/2024\/04\/\u062a\u0644\u0633\u06a9\u0648\u067e2-600x568.jpg 600w, https:\/\/ino.org.ir\/wp-content\/uploads\/2024\/04\/\u062a\u0644\u0633\u06a9\u0648\u067e2-768x727.jpg 768w\" sizes=\"(max-width: 2560px) 100vw, 2560px\" \/><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><div class=\"w-tabs-section\" id=\"ke00\"><button aria-controls=\"content-ke00\" class=\"w-tabs-section-header\"><div class=\"w-tabs-section-title\">Instruments<\/div><div class=\"w-tabs-section-control\"><\/div><\/button><div  class=\"w-tabs-section-content\" id=\"content-ke00\" aria-expanded=\"false\"><div class=\"w-tabs-section-content-h i-cf\"><div class=\"g-cols wpb_row via_flex valign_top type_default stacking_default\"><div class=\"vc_col-sm-8 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"wpb_text_column us_custom_f03ee871\"><div class=\"wpb_wrapper\"><div dir=\"ltr\" style=\"text-align: left;\">\n<p>The INO340 telescope is equipped with a KEPLER KL4040 FLI scientific CCD camera at the main Cassegrain focus, delivering high sensitivity optical imaging across a 3.3\u2032 unvignetted field of view. The KL4040 can also be equipped with a focal reducer at the Cassegrain focus, which provides a wider 6.6\u2032\u00d76.6\u2032 field of view for imaging larger sky areas.<\/p>\n<p>This camera offers three gain modes: High (sensitive to faint details, gain ~0.5\u20132.5 e\u207b\/ADU), Low (handles bright regions, gain ~4.5\u201335.7 e\u207b\/ADU), and Merge (combined High + Low for wide dynamic range).<\/p>\n<p>The KL4040 FI is a front-illuminated, cooled sCMOS camera with 4096 \u00d7 4096 pixels, 9 \u00d7 9 \u03bcm pixel size, and a 36.9 \u00d7 36.9 mm imaging area (diagonal 52.1 mm). It provides high quantum efficiency (~74% peak QE), low read noise (~3.7 e\u207b high gain), a dynamic range of 85.2 dB (HDR), and full well capacity of 70,000 e\u207b. The camera supports a maximum frame rate of 23 fps (QSFP interface optional) and features rolling shutter readout, with high-speed HDR mode producing 12-bit linear images. Dark current is approximately 0.08 eps at -10C, which is the chosen temperature for standard operations of the telescope.<\/p>\n<p>CCD Parameters<\/p>\n<table>\n<tbody>\n<tr>\n<td>Pixel Size (\u03bcm)<\/td>\n<td>9\u00d79<\/td>\n<\/tr>\n<tr>\n<td>Resolution (pixels)<\/td>\n<td>4096 \u00d7 4096<\/td>\n<\/tr>\n<tr>\n<td>Imaging Area (mm)<\/td>\n<td>36.9 \u00d7 36.9<\/td>\n<\/tr>\n<tr>\n<td>Electrons per ADU<\/td>\n<td>0.95 \u2013 1.05<\/td>\n<\/tr>\n<tr>\n<td>Saturation (e-)<\/td>\n<td>70000<\/td>\n<\/tr>\n<tr>\n<td>Peak QE<\/td>\n<td>74%<\/td>\n<\/tr>\n<tr>\n<td>Read Noise (High gain)<\/td>\n<td>3.7 e-<\/td>\n<\/tr>\n<tr>\n<td>Dark Current @ -20C<\/td>\n<td>0.08 eps at -10C<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>Filters for CCD Imaging on INO340<\/strong><\/p>\n<p>The INO340 telescope offers two high-quality filter systems: the Sloan (SDSS) u\u2032g\u2032r\u2032i\u2032 set and the Kron\u2013Cousins (KC) UBVRI set. These systems provide astronomers with flexible options for broadband photometry, supporting both modern SDSS-based calibration and traditional UBVRI stellar classification.<\/p>\n<p>The Sloan filters cover ultraviolet through optical wavelengths with sharply defined passbands that enable effective photometry and high signal-to-noise ratios for a wide range of targets. Observations using these filters are tied to the SDSS standard-star network, allowing high-precision absolute photometry in the AB magnitude system.<\/p>\n<p>The Kron\u2013Cousins UBVRI filters are specifically optimized for Silicon CCD detectors. They isolate critical spectral bands for stellar measurements while minimizing focus changes between filters. Each filter is manufactured with high optical quality and excellent out-of-band blocking to ensure accurate and repeatable photometry.<\/p>\n<table>\n<tbody>\n<tr>\n<td><strong>Filter Set<\/strong><\/td>\n<td><strong>Filter<\/strong><\/td>\n<td><strong>Central Wavelength (nm)<\/strong><\/td>\n<td><strong>Bandwidth (nm)<\/strong><\/td>\n<td><strong>Peak Transmission<\/strong><\/td>\n<\/tr>\n<tr>\n<td rowspan=\"4\">SDSS u\u2032g\u2032r\u2032i\u2032<\/td>\n<td>u\u2032<\/td>\n<td>354<\/td>\n<td>57<\/td>\n<td>&gt; 70 %<\/td>\n<\/tr>\n<tr>\n<td>g\u2032<\/td>\n<td>477<\/td>\n<td>139<\/td>\n<td>&gt; 80 %<\/td>\n<\/tr>\n<tr>\n<td>r\u2032<\/td>\n<td>623<\/td>\n<td>137<\/td>\n<td>&gt; 85 %<\/td>\n<\/tr>\n<tr>\n<td>i\u2032<\/td>\n<td>762<\/td>\n<td>153<\/td>\n<td>&gt; 85 %<\/td>\n<\/tr>\n<tr>\n<td rowspan=\"5\">KC UBVRI<\/td>\n<td>U<\/td>\n<td>365<\/td>\n<td>60<\/td>\n<td>&gt; 50 %<\/td>\n<\/tr>\n<tr>\n<td>B<\/td>\n<td>440<\/td>\n<td>100<\/td>\n<td>&gt; 70 %<\/td>\n<\/tr>\n<tr>\n<td>V<\/td>\n<td>520<\/td>\n<td>90<\/td>\n<td>&gt; 70 %<\/td>\n<\/tr>\n<tr>\n<td>R<\/td>\n<td>760<\/td>\n<td>250<\/td>\n<td>&gt; 70 %<\/td>\n<\/tr>\n<tr>\n<td>I<\/td>\n<td>800<\/td>\n<td>150<\/td>\n<td>&gt; 70 %<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>In addition to the above, the development of a dedicated spectrograph is presently underway, with implementation planned as part of the next stage of the INO340 instrumentation program.<\/p>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div><div class=\"vc_col-sm-4 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"w-image align_none\"><a href=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/filters1.png\" ref=\"magnificPopup\" aria-label=\"Link\" class=\"w-image-h\"><img loading=\"lazy\" decoding=\"async\" width=\"624\" height=\"416\" src=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/filters1.png\" class=\"attachment-full size-full\" alt=\"\" srcset=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/filters1.png 624w, https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/filters1-300x200.png 300w, https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/05\/filters1-600x400.png 600w\" sizes=\"(max-width: 624px) 100vw, 624px\" \/><\/a><\/div><\/div><\/div><\/div><\/div><div class=\"g-cols wpb_row via_flex valign_top type_default stacking_default\"><div class=\"vc_col-sm-12 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><\/div><\/div><\/div><\/div><\/div><\/div><\/div><div class=\"w-tabs-section\" id=\"r774\"><button aria-controls=\"content-r774\" class=\"w-tabs-section-header\"><div class=\"w-tabs-section-title\">Object Visibility Checker<\/div><div class=\"w-tabs-section-control\"><\/div><\/button><div  class=\"w-tabs-section-content\" id=\"content-r774\" aria-expanded=\"false\"><div class=\"w-tabs-section-content-h i-cf\"><div class=\"g-cols wpb_row via_flex valign_top type_default stacking_default\"><div class=\"vc_col-sm-6 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"wpb_text_column us_custom_f03ee871\"><div class=\"wpb_wrapper\"><div dir=\"ltr\" style=\"text-align: left;\">\n<p>At present, the STARALT tool is provided as a recommended resource for INO astronomers to assess target visibility and plan observations.<\/p>\n<p>The tool enables users to evaluate the visibility of astronomical targets from a selected observatory site by producing altitude\u2013time plots over a given night. This allows the identification of optimal observing windows, taking into account constraints such as airmass limits and twilight conditions.<\/p>\n<p>To use STARALT, users input the target name or celestial coordinates (RA\/Dec), select the desired observing date, and choose the observatory location. The resulting output provides a clear graphical representation of target elevation throughout the night.<\/p>\n<p>For INO-based planning, the <strong>Iranian National Observatory<\/strong> location can be selected directly from the <strong>Observatory<\/strong> dropdown menu within the STARALT interface, ensuring accurate site-specific visibility calculations for the INO340 telescope.<\/p>\n<p><a style=\"color: blue;\" href=\"https:\/\/astro.ing.iac.es\/staralt\/\" target=\"_blank\" rel=\"noopener\"><br \/>\nhttps:\/\/astro.ing.iac.es\/staralt\/<br \/>\n<\/a><\/p>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div><div class=\"vc_col-sm-6 wpb_column vc_column_container\"><div class=\"vc_column-inner\"><div class=\"wpb_wrapper\"><div class=\"w-image align_none\"><div class=\"w-image-h\"><img loading=\"lazy\" decoding=\"async\" width=\"695\" height=\"846\" src=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/06\/staralt.png\" class=\"attachment-full size-full\" alt=\"STARALT\" srcset=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/06\/staralt.png 695w, https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/06\/staralt-246x300.png 246w, https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/06\/staralt-600x730.png 600w\" sizes=\"(max-width: 695px) 100vw, 695px\" \/><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><div class=\"w-tabs-section\" id=\"zfc8\"><button aria-controls=\"content-zfc8\" class=\"w-tabs-section-header\"><div class=\"w-tabs-section-title\">Signal To Noise Calculator<\/div><div class=\"w-tabs-section-control\"><\/div><\/button><div  class=\"w-tabs-section-content\" id=\"content-zfc8\" aria-expanded=\"false\"><div class=\"w-tabs-section-content-h i-cf\"><div class=\"wpb_text_column\"><div class=\"wpb_wrapper\"><div dir=\"ltr\" style=\"text-align: left;\">\n<p>The INO340 SNR Calculator is a Python-based tool designed to estimate the expected signal-to-noise ratio for astronomical observations with the INO340 telescope. The pipeline combines instrumental parameters, site conditions, and astrophysical models to provide a physically consistent SNR estimation for a given target and exposure time.<\/p>\n<p>The calculation incorporates atmospheric extinction, airmass effects, sky background contribution (including Moon illumination and separation), detector characteristics (read noise, gain, dark current), filter transmission properties, and telescope collecting area. Sky brightness is estimated dynamically using a calibrated sky model, while target flux is derived from standard photometric conversions. The final SNR is computed from the total signal and combined noise contributions within the photometric aperture.<\/p>\n<p>The SNR Calculator is provided as a Python-based tool intended for local execution. Once set up, it can be run to access the graphical interface for input and calculation.<\/p>\n<p>Users are guided through a structured input sequence, including:<\/p>\n<ul>\n<li>Target coordinates (RA, Dec)<\/li>\n<li>Observation date and time (local Tehran time)<\/li>\n<li>Object magnitude and selected filter<\/li>\n<li>Seeing conditions and detector binning<\/li>\n<\/ul>\n<p>After entering the required parameters and selecting an exposure time, the tool performs a complete signal-to-noise calculation using the INO340 instrument and site model, and returns the final SNR estimate for the specified configuration. You can download the calculator by clicking the button below.<\/p>\n<p><a href=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/06\/INO_SNR_Calculator.zip\"\n   download\n   class=\"ino-vc-button\"><br \/>\nINO SNR Calculator<br \/>\n<\/a><\/p>\n<style>\n.ino-vc-button {\n    display: inline-block;\n    background: #0088cc;\n    color: #ffffff;\n    padding: 10px 18px;        \/* reduced height *\/\n    border-radius: 6px;\n    font-size: 14px;          \/* slightly smaller text helps *\/\n    font-weight: 400;\n    line-height: 0.8;        \/* prevents extra vertical space *\/\n    text-decoration: none;\n    box-shadow: 0 3px 0 #006699;\n    transition: all 0.12s ease;\n    position: relative;\n}\n<\/style>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div><div class=\"w-tabs-section\" id=\"vb62\"><button aria-controls=\"content-vb62\" class=\"w-tabs-section-header\"><div class=\"w-tabs-section-title\">Applying for Telescope Time<\/div><div class=\"w-tabs-section-control\"><\/div><\/button><div  class=\"w-tabs-section-content\" id=\"content-vb62\" aria-expanded=\"false\"><div class=\"w-tabs-section-content-h i-cf\"><div class=\"wpb_text_column\"><div class=\"wpb_wrapper\"><div dir=\"ltr\" style=\"text-align: left;\">\n<p>Researchers wishing to use the INO340 must submit a scientific proposal during an official call for proposals. Time is allocated on the basis of scientific merit, technical feasibility, and the suitability of the program for the telescope and its instrumentation.<\/p>\n<p><strong>Time Allocation<\/strong><\/p>\n<p>Observing time on the INO340 is awarded by the INO340 Time Allocation Committee (TAC) following a national call for proposals. The telescope operates in three-month observing semesters and all observations are conducted in service (queue) mode by the INO observing team.<\/p>\n<p>Calls for proposals are issued periodically for observing time. At present, project activities are temporarily suspended until further notice. Updates regarding future calls will be announced in due course. Interested applicants are encouraged to revisit this website for announcements at a later time. For general enquiries, please contact: ino@ipm.ir.<\/p>\n<p>Proposals are accepted from researchers affiliated with Iranian institutions, and exact deadlines for subsequent semesters will be announced with each call.<\/p>\n<p><strong>Observing Mode<\/strong><\/p>\n<p>All regular programs on the INO340 are conducted in service (queue) mode and executed by INO staff astronomers under suitable observing conditions. Programs are selected from the queue according to their scientific ranking and the prevailing conditions, including seeing, sky transparency, target visibility, airmass constraints, and instrument availability. This approach ensures efficient use of telescope time and maximizes scientific return.<\/p>\n<p>Once observations are completed, the data are delivered to the Principal Investigator through the INO data system.<\/p>\n<p><strong>Target of Opportunity Observations<\/strong><\/p>\n<p>The INO340 supports Target of Opportunity (ToO) observations for transient or time-critical events. Proposals requesting ToO status must clearly describe the nature of the transient phenomenon, the required response time, and any specific observational constraints. Approved ToO programs may be scheduled with priority when scientifically justified.<\/p>\n<p><strong>Data Policy<\/strong><\/p>\n<p>Data obtained with the INO340 are proprietary to the Principal Investigator and collaborators for a period of twelve months from the date of delivery. After the proprietary period, data may become publicly accessible through the INO archive in accordance with observatory policy.<\/p>\n<p><strong>Acknowledgement in Publications<\/strong><\/p>\n<p>We kindly ask authors preparing a paper using INO340 data to notify the Iranian National Observatory in advance of the publication (ino@ipm.ir), and to provide proper acknowledgement to the use of the INO340 in any published papers. Please copy the following paragraph, updating it with your proposal reference:<\/p>\n<p>Based on observations made with the INO340 telescope operated by the Iranian National Observatory (INO340 proposal(s) XXXXXXXX-XX).<\/p>\n<p><strong>Proposal Submission<\/strong><\/p>\n<p>Proposals must be submitted electronicallyProposals must be submitted electronically via email using the official INO340 LaTeX proposal form provided with each call for proposals. The submission package should include both the completed LaTeX source file (.tex) and the compiled PDF version of the proposal. All proposals must be sent to <a style=\"color: blue; font-weight: 600;\" href=\"mailto:ino@ipm.ir\">ino@ipm.ir<\/a><\/p>\n<p>A complete proposal consists of a scientific justification, a technical description of the requested observations, a target list with coordinates, the total requested observing time, and full investigator information. Additional sections such as calibration requirements, scheduling constraints, and backup programs must also be completed where applicable.<\/p>\n<p>Proposals received after the stated deadline will not be considered.<\/p>\n<p><a href=\"https:\/\/ino.org.ir\/wp-content\/uploads\/2026\/06\/INO340_proposal_form.zip\"\n   download\n   class=\"ino-vc-button\"><br \/>\nProposal Template<br \/>\n<\/a><\/p>\n<style>\n.ino-vc-button {\n    display: inline-block;\n    background: #0088cc;\n    color: #ffffff;\n    padding: 10 px 18px;        \/* reduced height *\/\n    border-radius: 6px;\n    font-size: 14px;          \/* slightly smaller text helps *\/\n    font-weight: 400;\n    line-height: 0.8;        \/* prevents extra vertical space *\/\n    text-decoration: none;\n    box-shadow: 0 3px 0 #006699;\n    transition: all 0.12s ease;\n    position: relative;\n}\n<\/style>\n<\/div>\n<\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/section>\n","protected":false},"excerpt":{"rendered":"The INO340 Telescope Overview: The INO340 is a 3.4-m Ritchey\u2013Chr\u00e9tien Cassegrain telescope operated by the Iranian National Observatory. Its primary mirror is made of ceramic ZERODUR\u00ae, with an optical diameter of 3300 mm, a thickness of 180 mm \u00b1 10 mm, and a mass of ~4000 kg. The mirror has a focal ratio of f\/1.49,...","protected":false},"author":6,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/pages\/10922"}],"collection":[{"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/comments?post=10922"}],"version-history":[{"count":20,"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/pages\/10922\/revisions"}],"predecessor-version":[{"id":11626,"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/pages\/10922\/revisions\/11626"}],"wp:attachment":[{"href":"https:\/\/ino.org.ir\/en\/wp-json\/wp\/v2\/media?parent=10922"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}