{"id":46494,"date":"2026-02-13T18:08:53","date_gmt":"2026-02-13T18:08:53","guid":{"rendered":"https:\/\/alicatstage.wpenginepowered.com\/?p=46494"},"modified":"2026-03-09T20:39:11","modified_gmt":"2026-03-09T20:39:11","slug":"echelle-spektrograf-mit-geschlossener-volumendruckregelung","status":"publish","type":"post","link":"https:\/\/www.alicat.com\/de\/articles\/echelle-spectrograph-closed-volume-pressure-control\/","title":{"rendered":"Echelle-Spektrograf Geschlossenes Volumen Druckregelung"},"content":{"rendered":"

[et_pb_section fb_built=”1″ _builder_version=”4.27.5″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_row _builder_version=”4.27.4″ _module_preset=”default” custom_padding=”2em||0px||false|false” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_heading title=”Veloce Echelle Spectrograph Utilizes Closed-Volume Pressure Control” _builder_version=”4.27.4″ _module_preset=”default” custom_css_free_form=”selector h1 {|| text-wrap: pretty;||}” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_heading][et_pb_image src=”https:\/\/www.alicat.com\/wp-content\/uploads\/2024\/04\/AAT-Dome-Milky-Way-Angel-Lopez-Sanchez-AAO-MQU.webp” alt=”Anglo-Australian Telescope pressure controller” title_text=”AAT-Dome-Milky-Way-Angel-Lopez-Sanchez-AAO-MQU” align=”center” force_fullwidth=”on” module_id=”article-hero-image” _builder_version=”4.27.5″ _module_preset=”default” custom_margin=”1.5rem||||false|false” custom_css_free_form=”selector img {|| object-fit: cover;||}” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_image][et_pb_divider color=”#2A3B47″ divider_weight=”2.5px” _builder_version=”4.27.4″ _module_preset=”default” height=”0px” custom_margin=”3rem||3rem||true|false” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_divider][et_pb_heading title=”Summary” _builder_version=”4.27.5″ _module_preset=”default” title_level=”h3″ global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_heading][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.27.5″ _module_preset=”default” custom_padding=”0px||0px||true|false” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.27.4″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.27.5″ _module_preset=”default” custom_margin=”||2rem||false|false” global_colors_info=”{}” theme_builder_area=”post_content”]Dr. James Gilbert was the technical lead for the Australian National University’s development of the Veloce echelle spectrograph<\/a>, which is now installed on the 3.9-meter Anglo-Australian Telescope<\/a> at the Siding Spring Observatory in New South Wales, Australia. Veloce integrates a highly-customized Alicat®<\/sup> closed-volume pressure controller<\/a> for stable precision pressure control of air inside the instrument. This article comes courtesy of our Australian distributor, Duff & Macintosh Pty Ltd<\/a>.[\/et_pb_text][et_pb_divider color=”#000000″ _builder_version=”4.27.5″ _module_preset=”default” height=”1px” custom_margin=”||2rem||false|false” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_divider][et_pb_text _builder_version=”4.27.5″ _module_preset=”default” custom_margin=”||2rem||false|false” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

The Veloce is a fiber-fed \u00e9chelle spectrograph designed to deliver high-precision radial velocity measurements for exoplanet detection at the Siding Spring Observatory. As with other high-resolution spectrographs using \u00e9chelle grating, the instrument’s precision is highly dependent on the refractive index of the atmosphere surrounding its optical path. Maintaining stable pressure, temperature, and air composition is therefore essential over the multi-month observation periods required to characterize an exoplanet\u2019s orbit.<\/p>\n

Veloce is unique in its construction. Spatial and mechanical constraints led to researchers building a lightweight design that operates at positive pressure rather than relying on a conventional vacuum vessel. The optical bench is housed within the inner chamber of a dual-enclosure system designed to support active environmental regulation.<\/p>\n

This article focuses on the pressure control system implemented within the internal enclosure and its role in maintaining stable atmospheric conditions over extended observing periods.<\/p>\n

[\/et_pb_text][et_pb_text _builder_version=”4.27.5″ _module_preset=”default” module_alignment=”center” custom_margin=”||0px||false|false” custom_padding=”||2rem||false|false” custom_padding_last_edited=”off|desktop” custom_css_free_form=”selector figure {|| display: table;|| margin-left: auto;|| margin-right: auto;|| text-align: center;||}||||selector figcaption {|| caption-side: bottom;|| display: table-caption;||}||||selector img {|| margin-bottom: 1rem;||}” locked=”off” global_colors_info=”{}” custom_css_main_element_last_edited=”on|phone” theme_builder_area=”post_content”]<\/p>\n

\"VeloceCAD rendering of the Veloce’s internal enclosure<\/span>\u00a0<\/span><\/figure>\n

[\/et_pb_text][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” header_2_font=”|300|||||||” header_2_text_color=”#808080″ header_2_font_size=”28px” custom_margin=”||1rem||false|false” custom_css_free_form=”selector span {|| border-bottom: 1px solid #000;|| padding-bottom: 5px;||}” global_module=”46104″ saved_tabs=”all” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

Challenge<\/span><\/h2>\n

[\/et_pb_text][et_pb_heading title=”Long-term air pressure stability” _builder_version=”4.27.5″ _module_preset=”default” title_level=”h3″ global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_heading][et_pb_text _builder_version=”4.27.5″ _module_preset=”default” custom_margin=”||2rem||false|false” global_colors_info=”{}” theme_builder_area=”post_content”]Veloce’s lightweight enclosure design created a practical challenge: internal air pressure around the optical bench had to be actively controlled throughout the year using a pressurized, dry air supply. Changes in ambient temperature and atmospheric pressure at the observatory occurred continuously over seasonal timescales, while the enclosure itself responded mechanically to pressure differences. Together, these effects meant that pressure stability could not be achieved passively and had to be actively maintained to avoid degrading spectrograph performance.<\/p>\n

The primary challenges encountered were:<\/p>\n