{"id":19832,"date":"2026-10-16T10:32:30","date_gmt":"2026-10-16T08:32:30","guid":{"rendered":"https:\/\/deep-space-astronomy.ch\/?post_type=product&p=19832"},"modified":"2026-10-16T12:10:46","modified_gmt":"2026-10-16T10:10:46","slug":"jeu-antlia-sho-ultra-2-5nm","status":"publish","type":"product","link":"https:\/\/deep-space-astronomy.ch\/en\/product\/jeu-antlia-sho-ultra-2-5nm\/","title":{"rendered":"SHO Antlia Ultra 2.5 nm, H-alpha, SII, and OIII Set"},"content":{"rendered":"

Three Filters for Narrowband Imaging<\/h3>\n

The Antlia SHO Ultra 2.5 nm set combines the H-alpha, SII, and OIII filters from the Ultra series. It allows you to capture the main emissions from nebulae in these three spectral bands separately. Each option listed here corresponds to the complete set of three filters in the same format\u2014either 2\u2033 mounted or 36 mm unmounted.<\/p>\n

Transmission of bands and bandwidth<\/h3>\n

The Ultra series has a half-width at half-maximum of 2.5 nm, with a tolerance of +0.3\/\u22120.1 nm. The manufacturer specifies a transmission of at least 95 % at 656.3 nm for H-alpha and at the 671.6 and 673.1 nm lines for SII. For OIII, the specified transmission is at least 92 % at 500.7 nm. The flat-top spectral profile is designed to minimize transmission loss caused by the centerband shift within the optical beam.<\/p>\n

Quartz Substrate and Treatments<\/h3>\n

Ultra filters are manufactured on a quartz substrate, whose low coefficient of thermal expansion contributes to the component\u2019s stability. Antlia combines this glass with fine polishing on both sides and a controlled optical coating process. Out-of-band rejection is specified at a minimum of OD5. The design is intended to reduce spurious signals outside the useful bands as well as halos around bright stars.<\/p>\n

Choose the format and focal ratio<\/h3>\n

The 2\u2033 version uses slim, black-anodized M48 \u00d7 0.75 threaded mounts. The 36 mm option consists of unmounted discs with blackened edges; it requires a housing designed for these filters. The nominal thickness is 2 mm for both sizes. Antlia recommends a focal ratio of f\/3.5 or greater to achieve the best optical performance from the Ultra 2.5 nm series. This recommendation should be taken into account before selecting this set for a fast instrument.<\/p>\n

Individual Monitoring and Content<\/h3>\n

Antlia states that each filter is individually measured and that the transmission and block curves provided in the box correspond to actual measurements. The attention to detail regarding thickness and polishing ensures good parfocality among the filters. This package differs from the SHO Pro 3 nm kit and the three Ultra filters sold individually: it includes H-alpha, SII, and OIII. Antlia does not recommend using these filters for solar imaging or nighttime visual observation. Never use these filters to view the Sun.<\/p>\n

Technical specifications<\/h3>\n\n\n\n\n\n\n\n\n\n\n
Contents<\/th>\nThree filters: H-alpha, SII, and OIII<\/td>\n<\/tr>\n
FWHM<\/th>\n2.5 nm, +0.3\/\u22120.1 nm<\/td>\n<\/tr>\n
Substrate<\/th>\nQuartz<\/td>\n<\/tr>\n
Transmission<\/th>\nH-alpha and SII \u2265 95 %; OIII \u2265 92 %<\/td>\n<\/tr>\n
Blocking<\/th>\n\u2265 OD5<\/td>\n<\/tr>\n
Nominal thickness<\/th>\n2 mm<\/td>\n<\/tr>\n
Recommended Focus Report<\/th>\n\u2265 f\/3.5<\/td>\n<\/tr>\n
Formats<\/th>\n2\u2033 mounted or 36 mm unmounted<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div><\/div>","protected":false},"excerpt":{"rendered":"

The Antlia SHO Ultra 2.5 nm set combines the H-alpha, SII, and OIII filters from the Ultra series. It allows you to capture the main emissions from nebulae in these three spectral bands separately. Each option listed here corresponds to the complete set of three filters in the same format\u2014either 2\u2033 mounted or 36 mm unmounted.<\/p>","protected":false},"featured_media":19830,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_brand":[791],"product_cat":[780,801],"product_tag":[],"class_list":["post-19832","product","type-product","status-publish","has-post-thumbnail","product_brand-antlia","product_cat-filtres-bande-etroite","product_cat-filtre-astrophotographie-du-ciel-profond","first","on_supplier","taxable","shipping-taxable","purchasable","product-type-variable"],"_links":{"self":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product\/19832","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/comments?post=19832"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media\/19830"}],"wp:attachment":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media?parent=19832"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_brand?post=19832"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_cat?post=19832"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_tag?post=19832"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}