{"id":18028,"date":"2026-09-28T09:51:48","date_gmt":"2026-09-28T07:51:48","guid":{"rendered":"https:\/\/deep-space-astronomy.ch\/?post_type=product&p=18028"},"modified":"2026-11-14T11:51:26","modified_gmt":"2026-11-14T10:51:26","slug":"takahashi-qb073x-fsq85edx","status":"publish","type":"product","link":"https:\/\/deep-space-astronomy.ch\/en\/product\/takahashi-qb073x-fsq85edx\/","title":{"rendered":"Takahashi QB0.73X: Reducer for FSQ-85EDX"},"content":{"rendered":"

Reducing the focal length of the FSQ-85EDX<\/h3>\n

The Takahashi QB0.73X reducer, part number TKA37580, is designed for the FSQ-85EDX telescope. In this configuration, the manufacturer specifies a focal length of 330 mm and a focal ratio of f\/3.9. This model should not be confused with the older QE0.73X: it is an updated version designed to improve correction for full-frame sensors.<\/p>\n

A four-lens system<\/h3>\n

The QB0.73X uses four elements in two groups, including one ED glass element. The specified corrected image circle is 44 mm. Field correction is a key consideration for astrophotography with a large sensor; the final result depends on the mount, the distance to the sensor, and the focus.<\/p>\n

Connection and Distance to the Sensor<\/h3>\n

The reducer attaches to the telescope's rotating focusing collar. The manufacturer\u2019s specifications list a male M72x1 input and a male M56x0.75 output. Its mechanical backfocus is 72.2 mm: this value applies to the reducer and should not be arbitrarily replaced with the standard distance of another accessory.<\/p>\n

Prepare the photographic connections<\/h3>\n

Takahashi describes how to use the CA-35 adapter for the SKY-90 at the output of the reducer to achieve a distance of 56.2 mm for a wide-field T-ring and a camera body. For a camera, check the connections and distances in the official FSQ-85EDX diagram. The telescope, camera, adapter, and T-ring are not listed as included with this model.<\/p>\n

Technical specifications<\/h3>\n\n\n\n\n\n\n\n\n\n\n\n
Features<\/th>\nValue<\/th>\n<\/tr>\n<\/thead>\n
Reference<\/th>\nTKA37580<\/td>\n<\/tr>\n
Corrected image circle<\/th>\n44 mm<\/td>\n<\/tr>\n
Mechanical Input Interface<\/th>\nM72x1 male thread<\/td>\n<\/tr>\n
Mechanical Output Interface<\/th>\nM56x0.75 male thread<\/td>\n<\/tr>\n
Mechanical backfocus<\/th>\n72.2 mm<\/td>\n<\/tr>\n
Dimensions<\/th>\n78 mm x 63 mm<\/td>\n<\/tr>\n
Weight<\/th>\n520 g<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Composition<\/h3>\n

QB0.73X reducer only. The photographic adapters and the instrument must be purchased separately.<\/p>\n

Takahashi's Official Profile<\/a><\/p>\n<\/div><\/div>","protected":false},"excerpt":{"rendered":"

QB0.73X Reducer for FSQ-85EDX: 44 mm corrected image circle, 72.2 mm mechanical back focus, four-element, two-group optical design.<\/p>","protected":false},"featured_media":18023,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_brand":[947],"product_cat":[650],"product_tag":[],"class_list":["post-18028","product","type-product","status-publish","has-post-thumbnail","product_brand-takahashi","product_cat-rducteurs-correcteurs-ap","first","on_supplier","taxable","shipping-taxable","purchasable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product\/18028","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=18028"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media\/18023"}],"wp:attachment":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media?parent=18028"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_brand?post=18028"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_cat?post=18028"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/product_tag?post=18028"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}