{"id":21680,"date":"2026-11-07T09:45:31","date_gmt":"2026-11-07T08:45:31","guid":{"rendered":"https:\/\/deep-space-astronomy.ch\/?p=21680"},"modified":"2026-11-07T14:07:15","modified_gmt":"2026-11-07T13:07:15","slug":"askar-71f-astrographe-champ-plat-71mm-test-prix","status":"publish","type":"post","link":"https:\/\/deep-space-astronomy.ch\/en\/askar-71f-astrographe-champ-plat-71mm-test-prix\/","title":{"rendered":"The Askar 71F: a flat-field quadruplet for CHF 385"},"content":{"rendered":"<div class=\"product\"><div class=\"product\"><p>The Askar 71F is a 71-mm f\/6.9 flat-field quadruplet astrograph. It features a built-in field flattener, a 44-mm image circle (full frame), and weighs 2.5 kg. No need to buy an optional field flattener: just plug in the camera and it works. At CHF 599 (tax included) in our store, it\u2019s the most compact of the Askar flat-field models for portable deep-sky photography.<\/p>\n<h2>All the info at a glance<\/h2>\n<ul>\n<li>Optics: air-gap quadruplet, APO with 1 ED element<\/li>\n<li>Opening: 71 mm<\/li>\n<li>Focal length: 490 mm, f\/6.9<\/li>\n<li>Field flattener: built-in, 44 mm image circle (full frame)<\/li>\n<li>Focusing system: 1:10 rack-and-pinion, 50 mm travel<\/li>\n<li>Weight: 2.5 kg (tube), 3.0 kg with clamps and tray<\/li>\n<li>Length: 372.5 mm (defogger retracted)<\/li>\n<li>Tabletop: Vixen 230 mm included<\/li>\n<li>Connectors: M64, M54, M48 (with M48 filter thread)<\/li>\n<li>0.75x reducer: optional, for f\/5.2<\/li>\n<li>Price: CHF 599, including tax (Swiss VAT included)<\/li>\n<li>Availability: In stock in our store<\/li>\n<li>Warranty: 2 years<\/li>\n<\/ul>\n<figure><img decoding=\"async\" src=\"https:\/\/deep-space-astronomy.ch\/wp-content\/uploads\/2026\/11\/askar-71f-detoure.png\" alt=\"Askar 71F Flat-Field APO 71 mm d\u00e9tour\u00e9\" \/><figcaption>Askar 71F: flat-field quadruplet, 71 mm f\/6.9. Credit: Askar. Background removed.<\/figcaption><\/figure>\n<h2>Flat-field quadrupole: the flattener is inside<\/h2>\n<p>The 71F is a quadruplet: four lenses, one of which is made of extra-low dispersion (ED) glass. The first group corrects chromatic aberration, while the second group (the field flattener) corrects field curvature. The result: a flat field across a 44 mm image circle\u2014enough to cover full-frame (36\u00d724 mm) with room to spare. No need to buy an external flattener or calculate optical extension.<\/p>\n<p>Compare this to a conventional triplet: the triplet corrects chromatic aberration but leaves the curvature. An external flattener (CHF ~200) must be added to achieve a flat field. The quadruplet does both at once. It\u2019s simpler, and it works.<\/p>\n<h2>71 mm at f\/6.9: versatile and portable<\/h2>\n<figure><img decoding=\"async\" src=\"https:\/\/deep-space-astronomy.ch\/wp-content\/uploads\/2025\/03\/960dd318-21f0-427a-8225-4be7d1f01151-1.png\" alt=\"Askar 71F Flat-Field t\u00e9lescope astrographe 71 mm\" \/><figcaption>Askar 71F: the most compact flat-field quadruplet astrograph in the F series. Credit: Askar.<\/figcaption><\/figure>\n<p>With a focal length of 490 mm and an aperture of f\/6.9, the 71F is a versatile astrograph. It\u2019s not as fast as an f\/5, but it\u2019s fast enough for wide-field deep-sky photography: M31 Andromeda, M42 Orion, the Pleiades, and the Milky Way in wide-field views. Exposures ranging from 60 to 180 seconds are sufficient with a modern camera.<\/p>\n<p>The 0.75x reducer is available as an option. It converts the 71F to f\/5.2 (367.5 mm focal length) for an even wider field of view. At f\/5.2, short exposures capture large, expansive subjects.<\/p>\n<p>Weighing 2.5 kg and measuring 372.5 mm long, the 71F fits in a backpack. It\u2019s the astrograph you take with you on trips, under a truly dark sky, far from the city. When mounted on a lightweight mount (AM3N, Wave 100i, Star Adventurer GTi), it doesn\u2019t add any extra weight.<\/p>\n<h2>The Askar F Series: 60F, 71F, 91F, 111F, 131F<\/h2>\n<figure><img decoding=\"async\" src=\"https:\/\/deep-space-astronomy.ch\/wp-content\/uploads\/2025\/03\/960dd318-21f0-427a-8225-4be7d1f01151.png\" alt=\"Askar 71F Flat-Field d\u00e9tail construction\" \/><figcaption>Askar 71F: High-quality construction; Vixen collars and tray included. Credit: Askar.<\/figcaption><\/figure>\n<p>The 71F is part of Askar\u2019s F (Flat-Field) series: 60F, 71F, 91F, 111F, 131F. All are flat-field quadruplets with a built-in flattener and a 44-mm image circle. The difference lies in the aperture and weight:<\/p>\n<ul>\n<li><strong>60F<\/strong> : 60 mm, the most compact, for travel.<\/li>\n<li><strong>71F<\/strong> : 71 mm, the all-arounder. The best balance of portability and performance.<\/li>\n<li><strong>91F<\/strong> : 91 mm, more light for faint objects.<\/li>\n<li><strong>111F<\/strong> : 111 mm, the high-performance wide-angle lens.<\/li>\n<li><strong>131F<\/strong> : 131 mm, the large flat-field astrograph.<\/li>\n<\/ul>\n<p>The 71F is the perfect compromise: wide enough for deep-sky photography, light enough for travel. Weighing just 2.5 kg, it\u2019s the astrograph you\u2019ll reach for without hesitation.<\/p>\n<h2>Which mount should I use for the 71F?<\/h2>\n<p>Weighing 2.5 kg per tube, or 3 kg with clamps and base, the 71F can be mounted on:<\/p>\n<ul>\n<li><strong>AM3N<\/strong> : harmonic drive, 12 kg payload. Ideal with plenty of headroom.<\/li>\n<li><strong>Wave 100i<\/strong> : harmonic drive, 10 kg payload. Compact.<\/li>\n<li><strong>Star Adventurer GTi<\/strong> : For traveling light, the payload is 5 kg. Just enough.<\/li>\n<li><strong>HEQ5<\/strong> : Classic equatorial mount, 13 kg payload. Extremely stable.<\/li>\n<\/ul>\n<h2>Why shop at Deep Space Astronomy?<\/h2>\n<p>We're not just a retailer. We test, advise, and provide support.<\/p>\n<ul>\n<li><strong>Personalized Advice<\/strong> : We can help you choose between the 60F, 71F, and 91F models based on your mount and your targets. Contact us by phone, WhatsApp, or schedule an appointment in Nyon.<\/li>\n<li><strong>After-Sales Support<\/strong> : Do you have a question about the flattener, optical alignment, or image processing? We're here to help.<\/li>\n<li><strong>14-Day Return Policy<\/strong> : Not satisfied? Return the product within 14 days.<\/li>\n<li><strong>Secure payment<\/strong> : Twint, credit card, invoice, Apple Pay, Bitcoin. Pay in 3 or 4 installments with no fees.<\/li>\n<li><strong>Free shipping in Switzerland<\/strong> Starting at CHF 200. Free pickup in Nyon.<\/li>\n<\/ul>\n<p>L\u2019<a href=\"https:\/\/deep-space-astronomy.ch\/en\/product\/71f-flat-field\/\">The Askar 71F is priced at CHF 599, including tax<\/a> in our store. Be sure to check out the <a href=\"https:\/\/deep-space-astronomy.ch\/en\/marque\/askar\/\">Askar line<\/a> and the other flat-field astrographs in the F series.<\/p>\n<h2>Sources<\/h2>\n<p>This article is based on Askar\u2019s official specifications (via High Point Scientific, First Light Optics, and Mile High Astro, 2026) and on the product listing in our store. In-store price: CHF 599 (including tax).<\/p>\n<p>CBurkhalter<\/p>\n<\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>Askar 71F: 71 mm f\/6.9 APO quadruplet astrograph, built-in field flattener, 44 mm full-frame image circle, 2.5 kg. CHF 384.97 (tax included) in-store.<\/p>","protected":false},"author":187,"featured_media":21685,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[827],"tags":[],"class_list":["post-21680","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-actualites"],"_links":{"self":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts\/21680","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/users\/187"}],"replies":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/comments?post=21680"}],"version-history":[{"count":2,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts\/21680\/revisions"}],"predecessor-version":[{"id":21686,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/posts\/21680\/revisions\/21686"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media\/21685"}],"wp:attachment":[{"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/media?parent=21680"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/categories?post=21680"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/deep-space-astronomy.ch\/en\/wp-json\/wp\/v2\/tags?post=21680"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}