{"id":2274,"date":"2025-07-11T21:38:13","date_gmt":"2025-07-12T03:38:13","guid":{"rendered":"https:\/\/albersheim.com\/wordpress\/?post_type=blog_post&p=2274"},"modified":"2025-07-11T21:38:13","modified_gmt":"2025-07-12T03:38:13","slug":"the-blue-horsehead-nebula","status":"publish","type":"blog_post","link":"https:\/\/albersheim.com\/wordpress\/blog-post\/the-blue-horsehead-nebula\/","title":{"rendered":"The Blue Horsehead Nebula"},"content":{"rendered":"\n

The Blue Horsehead Nebula, designated as IC 4592, is a beautiful reflection nebula in the constellation Scorpius, which is low in the southern skies, near the rising Milky Way core.<\/p>\n\n\n\n

Distance:<\/p>\n\n\n\n

The Blue Horsehead is about 420 light-years (2.5 trillion miles) away from Earth.<\/p>\n\n\n\n

Equipment:<\/p>\n\n\n\n

\u2022 Telescope: SVBony SV503 80ED 560mm, an f\/7 Doublet Refractor telescope with a 0.8 Reducer\/Flattener to reduce the focal length to 448mm and aperture to f\/5.6<\/p>\n\n\n\n

\u2022 Mount: SkyWatcher HEQ5 Pro<\/p>\n\n\n\n

\u2022 Camera: ZWO ASI2600 MC Pro<\/p>\n\n\n\n

\u2022 Filter: None needed – Bortle 3 dark sky area<\/p>\n\n\n\n

\u2022 Guiding: ZWO ASI120mm Mini Monochrome Guide Camera with the ZWO 30mm f\/4 Guide Scope<\/p>\n\n\n\n

\u2022 Automation: ZWO ASIAir Mini<\/p>\n\n\n\n

Imaging:<\/p>\n\n\n\n

Since this target is a reflection nebula, lit by the multiple star system called Nu Scorpii, no filters are needed for narrowband emission wavelengths, for example. However, it is a very faint nebula that really requires dark skies to and longer sub-images to get sufficient details.<\/p>\n\n\n\n

We went to the dark sky site of Florissant, CO, a Bortle 3 area, so I could target these darker and fainter targets. However, due to cloudy skies, I was only able to capture 21 sub-images of 5 minutes each (105 minutes total), calibrating a stack using 60 darks, 60 flats, and 60 dark flats. processed in Siril, stretching and color processing in GIMP, and adding final touches in PhotoShop. In another evening, I tried shorter sub images, due to the clouds, and got 40-3 minutes images, but the single-to-noise was not sufficient to pull out the details.<\/p>\n\n\n\n

After seeing the resulting image from a limited amount of 5-minute subs, I\u2019m definitely looking forward to re-imaging this target at our next dark sky site, hoping for clear skies!<\/p>\n\n\n\n

\"Blue
Blue Horsehead Nebula<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

The Blue Horsehead Nebula, designated as IC 4592, is a beautiful reflection nebula in the constellation Scorpius, which is low in the<\/p>\n

Read More<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"tags":[],"blog-category":[],"class_list":["post-2274","blog_post","type-blog_post","status-publish","hentry"],"aioseo_notices":[],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/blog_post\/2274","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/blog_post"}],"about":[{"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/types\/blog_post"}],"author":[{"embeddable":true,"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/comments?post=2274"}],"wp:attachment":[{"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/media?parent=2274"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/tags?post=2274"},{"taxonomy":"blog-category","embeddable":true,"href":"https:\/\/albersheim.com\/wordpress\/wp-json\/wp\/v2\/blog-category?post=2274"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}