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Michael A. Stecker
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 NGC 6791 -- old open star cluster in Lyra NGC 6791 is an open star cluster in the constellation Lyra. At roughly 8 billion years old, and with an iron to hydrogen abundance ratio that is more than twice that of the Sun, it is one of the oldest and most metal-rich clusters in the Milky Way which is contrary to the typical rule-of-thumb where older means more metal-poor. This is a joint project of James Foster and Michael Stecker using my Celestron 11-inch SCT at f/7.5 and a ZWO ASI2600MC-Pro color camera on a ZWO AM7 harmonic mount. Exposure time was 100-sec X 85 or 142 minutes (2.37-hours). file: NGC6791color142min2c11am7-asm.jpg Click here for full resolution image Photographic Data Date: July 9, 2026 Telescope: Celestron C11 11-inch SCT at f/7.5 aperture: 2,794 mm, focal ratio with Starizona reducer: f/7.5. reduced focal length: 2,095 mm Mount: ZWO AM7 harmonic (strainwave) mount Imaging Camera: ZWO ASI2600MC-Pro APS-C color astrocamera Guiding: Off-axis Exposure: 100-sec X 85 (2.37-hours) .photographic site: James Foster observatory at Pinon Pines Estates (Frazier Park) California (Bortle 4 at 5,500 ft elevstion) |
