Is Your Celestron Telescope Lying About Its Focal Length? (SCT Backfocus Planetary Impacts) скачать в хорошем качестве

Is Your Celestron Telescope Lying About Its Focal Length? (SCT Backfocus Planetary Impacts)

I measured Jupiter through my Celestron C9.25 and NexStar 6SE, and the math didn't add up. According to the pixel scale formula, I was missing nearly 20% of my magnification! It turns out, plugging a planetary camera directly into the back of a Schmidt-Cassegrain telescope comes with a hidden optical penalty. In this video, we head into the physics lab to calculate exactly what went wrong with my image scale, and then head out under the stars to fix it. We cover the difference between native SCT focal length, the optical path length of star diagonals, and how to build the perfect 139mm rigid T2 extension train for the ZWO ASI678MC to get your telescope operating at its true f/10 and focal length potential. This video is centered around the C9.25 results, but the same issue applies to all SCTs, including my NexStar 6SE. With the NexStar mount it will be impossible with modification to put much backfocus distance on due to physical interference with the base. This is most applicable to an EQ mount, or a NexStar with a wedge in some cases. ⏱️ VIDEO CHAPTERS 0:00 - The Mystery of the Missing Pixels 0:17 - A Commenter Spots an Error 0:51 - The Pixel Scale Formula (Where did the math fail?) 1:30 - The Star Diagonal Secret 2:16 - Building the 139mm Backfocus Train 2:55 - A Warning About SCT-to-T2 Adapters 3:33 - Field Testing on Jupiter (Live Capture!) 4:37 - Stacking and Processing the Results 5:20 - The Final Math: Did it work? 9:45 - The Best Jupiter Pictures I've Ever Taken 🔭 GEAR USED IN THIS VIDEO (As an Amazon Associate, I earn from qualifying Amazon purchases and you pay the same amount, while supporting this channel) ► Telescope: Celestron C9.25 on an AGT/AVX mount (https://amzn.to/4rBrSeE). ► Camera: ZWO ASI678MC (https://www.highpointscientific.com/z...) ► Adapters - I bought a couple packs of extension tubes to get the right length options. ► SCT-to-T2 Adapter (https://amzn.to/4aK4XGD) ► T2 Extension Tube Pack 1 (https://amzn.to/3MVX88T) ► T2 Extension Tube Pack 2 (https://amzn.to/4b6Agf9) ► T2 to 1.25” filter adapter (https://www.highpointscientific.com/z...) 📥 Free Software Used in this Video: ► SharpCap (Alignment, Focus, Capture): https://www.sharpcap.co.uk/ ► AutoStakkert (Stacking): https://www.autostakkert.com/ ► RegiStax (Sharpening): http://www.astronomie.be/registax/ ► GIMP (Photo Editing): https://www.gimp.org/ ► Stellarium (Sky Maps and Object Details): https://stellarium.org/