aikenji1. Bright Clouds Features Near Neptune’s North PoleNeptune has a dynamic atmosphere composed mainly of hydrogen, helium, and methane, with bright cloud features often visible at infrared wavelengths. Because Neptune is more than four billion kilometers from Earth, subtle atmospheric structures are extremely difficult to observe from the ground.On August 26 in East part of China, I was fortunate to have a night of exceptionally good seeing and transparency ahead of an approaching typhoon. So I decided to make an observation of Neptune using IR filter. To my surprise, I detected a prominent bright cloud feature near Neptune’s north polar region, and it appears around C.M. 250°.To verify the reality of the feature, I continued imaging for approximately three hours to create a rotation animation. The animation finally reveals two bright cloud features near Neptune’s north pole. They can be seen rotating with Neptune, while Triton’s orbital motion is also visible. It was exciting to reveal Neptune’s atmospheric features with an amateur telescope from the ground.2. Imaging and Processing DetailsThe observation was made with a Celestron C9.25, a QHY678M monochrome camera, and a 720IR filter.I captured 25 sequences of 8,000 frames each, with 50 ms exposure per frame, covering approximately three hours. The sequences were stacked with AutoStakkert! 4 and sharpened using wavelet processing, revealing the bright spots near Neptune’s north pole. A continuous GIF generated directly from the raw data is also provided to demonstrate the reality of the features.The infrared data were then used as the luminance channel and combined with color data captured on the same night, producing the final three-hour rotation animation.raw footage
