In the From the Vault series, I feature an older image which hasn’t been seen here before and I talk about the capture and processing and hopefully highlight why this image is special to me.
The feature image in From the Vault this week shows a Dynamic Jupiter in Motion with an image montage and a 21-frame animation bringing Jupiter alive and is something you must see! You can watch Ganymede and Europa transit across the face of Jupiter, the GRS rotate into view, and the volcanic moon Io pop out from behind Jupiter in the last few frames. Albedo features on Ganymede are visible in practically every frame, including while transiting Jupiter, and icey Europa actually reveals its crescent phase while contrasted against the backdrop of the gas giant.
This montage of images was captured on the morning of the 23rd March, 2007 over a period of more than 2 hours in conditions that peaked in the excellent range. Click the image to see the full-size version.
Continue reading to see the animation and learn more about the capture and processing of this image.
The animation shows all 21 frames captured in almost 2.5 hours and has been processed into a sweep back and forth animated gif. It’s just over 2 megabytes so may take a minute or so to download in its entirety, then sit back and enjoy.
The animation shows clearly the effect that the atmospheric conditions, or the “seeing”, can have on an image. In the first few frames of the animation, the seeing is not very good and the details are blurry and appear soft. But the conditions improved as the session progressed and you can see that reflected in the quality of the frames in the last half of the animation. They’re much sharper, more detailed with better colour.
The image and animation proved very popular in the broader astronomical community, and was featured on a number of websites, won astrophotography awards and was published in magazines, including:
- Astronomy Picture of the Day (APOD) – 29th March 2007
- Spaceweather – 1st April 2007
- 1st place in the Solar System category of the 2007 CWAS Astrofest awards
- 1st place in the Solar System category of the 2007 South Pacific Star Party astrophotography competition
- Published in Astronomy, Astronomy Now and Sky&Telescope magazines.
For the other planetary imagers amongst us, as promised continue reading below for my capture and processing details for this image, including links to my step-by-step tutorials for producing better planetary images.
I used my standard Planetary Imaging Equipment to capture the data – the 12″ Newt on an EQ6 with the DMK21AU04, 5x powermate and Astronomik LRGB filters. While the seeing was excellent, the transparency deteriorated as heavy dew began to fall once temperatures started to drop. With the tube pointing almost straight up, the mirror began to fog up and reduce the available light coming in.
In practise, that meant that I had to drop the framerate from 30fps during the first half of the session to 15fps in the last half, and even with the increased exposure time, the histogram was still only 3/4 full with gain at maximum. I also experimented with capturing clear luminance data, as the clear filter allowed a faster framerate and shorter exposure time – one of the most important aspects for obtaining good, high-resolution planetary data. Capturing unfiltered light doesn’t always work out though, as capturing at the broader wavelengths can sometimes result in softer data, especially when the planet is a lower altitudes. Fortunately though, on this morning with the seeing so good and Jupiter up so high, the luminance data was sharp when processed and half of the images used were processed as LRGB images, while the other half were straight RGB.
For the RGB images, each channel was recorded for about 40-50 seconds, while for the LRGB images, the Luminance data was captured for 1 minute and each RGB channel was captured for 15-20 seconds. Knowing that the seeing was so good and that I had enough data for an animation, I was conscious to keep recording times to a minimum so as not to blur the motion of the moons and so I could also keep the interval between images consistent.
I pre-processed the data using Ninox, and then used Registax 4 for alignment, stacking and wavelet processing. Approx 850 frames were stacked for the luminance channel and approx 250-300 for the colour channels. The images were then opened in Astra Image 2.5Max to process using LR Deconvolution on each channel and recombined into an LRGB colour image using Photoshop, where further levels, saturation and colour balance adjustments were made. The final animation was created using Jasc Software Animation Shop 3.
For more information on my capture and processing routines, please take a look at my articles which include step-by-step tutorials for capturing and processing planetary images:
I hope this journey into the past has shown you why the memories of that brilliant morning will stay with me forever. If you love this image as much as I do, it’s available to purchase as a greeting card, matted, canvas or framed print at RedBubble.
Thanks for reading and thanks for allowing me to share with you.