Animation of Uranus and Ariel, Umbriel, Titania and Oberon.
Hello,
Between 11:18pm on 26th August and 1:43am on 27th August I spent a couple of pleasant hours recording Uranus and four of his brighter moons; Ariel (14.4m), Umbriel (15.0m), Titania (13.9m) and Oberon (14.2m).
Using a Tak Mewlon 180mm F12, WO x2.5 Barlow and SBIG ST7 ccd camera, I experimented with sub-frame exposures ranging from 5 secs to 30 secs, trying to establish the optimum exposure to minimise the overwhelming glare from a grossly over-exposed Uranus yet still record the very much fainter moons.
When I later blinked the finished images output from the 5, 10, 15, 20 and 30 sec frame sets, I was astonished to discover a faint star (15.9m) moving through the field as well as some movement of the moons of Uranus, having aligned on Uranus as a reference point. An animation was called for!
Using the 20 sec exposure data set, I aligned, stacked and combined 30 sub frames for Luminance data (Uranus and moons) and 5 sub frames for RGB data (Uranus only) to produce an LRGB final image, which I then finished in CS3 using various Noel Carboni Actions to reduce the bloat of the moons and enhance their appearance.
Using this (heavily processed) final LRGB image, I overlaid the 10, 15, 20 & 30 second frames and then copied and pasted the moons to place them in their recorded position. Note that the raw frames showed much bloating of the moons due to the long focal length (5400mm) and long exposures (10-30 secs) so I just used my eye to place the finished moons from the LRGB image into the centre of the bloated moon in the 10-30 sec frames.
Therefore, each frame that makes up this animation is a composite and not a direct result of just processing the original data. There are “errors” based on brightness and positioning due to the capture technique and post processing involved. But, it sure was fun putting this together!
That is ingenious, Dennis. Very well done. Excellent stuff. (What mount are you using? Must be a doozie.) Congratulations, and thanks for sharing.
Brian.
I thought it might be useful to show how I assembled each frame, by Layering the finished 30x20sec LRGB Uranus + moons image with the appropriate CCDStack output Frame for the 10, 15, 20 and 30 sec series of frames.
Setting the blend method to “Difference” in Photoshop, I could then adjust the moon positions to be in the centre of the bloated moons of the CCDStack processed reference frames.
This is how I built up each of the 4 frames that went into the animation. The 5 sec series of images only recorded Titania and Oberon so I omitted these.
That is ingenious, Dennis. Very well done. Excellent stuff. (What mount are you using? Must be a doozie.) Congratulations, and thanks for sharing.
Brian.
Whoops – forgot to mention that it’s a Tak EM200 mount!
Thanks for sharing and taking the time to do this animation. You are always presenting top notch stuff that is different from the usual fare (I still love the usual fare too). Keep up the great work - I look forward to you next piece.
Hi Dennis
Thanks for sharing and taking the time to do this animation. You are always presenting top notch stuff that is different from the usual fare (I still love the usual fare too). Keep up the great work - I look forward to you next piece.
Thanks Matt!
The Mewlon 180 at F12 lends itself quite nicely to these types of project and I enjoy pursuing them. I also enjoy sharing the results, just like I get pleasure from seeing the results of the efforts of others when they post their work on Ice In Space.
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