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Lunar X animation and pictures

michaelmorris

By michaelmorris
in Imaging - Solar

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michaelmorris

michaelmorris

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Last Monday Night (22nd March) Doc kindly posted a reminder that the Lunar X (aka Werner X) was visible. http://stargazerslounge.com/observing-lunar-solar/100040-lunar-x-out-tonight.html

Equipped only with a song and boundless optimism I ventured forth in to the ink blackness to surveyor the selenetic vistas. And blow me down, up it came!

I rather foolhardily decided that this make be a marvellous imaging session so spend 4.5 hours taking 35 x 1200 frame AVIs of the unfolding event under appalling seeing conditions until the Moon started to set behind nextdoor’s Bay tree. It was only when I had finished that a realised the true monstrous extent of the leviathan I had sporned - 18.5GB of data in 35 AVIs. :(:eek:

I have spent around 50 hours processing the AVIs in Avistack, Registax and Photoshop, putting together the final images and constructing the time-lapse video with Microsoft Moviemaker. (Yes, you’re correct – I have no life).

Each final image consists of the best 144 frames stacked from a 1200 frame video taken by a mono-chipped Toucam Pro II fitted with an infrared pass filter shooting through a Meade 8" LX200 telescope (focal length 2000mm). I’ve posted the output of this exercise in three forms.

Firstly there is a link to the time-lapse video, which I have posted on Youtube.

Below is an animated GIF of the time-lapse sequence. Single click on the picture to start the animation.

On the next posting is a montage of the selected images from the sequence.

post-13232-133877436596_thumb.gif

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brianb

brianb

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Very nice! A lot of effort - maybe more than necessary - when shooting at reasonably small scale you can "get away with" a few dozen frames at low gain - but what's done is done, and it works very well.

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Doc

Doc

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To actually see how the "X" is formed out of the darkness of the terminator is just fantastic. Thankyou for taking so much time to produce this, I could watch it time and time again.

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Leedsgreen

Leedsgreen

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Michael,

Thanks very much for all your effort. Like others, I've often wondered what the 'Lunar X' actually is and now I know! Great to watch the GIF animation and see it form.

BTW when taking AVIs of lunar surface, what is the generally accepted length of time for each batch without noticeable terminator/shadow creep? One minute, five minutes, one hour? Do you know?

Thanks again,

Nick

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michaelmorris

michaelmorris

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Thanks for the kind words guys, much appreciated. I'm pleased with the result.

BTW when taking AVIs of lunar surface, what is the generally accepted length of time for each batch without noticeable terminator/shadow creep? One minute, five minutes, one hour? Do you know?

Nick

Nick

Martin Mobberley's excellent book 'The Lunar and Planetary Webcam Users' Guide' recommends no more than 240 seconds (4 minutes). I usually go for between 120 and 200 seconds.

Martin Mobberley calculates that the terminator sweeps across the lunar surface at 15km/hr at the lunar equator. The exact angular movement per minute will depend upon a number of factors - the position of the terminator and the image scale of your picture. I would have thought that the effect of foreshortening when the terminator is near the limb would greatly increase the length of time before the terminator would move one pixel on a camera. The terminator will travel slower across the polar regions, so you will have more time to image in these areas.

The longer the focal length of your system, the larger the image scale is going to be and hence the quicker any movement of the terminator will be noticeable.

This sounds like a nice idea for a neat little spreadsheet for any mathemeticians out there to put togther (and share please) :(

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michaelmorris

michaelmorris

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Nick

With regard ot my previous post on factors affecting the length of time one can image the Moon without seeing movement - I forgot to mention libration. I suspect that this will not be a significant limiting factor as the movement is very slow. As you can see from the GIF animation, there is a slight noticeable apparent rotation of the Moon during the 4.5 hours of the time lapse video.

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Leedsgreen

Leedsgreen

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Wow! That's interesting Michael. Roatation in my AVIs is due to my fixed AZ mount. I didn't think libration would be noticeable over a (relatively) short timescale. Amazing.

Out of interest, the other day, I was looking at Virtual Moon Atlas and 'clicked' the moon forward a day at a time. By putting the settings at full illumination, it was fascinating to watch the libration speeded up. A real wobble going on there (and quite intricate in detail).

Cheers,

Nick

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