First rough trial of rotating timelapse table

[kinetic]

Inspired by Phil Hart's fantastic body of work , I have been
attempting to get either a good star trail set of the SCP or
alternatively, a complete dusk till dawn 360 pan timelapse.
Suffice to say, it hasn't been an easy road :)

Here is a daytime test, followed by a night test, shortened by dew
on the camera lens.
http://www.youtube.com/watch?v=WdVRvXfAO4I
http://www.youtube.com/watch?v=_yFD2eAq_64

Steve

[peter_4059]

Nicely done Steve. Can you post some pics of the rotating table?

[kinetic]

Sure mate, I'll post one in a sec

Edit: pics of the clockwork and bracket,
and a single frame.

[kinetic]

Tonight's result,
http://www.youtube.com/watch?v=dr_RNJ-rpKM

and a crop which removes most of the vignetting and
much clearer frames:
http://www.youtube.com/watch?v=D7VGMIdseRU
2 hrs total, 84 frames
19 mm FL @ f 4.5 / ISO 800
Vignetting caused by dew hood.....no dew though :)
Still trying to find an easy way to batch adjust curves and crop.
Irfanview so far....
Here is a crop /auto background and curve tweak of frame 2.

Steve

[iceman]

Nice work Steve!

[kinetic]

Thanks Mike,
It would look far better if I could work out how to batch
adjust the 84 full frames with a certain curve.
There is quite some good detail in just a 30sec exposure.
The next set, hopefully tonight, will be at 28mm FL with no
vignetting.
But that will probably cause the stars to trail.

Steve

[Dennis]

Excellent work Steve, both in the construction of the driven table and the resulting movies. You must be very pleased with the results!

Have you tried fitting dew straps to the lens barrel – they should prevent any dew forming based on my experience at Qld Astrofest a few years ago, during a night of very heavy dew formation.

Cheers

Dennis

[alexch]

Nice work, Steve.
On dewy nights I use a disposable hand warmer ($1.50 at Rays Outdoors) attached the the lens near the front element by a rubber band. Works well every time and lasts about 6 hours.

[kinetic]

Thanks Dennis, Alex,
This is hardly an engineering marvel, an old chart-recorder clockwork
mechanism sitting on it's end with a bodged up 1/4 thread :)
This is more like what would be ideal:
http://www.bmumford.com/photo/rotary/index.html


It wouldn't be beyond me to make one of these either, although I
wouldn't buy the mill rotary table, that could be a simple home
lathe hobbed worm gear etc with a bartel stepper set or PIC micro
with step rates selectable. One day maybe :)

Alex, I'm thinking of a similar thing.
For now, the huge shroud you see is off the front of a cheap
$49 department store refractor I have :)
Fits the rubbery perimeter of the 18-55mm lens beautifully.
This is where I would fit some resistors if I did it.

Steve

[kinetic]

Another movie attempt tonight.
This time lens was at 28mm FL....
http://www.youtube.com/watch?v=C4glWGFCcnc

frame 168 resized and curve tweak, almost no vignetting
but the FOV is no good. Extra wide angle is the go , obviously :)

Steve

[ChrisM]

Steve, interesting work that you're doing - both the trials and research. On the bmumford site, I really like the night sky time lapse movie with the wind turbines and observatory.

Chris

[kinetic]

Thanks Chris,

just a short one tonight. A lot of smoke from the first winter slow combustion
wood fires tonight. Some curve applied to this frame set and a gaussian
blur. Lens was at 18mm FL again.
http://www.youtube.com/watch?v=jymV9JRvMwI

Steve