Friday, September 22, 2017

September 22, 2017: Colliding water drops and a mist around the region of the collision

One of my friends (Chris Ang) suggested I change my white background to a color.  I did some timing experiments today against a white background and arrived at a more or less stable set of parameters (delay and drop size).  The result was that often there was a white mist associated with a collision between drop and Worthington jet and the mist appeared directed downward.   The Pluto parameters for the collisions below were:  flash delay:70 ms, drop 1 size: 4 ms, drop 2  delay 55 ms, drop 2 size: 5 ms.

Professor A. L. Yarin at the University of Illinois, Chicago has suggested 

"Nobody saw what you found due to chaging the background, as to myknowledge.
However, this resembles something which was discussed in relation to drop
breakup: viscous stripping. I mean a very fine atomization due to
viscous vorces from the air side stripping a thin layer from the drop on
top of the Worthington jet (in your case). I bet you can try to publish
your finding with more details and analysis, e.g. in Experiments in

No discernable mist - perhaps a collision is necessary

Mist projected downward below the smaller drop.  Of considerable interest to me are the two vertical lines connecting the middle small drop with the large upper drop.  As if the two are still loosely connected.

No discernable mist

Almost like a rocket igniting and exhaust projected downward

Mist sort of directed up then away to the sides and down.  Here is another example of a connection between the two water objects - two vertical lines connecting the upper drop with the misty region above the head of the pawn

Hat formation with mist dropping from the lower edge

Update Oct. 29, 2017
The anomaly (streamers, mist ext) appears to be associated with hat or disk formation.  Here are a few examples.


ISS Transits Observed over Plant City, Florida

The viewing conditions in high humidity Florida were pretty good this morning - for viewing the ISS passage is it passed from NW to NE to SE.  Maximum was at 05:55 at 88 degrees

This morning there was a bright passage of the International Space Station which I was able to photograph and capture with video.

Here is a still shot (20 sec exposure) as it passes to the left of Orion

Morning passage of the ISS (Sep 23)

VIdeo of the Dawn ISS passage

Sept 24, 2017 Evening Passage of ISS

Evening stars with cloud

Composite of 4 5 sec exposures of the ISS passage

ISS (starting in the middle of the frame) passing from left to right

October 15, 2017 

ISS transit from lower left, behind a cloud then continuing to the upper right

A 20 sec exposure of the ISS transit

ISS fading as it passes into the earth's shadow

A control image - an aircraft passing near by show blinking green and red lights.  The ISS has no visible running lights and appears as only dot of reflected sunlight

Thursday, September 21, 2017

September 21, 2017: Colliding Water Drops

Experiments with water drop splash have progressed to exploring the collision of a water drop and a rebounding water drop.  The idea is to delay the 2nd drop until the rebound of the 1st drop reaches its maximum. 

My setup -  remote flashes to stop the motion of the drop interactions.  Flash strength: 1//128 manual mode - with Yongnu remote triggers.  A plastic tub for receiving drops and a needle hanging by a tread from the drop maker as a focus. A ring stand that holds the Pluto Valve (drop maker) .  In the foreground is a Pluto trigger, camera (Nikon 5300).  The Pluto trigger, in water drop mode, provides drop size and drop delay for 3 drops. 

A single drop

A rebound drop captured 55 msec after dropping

Collision of the 2nd drop and the rebound drop

Development of the collision

Development of a lamp shade as the 2nd drop collapses.  Surface tension appears as a glue that holds the lamp shade as a coherent object.

Continued development of the lamp shade

An example of a fully developed lamp shade

Wednesday, September 20, 2017

September 20, 2017: International Space Station

Yesterday was supposed to be a bright passage of the International Space Station - but clouds got in the way.  This morning, the sky was clear.  

Cassiopea and Polaris

Sirius and Orion

International Space Station passing under Venus ( the blinking object in the lower 1/4 of the frame moving left to right)

International Space Station under over Polaris.  Overlay of 4 10 sec exposures

International Space Station passing over Venus

International Space Station passing over Venus

International Space Station passing over Venus.   Overlay of 2 10 sec exposures

Oct 15, 2017 ISS Transit

20 sec exposure of the ISS transit

ISS transit as is passes into the earth's shadow - i.e. the earth is between the ISS and the sun.

A calibration - distinguishing an aircraft from the ISS.  The aircraft has blinking lights at the tips of each wing and appears as this.   The ISS has no visible running lights so all I see is the reflected sun light

Sunday, September 17, 2017

September 17, 2017 Little Manatee Property

Exploring a small tract adjacent to a Hillsborough Nature Preserve on the Little Manatee River.

Uloborus glomosus and her stabilimenta

Uloborus glomosus

Feather legs of Uloborus glomosus

Anyphaenidae (ghost spider) or Hibania gracilis

Anyphaenidae (ghost spider)

Anyphaenidae (ghost spider)

Leucauge venusta and web

Face of DIctyna sp. (female mesh web spider)

Maybe mom Dictyna sp guarding her egg sacs (I think) - A female mesh web spider

Friendly Lizard

September 17, 2017 More water drop photography

Chris Ang suggested using colored water - so I added some green food coloring.  The results are much more dramatic.  I'm shooting at 1/100, flash at 1/128 intensity (short flash pulse), ISO 100, f/25 (to maximize depth of field)

A drop entering the water and the splash response projecting upward around the drop

A fully developed splash "crown" 

Two drops falling into a crater formed by the 1st drop falling into the water

Interesting distortion of the drop falling into the crater

My focus plumb bob - a needle superglued to a small pin

A closeup of the thread and pin.  I tape the thread to the side of the outlet of the drop maker and focus on the point where the pin touches the water.