When do you throw your food away?

It is a challenge for all of us: we do not want to eat bad food, but neither we want to be bad for the environment or a shame to hungry people. So when do we throw our food away? When the date is expired, or when it looks or smells bad? Every person has its own way, but it makes sense to give it more thought. Therefore I made this diagram to make a fair and healthy decision.


Diagram to determine if your food is good or bad


Rule of thirds
When you buy a product, look at the 'best before' date. Count the days, weeks or months that is in the future and add one third: this is the more realistic date of expiration. So: the for milk you may have three days left, but you can probably use it four days; for a glass of vegetables for which you have 9 months will last 12, etc. Some products like flour, pasta, rice and some canned food will even last much longer. Meat that expires the next day, may last 0.3 day longer, but with such low margins you better stick to the date!

Why is it important not to throw it away on the expiration date? Because manufacturers reduce the expiration date every year silently and this seems an ongoing loop. So more and more food is wasted every year! See here (NL) and here (DE). Throwing it away on the expiration date is not very responsible.


The shelf life is actively reduced by manufacturers that set the expiration date earlier. As a result people are surprised that their food is expired earlier, but still throw it away, increasing food waste. They buy a new package instead. As a result sales go up. Now the manufacturers have an incentive to further reduce the shelf life of their products. Completely unnecessarily from the point of the food quality! Therefore it makes sense to use the diagram above to determine if you should throw your food away instead of the date!

Final notes
-  It is mostly safe to follow the diagram here, but it is on your own risk. Internet resources like this one can give you advice but cannot be hold responsible
- The manufacturer can be hold responsible for food going bad when it happens before the 'best before date'. Therefore it is logical to have the date early set, but there are not any legal rules for how early.
- Because the date is set earlier year by year, the rule of thirds is very rough and may be one day rather a 'rule of halfs'.

The supermoon of 14.11.2016 explained

Supermoon
The Moon has an elliptical orbit around Earth, and the Earth is not exactly in the middle (like the yolk in the egg). Therefore each month the Moon has a close position to Earth (Perigee) and a far position to Earth (Apogee). When it is close, it appears on average 14% larger (in diameter) and 30% (surface area) brighter when it is full moon. When both Perigee moon and full moon occur together, we speak of a supermoon (in far position of a micromoon).

The Earth has a similar elliptical orbit around the sun and also has a close and far position to the sun, together with the Moon. Hence, sometimes the gravity effect of the Sun is stronger than  other times, causing the Moon to vary in its far and close position. The close position varies roughly between
356.000 and 371.000 km while the far position varies roughly between 404.000 and 407.000 km.


Far and close distances for every moon rotation from 2001 to 2100. Data Source: Moon Perigee and Apogee Table Courtesy of Fred Espenak, www.Astropixels.com. Full moons are in yellow, data Source: Keith Cooley, http://home.hiwaay.net/~krcool/Astro/moon/fullmoon.htm.

When the Earth would not turn around the Sun, the close distance would always fall together with a full moon. But because of the rotation around the sun, the light angle changes, causing a small shift in the cycle of full moon. After 14 moon cycles, both cycles are in the same position again, with a full moon in the close position, hence almost once every year! The interesting thing is that it is mostly never the same position relative to the sun, and therefore somewhere between 356.000 - 371.000 km as explained above. And that makes the the 14.11.2016 special; this full moon in Perigee position is closer than after most other 14 moon cycles. A super close, superbig moon! However this difference is much smaller than between a Perigee and Apogee month.


A close-up of the previous graph (only the very low band with full moons!), with the 100 closest moons from 2001 to 2100 and full moon in yellow and the dates everyone is talking about in orange. Closer moons will follow several times this century, so it is not so rare. And remember from the first graph: the distance and hence appearance diameters of all full moons in this graph do not much differ to the eye and are actually all supermoons!


The moon illusion
People often think they see a supermoon. But in fact they are victim of the so called moon illusion! A very good explanation is on Wikipedia.

Macro photography in millimeter range: microscope vs DSLR camera

In this small review I compare two imaging methods, the VHX2000 microscope and a Canon EOS 7D camera with a reverse ring, for an object of a few mm in size.



This motive, a 30 million year old ant trapped in Baltic amber, is about 3 by 4 mm. Wit a normal macro lens or extension tubes, it is not possible to get such a small object so detailed captured. Reversing a wide angle (zoom) lens with an adapter (reverse ring or retro adapter) gives high magnifications and it is possible to get a good picture (right two images). I also had the opportunity to use a microscope with camera, the VHX2000 from Keyence, which is specially built for imaging small objects. I found that both are not perfect solutions, which makes a comparison meaningful.

Before I get to the differences, some words on what they have in common. Both work with lenses and a digital sensor. The depth of field is very limited and both require a stack of 10-20 images from bottom to top that are either merged in a stacking program like CombineZP or Photoshop*. They both disappoint in image quality and detail for printing on a A3 format. For more detail you need to zoom in and make a mosaic composite**. The ant image is based on a single stack image.

VHX2000	DSLR
Stability
Stable platform present	Need to stabilize camera and object carefully
Image Quality
1600 x 1200 (3200 x 2400) pixel resolution	5184 x 3456 pixel resolution
Compressed/filtered data	Raw data
Crisp sharpness difficult	Crisp sharpness difficult
Details such as hairs visible	Details such as hairs visible
Photo stacks by software	Photo stacks manually
Optimal stacking	Non-optimal stacking (movement of camera possible when turning wheel)
Light
Artificial light	Natural and artificial light possible
Light from all sides (adjustable)	Light from one side (with natural light)
Light can work 'flat'	Lighting very flexible in giving depth
Clipping of light areas	Fewer clipping areas (with Raw data)
Other
Zoom under 1 mm possible	Zoom limited (here to about 2 mm objects)
Relatively fast	Time consuming
Expensive	Not expensive, when camera and lens are already in possession

Conclusion:
The pictures with either a VHX2000 or a reverse ring are slightly different, especially concerning color. The reverse ring method is more complicated and time consuming but gives an image quality that can keep up with a microscope image (apart from small lens distortions that are not considered here). For the price and quality, a reverse ring is a very attractive alternative to a microscope, when the object is not smaller than about 2 mm.

* On digital stacking:
1) CombineZP (freeware for stacking) gives nice results with the pyramid weighted average method. The idea is that the software reconstructs the 3d depth of the object. From the bottom layer, the sharpest is considered and build up to the top layer with complex algorithms.
2) Photoshop can also yield nice results with a different method. It just keeps the most sharp part from each layer. Sometimes the result is nicer than CombineZP, sometimes not. To do this, choose File => Scripts => Load files into stack. In the layer palette, select all layers. Then choose: Edit => Auto-Align Layers, followed by Edit => Auto-Blend Layers. Sometimes the result is better without Auto-Align (eventually manual align).

** Mosaic composite:
E.g. a mosaic of 6 image columns by 6 image rows with overlap in area for stitching gives at most 3 times more detail. With 20 stack layers per image, you need to manage 36x20=720 images (which I only did once). First you stack each mosaic part with the favored software, after which the mosaic is stitched together. This is time consuming because it often requires manual adjustments, and is only justified when an image is indeed to be presented at A3 format.