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How Night Vision Goggles Work:

As you have seen night vision scope in movies and games. And are used by hunters, soldiers and law enforcement agencies. But there are still many people who don’t know how night vision works. A best night vision goggles can help you see over 200 yards without any problem. 

Basically, there are two types of night vision which are commonly used passive and active.

Passive night vision simply amplifies the available light and does not work in absolute darkness.

Active night vision is the type which is found on camcorders. These projects a near-infrared light source out. Optics in the camera is sensitive to this spectrum but it is out of visual range so you can't see it.

Night vision goggles depend on the photoelectric effect. 

When light particles (photons) enter the goggles they hit the photocathode. When photons collide with photocathode as they are light sensitive. They are converted into electrons. The goggles then amplify these electrons by using a photomultiplier. Because of this more electrons are leaving than the electron entering. 

The final process is a phosphor screen by which electrons emits tiny flashes of light. This results in much more photons which makes the scene appear brighter on the screen. That's why the night vision goggles display green colors. Its reason is that the electrons lose all the color information turning the scene black and white. 

Since human eyes are more sensitive towards green light so this color was chosen for the night vision goggles to display and also because it's easier to look at green pictures for long periods of time than it is to look at black and white images.

This process produces a lower resolution and blurrier version of the original scene. First generation devices consist of a high-pitched noise which occurs when the goggles are switched on. 

The second generation are more advanced but are expensive. Its MCP consists of millions of tiny glass tubes which releases thousands of more electrons which produce a better image.

Third and fourth generation night vision goggles make use of chemical layers which covers the phosphor screen which results in a brighter image and improves vision.

If you are interested about night vision scope Ultimate guide to buy a night vision scope

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What is a compound bow?

Compound bows are the modern version of recurve bow. It has a levering system which are usually of cables and pulleys, which are used to bend the limbs. They are very popular both for hunting and practice. Its pulley system makes it easier to shoot with accuracy. Because of this, it is energy-efficient than other bows. 

The higher-technology construction and number of tools make it easier for target practice or bow hunting. They are made up of components such as the limbs, sights, and stabilizers. Limbs are made of fiberglass like materials which can withstand great strains. Risers (quivers) are made to be firm as possible. Also, there is a cam or wheel at the end of each limb.

 There are several different types of cams to store energy in the limbs. The four most common types are single cam, dual cam, hybrid cam, and binary cam.

The bow strings and cables are made up of high-modulus polyethylene which offers great tensile strength and minimal stretchability so that it can transfers energy to the arrow as smoothly as possible.

Advantages of a compound bow:

You will still have to practice compound bow but not as much as recurve bow. Because you don't have to rely much on physical strength. As it allows more accuracy and power to hit a target from a greater distance. 

Also in compound bows, a lot of customization can be done and offers tools, like scopes and stabilizers which can be added to increase accuracy and targeting.

Basic Advantages:

More customization

Accuracy and power

Shoot target with a greater distance

Requires minimum upper body strength

Disadvantages of a compound bow:

These bows are heavier and bigger than a recurve bow so you have to be sure to size your bow correctly when buying. As Compound bows are bigger so a good case will be required to protect it. Tuning, and maintaining of compound bow requires skills.

Basic Disadvantages:

Heavier and bigger than a recurve bow

Requires Maintenance

The Draw length is very important

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Airbrush Buying Guide:

There are different types of airbrush and all of them have different features.

Before buying an airbrush you need to understand the different parts of the entire airbrush system. Such as double action, internal mix airbrush, single action, and double-action airbrush. All of the airbrushes use either single action or double action control mechanism. For fine work single-action, airbrush is all you need. For those who want more detailed and control work, double-action airbrush is ideal for them.

Single action vs Double Action Airbrush:

This part determines how much control you might have while painting your models or miniature figures.

Single Action Airbrush:

Single airbrush allows both the air and the paint flow without any possible adjustment. You can adjust the paint flow separately through a knob usually located near the tip of the airbrush which will adjust the needle position in the nozzle. The benefit of the Single-action airbrushes is that they are a great choice for beginners because they are easy to control and maintain. They are cheaper than double action airbrush and easy to clean. The downside of this type is that it is not as precise as a double-action airbrush.

Double action airbrush:

Double airbrush allows more control and gives precise results than the single action airbrushes. This type allows users to control both air and paint flow with the trigger. Pressing the trigger down allows air to flow through the airbrush and trigger back will allow paint to flow through. The further you push down or back increases the paint or airflow. The downside of double-action models is that they are expensive than single-action types and difficult to use for a beginner.

GRAVITY VS SIPHON FEED AIRBRUSH:

This part covers how the paint is fed into the airbrush.

GRAVITY FEED AIRBRUSH:

Gravity feeds have a paint cup at the top of the airbrush. Gravity is used to pulls the paint into the airbrush. Gravity feed airbrush allows users to work with lower air pressure which gives you more control on painting fine lines and details. The downside of this is a smaller cup size for storing paint which will require you to refill your paint supply when painting a large area.

SIPHON FEED AIRBRUSH:

Siphon feed airbrushes have their container located at the bottom of the airbrush. When air passes through the tube the paint is pulled up by a vacuum into the airbrush through the stem to get atomized.

The siphon fed airbrushes are larger than gravity feed airbrushes which allow for a larger amount of paint storage. It is useful if you want to paint a large surface without having to refill the bottle. And also allow painting at any angle. Cup sizes will range from 0.9 ml up to 15 ml. Downside is required a little bit of more paint and requires more clean up time.

Internal Mix vs. External Mix:

Its the place where paint mixes with the air. It is important because it changes the way the spray looks when it hits the surface.

Internal Mix:

Internal mixing means when paint enters the airbrush its mixes with air and atomized. Which produces a fine and smooth finish.

External Mix:

In External mix, the air does not enter directly in the airbrush but instead flows outside the nozzle and it is atomized as soon as air leaves the nozzle.

AIRBRUSH NEEDLES:

Needles and nozzles are very sensitive. As they can be bend or damaged easily. The best size airbrush needle for modelers to start with is going to be .5mm as this will produce a great all-around spray (needle and nozzle combination will determine the final effect).

Ultimately the choice of the nozzle\needle will depend on what you are going to do with it.

AIRBRUSH NOZZLES:

If you need to paint a thin line then you will need a finer nozzle. But If you need to work on a large area, then you need an airbrush with a large nozzle. There is a different size on nozzle\needle (0.2 mm, 0.3 mm, 0.4 mm, o.5 mm, 0.6 mm) but it will depend on you for what are you gonna use it for.