Multiply as above, but this time write your answers in a new row, shifted one digit place to the left. Twilight Factor is the theory that small bright images can have as much detail as large dim images. Here is the best explanation of the theory behind the twilight factor: let's say you're reading a newspaper. If you're in low light, you have to hold the paper closer (increased magnification). If it's bright out, you can hold the paper further away (decreased magnification). You've probably noticed that most binoculars are described by two numbers separated by an x, 8x42, for example. That first number is the magnification (more on that in a second), and the second number is the size (in millimeters) of the objective (front) lens. The size of the objective lens largely determines the overall size of the binoculars, so that second number essentially describes their size. Powerplant: 1 × Pratt & Whitney JSF119-PW-611 augmented turbofan, 25,000lbf (110kN) thrustdry, 40,000lbf (180kN) with afterburner

The first is the F-35A, a conventional takeoff and landing (CTOL) variant. It is the smallest and lightest version, and is intended primarily to replace the U.S. Air Force's aging F-16 Fighting Falcons and A-10 Thunderbolt IIs. This is the only version with an internal gun, the GAU-22. The F-35B is the short-takeoff and vertical-landing (STOVL) variant due to replace the U.S. Marine Corps AV-8 Harrier IIs and F/A-18 Hornets, and Royal Air Force/ Royal Navy Harrier GR7/GR9s beginning in 2015. The Royal Navy will use this to replace its Harrier GR7s and the RAF replace its Harrier GR9s. The U.S. Marine Corps will use the F-35B to replace both its AV-8B Harrier IIs and F/A-18 Hornets with a design similar in size to the Air Force F-35A, trading fuel volume for vertical flight systems. Like the Harrier, guns will be carried in a pod. Vertical flight is by far the riskiest, and in the end, a decisive factor in design. Lastly, the F-35C, a carrier-based (CV) variant, will replace the "legacy" F/A-18 Hornets and serve as a stealthy complement to the F/A-18E/F Super Hornet. Bevilaqua, Paul M. (September 2005). "Joint Strike Fighter Dual-Cycle Propulsion System". Journal of Propulsion and Power. 21 (5): 778–783. doi: 10.2514/1.15228.Gas-Filled are binoculars that have been filled with gas-like nitrogen to prevent interior condensation. This can happen when a pair of binoculars is moved from a warm environment to a cold environment or vice versa. This causes condensation inside the internal optics, fogging them up. Mold can also form over time from repeated condensation. Most weatherproofed optics are gas-filled, but not always. Uses FY18 DOD PROGRAMS F-35 Joint Strike Fighter (JSF)" (PDF). dote.osd.mil. 2018. p.25. Archived from the original (PDF) on 26 June 2019. Long multiplication means you're doing multiplication by hand. The traditional method, or Standard Algorithm, involves multiplying numbers and lining up results according to place value. These are the steps to do long multiplication by hand:

If you're looking for something with greater than 12x magnification, binoculars may not be for you. Above that mark, hand shake becomes unwieldy, even for the steadiest hands in the west. At that point, you'll be looking at a tripod-mounted spotting scope instead. Fulghum, David (5 March 2001). "Navy X-35C JSF Demonstrator Lands Slower, Flies Farther". Aviation Week. Bevilaqua, Paul M; Shumpert, Paul K, Propulsion system for a vertical and short takeoff and landing aircraft (patent), United States: Patent genius, 5209428, archived from the original on 25 February 2012 , retrieved 9 January 2010 . When choosing a pair of binoculars, you are faced with making compromises. Binoculars that you use for astronomy will not be compact, and you probably won't take them hiking. Below are some things to consider based on use: Hiking/Travel Multiplication Table is an useful table to remember to help you learn multiplication by 35. You should also practice the examples given because the best way to learn is by doing, not memorizing. Online PracticeArmor is an outer coating of rubber or synthetic material. This protects the binoculars from scratches and corrosion. It can also make the binoculars easier to hold. A rubber coating does not make a pair of binoculars waterproof. Another consideration with focusing is the ease and smoothness of the system. The focal knob should comfortably be positioned under your index finger as you hold the binoculars. It should operate evenly and smoothly without any looseness, stiffness, or irregularities of movement.