Night Watchmen - Part III

If nighttime navigation is a regular part of your boating, you need several pieces of electronics to make your passages as safe as possible. An electronic chart display (ECD), coupled with a GPS, is one of them. This shows your position on an electronic chart relative to the shore, buoys, reefs, and other obstructions. A radar is number two. This shows surface obstructions including boats, buoys, and shorelines nearby. By cross-checking between the two you give yourself a huge advantage in terms of safety--essentially, you know where you are and you know where most other boats are. But there is one more item that will complete your safety package: a night vision viewer. Simply put, it's one thing to see obstructions on an electronic screen, but it's quite another to see them with your own eyes.

As good as radar is, it's not perfect. Depending on the size of your antenna and the quality of your display, your radar is prone to overlooking some obstructions, typically small boats, low-lying islands, and any floating object (such as lobster pots, logs, etc.) that's not equipped with a radar reflector. But when you have night vision equipment aboard, night becomes day, and you'll be able to see everything within the field of view of that equipment. And that's where Tasco's new NV-250 comes in. Essentially, this unit is about the size of a 375-mm telephoto camera lens, and it works by taking low levels of ambient light and magnifying it 65,000 times. When you look through the unit's panoramic viewfinder, what you get is a razor-sharp, super-bright image of the nighttime scene in front of you, and in terms of a quality presentation, the Tasco is the clearest I've seen to date.

In case you are not familiar with Tasco, the company was originally founded in 1954 and it is a major player in the fields of recreational and sport optics. Tasco has more than 100 models of binoculars, 100 rifle and pistol scopes, 60 different telescopes, and 25 microscopes in its product lineup. So that's why Sam Gill, Tasco's communications manager, says the transition from traditional optics to night vision equipment was a natural for the company.

"This year we got into night vision equipment full steam," he says, "and it's our feeling that recreational outdoor activities [camping, hiking, boating] are on the rise. So the challenge was to bring in a high-quality night vision product, but at a reasonable price. What we have right now will set a new standard for the general consumer market," and Gill says the company will add even more night vision products to its existing line.

For the time being, Tasco offers both Generation I (GEN I) and II (GEN II) night vision viewers, and there are significant differences between the two. All night vision systems use a light-intensifier tube to gather any available light and convert it to electrical energy in the form of electrons flowing through the tube. A device called a photocathode actually converts the light into an electron image at the front of the tube, and that image is sent to the back of the tube where it appears on a small video screen for viewing. This is how a GEN I unit works, and though it creates an acceptable image, it is somewhat lacking in terms of sharp resolution and brightness. A GEN II unit, on the other hand, places a device called a microchannel plate between the photocathode and video screen, and when electrons pass through it, they cause additional electrons to be emitted and sent back to the video screen. These extra electrons create both a sharper and brighter image, and the NV-250 is a GEN II unit.

The big difference between the NV-250 and other units I've tested is at the viewing end. Unlike some units that have separate eye cups or are only a monocular, the NV-250 has an extra-wide, panoramic lens that not only magnifies the video image, but also makes it possible to look at it with both eyes simultaneously. This "stereo" presentation helps you determine depths-of-field (relative distances between objects), and there's no need to adjust or focus individual eye pieces, since a manual-focus ring at the end of the unit takes care of that (you focus it just like a camera lens). So overall, the NV-250 provided the best all-around picture of any night viewer I've seen, and it's easy to use as well.

A single switch atop the unit turns it on, and there are three small buttons on the side that control the unit. The first one--the select (SL) button--lets you toggle back and forth between the night viewer control and control for its built-in infrared (IR) imager. In extremely dark conditions or if you need to put an invisible "spotlight" on an object, the IR imager is designed to illuminate any object up to 100 yards away. Unfortunately, the IR imager was not working on the unit I tested, so I cannot comment on its effectiveness (and given its short range, it has little use in the marine environment, anyway).

The other two buttons are "+" and "-" keys, and they let you increase/decrease the brightness of the display and IR beam. In addition, the NV-250 has a unique feature called the "Smart Sensor" that's designed to extend the unit's normal battery life of 30 hours (it uses two 3-volt lithium batteries). When activated, the Smart Sensor turns the unit on when you look into the viewfinder, and automatically turns it off when you move away. This is a great feature for those times when you're in narrow or crowded channels and you want to check the night viewer often.

As a marine unit, the NV-250 is not specifically designed as such (it's not waterproof and definitely doesn't float), and so it is probably best suited for use in the protected pilothouses or lower-helm stations of motoryachts and cruisers. Though the unit has a handstrap and it is portable, it's relatively heavy at just under four pounds, and my arm tired after about 60 seconds of holding it up for viewing. As such, you'll probably want to mount the unit on a swivel stand next to the wheel, and in any case, control of the unit is a two-handed operation.

As far as performance is concerned, the unit has extra-sharp clarity, and I easily spotted birds, unlit can buoys and boats, distant docks across a dark harbor, low-lying islands, lobster pots, and even a sandbar that was about to emerge above a falling tide (the mixing currents and foam on the water were the tell-tale signs). You can see now why night vision gear is a big plus, particularly since most of these items would never appear on radar.

Focusing the NV-250 is a simple matter, and though the unit's field of view is relatively narrow at just 14 degrees (a sister product, the NV245 widens that to 17 degrees), I appreciated the unit's 4.5X magnification which brings distant objects clearly into view. Still, I take some exception to Tasco's sub-par owner's manual which lists the focal length as three feet to infinity. In fact, with the lens cap off, the focal length is about 11 feet to infinity. With the lens cap on, you can still use the unit in daylight conditions since the cap has a pinhole in it, but that's the only time you get a minimum focal distance of three feet. In any event, close-up focusing has little bearing on how you'll use the unit as a navigation tool since you'll be focused on infinity almost all the time.

Tasco also says the unit has an optional adapter for still and video cameras. Unfortunately, the adapter equipment they sent me was unsuitable for this task, and Tasco needs to modify this option package before delivering it to consumers.

Overall, however, the NV-250 (list price: $3,038) proved to be a remarkable night vision viewer, and it should be well-accepted by those motoryacht owners who want to add that extra measure of safety to their nighttime-electronics mix.

For more information contact Tasco, (954) 52-3600. Fax: (954) 252-3705.