There appears to be a peculiar law of the universe involving technology: Every major step forward will have a major catch. For computer driven telescopes able to drive themesleves to thousands of objects in the sky, the major catch is an insatiable hunger for power. With some of the smaller ones, such as the NexStar 5i or the NexStar 6SE, this literally means they will drain a set of AA batteries in one night of observing. Even the smaller representatives of these telescopes such as the NexStar 80GT and the NexStar 102SLT hunger for power, and use batteries up quickly. In larger GoTo telescopes, such as the NexStar 8 GPS or the CPC 800, NexStar 11GPS, or CPC 1100, they have no provision for a battery at all. Instead, the larger telescopes simply have an input for 12 volt power. And all of these telescopes become useless if the power doesn't keep coming. In comparison, the older telescopes requiring the observer to figure out where to point the scope came with much lower power requirements, where even a large telescope like a Celestar 8 only needed a 9 volt battery to meet its needs for power for 8 months of use, and the CG-4 Drive can also run for months on one pack of four D cells. The solution is to have a really big battery, and that is precisely what the Power Tank is.

Background

Various rechargeable batteries to meet the power requirements for users who wanted to run telescopes, cameras, and other pieces of equipment like dew heaters began to become somewhat common in the 1990s as the list of equipment going out to observe for an advanced user quickly grew. Back then, the biggest needs came from things to prevent the front ends of telescopes from fogging in areas with high humidity. But these were not purpose-built telescope batteries, but were automotive battery chargers, or even groups of batteries built into a cooler to carry them. But as a change swept across the industry which turned the bulk of the telescopes themselves into high power demand products, the need to attach a cord became a real problem.

What was at stake with the high demand for power was the best case usability of these telescopes, out away from where city lights interfere. The old school scopes made this trip gracefully, with no obvious difference in use since the battery went out to the back yard, too. But for deep power requirements, the only answers were to hook up to a car or start building your own equipment.

Description and Usage

The answer to the need for a portable power source for computer guided scopes is the power tank. And for a product born of desperation, it does put its best foot forward.

If you didn't look at it carefully, you might think this product is just some sort of rechargeable lantern/ car charger. It has two lights, one large one with a hinge so it can be tilted up and down, as well as a smaller fixed light capable of flashing, which also has a red filter to provide enough light for setting up and tearing down a large scope. It also has traces of the practical in the form of two 12V terminals which will let you recharge a car battery with it (note, this battery cannot start a car by itself).

But on its left side it has a series of power ports and car cigarrette lighter type power plugs as well as a set of status lights and a mode selector switch which reveal this battery is something else; a portable power station. There are two more output plugs as well as a charging plug for the battery itself. One output is labeles 6V, and one is 9V.

The other side of the battery has a built in compartment for a car adapter and cord, which is essentially an equivalent of the Celestron Car Adapter. This part serves two functions: First, it is the adapter you need to run a NexStar series telescope straight off the battery. Second, it allows you to charge the battery from a car, a handy thing if you have taken it out into the woods as a power source.

The charger also comes with a separate plug-in charger, which has a 15V output, and appears to be unique configuration for this battery (so it doesn't serve dual-duty as a power source for one of them). This charger isn't as fast as a chage from a car, but it probably is a little easier on the battery itself.

The battery has a switch by the handle for either completely turning the battery off, turning it on, and for charging. There is a series of little status LED lights on the side to tell when the battery is on. And, of course, at least one of them is green, so the astronomical red light mafia can complain. If you go to a star party, they will make themselves known by stopping by and suggesting writing over the light with a marker. Please note, it is considered impolite to suggest they go stub out a cigarette in their eye.

The battery works surprisingly well, and if you are able to recharge during the day, it can drive large scopes all night on consecutive evenings. When you are setting up, all you do is set the battery underneath the telescope, plug it in to the drive, and from there you can forget about it. It does have some weight, but the large handle and well formed shell really make it feel more like a lantern flashlight than a telescope power supply.

My one nit on the red light it has on board is this is NOT and LED. Therefore, it can use a noticable amount of power, and so I am exploring putting in an LED set to get purer red light, and one I might consider leaving on when a lot of people are walking around. There is one neat feature where the red light has a switch with a flasher mode, so in case of a roadside emergency, this light can also be a warning beacon.

The large spot light is extremely bright, and thoughtfully has its own switch. If you are out with other astronomers, this is the light to use in case of a real emergency. Otherwise, the Power Tank really is kind of like a big lantern. It does have the power taps for recharging a car battery, but I have not needed to use these, so I am not sure how well this works.

Conclusion

The Celestron Power Tank is a convenient a solution for the power hungry computer driven telescopes. If you just need a power source for one scope, it is absolutely trouble free. I am certain if you have a truck-stop car hair dryer plugged in in to defog the front of the scope, battery life will suffer. But the Power Tank does the bulk of the job without a complaint, is easy to use, and has some convenient backup functions.

Recommended: Yes