Which power source is best for a Nexstar 8

[sarahgold]

Hello everybody,

I am a total beginner and just kicking off with my very first scope, which will be a Nexstar 8. Not the SE version, but the silver one from just before. I have not received it yet, however, I have read that the integral batteries don't last long. I was wondering which external battery to get to keep it running for a few hours viewing a night. People have mentioned power packs and jump starters, however, what kind of power leads and connector bits do I need to get onto the motorised arm? I can't imagine that it works out of the box, without having the correct bits n pieces handy. Sorry if this is a silly question, only I literally have not used any scope before and have never had to handle power tanks/super jumpers etc :-)

Really giddy about trying all out, at the end of the month, so just want to be powered up and set for a good first night out!

Many thanks and best regards to all the members

Sarah

[jonathan]

A typical 12v jump starter pack or the Celestron Power Tank should work with it, you may wish to make or purchase a good quality power lead as well.

The ideal battery will be what is known as a Leisure battery, the type used in caravans or in golf buggies, they are designed to be discharged at a slow rate, the power tanks and starter batteries are normal lead-acid car batteries which are designed for short bursts of high power (for starting a car). I am planning on purchasing a leisure battery to replace the lead-acid one in a starter unit I have - I will then have a ready-made case with sockets etc already in place, but a better battery inside.

The power tanks and starter batteries work fine, but you should try not to run them down beyond 50% charge and you must charge them as soon as possible after use, otherwise they suffer and can quickly lose capacity if not looked after properly. You can estimate how much your mount draws and calculate how long it will take to drain down to 50% of the Ah rating of the battery, usually they are something like 7Ah but if you can get 17 or 20Ah that would be better, especially if you have dew heaters running (see below).

The Skytron power cable is pretty well made and they do one suitable for the Nexstar SE (which I assume will have the same fitting - best ask FLO before ordering) http://www.firstlightoptics.com/astronomy-cables-leads-accessories/skytron-power-supply-cable-for-skywatcher-celestron-mounts.html

For an 8 inch SCT you will definitely need some dew protection, if your purchase does not include these then the minimum you have should be a dew shield. You can make one out of some thin camping mat or thick card rolled into a tube that fits over the end of the telescope, or purchase a ready-made one. I have the Astrozap one and it is very well made, slots on and off like a glove.

May also need to consider dew heater tapes and heater controller, you can make your own if you know a bit of electronics but if you have the money it's far easier to just buy them, I have the Astrozap stuff and it works pretty well.

http://www.firstlightoptics.com/dew-prevention.html

[Slim]

Where are you going to be using it? If it's in the back garden within reach of a socket in the house via an extension cable you could get a 240v to 12v power supply unit similar to a one that comes with a laptop for example. I picked one up for my NEQ6 from Maplins for about £20. That way you don't have to worry about batteries running out. I've also got a jump starter for when I go to my dark site.

[BigBlueOne]

Hi Sarah,

On the forum theres a few posts regarding which battery

is best for what, I started with a battery pack from maplins

a 5 in 1 does tyres and such that gave 17aH output price

about £48.

Now I use a battery I purchased from a car spares shop

50aH for £53, I depends really on what you intend to run and how long you would like to run it for. The more power the battery

has the 70 or 80aH battery or higher are very pricey.

Hope this helps BigBlueOne.

[jonathan]

The more power the battery

has the 70 or 80aH battery or higher are very pricey.

Hope this helps BigBlueOne.

Also, the bigger and heavier they are too. 17Ah is heavy enough, but manageable with one hand if it has a suitable carry handle (like the Maplins 5-in-1). A 50Ah battery must definitely be a two-handed job, bit of a back-breaker too I imagine! For us weedy types, anyway.

[Dunkster]

Also depends on your expected sessions... I have the 7Ah Celestron power tank and I've not exhausted it yet! I expect I might if life didn't get in the way of observing though (an all-nighter for example)

[sarahgold]

Hello Everybody,

Many thanks for the kind replies and wonderful help and advise. It is fantastic to see how helpful the Stargazer community are :-)

Initially I was looking at perhaps a Skywatcher Power tank, however, I think I will get a Maplins 5/1 17Ah instead. I was a little worried about having a heated Astrozap dew shield, and the scope powered at the same time. I will be mostly observing away from my mains supply, as my garden is surrounded by very high hedges.

I plan to get the following to compliment the Nexstar 8

Astrozap Flexi-heat Dew shield

HitecAstro single channel, dual port Dew controller

Astrozap Dew heater Tape for 1.25mm finder

SkyTron power supply cable for celestron mounts

I am hoping that the Maplins 5/1 17ah will be man enough to power the above for perhaps 3 to 5 hours a night with no hiccups! If anybody has a similar set up and can confirm, it would be great.

Thanks again guys for the help and I can't wait till next week when my scope arrives!

best regards

Sarah

[M4lcs67]

I use the Maplin 3 in 1 powertank for my 127 SLT. Works great and only around £27 at the moment. You will need to get a powerlead though to go with it. FLO do them for £12/13.