power for cg-5 goto equatorial mount

[aaronkmk]

Ok so got my scope today and it only came with a power adapter for my cars cigarette lighter socket.. in the book it says it's a 12v AC..if I go to jaycar or a similar electrical shop is that all I need to say to get portable power

Cheers Aaron

[killswitch]

12v DC you mean

You can get an SLA or AGM battery from Jaycar. You also need an adapter (alligator clips to 12v cig plug). Also a 12v battery charger.

The jumpstarter units work okay too but they dont last as long.

[julianh72]

Yes, a "jump starter" with a cigarette lighter output such as this http://www.jaycar.com.au/productView.asp?ID=MB3692 would be fine to power a telescope.

Or for a cheaper, lighter, more compact option, you could look at a 12V SLA (Sealed Lead Acid battery) and charger, and make up your own cable to connect the battery to the scope. (For my Celestron SLT / Meade LX90, I just cut the cigarette lighter adapter off, and soldered on some red and black terminal lugs to clip to the battery terminals - make sure you get correct polarity before you plug it in!!!)

See this link for some SLAs and chargers - less than half the cost of a jump-starter (but of course, a jump starter can be used to power more devices, and for longer):
http://search.jaycar.com.au/search?w=sla&view=list

Something the size of a CG-5 probably pulls one or two amps peak when slewing at high speed, but more like half an amp (or less) while tracking, so a 7 Amp-Hour 12 volt SLA would pack enough juice for at least 14 hours operation - more than enough for a couple of night's viewing between charges.

[julianh72]

That one plugs into a 240 V AC socket, and gives you a 12 V "cigarette lighter" socket, into which you would plug the supplied cigarette lighter cable. If you have access to a 240 V AC socket where you are going to use the scope, it would be simpler (and cheaper) to just use a 12 V DC output "wall wart" power supply, which can supply 12 V at 1 1/2 amps (continuous) or more. (You might even already have one lying around at home.)

I think what the OP is after is a "stand alone" 12 V DC power source, which means some sort of 12 V battery and a cable with the necessary jack on the end - see my previous post.

[brian nordstrom]

:)I got mine from super cheap auto , same as the ones from Jacyar except it has 2 socket outlets , its yellow and USB plug as well this is very useful
, its a 900A and I payed $99 for it 5 years ago and its still going strong .

Just remember never leave it sitting longer than 4 weeks before charging it up , this stops the battery form 'over discharging' and dying .

Brian.

[killswitch]

Yeap read it incorrectly. Bloody small phone screen.

[Amaranthus]

This is correct, but it's actually healthier for the life of a LAB to charge it after every night, if you can, rather than leaving it until drained. (Optimum time to charge a lead acid battery is when they reach around 50% of their total charge, so 3-4 Ah use for a 7Ah battery)

[aaronkmk]

I thanks for the help guys much appreciated..
Think I might go for the jump starte r pack just for convenience..

Do they come with a plug to charge the battery in the jumpstarter???

So keen fir tonight first time I'll get to look through the scope.. hopefully I can master the alignment process..

[Amaranthus]

If you know any bright stars, then do the auto two star alignment - quick, and accurate. Two good ones right now are Hadar and Spica, or Canopus and Regulus - get them at about 70+ degrees separation and better not to cross the meridian.

[Camelopardalis]

Barry that is sound for the SE mount but the equatorial software is slightly different...

If you have a good view all around you'll have plenty of bright stars to choose from, if you don't know where the stars are then use a star chart or app on your smart phone or computer.

With the scope in the home position, select two-star alignment and then chose a star you can see from the list. It will go there...centre it in the eyepiece and then select the second star. Same again. Once done it might ask about calibration stars. You don't have to add any, but if you do it refines the model of the sky that the onboard computer has and it will improve your goto accuracy.

Good luck!

[Amaranthus]

Interesting - there is no calibration star option for the alt-az mount, and based on my experience, redoing alignment stars after the initial two makes little/no difference on pointing accuracy (for my SE). So I wonder why they include this for the EQ mount?

[GeoffW1]

Hi,

I've been using this one

http://www.batteriesdirect.com.au/shop/product/13282/fusion-agm-vrla-12v-14ah---cyclic-use.html

for a few years now. It performs very well over a single session. I charge it with an auto trickle charger with smart cut-out, because this type does not like overcharging.

Cheers

[Camelopardalis]

No, but there is "Precise goto"...which looks like it "calibrates" on a star in the vicinity of the object you want to view.

It is interesting how different the software is between the alt-az and equatorial mounts, but using two-star align and adding 4 calibration stars is pretty quick (it's doing all the slewing, you just agree to the stars) and accurate (in my experience). More accurate than the SE for sure, but the SE is hard to beat for convenience :D

There's also the polar alignment assist "all star", but that currently doesn't work for the southern hemisphere, at least for the AVX :sadeyes: (strange because the Skywatcher equivalent works quite well)

[Amaranthus]

I've heard that for some mounts, you can add up to 50 calibration stars to refine their sky map - useful when you've got the mount semi-permanently set up. I've used precise GOTO a bit (will use it more now for AP), and I do a local sync a lot - the latter definitely helps with the SE.

[Camelopardalis]

Wow, now that would be nice to have :D

I've not used the Precise goto but have occasionally synced to a local star during the course of an evening, once in a while the gotos drift (operator error no doubt!). For my imaging session the other night I just used auto 2-star.