[gregbradley]

There are several trackers on the market and I have had a few over the years.

There is also a good You Tuber reviewer who reviews the 3 main contenders.

He rates the iOptron unit highly.

Going overseas means you need something small and light and easy to use.

My first unit was a Vixen Polarie. I have taken it overseas as it is small and light and takes internal batteries (AA). It has fairly high periodic error around the +/- 20-24 arc seconds level. It will also do time lapses. I agree with Peter this is one of the better choices. There is a newer model which is more expensive but has extra features.

20 arc secs is about the limit of error you want. But taking widefield images using say a 14mm F2.8 lens like a Samyang periodic error is not much of a concern as the widefield is very forgiving. If you want to do 30 or 50mm then that is a different story. Vixen's polar scope is also quite good.

Fornax makes a Lightrack 11 mount. Not sure if it takes internal batteries, best to check their site. I always use a power brick to power mine.
It has very low periodic error - around 3 arc secs or perhaps less.
It has a swing arm that has to be turned back to the start after 2 hours. Not really an issue if you are doing a night scape of say 8 exposures x 30 seconds ISO3200.

Also longer heavier lenses can make the motor skip as it uses a friction drive. Balance is more important. A gimbal mount being recommended (about $50 on ebay).

It's larger and heavier. Also you need to calibrate a polar scope before you can use it which is a pain.

iOptron Star tracker I haven't used but it rates well, is small, light and I think it takes internal batteries - check their site.

Unitec Swat - a premium Japanese tracker. I have the Swat 330. I was out using it the other day. It will take a load of up to 15kg!. Periodic error is conservatively listed as 14 arc seconds. . It's very solid and a bit heavy but not large. There are a large number of high end accessories for it. As good as it is I don't think I would take it overseas as it's too heavy (about 1.5kgs or so). It's also the most expensive on this list at around AUD$2400. I have to translate the manual to use it. I stumbled/bumbled my way through it the other night.

Move Shoot Move have a couple of very small and light trackers.
Haven't used them.

It depends also on what focal length you intend to shoot at. I find it's more about how accurate your polar alignment is than the periodic error.
It's should be way easier in the northern hemisphere as you merely line up Polaris.

A decent tripod is needed. A carbon fibre one makes sense to keep the weight down.

If you plan on longer focal lengths than about 24mm then expect a big jump in perfection of polar alignment to be required.

I often read that such and such mount can do 300mm and laugh. The longest I have been able to achieve is about 55mm!!.

300mm would require counterweights.

To achieve a decent polar alignment I use an ASIAIR + wifi unit which has a polar alignment feature. I would practice using the unit with your phone before you venture out in the dark and wonder why the camera is not connecting to the ASIAIR. It's a bit fiddly but once setup and you have drilled how to use it then it becomes my go-to method for polar aligning a tracker unit. But in the northern hemisphere a lot of this difficulty is not there.

I also have a Skywatcher GTi unit. It's larger and heavier so taking it overseas would be out of the question unless you buy one over there.

What type of nightscape are you thinking of? What focal length?

If you are using 14mm lenses then you don't really need a tracker. Simply take 15 second exposures and up the ISO to 6400. Most modern mirrorless cameras have really low noise sensors so you can do that. Simply take double the normal number of exposures.

Greg.