Astrotrac TT320X with ST4 port and Polar Scope Part 1

[simon84]

Been after on of these little beauties for some time now as the NEQ6 and Equinox 120 are on there way out.

First impressions were a bit understated really but only because of its actual physical size, when you start looking a bit closer you start to see the effort and workmanship that has gone into these. In the box was the Astrotrac itself, the polar scope, a nicely written instruction manual which covers everything from setting up to polar aligning, there is also a 12v power lead with cigar adapter one end and connector the other. It can also be powered via 8 AA batteries but the battery holder is an optional extra which I didnt get.

Its manufactured from aircraft grade aluminium and I think everything apart from the thread is machined and assembled at Astrotrac in Bristol. The thread that controls the tracking and drives the camera is manufactured in the states and then sent over.

Its more or less just a length of M4 or M5 thread with a pitch of about 0.5 to 1mm. The tolerances involved in the thread manufacturer are fairly high as under closer inspection (x4 mag) the thread appears to be very uniform indeed and this is backed up by claims of unguided tracking of upto 20 minutes at short focal lengths. Its protected on both sides of the unit with a clear plastic cover on the top which in the dark is illuminated.

The Astrotrac itself is very well made with a lot of aluminium machined out of the frame work to keep the weight down to a really impressive 1KG. It has a really nice feel to it and fills the user with confidence that its going to do what it was designed for. The ST4 autoguider port and power socket are on the main motor part of the astrotrac and is the part that dosnt move so you can happily leave the cables just hanging as it shouldnt effect the unit when its tracking.

It has a built in polar scope holder which swings around the camera pivot point at 15 degree increments and is fairly sturdy, there is a little bit of play when in its position but not enough to cause a problem. The polar scope itself appears to be very well made with a nicely detailed reticule for both hemispheres and a reasonably strong magnet to hold it flush to the holder. It is an illuminated reticule and comes with the standard red light which can be dimmed to suit.

The Astrotrac can be used in either the Northern or Southern hemisperes simply by either rotating the drive part of the unit either left or right. It is held in place for storage by a spring loaded ball bearing and is more than up to the task and when closing you get a very reasurring click.

The unit has a female standard camera thread underneath ready to be fitted to most tripods or heads and has the larger 3/8 thread on top to take a ball & socket head or whatever you prefer to use to mount your camera on. These fittings have been fine for my equipment but adapters are readily available should there be any problems.

The four controls on the unit are nicely placed and are illuminated and operating the Astrotrac really couldn't be any simpler with the operator pressing the "play" button once to set the unit up and then a second press to start the unit tracking. Once the two hours tracking time is up a press of the rewind button resets the unit ready to start again. There is a very visible green flashing led when the unit is tracking which changes to red once your two hour tracking time is up. These led are all dimmable with five settings. The unit also beeps to let the user know they have started tracking and then beeps when the last 10 minutes is about to start. This volume is also controlable with 5 steps.

The Astrotrac automatically starts at Sidereal speed but can be changed to lunar or solar speeds simply by holding down one of the buttons and then powering up. This is confirmed by a triple beep.

Overall the unit is very well made and has honestly made me glad that I have purchased one.

I'm really looking forward to getting outside with it and have a range of lenses from 20mm to 500mm to try it out with so hopefully part 2 of this review wont be too far away.

[ashworthacca]

Great stuff, I'm really interested to read part 2 and if possible see some photo's of it set up??

Regards

[simon84]

Photos will be coming, at the moment my tripod isnt enough to support everything and needs upgrading but I will set it up on it for a few photos.

[astroimpulse]

Woo hoo!

Glad you got it Simon

I guess the last thing you want to do is get some pics of it up. Camera on the Astrotrac and taking pics of the sky will be the priority

[simon84]

Me too, very happy with it indeed.

I dont mind, missed last night which was very clear here indeed. I'm down to one dslr at the moment so any pictures of it will be minus camera but I have an old three way head I can pop on top of it. This will be changed for a Manfrotto 496RC2 ball and socket head as soon as I can get one.

[simon84]

Pictures now added, some close ups of the astrotrac, one of the system setup with my 170-500mm Sigma lens and one of the illuminated reticule in the polar scope.

[Coco]

I loved my Astrotrac, I bet I would have given up imaging by now had I not started with an Astrotrac instead of an EQ mount..

Gives you buckets of confidence and is quick to get into..

BTW, I wish that polar scope was in my NEQ6, its a cracking scope.

[simon84]

Your not wrong about that polar scope, its one of the best I've seen. Compared to the one in my NEQ6 its amazing.

I'm downgrading from an EQ mount to the Astrotrac, back issues. I'm sure I will miss the EQ mount but with the Astrotrac I can get out there anytime and pretty much anywhere.

I will be adding the Astrotrac wedge and portable pier next year to the setup which will allow for a very stable setup and can take an load of 15KG!!!!!

[ollypenrice]

Fine review. Many thnaks and looking forward to part two. I didn't know they could be ST4 guided. How does this work? Presumably a compact guider like a finder-guider?

Olly

[simon84]

Thanks Olly, I'm looking forward to Part Two aswell but at the moment the weather is not playing ball.

I've not looked too much into the guiding side of things just yet but I would have thought a finder/guider would do the job quite well. Being able to mount 15KG when using the wedge does allow some other hardware to be installed on top of the Astrotrac instead of a tripod head.

When I get the pier and wedge next year I will be adding a guider into the mix with something like a clamp rail to mount the camera and guider onto. Kevin (BeyondVision) showed me a picture of his setup using a clamp rail and I think a set of finder/guider rings could be adapted to fit on there. I'm sure he wont mind so here is the link to that image, http://ukastronomers.com/BeyondVision/image/8924_large.jpeg

[ollypenrice]

More thanks!

Olly

[simon84]

No worries Olly, is there to be an Astrotrac winging its way over to the South of France?

[MartinB]

Very pleased with my Astrotrac Simon. What are you using between tripod and astrotrac at the moment to adjust alt and az?

[simon84]

At the moment I'm using a cheap tripod with a pan head which is simply not up to the job by any stretch.

For now its really going to be used mostly in the garden so I'm going to get the Astrotrac Wedge from FLO asap and mount that on my pier which will be a much more solid base for it.

For out in the field rather than buy a new tripod and geared head, for around the same money you can get the Astrotrac Portable Pier which in conjunction with the Wedge will be a very strudy portable option aswell. I'm not sure if you've had a look at the pier but everything inculding the Astrotrac stows away inside it which can then be slung over your shoulder in the bag they have made for it.

[ollypenrice]

No worries Olly, is there to be an Astrotrac winging its way over to the South of France?

Well, I've had several visit but as I now have a spare EQ6 I don't know that I can justify it, and I don't need portability. However, I like to be up on the kit for when I'm asked questions. These are a very clever idea.

Olly

[simon84]

The Astrotrac is very clever using a fine thread to drive the camera, I cant remember how big the gear would have to be to get the equivelant tracking but it was far too big to fit into an NEQ6.

I've been making a widefield rig similar to Psychobillys for my NEQ6 which would have allowed a couple of dslrs, a finder/guider and an rdf on it, but because I cant handle the NEQ6 now I've sold it so the widefield adapter has gone unfinished. I might try and finish it one day for someone to try out but I can get the same setup using the Astrotrac.

I've found the Manfrotto 131DD which is a rail which fits onto a 3/8 thread which you can then mount two clamp heads on, one for the camera and one for the guide scope. Those rails also allow a head to be fixed to each end of it so you could in theory have three cameras guided which would allow for instant mosaics of the entire sky if you had wide enough lenses. I can see myself buying another dslr to go with the other two at this rate.....lol.

[simon84]

Well I didnt realise it but the Manfrotto 131DD is actually more or less the same thing that Astro Developments make but at half the price so I've now ordered one from AD which should be here the early part of next week, so I can now mount upto four cameras.

This will also allow me to modify a set of finder/guider rings to fit on a ball and socket head so can someone please tell me why I sold my QHY5 finder/guider.......DOH!

[simon84]

Another note regarding attaching the Astrotrac to a tripod or mount. I've just realised that there is a 3/8 to 1/4 inch adapter already in the Astrotrac.

So you can mount on either format without having to purchase a seperate adapter. On the top of the Astrotrac though there is only a 3/8" thread so if you have accessories that use 1/4" you will need to get an adapter for it. I wouldn't advise doing that though as it could add flexure into the system.

[stevenson166]

Rivetting stuff guys and the path that i intend to take , Simon i notice you have a Manfrotto 055XPROB which i very nearly bought today, is this the one you refer to as not up to the job ? and what alternatives are there you or anyone else could recommend at a reasonable price. When i viewed the Astrotrac demo linked on this site the guy from Astrotrac just stated using a general high street tripod. Is yours not ideal because you are mounting more than 1 SLR ?

Thanks Paul

[Stephen Greenfield]

Got mine recently and only got to do a few quick pictures of the orion nebula and horsehead.

On the whole very happy with it, have enclosed a pic of what mine is sitting on top of :-)