Basically my mind has settled on the Vixen Polarie and I don't think I can be talked out of it, it offers supreme portability given it's not much bigger than an old VHS tape and the results I have seen are every bit impressive.
Not trying to talk you out of it, but have you seen the new iOptron mount?
The SmartEQ has goto but can only take an 11pound(5kg) payload, tho it looks pretty good for the US$399 price. It's not on their site yet, but there are a couple of Youtube sneak preview vids from NEAF an they are listed at the following site: http://www.altairastro.com/product.php?productid=16498
I have briefly skimmed over that before, I think it would be a great option at that price. I best not think it over too much. Plus I'm after something before it's June release.
For me I want something that is easy with air-travel, recently we did a trip and it was easy enough to take my camera tripod, camera & accessories and with the polarie that's essentially all I would need on top of what I would already be taking.
I think the other mount options would be great as a 'put in the car' portabilty option and maybe one day when I don't have to drive so far to find dark skies I would consider it more seriously.
I wonder if Peter decided to go the AT route in the end?
I bought the Pentax kit to try it out, it works just as they claim it does, it is really neat. I bought the k-r pentax DSLR and the GPS unit that has the startracking feature. You just do a 30 second calibration and you get great tracked shots from a standard tripod, it is amazing.
I will be selling it up shortly though as I have caught the solar bug, but for anyone interested in wide field, it doesn't get any more compact that just a DSLR on a tripod and nothing else to worry about! The Pentax can take just about any lens with inexpensive adapters too.
Quote:
Originally Posted by mymoon
I too am an Astrotrac user. I have to modify the astrotrac to allow me to image at 3 deg N.
But the Astrotrac fondly known locally as the Gunting (scissors) is still a lot of equipment to cart around and set up. Ok by car but if there is any air travel involved this Pentax alternative looks interesting especially if it was a combined terestrial and astrophotography trip as it would be for most trips..
I bought the Pentax kit to try it out, it works just as they claim it does, it is really neat. I bought the k-r pentax DSLR and the GPS unit that has the startracking feature. You just do a 30 second calibration and you get great tracked shots from a standard tripod, it is amazing.
I will be selling it up shortly though as I have caught the solar bug, but for anyone interested in wide field, it doesn't get any more compact that just a DSLR on a tripod and nothing else to worry about! The Pentax can take just about any lens with inexpensive adapters too.
Interesting. What was the battery life like? Ever try running it for 4 hours of photography for example?
The Pentax did always look good, hopefully more companies will follow a similar path.
That's a good question too, did it have any extra overheating issues aswell by running the GPS unit for an extended period?
I just ordered the Polarie so it's inbound from Austria as I type.
I'm considering an AstroTrac setup & was wondering if the wedge is a 'Must Have' accessory or is it just a nice extra? Does it make the imaging process easier/better? Your view would be appreciated.
I'm considering an AstroTrac setup & was wondering if the wedge is a 'Must Have' accessory or is it just a nice extra? Does it make the imaging process easier/better? Your view would be appreciated.
Cheers,
Kim
Kim,
You need one type of wedge/mount or another to put the AstroTrac at the right angle to align with the south celestial pole. The two most common options are the geared Manfrotto head or the AstroTrac made wedge. A lot of people use either of these, I haven't heard specific complaints about either.
I prefer the wedge because I think it's machined nicely, is solid, is made for the job, has fine adjustment, etc. I also think it leaves the AstroTrac more centrally balanced on the tripod to what the Manfrotto geared head does.
A lot of other people seem to use the Manfrotto geared head with success, so it can't be that bad.
The advantage of the AT is weight, the electronic package and reliability. I have agonized over buying one for several years.
EDIT: so as not to be misleading and referring to the potential of these devices in general, favouring the design over similarly priced conventional drives, including the capacity to produce very low PE values - the need for correcting the drive because of inherent geometrical characteristics is noted...
The tangent arm design is attractive because of the effective diameter of the RA gear and the very fine resolution of the worm itself. Even without a microprocessor the AT would track accurately.
EDIT: given the capacity to fabricate this kind of performance with relative ease...
I think the <5 arc seconds peak to peak (no correction) is conservative. A good tangent arm is quite capable of that.
The reason I didn't buy it, was concerns about rigidity - I think these are unwarranted providing the tripod / pier /wedge is solid enough.
A second reason was the quality of the finder scope. Which I hope is fixed, after mentioning its shortcomings (build quality) to the manufacturer. I bought one to align the Tracker - and it worked very well with some modification.
If you have a solid tripod that can be accurately leveled and stay in alignment when locking down, the rest is academic.
I think about the AT frequently, like something I should have done. Occasionally, some of the big US stores sell demo packages at a reduced price.
The reason I didn't buy it, was concerns about rigidity - I think these are unwarranted providing the tripod / pier /wedge is solid enough.
You are right that rigidity comes entirely down to the tripod it is on, and what you use to angle it at the SCP (wedge etc). The AT its self really doesn't have anything which can not be rigid, it's flat surfaces against flat surfaces. A solid tripod, the more solid the better, is a must.
Quote:
Originally Posted by rcheshire
A second reason was the quality of the finder scope. Which I hope is fixed, after mentioning its shortcomings (build quality) to the manufacturer. I bought one to align the Tracker - and it worked very well with some modification.
I wouldn't rely on the polar scope in the southern hemisphere. Bit hard to use. I don't recall them changing the design but maybe if you think so
Quote:
Originally Posted by rcheshire
I think the <5 arc seconds peak to peak (no correction) is conservative. A good tangent arm is quite capable of that.
I have never seen error in my photo's which is in RA and not a result of polar-mis-alignment. Most of the drift I see is due to atmospheric refraction because I often image with the horizon included and continuing up to a reasonable altitude (wide field).
I have never seen error in my photo's which is in RA and not a result of polar-mis-alignment. Most of the drift I see is due to atmospheric refraction because I often image with the horizon included and continuing up to a reasonable altitude (wide field).
The AT, from what I can see is very accurate with good polar alignment.
Shorter exposures and more of them perhaps to minimize refraction artifacts?
Quote:
A solid tripod, the more solid the better, is a must.
The AT, from what I can see is very accurate with good polar alignment.
Shorter exposures and more of them perhaps to minimize refraction artifacts?.
exactly that is what I do but you only learn when you have good RA tracking just how much impact refraction has This is where Registar has big advantages over DSS.
...
The tangent arm design is attractive because of the effective diameter of the RA gear and the very fine resolution of the worm itself. Even without a microprocessor the AT would track accurately.
...
I think the <5 arc seconds peak to peak (no correction) is conservative. A good tangent arm is quite capable of that.
...
The AT has an Isosceles drive, which has even less error than a tangent arm, but both still need the uC to compensate once exposures go past a few mins.
Thanks for the feedback . I already have a Manfrotto 055XPROB tripod & a 496RC2 ball head so all I need to buy is the Astrotrac & the 410 Geared head. My birthday is in three weeks so I might starting giving hints to my family!
I just placed an order on a Astrotrac. I've been contemplating one for over a year and finally decided to just bite the bullet and cough up the dough! Can't wait for it to arrive
Nice!
Who did you order it from and how much was the shipping?
I have a dark-sky trip planned soon but due to work commitments(aaargh!!) I don't get enough time in my metal-shop so my homebrew tracker doesn't look like it will be finished in time
Congrats Mohammed! If you haven't found it already, the Astrotrac Yahoo Group is a great resource of information, especially with regards to helpful tips and tricks (just search for "astrotrac yahoo" on Google).
Watch out for the polar scope holder - it's very, very easy to knock it out by accident (I do it virtually every time). Some people use rubber bands, cable ties, etc to hold it in place.
The polar scope is a bit dim (in my opinion) for finding the Sigma/Chi Octans alignment stars, but once you get them the polar alignment is pretty good. My shots from last weekend (in the Deep Space forum) were taken with a 135 mm lens x 3 mins... pixel perfect with no trailing using the polar scope to align.
that is what I do but you only learn when you have good RA tracking just how much impact refraction has 
. I already have a Manfrotto 055XPROB tripod & a 496RC2 ball head so all I need to buy is the Astrotrac & the 410 Geared head. My birthday is in three weeks so I might starting giving hints to my family!
Look forward to hearing how you go 
