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  • Astrotrac TT320X-AG First Light Report & Review

    Astrotrac First Light Review Introduction

    I received my Astrotrac for testing a few days ago but could not use it since I could not find my Manfrotto plate for my 840RC2 head so I had to order another one. See below several parts are required otherwise you will not be able to use this unit - one is a non-standard part and is very hard to find.

    In the Box

    What the Astrotrac with autoguiding comes with:

    1. 2 power adaptors: one 8X AA battery and one 12V car/battery adaptor
    2. The Astrotrac unit
    3. a manual
    4. an autoguider cable that seems to have a small plug at one end and may not be useful to connect to common autoguider ports due to the smaller plug size.

    The manual (version 1.0) that I received did not include any information about autoguiding for some reason despite the new unit having an autoguiding port and coming with the cable above.

    Despite my friend paying about $580 USD plus shipping and sending it to me, I still needed the following to actually start use it:

    • Tripod (photographic) cost of my Manfrotto tripod about $200-300 with Manfrotto head - luckily I have one for photography
    • An extra tripod head - luckily I had an extra as I purchased one a while back for the Pentax we have. Can be purchased for $40
    • The most valuable piece which is almost impossible to find and clearly should be included in the Astrotrac is a tripod plate bolt to 3/8" 16 tpi thread adaptor - luckily I had one included with the Chinese made extra tripod head above. Without this you will have problems to even use it properly as the connections between the tripod heads and Astrotrac cannot be made. Priceless.

    At $580 the unit does not have a polar scope which is sold separately. The manual mainly mentions Wide field lenses will have no problem with rough alignment, unfortunately I found not to be the case. Furthermore, my manual mainly described polar alignment with the polar scope which was not included and is sold separately.

    I did not bother to receive this polar scope unit, as there are many reports of the polar scope falling off the unit and requiring mods to keep it on. At this price after receiving the unit, there should be a small green laser or polar scope included as part of the unit or at the minimum some basic polar alignment tools for angles and compass built on the unit.

    The Astrotrac Unit

    I was able to setup the unit for southern hemisphere tracking by flipping the arm. After plugging in the 12V adapter, the unit lit up red on the buttons. With power and tracking there is a green light that flashes on and off but is not bothersome - it is a nice touch but I found it could be better placed or more obvious - I noticed it after some time checking on the unit. The unit is very quiet after initial power up, although there is some high pitched sounds and louder gear movements on initial start up.

    With the arms collapsed in the unit is very portable and can easily fit with many other items in a large backpack or small suitcase.

    Initial Results

    With rough polar alignment as the manual mentions, I tried various exposures unguided at 50mm from 30s to 2:30s. In the live view with magnification, there was clear trailing of the stars even at 30s which was disappointing.

    I will be posting crops of my photos as well as photos of the unboxing, Astrotrac unit and accessories included.

    Initial Conclusions

    The unit has potential so far as a portable astrophotography rig for shorter unguided exposures, but due to its high cost, and lack of a polar scope (despite its main focus being astrophotography) I would recommend looking at other alternatives as it can approach more than $1000 for someone to buy all the items together. With the recommended Manfrotto gear heads (x2), polar scope, tripod and Astrotrac one is looking at near $1500.

    Obviously one would still require a camera and remote shutter release or programmable shutter to use the unit properly for astrophotography however I did not include this in the cost above as this additional cost for camera is assumed with any astrophotography rig.

    Without accurate polar alignment the unit cannot function as an accurate astrophotography tracker so one must find a method to polar align accurately in order to get the best use out of the system. I will be retesting the unit with a green laser or some sort of finder, and posting the results in a long term review.

    Furthermore, if autoguiding is needed for anything more than 30 second exposures, then the main purpose of the unit (portability) will cause its function to be severely diminished with the addition of guidescope, guider, and cabling/laptop.

    Initial comparison to the Merlin Multi-mount which is an alt-az which I modified with Goto demonstrated similar trailing patterns at more than 1 minute, and in fact I was able to get non-trailing stars with 1 minute exposures with the same lens when I did 2 star alignment on nearby stars.
    This article was originally published in forum thread: Astrotrac TT320X-AG First Light Review started by admin View original post
    Comments 9 Comments
    1. jerryTheC's Avatar
      jerryTheC -
      Surprised they didn't include the adapter - but at least for Manfrotto, you can get quick release plates with 3/8" screws (not 100% sure if that applies to the smaller plates, but it definitely does for the bigger ones), so you're not completely stuffed if you can't find an adapter - maybe they're assuming that if you're buying an extra head, you'll get a 3/8" one.

      It's always surprised me that they don't do a scope style polar attachment to go between the tripod and the drive - it's not like it's a complicated design, and a scope style fitting would be a lot easier to do fine adjustments on than most tripod heads.

      But not including a 3/8 to 1/4" adapter seems almost certain to generate at least some annoyed customers...
    1. bfonseka's Avatar
      bfonseka -
      I bought the "holiday deal" which included the tripod, geared head, ball head, polar scope - basically everything you need to get started. Because of this, I had no issue with the 3/8" thread size. The polar scope is a waste of time from where I tried it out in Sydney as for me South was the absolute worst for LP. My polar alignment was easy and fairly accurate purely by using the compass and inclinometer method (Android phone) - I remember you commenting on the pic on my first light thread.
      Astrotrac - first light

      This was greatly improved on the second night with installing the guide scope in place of the imaging camera and doing a quick drift alignment. Took me under 10 minutes and then I shot a 2-minute unguided sub with a 85mm lens (left 3 stops ND on to deliberately lenghten the exposure for testing). I have posted my 100% crop - which has only the tiniest hint of trailing. I only drift aligned for azimuth as I couldnt see the east or west horizons from where I trialled it out (my back yard).
      To make a connection to the Autoguider, all I used is a RJ45 joiner which places like Jaycar sell. You insert the astrotrac guide cable on one side and the ST4 cable from the guide camera on the other. Worked a treat. I am just waiting on some JST connectors from an eBay seller to make a special guide cable to go all the way from my Lodestar (JST connector) to the Astrotrac (8P8C RJ45) without the intervening joiner. For the less electronically inclined - the joiner is very easy and it does work.
      I am still waiting for a chance to take it out to a dark sky site to give it a run. The weather has so far not cooperated with the phases of the moon and my work schedule.
      The specified unguided peak to peak RA error is only around 5 arc seconds, so for anything under about 200mm there should be no improvement seen with autoguiding. There is only a RA drive - so you cannot correct in the DEC axis for polar alignment error.
      The cannot do a polar scope down the RA axis as that is where the scope attaches to the tripod. That is the clever part of the design which removes the need for a counterweight.
    1. admin's Avatar
      admin -
      Thanks for your feedback, I agree its very unprofessional and extremely frustrating. If I can get the part with a $40 Chinese tripod head, it should be included along with a polar scope in the Astrotrac.

      At the moment the Multimount ($180 with 80mm Mak, tracking mount, accessories) is doing circles around the Astrotrac.

      It is equivalently 5 times cheaper (mount cost only), and with the Goto upgrade allows similar exposures unguided if not better 10 x1 minute frames in Sydney City:

      more here:
      Wide Field Rig Testing Goto Modded Multi Function Merlin Mount & Canon DSLR
    1. bfonseka's Avatar
      bfonseka -
      I have attached 3 quick shots of my Astrotrac setup showing how I have it setup for PHD drift alignment followed by the imaging setup with a 5D Mk3 and 70-200 F2.8L IS.
      The guidescope is a Orion Miniguider. I have a Borg helical focuser in place of an extension tube which makes the scope much easier to focus - the focuser being way more expensive than the guidescope! The detailed shot shows the RJ45 joiner used to connect the autoguider cables together.
      I consider the geared head absolutely essential for repeatable accuracy in polar alignment. PHD drift is the fastest and easiest and most accurate method I can figure out for us in southern hemisphere for polar alignment. I do not intend to use autoguiding as if it is anywhere near the specified accuracy for tracking (5 arc seconds peak to peak), I will not need guiding at all.
      The manual sent with the device is the old version for the non AG version of the mount - which is just not good enough for a brilliantly engineered and built device like this. That said, just the straight through RJ45 8p8c joiner worked as I expected.
      The pics were off my point and shoot - I just placed the mount in my converted garage photo studio.
    1. jerryTheC's Avatar
      jerryTheC -
      Hmm - have you ever tried one of the Kenko sky memos? The Astrotrac should be more accurate according to the specs, but the polar finder on the sky memo is brilliant and makes aligning dead easy. Not a cheap beastie - probably getting close to a goto mount - but nicely engineered, and about twice as accurate as the Polarie (which isn't too surprising given the cost and design)

      The other thing I've wondered about with the Astrotrac is whether the very short threaded bit for attaching the polar finder causes any accuracy problems - I expect it's fine, it just doesn't look that way compared to big thick equatorial mount bodies
    1. bfonseka's Avatar
      bfonseka -
      The Astrotrac polar finder is held magnetically - its not threaded at all - hence all the complaints about it falling off - which indeed it does. When you live in a light polluted city in the southern hemisphere, you need quite a serious polar scope (probably about 50mm or bigger aperture) to manage to find Sigma Octantis. I have never ever seen Sigma Octantis (our very dim pole star) from Sydney and positively identified it with even 7x50 binoculars let alone a puny little polarscope. It truly is a real pain to find unlike polaris. My little guidescope on the quick release plate setup worked very well to help me line up with a PHD drift alignment. The key was having the geared head - I would not give myself much of a chance without it.
      The cost of the Astrotrac mount is minimal compared to even my guide scope assembly as shown in the pic. That is a Starlight Xpress Lodestar ($650) on a Orion mini guidescope and a Borg helical focuser. The guide camera on its own is more expensive than the Astrotrac! So I consider the astrotrac a low cost mount in my scheme of things.
    1. bfonseka's Avatar
      bfonseka -
      My Canon 200mm F2.8L lens arrived today. I had a quick try tonight with the 5D Mk3 + 200mm F2.8 and the results were very encouraging. I used my PHD drift alignment method with the Lodestar and Orion mini for polar alignment. I didn't push the system too far as I have to catch a flight at 0630 tomorrow.
      These images are from a single 30 second exposure of the Eta Carina region at ISO 400. Have have used the photoshop blur layer method for gradient and vignetting removal. The aperture of the lens was reduced to 52mm using a 72-67mm and 67-52mm step rings to avoid the aperture blades putting diffraction spikes on stars. I think this image is at approximately F3.8 (FL=200mm, aperture = 52mm) This method introduces some amount of vignetting (removed in processing), but I think it looks nicer than 8 diffraction spikes on bright stars.
      The main image is a full frame and I have added a pixel-for-pixel 100% crop to show the tracking - unguided. I still have no way of guiding whilst imaging, but I am very happy that this is now a 100% workable and portable system. I do not intend using a guider with the system as this is my "wide field" setup. Apart from the polar alignment stage with PHD graphing, I do not need a laptop - just the camera on a timer release is adequate. The mount + tripod + ball and geared heads weigh a total of 5.5kg, so its extremely portable. The camera + lens combination was about 2kg.
      So I think my astrotrac system is now finally ready for trips to dark sky sites.
      If the skies are clear next week I will update this thread again with how tracking is on longer exposures and how the lens performs fully open at F2.8
    1. OleCuss's Avatar
      OleCuss -
      Any updates on satisfaction or dissatisfaction with the AstroTrac? I'm kind of getting interested in trying to get one and I really don't know of a better alternative for use with a DSLR. The current idea for me would be to get the mount and put a Canon EOS 60Da on it with a few different lenses.

      The lack of need to mess with counterweights is an advantage - and the capacity is good.

      They are selling a complete package, and since I have no really good camera tripods and heads I would be inclined to go with that.

      But I figure I could also get a CGEM DX for about the same as buying a complete AstroTrac system so I might dump the AstroTrac idea entirely since I really don't do all that much travel.
    1. j.gardavsky's Avatar
      j.gardavsky -
      Hello all,

      I have purchased the AstroTrack from OptCorp as refurbished used item, a couple of years ago. Even if totally overpriced, the AT is a fairly good solution for grab-and-go AP equipment.

      As above, I am missing an included fine adjustable head for the polar alignment. The included polar scope is a sort of 'curse', regarding both the comfort of its use, and the electrics inside. When replacing the expensive 'quartz watch' battery (don't understand, why they do not take a recharchaeble AAA, or alike) in dark, I have managed to break one of the connecting wires. Friendly people at the nearby university have welded it together again.

      The reported tests have shown, that the AT tracks without visible trailing up to 20 minutes exposure time at the focal length of 180mm. My tests have shown, that with my polar alignment skills, the stars are still pin points up to 5 minutes at 300mm focal length, see the attached pic, which shows Delta Cassiopeiae at lower left, and the M103 and NGC 663 clusters from lower right to upper left. The pic has been taken with the Zeiss Sonnar f/4 300mm on the Kodak E200 slide film, and scanned, without any sophisticated post-processing.


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