I completely disagree on several levels. Field rotation is the apparent rotation of objects in the scope’s field of view, either through the eyepiece or on your camera’s sensor. I also purchased the optional shroud to keep stray light from entering the bucket. Typically, when buying a Dob, you are trading the accuracy and precision of an equatorial mount for the larger aperture (mirror size). But, when Orion sets in the west, his dog has yet to set and is now above Orion in the sky. ... 5.0 out of 5 stars Great value in a 16-inch Go-To Dobsonian … My typical video processing: convert to AVI (if needed), process video in AutoStakkert (stack video frames), and pull out details using wavelet layers in RegiStax. Whichever method you use, the accuracy seems to be the same and when you have found the target, wherever you’re pointing in the sky, the motors automatically continue to follow it. Where field rotation is a problem is during exposures. Generally speaking, the maximum exposure time to minimize and overcome the effects of field rotation is 30 seconds. Try this one day. On a night of good seeing, we found the optics of the scope gave us well-contrasted views of Jupiter and the Moon. Overall, the XX16g’s innovative design features enhance the appeal of owning a large Dobsonian and we expect to see several at this year’s UK star parties. For DSO processing, I use Nebulosity to review and toss out bad subs. Image 1 shows the effects of field rotation. A lighter, less overly robust head would have eliminated this task and saved further weight. Heaven forbid we actually clip off the horse’s head due to field rotation! Like many of you, my love of this hobby began at an early age. But most importantly, develop your own! Simply put, field rotation causes objects to form arcs much like star trails. A fair amount of the assembly time was spent attaching the nine 1kg counterweights, which help balance the head unit that houses the secondary mirror. The first we eluded to already, keep your exposures to 30 seconds or less. During exposures, the field rotation effects are being captured by the sensor! First, lots of subs can help counter the shorter exposure times. Many folks out there (I call these folks the “naysayers”), including formal and professional sites, will tell you Dobsonian scopes cannot do astrophotography. However, your guide star needs to be as close to your target as possible. Additionally, a greater number of subs will substantially assist with noise reduction. And, needless to say, M42 is jaw-dropping. But it can also be broken down into separate parts that will fit in an average car, allowing you to take it away from the city lights and make the most of that big aperture. Overall this unit is thoughtfully designed for the practical amateur astronomer. A refractor telescope of similar size and image quality would be much more expensive. I then use PixInsight for debayering, dark/flat/bias calibration, image registration, image integration (stacking), and image post processing. You can tell if one or both axes are off when reviewing frames (subs, frames, lights, are all synonymous) prior to processing. Read honest and unbiased product reviews from our users. I am not aware of any requirements that AP photos be on the order of something we’d see from HST. It fills the entire field of view and many of its colors are easily seen. I have transported it a number of times with zero issues. They’re simple to setup, easy to operate and provide excellent value for the aperture size. And, of course, the sizeable aperture gave great views of deep-sky objects, including the Orion Nebula with its bat-like wings and the sweeping chains of stars of open cluster M35. near the edges of the field of view would be rejected and only data near the center of rotation of each frame would survive the pixel rejection process. For a given dollar amount, Dobs have a greater light collecting ability. Dobs since then have morphed quite a bit; truss tubes, outstanding optics, GoTo and tracking capabilities, etc. If I hold my iPhone to the eyepiece of a small alt/az scope I bought at a garage sale last week and snap a picture then it’s done - I’ve just entered the world of AP and the word “can’t” is instantly removed from my vocabulary! If, out of 100 subs, 10 frames have noise at coordinate x,y but the other 90 do not, your stacking software will average the values of all the pixels at location x,y. The ground board is quite bulky, and slightly larger and heavier than perhaps it could have been. There are lots of features near the edges of the field that I would not want to lose! Astrophotography with a Dobsonian brings its own set of unique challenges. The Sky-Watcher 16 Inch Dobsonian Telescope was built to near perfection as the structural and mechanical components of the OTA display carefully crafted construction and excellent stability. With excellent light grasp, point-and-view ease of use, convenient portability, and a low price, the XT6 Classic Dobsonian reflector should be on the top of any beginner’s telescope wish-list. It will simply keep the guide star “frozen” in the frame and everything else will appear to rotate around it. Find helpful customer reviews and review ratings for Orion 8968 SkyQuest XX16g GoTo Truss Tube Dobsonian Telescope at Amazon.com. The XX16g’s innovative design features enhance the appeal of owning a large Dobsonian. Pictures allow us to carry our hobby with us and share its joys with others. First, what is AP? Another challenge to Dobsonian AP with is tracking. Also the physical construction of the unit is … Their performance envelope will expand with trial and error just like ours did. Field rotation also results in a loss of image data near the edges of the field. Keep at it! More subs will produce a better result. There are some systems out there that rotate the camera/focuser in the direction of and at the same rate of the field rotation.