mount

“Unitec SWAT-310” – Great ! The Legendary Equatorial Mount (2)

East and West, ancient and modern, We’ll review the “Legendary Equatorial Mount” ! This article is about Unitec’s EQ mount “SWAT-310”.

This SWAT-310 equatorial mount has been playing a great role as my main equatorial mount since last year. Simple operation, outstanding stability and reliability, and versatile expandability. It is one of the most powerful portable equatorial mount in Japan.

Now, let’s take a look at the details.

Unitec SWAT-310
https://www.unitec.jp.net/products.htm#SW31

※Unfortunately, this product is only available in Japan at the moment, but I think that it is a good product that can be widely used in mid-latitude countries.

Great ! The Legend of “SWAT-310″(1)

Great! Uniaxial Drive Equatorial Mount

Photographing with Vixen’s FL55SS fluorite optical tube. The high tracking accuracy of the SWAT equatorial mount makes it ideal for shooting with short-focus refractor tubes and telephoto lenses.

The SWAT equatorial mount is a 1-axis driven portable equatorial mount. A simple configuration that is divided into only the red meridian drive for “tracking diurnal motion. Therefore, there is no need for any troublesome installation or operation other than polar axis alignment. Just turn the power on and the tracking starts immediately.

Shooting with Sigma 105mm F1.4Art. With this focal length, the image is a solid point image even if you don’t think about it.

In addition, its high rigidity and tracking accuracy make it ideal for “no-guide” shooting (*). Once the lens is mounted and pointed at the target, all you have to do is release the shutter.

(*)It is also possible to operate with a single-axis autoguide because it is equipped with an autoguide terminal. I’ve never done it ^^^;;

Cassiopeia seated in 10 minutes of total exposure. EOS6D SIGMA105mmF1.4Art F2.0 1 min. x 12 shots at the foot of Mt. Hakusan SWAT-310

With the SWAT equatorial mount, you don’t have to think about it anymore if your focal length is up to 200mm or so. This is the benefit of the concept of “achieving the highest level of rigidity and accuracy instead of being solely single-axis driven. Challenging the limits of your equipment is also fun to play with, but on the other hand, there’s another way to enjoy it is to use your excess power to your advantage.

Great! Guide system for long-focus tubes

The camera is equipped with the FOT85 tri-element apo lens barrel. Although the declination fork was overloaded in terms of strength, there was plenty of room for declination tracking.

The SWAT-310 equatorial mount has a nominal tracking accuracy of ±7 arc seconds and a mounting weight of 10kg. If you “push to the limit”, you can mount an equipment with a focal length of 600mm class, 5 to 7kg class(*). I can’t “think nothing”, but the SWAT equatorial mount has enough potential to operate a long-focus system.

(*) In most cases, the bottleneck will not be the SWAT itself, but the tripod or deciduous axis system.

FOT85(fl=560mm, F6.6), EOS6D ISO6400 1min x 70 images, SWAT-310 Equatorial Mount, Imazu, Itoshima

This is the NGC 4565 taken by the above system. The yield was not 100% due to some deflection in the fork area, but even at 1 minute exposure, the stars are a blur in the post-composite image. This is an example of the SWAT equatorial mount’s high tracking accuracy being demonstrated.

Great! Handy Eye Vision System

Gazing at the moon from the balcony. The optical tube is a BORG76 achromatic. Take a commemorative photo with a smart phone attached^^

The SWAT equatorial mount is not only for photography but also for the equatorial mount. Even if you just point the polar axis to the north by eye measurement, the tracking accuracy is enough for easy observing. There is an overwhelming difference in convenience between “manual tracking” and “automatic tracking” for easy observing at high magnification.

It’s about 5km away including a tripod, so I put it out on the balcony if the weather is good and enjoy watching it. This is going to increase the utilization rate.

This one is equipped with an 85mm refractor apo lens barrel, which is much larger than this one and still has enough weight for the SWAT itself. If you set the polar axis well, once you introduce the object, it will track you all the time (it’s a matter of course). Such a surprise? The SWAT equatorial mount is also interesting because you can use it. How about “Visual Viewing with a Portable Equatorial Mount“?

Features of the SWAT equatorial mount

Let’s take a look at the features of SWAT equatorial mount again.

Unitech’s first SWAT equatorial mount, the SWAT-200, was released in 2012. Since then, it has been improved over and over again, and the model we’re going to introduce here, SWAT-310, is the latest model that was released in April 2018.

Unitec SWAT-310
https://www.unitec.jp.net/products.htm#SW31

“Single Axis” driven equatorial mount

A side-by-side view of the Vixen-SXP equatorial mount, a medium-sized German equatorial mount that supports two-axis automatic installation. The difference of this magnitude is the division of “one axis”.

SWAT” stands for “Single Way Axis Tracker“. This Single Way is an important concept.

In order to realize “two-axis auto-guide” or “automatic introduction”, two rotary axes (longitude and latitude) and a drive mechanism are required. Instead of focusing on a single axis, we have increased the accuracy and rigidity of that single axis to the limit. That is what the SWAT equatorial mount is all about.

Although it is described as a “portable equatorial mount” on the manufacturer’s website, the rigidity, accuracy, and load-bearing capacity are not inferior to those of a medium-sized full-fledged equatorial mount, and in fact, if you take out only “one axis”, it may be superior.

Our policy of “Dealing with what we can do with a single axis” brings an incomparable sense of usability and reliability the moment it matches the user’s purpose of use. I can take a picture just by shooting the shutter toward the target without thinking about it. There is such a sense of trust in SWAT.

High rigidity, high accuracy, ±7 arc seconds of tracking error

SWAT-310 equatorial mount. It’s heavy when I say heavy, but it’s light when you consider that this stand can carry 10 kg.

The chassis of SWAT-310 is made of machined aluminum alloy(*) to ensure very high rigidity. It’s so heavy (2.4kg) that you might think it’s a balance weight when you pick it up, but it’s so stable that there are no moving parts except for the polar axis.

(*)The first generation SWAT-200 was die-cast, but after SWAT-300, it was machined from aluminum.

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Quoted from the manufacturer’s HP. https://www.unitec.jp.net/products.htm#SW31

The equatorial axis assembled in a box-shaped housing is driven by a worm wheel, which is rather larger than a medium-sized German equatorial mount with a diameter of 106 mm and 210 teeth, but the tracking error is claimed to be “±7 arc seconds.

(*)Actually, I haven’t strictly measured the tracking error of the actual SWAT-310 that I use (the actual measurement data from the manufacturer will be described later), but as long as I see the result of shooting at 500mm class and the verification cases of other users, I feel it is safe to judge that all these criteria are satisfied. All individuals are tested for tracking accuracy before shipment.

The tracking accuracy of ±7 arc seconds can be said to be very high. The V-spec with the PEC function, which will be described later, will have even higher accuracy. This accuracy is even with a long focal length of about 600mm, it is possible to shoot without autoguide if the exposure time is shortened(*).

(*)210 teeth is 6.9 minutes per worm gear revolution, and assuming the tracking error is a sine wave of ±7 arc seconds, the tracking error is about 100 seconds, with a maximum of 7 arc seconds. At a focal length of 600mm, 10μ on the sensor is 2.8 arc seconds, and 100*2.8/7=40 seconds exposure.

The secret of the SWAT equatorial mount’s high accuracy lies in the large diameter worm wheel, the optimal choice of materials for the worm wheel and gears, the wrapping process, and the aging process. I won’t go into the details of that in this paper, but please refer to the links below.

SWAT Blog Columns
http://unitec.cocolog-nifty.com/blog/cat23833278/index.html

Heavy equipment can be mounted

The Canon EF400mm f/2.8LII is mounted. It weighs 4.7kg including the camera. The balance weight is the stock optional 2.2kg and is balanced in this condition. Three 150mm-long weight shafts are used, and the weight of all equipment mounted on the SWAT body is almost 9kg, which is close to the nominal 10kg loadable weight

SWAT-310 can be used for heavy equipment. Due to the close proximity of the rigid housing and the equatorial head, the center of gravity does not shift significantly from the center of the tripod, even when heavy loads are mounted.

The nominal carrying weight is 10kg, but I felt that it is quite capable of carrying this weight in actual use. Rather, the strength of the entire system other than the main body of the SWAT equatorial mount, such as the tripod, the dovetail, the L-shaped plate, and the equatorial axis, becomes a neck.

The weight of the SWAT-310 is limited to 10kg because it is equipped with the “red longitudinal interlocking scale ring”, which will be described later, but the SWAT-350, which is a higher model, can be loaded up to 15kg. In terms of strength and accuracy, it can be thought of as “a product cut out of the red longitudinal axis only from a medium-sized equatorial mount”.

Highly versatile pole-axle frame head (turntable)

35mm interval, M6 and M8 threaded holes are cut. There is a 1/4″ male thread in the center to which a camera head can be attached. The diameter of the turntable is actually a measured 77mm.

The polar axis head of SWAT equatorial mount is called “turntable” and is used by attaching parts such as camera head and various dovetail. This “turntable” has 35mm spaced M8 and M6 screw holes and 1/4″ male screws, making it highly versatile. The diameter of the joint surface of the turntable is also large (77mm) so that various parts can be securely mounted.

It’s just an impression, but in a nutshell, “From here on out, you can do as you please“. It has a strong sense of presence, but does not assert itself. It’s like “Let me handle the equinox drive.

Higher accuracy , V-spec system

This is a live-action image of SWAT-310 V-spec (beta) used by the author. That’s two turns of worm gear. The tracking error of this individual is within ±3.8 arc seconds under the eastern load. Courtesy of Unitech.

The SWAT equatorial mount boasts a high tracking accuracy of ±7 arc seconds, but a version with even higher accuracy called “V-spec” is currently under development. The difference is, without a doubt, PEC(*) built-in.

(*) Abbreviation for Periodic Error Correction. A mechanism that remembers the amount of error on an individual basis and drives the worm gear so that the error is cancelled out when it is driven, based on the fact that most tracking errors are periodic errors that occur during the worm gear rotation period.

This will further improve the tracking accuracy of SWAT-310. I heard that the product specification and warranty accuracy have not been fixed yet, but the current feeling is that “When the load direction is not specified at the start-up, it is about ±5 to 6 arc seconds even if the load is unbalanced east-west, and when the load direction is specified east-west, it is about ±4 to 5 arc seconds”.

When the tracking error on the red longitude axis becomes small to this level, other factors of the tracking error become apparent. There are various factors that contribute to guide errors, such as deflection, sinking, and atmospheric refraction due to changes in the center of gravity of the equipment, and these must be eliminated one by one.

I would like to supplement the “specification of the load direction at startup” in detail.

The diagram above shows a schematic of the engagement of the worm wheel gear. If there is a small amount of clearance between the wheels and gears, the engagement surfaces will be different depending on whether the equatorial mount is balanced east or west. For this reason, the behavior of the SWAT equatorial mount’s piliodic motion is almost always different depending on the east-west loading direction.

For this reason, the PEC data built into the V-spec has different values for the east load and west load, and you can specify which PEC information to use by pressing the button at startup(*). The tracking error in this case is about ±4 to 5 arc seconds (provisional value in the beta version).

(*)Note that if the load specification at startup and the actual balance direction are reversed, the tracking accuracy will be worse.

In case of “Normal mode”, which does not specify the load direction, the correction will be “balanced” to correspond to either unbalanced load. In this case, the tracking error is slightly larger (±5 to 6 arc seconds) (provisional value in the beta version).

It is the author’s opinion, including speculation, that “different behavior of periodic error depending on the loading direction” may be a common event to some extent. There are a number of factors that can cause differences in behavior, such as the difference in accuracy between the two surfaces at the time of gear cutting, the direction of load during gear lapping (grinding in an interlocking state to reduce error), and the degree of adjustment of the final gear clearance. In any case, I would like to applaud Unitek’s stance in actually measuring the tracking accuracy of its products and implementing an optimal compensation mechanism.

How to measure your equatorial mount’s periodic error is featured on Unitech’s blog. It’s a relatively simple method, so if you’re interested, why not give it a try?

Example of the SWAT equatorial mount system configuration

Minimum configuration

The most unbalanced shot is when shooting the zenith in the vertical position. The camera head must be firmly fixed to the turntable, especially when the camera is on the east side, because the torque is applied in the direction of the camera head loosening.

This is the simplest configuration using a SWAT equatorial mount. The SWAT equatorial mount is attached to a camera tripod and the camera is mounted on a turntable with a free head.

In this configuration, the balance between east and west is disturbed except in south-central time, but the driving and holding power of SWAT-310 has a lot of room, so the guide is much more stable compared to a small portable equatorial mount.

However, heavy equipment and long focus/long guides have their limitations. In that case, the German or forked configuration, which will be described later, should be used to adjust the balance between east and west.

The bottom of the SWAT-310. The top two peepholes are also M6 threaded holes, which allow you to mount a polar axis telescope stay.

The easiest way to connect the SWAT body to the tripod is to use the 3/8′ thick screw cut into the bottom of the SWAT body. If it is a thick screw, it can be fixed quite firmly even if it is fixed at one point.

Of course, you can use a 1/4<->3/8 adapter and mount it with a thin thread, but for heavier equipment, a thicker thread is recommended for this connection.

Another option would be to attach an Arca Swiss plate to the two M6 threaded holes on the bottom of the body and connect it to an Arca Clamp tripod. I used this method until I installed the “Polar Axis Fine Motion Unit” described below in the spring of this year.

Fine Drive Unit for Polar Axis

Installation of the optional polar microtremor unit. The main body can be attached and detached with a “taper catcher / taper adapter” with one touch. The total weight of the parts is 900g.
SWAT and Polar Axis Microtremor Unit
https://www.unitec.jp.net/option.htm#KBU

That said, it takes a lot of practice to get the polar axis exactly right in the smallest configuration. After all, The polar axis fine movement unit is never more than a certain .

The structure assumes a horizontal surface on both the bottom and top. The arc-shaped “goniostage” has an operating range of ±8° (this is an older model, so the details are slightly different in the latest version). The bottom right is the “tapered adapter (thick screw type)”

I think the genuine SWAT polar axis fine movement unit is one of the best among the many similar products for portable equatorial mount in terms of variety of connection methods, robustness and smoothness of fine movement. The “gonio system”, a mechanism in which arc-shaped members rub against each other, allows for stable support of even heavy equipment.

The bottom connection is a 3/8″ thick screw. The top tapered catcher can be easily removed with two M6 screws, and when removed, 35 mm spaced M6/M8 holes appear. This can also be used to replace general-purpose parts such as the Arca Clamp.

Double head base

SWAT Double Head Base</a
https://www.unitec.jp.net/option.htm#DUB

With the optional “Double Head Base”, two cameras can be mounted or assembled in a German-style configuration. The double head base has a “C” shaped plate with two knurled M6 screws for easy mounting on a turntable and two 1/4″ screws with crossed handles for mounting a camera head or two other heads.

On the left is an example with two cameras attached. The double head base can be slid into the turntable to prevent it from losing its balance to some extent if there is no extreme weight difference(*).

(*) However, it is a little difficult to slide it with the camera attached. The plate of the double head base is compatible with the Vixen Arigatas, so it is easier to use the Arimizo Catcher (described later) on the turntable for balance adjustment.

Inside is an example of a German-style configuration with optional weight shafts and balance weights. The double head base has M6 screw holes on both sides and the weight axis is screwed into the holes.

On the right is an example of using the Teresco Workshop’s PET Bottle Adapter. This configuration is perfectly balanced.

The double head base is relatively affordable at 9,000 yen (suggested retail price) and highly versatile, making it one of the most promising options.

Alca Swiss specification and fork configuration

With the Arca Clamp on your turntable, you’ll be able to fit a variety of Arca Swiss compatible parts.

SWAT Arca Swiss Catcher
https://www.unitec.jp.net/option.htm#ASC

In the image above, the optional “Arca Swiss Catcher” has been installed. Compared to standard camera clamps, the M6 clamps have the following advantages: they can be clamped at two points with M6 screws, have a wide width of 65mm and high clamping force, and have a long handle so that they do not interfere with the turntable. The suggested retail price is 5,500 yen (excluding tax).

The lens is a Sigma 105mm F1.4Art, which is well-balanced and can be aimed at the entire sky. No blind spots, Ina Bauer at will.
SWAT Simple Fork Unit DX.
https://www.unitec.jp.net/option.htm#SFDX

There are a lot of ALCA-SWISS compatible parts available in the world, and the combinations are endless. A variety of applications are possible with a single idea. The image above is an example of my favorite fork system with the Simple Fork Unit DX (stock option).

The “Simple Fork Unit DX” was fitted with a panoramic head, and through the general-purpose Arca Plate Clamp, we were able to assemble a all-sky blind angle-less system.

However, when using ALCA Swiss parts, careful consideration must be given to the strength of the individual parts. In the case of aluminum alloys, even if the wall thickness is about 7-8mm, long plates may be deflected by the loading of heavy equipment(*).

(*)Unitech’s HP states “up to a focal length of about 200mm”. It’s not a general statement, but for cantilevered fork operations, it’s best to keep it within the “no flow exposure time” range.

Vixen style dovetail and German configuration

The arimizo catcher is attached to the turntable and the double head base is attached.
SWAT Arimizo Catcher
https://www.unitec.jp.net/option.htm#AC

The “Arimizo Catcher” is an optional part that can be used to attach a Vixen compatible Arigatas to the turntable. The optional “Double Head Base” is also a Vixen standard dovetail, so it can be attached to the dovetail catcher as shown in the image above. Although the range of movement is not long, it can be slid to some extent to adjust the balance.

An example of a German-style configuration using a “rotating unit. The optical tube is a RedCat51.
SWAT and rotating unit.
https://www.unitec.jp.net/option.htm#KU

The above configuration is an example of a German equatorial mount with SWAT optional parts. For the declination axis, we used a “rotating unit” of Fine movement and scale ring support.

With a weight of 900g and a suggested retail price of 34,000 yen (excluding tax), this is also a full-fledged product.

The “rotating unit” is a pretty serious declination axis. It is so powerful that only the equatorial axis of a medium-sized equatorial mount is cut out. Since the head has M6/M8 screws with 35mm spacing, a variety of astronomical equipment can be mounted on it. The center is a 1/4″ screw. A tapered catcher is used on the red longitudinal side.

 Tripod for SWAT-310

Unitech does not sell any special tripods for the SWAT equatorial mount. It is assumed that the user will choose a tripod with a 1/4 thin thread or 3/8 thick thread, which is the standard for general camera tripods.

If you already have a sturdy camera tripod, you can use it, but some of the tripods sold as “camera tripods” have a little less holding power for astrophotography, so if you’re buying a new tripod, I recommend a tripod from an astronomical manufacturer in terms of strength and cost performance.

The SWAT-310 equatorial mount on K-ASTEC’s PTP-C22 carbon tripod. Before the introduction of the Polar Axis Fine Drive Unit. This configuration is substituted by the “tripod adjuster” under the north leg.

The author mainly uses K-ASTEC’s PTP-C22 carbon tripod. This pipe is 40mm in diameter and very solid, and matches well with the SWAT-310. There are other 40mm pipe diameter carbon tripods in the same class from companies like Cytron Japan and more blue. The actual selling price is about 45,000 yen to 65,000 yen.

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Quoted from Unitech’s HP: https://www.unitec.jp.net/option.htm#VTA
SWAT Vixen Tripod Adapter.
https://www.unitec.jp.net/option.htm#VTA

If you’re looking for a cospa, I recommend the Vixen AP Tripod (APP-TL130, price 19,980 yen including tax) on the left of the image above. Although slightly inferior to carbon tripods in terms of rigidity and weight, it is better than camera tripods because of its solid head.

Because the AP tripod can not be connected as it is, an adapter is needed. The image above right shows the Vixen Tripod Adapter, an optional part of the SWAT. The center screw is a thick 3/8 thread, so you can be sure of its strength. It’s also thin, so it doesn’t stand too tall when used with a micromanipulation head, and it’s recommended when using a 45mm diameter tripod such as an AP tripod or Vixen SX tripod.

Tripod adapters are also available from Vixen. The Head Adapter (5,184 yen including direct sales tax) is engraved with steps for both 45mm and 60mm diameters at the bottom, and can be fixed to a tripod with the M10 screw with a horn.

The 1/4 inch screw is a little short and a little unsettling, but it can be used with older standard GP tripods, which is an advantage.

Above left is the installation on Vixen’s ASG-CB90 carbon/aluminum hybrid tripod. This tripod has a reinforced non-slip stay compared to the AP tripod, and the narrower pipe is reinforced with aluminum inside. This tripod is very solid because it is also recommended by AXJ equatorial mount.

On the right is the Sky-Watcher’s EQ5GOTO Equatorial Mounted Tripod. The 44mm diameter stainless steel pipe is heavy, but it’s solid. I’m going to use this when I’m loading heavy equipment.

Other tripod adapters for both 45/60mm are available from Kasai Trading. It’s a little heavy, but this one has a 3/8 thick thread.

Great ! The Legend of SWAT-310 (1)

Great! for overseas astro trip

Shooting with twin configurations of 300mm f/2.8 and 105mm f/1.4. The weight of the equipment is about 6kg, so there is still plenty of room for this.

The main body weight of SWAT-310 equatorial mount is 2.4kg, which is very heavy for a “portable equatorial mount”, but when you consider the ratio of the weight of the system and the weight of the mountable weight, the performance is incomparable. This is the expedition abroad that comes to life.

The above system is the SWAT system that I used in my expedition to Western Australia. It carries two heavy equipment (a Canon sunnipa and a Sigma 105mm f1.4Art). The SWAT equatorial mount can be used safely even with such heavy equipment.

For the sake of weight reduction, options such as the heavy “Polar Axis Fine Drive Unit” and “Rotary Unit (Declination with Fine Drive)” have been omitted. It is also possible to change the composition of the parts according to the purpose Only the SWAT Equatorial Mount can be changed flexibly.

EF300mmF2.8L α7S ISO6400 30 seconds x 7 photos SWAT-310 at WADDI Firms, Western Australia

The Large Magellanic Cloud, taken with a 300mm telephoto lens, is a simple, uniaxially driven, auto-guided system that requires no computer and only a mobile USB battery to power it.

SMA 105mmF1.4Art F2.0 EOS6D 4min x 13 shots with STC Astro DUO filter at SWAT-310 Western Australia Wad Firms

This shot of the Large Magellanic Cloud with the 105mm f/1.4Art is a one-shot narrow-band shot of the Large Magellanic Cloud, and thanks to the SWAT equatorial mount’s high-precision tracking capabilities, it can handle long focal lengths and long exposure times.

Great! Scale ring

The scale ring of SWAT-310. In order to be introduced by the scale ring, a scale ring is also required on the declination axis. This image uses an optional “rotating unit”. The panoramic head of the “Simple Fork Unit DX” is also engraved with a declination scale.

One of the major features of SWAT-310 is that it is equipped with a scale that is linked to the red longitude drive. Once the equinox coordinates are aligned with the bright object, there is no need to adjust the time angle at each introduction because the scale ring rotates in sidereal time (*).

(*)There are many products, such as the SWAT-350, which is a higher-end model, that simply rotates the scale ring of the red line freely. I think it is safe to say that the scale ring is useless for practical use unless it is interlocked with the red longitude drive. In order to achieve this specification, the structure of the red longitudinal shaft, worm wheel, and scale ring had to be greatly modified from the SWAT-350, and the load-bearing capacity of the SWAT-310 was reduced to 10 kg.

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The “scale ring” is very useful for an equatorial mount that does not have an automatic introduction mechanism. The scale notch is 2°, which is small enough compared to the 5° angle of view of a 500mm telephoto lens, and as long as you are photographing with SWAT, you can easily introduce the object with the scale ring alone(*).

(*)When you use a telephoto lens over 300mm in length, it becomes difficult to use only the viewfinder of the camera depending on the subject (e.g., the Markarian Chain in Virgo, the sub-ring Nebula in Gemini, IC 1396, etc.). The hardest ever for the author was Sh2-126 in the constellation Lyra^^^;

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SMAF 105mmF1.4Art F2 EOS6D 1 minute x 15 photos, 9 frames mosaic SWAT-310 at Koishiwara, Fukuoka

With the SWAT-310, mosaic photography can be done using only the scale. The image above is a mosaic of nine frames with 15° increments in the direction of declination and 10° in the direction of longitude using a 105mm lens. The error in the seam is less than 1° square.

Great! Galactic Coordinate Mosaic System

The “Galactic Coordinate Mosaic System” is made with ALCA Swiss parts, taking advantage of the SWAT equatorial mount’s expandability. The panoramic shooting system was mounted on a unit tilted at about 28°. The “Galactic Polar Axis Alignment (*)” uses a scale ring. It’s a bit of a rough installation, but it’s been practical enough.

(*)It should be noted that in the southern hemisphere, the scale ring of the declination axis is opposite to the northern hemisphere, so the scale will not be correct as it is.

SIGMA 105mmF1.4Art F2 4-minute x 80-frame mosaic by SWAT-310 at wadi Firms, Western Australia

Result from the above system, 80 frame mosaic composite of images with a 4-minute exposure per frame. The silver equivalent covers 1/3 of the sky from Capricorn to Capricorn. The rest of the film will be filmed in the future.

How to use it (Tips)

To make better use of the SWAT equatorial mount. Here’s a summary of what I’ve noticed so far from using it, including details, weaknesses and their completions.

Polar scope

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Quoted from Unitech’s HP: https://www.unitec.jp.net/option.htm#pf-l
SWAT Polar Axis Telescope PF-L
https://www.unitec.jp.net/option.htm#pf-l

Two types of optional polar axis telescopes are available. One is an optical polar axis telescope. Currently, Vixen’s Polar Axis Telescope PF-L(*) and the dedicated hardware are sold. Use the M6 screw holes on the back of the unit as shown in the image above. The four threaded holes allow you to choose a position that will not interfere with your equipment.

(*)The Vixen PF-L has been improved to PF-LII, which has a lower magnification than the old model, but if you use the application “PF-L Assist”, you can adjust the polar axis using only the North Star in the old model without any problem.

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SWAT and Electronic Polar Axis Telescope “Pole Master SWAT”
https://www.unitec.jp.net/option.htm#PMS

Another option is to use the Pole Master SWAT, an electronic polar axis telescope. This product is a set of the Pole Master and the adapter, so if you already have a Pole Master, you can buy the adapter alone and use it.

Standby Function

The MODE LED is “green/non-blinking” to indicate stellar tracking. The LED is recessed so it does not get in the way even in a dark place.

The V-spec SWAT equatorial mount has a “standby” function. The camera is driven at a high speed (16x speed) for about 1 minute immediately after turning on the power to stabilize the tracking accuracy in a short time(*).

(*)In my experience, many equatorial goggles are not stable at “just after turning on the power” or “just after changing the posture”.

In fact, the SWAT equatorial mount has been adjusted to leave a small amount of backlash in the worm-foil gear (*).

(*) “Tightening (crimping) the gear joint” can eliminate (reduce) backlash, but on the contrary, it prevents the gear from rotating stably at a constant speed.

In the SWAT equatorial mount before V-spec, which does not have a standby function, it is recommended to turn on the power to stabilize the operation of the SWAT equatorial mount some time before the start of shooting in order to reduce the instability of the initial state of drive start caused by the slight backlash(*).

(*) That’s also why there’s no “power switch” in the main body.

Generally, it is said that “It is better to make the east side slightly heavier” for equatorial mount, and this is true for SWAT equatorial mount. If the east and west are completely balanced, it will take a long time to stabilize the operation and the tracking accuracy will be adversely affected. It’s important to “weight the east side slightly(*)“.

(*)In the southern hemisphere, the opposite is true for the western load.

Power supply

(middle) AA battery box included: left) USB 5V-9V boost cable, right: USB cable

The SWAT equatorial mount is powered by a common “5.5mm O.D., 2.1mm I.D., Center Plus” cable. The recommended voltage is 6 to 12V, and a battery box with 6 AA batteries (9V) is included.

I’ve been using a 5V USB mobile battery, but it can be underpowered and is not guaranteed to work (*). It is recommended to use a cable with a converter that boosts 5V to 9V like the image above .

(*)When driving at 16x speed, there are problems with equipment weight and large imbalances, such as in winter when the battery voltage drops. The lower the voltage, the smaller the driving torque will be.

Auto Guide

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Quoted from Unitech’s HP: https://www.unitec.jp.net/option.htm#rc-01
SWAT Remote Controller RC01
https://www.unitec.jp.net/option.htm#rc-01

I basically don’t use either autoguide or electronic telescope in SWAT, and all the articles up to this point have been written on the premise of “no guide” (no touch guide) shooting.

To perform autoguiding, connect the optional “Remote Controller RC01” to the SWAT main unit and use the ST-4 compatible guide cable terminal on the controller side.

Support for high and low latitude regions

The SWAT equatorial mount has an edge structure that is tilted by about 35°, and the polar axes are aligned at 35°N latitude when the body is horizontal.

The polar axis fine movement unit tilted at maximum angle. It is almost the same as in Japan.

If you use it in high and low latitudes, you can tilt it in some way, but the range of movement of the optional polar axis fine movement unit is ±8°. Assuming a maximum tilt of 10° on the tripod side, this means a latitude range of 17° to 53°. If you want to go further beyond this range, you will need to do something like sandwiching an edge-shaped part.

The SWAT also has 1/4″ and 3/8″ screw holes on the back. This hole was originally set horizontally to be used as a turntable for time-lapse photography, but you can also use this position in polar regions from 70° to 90° latitude(*).

(*)It is unclear how the polar region works at low temperatures^^;;; the polar axis telescope seems to be hard to look at, but the starry sky at the polar region is one of the things I would like to see at least once.

scale ring in the southern hemisphere

Scale ring is very useful for mosaic photography in the introduction of an object, but when using it in the southern hemisphere, it is necessary to be careful. In the southern hemisphere, the direction of the equinox is opposite. As it is, the direction of the increase in the equinoxes will be reversed.

Southern hemisphere specification scale ring

When I was about to introduce an object in the southern hemisphere, I noticed that the lens barrel was facing the day after tomorrow^^ After I returned to Japan, I consulted with Unitech, and they made a PDF file with the scale facing the opposite direction. If you print a sticker and attach it to the scale ring, it becomes a southern hemisphere specification. I would like to try it on my next expedition.

Storage case

 

The entire system weighs 11.5kg, which is the minimum required, and can be stored like this in a large camera bag.

There is no such thing as a “storage case” as an optional part of the SWAT system. As flexible as the system is, it is safe to say that there is no such thing as a universal storage system. It is necessary to improve the transportation and storage environment with appropriate measures.

The above image is an example of the minimum system configuration. the SWAT equatorial mount is more compact than “Sky memo RS” or “JILVA-170”, and the storage is not bad, and if it is a large camera bag, it can be stored as shown in the above image by adjusting the partition(*).

(*)It would be great if the rectangular enclosure could be separated from the circular equatorial axis, but this is an impossible order^^

This is a full set configuration. The SWAT main body and a set of parts are stored in a plastic case with a cardboard partition. This case contains the whole set of everything. The total weight of the above is about 10kg.

What we want for “SWAT-310”

I have been using the SWAT-310 equatorial mount for more than a year. As I was writing this article, I thought about it again, and to be honest, I have nothing more to ask for in a SWAT equatorial mount(*). This is actually a great thing, isn’t it?
<It’s not just a simple fork unit and a double head base, but also a thicker and sturdier version of a simple fork unit and a double head base, or a polar axis telescope that costs more than a quarter of the price.

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However… there is only one caveat. The same thing as the popularly called “BORG swamp” applies. SWAT swamp. If you add up the price of the parts that are piled up, how much is it going to cost? No, let’s not even think about it. It’s not that there isn’t a

The SWAT-310 is reasonably priced at a suggested retail price of 115,000 (excluding tax), but there is almost nothing to be done with just the main body. This is the one thing you need to keep in mind. The basic idea is to organize what I want to do and put all the necessary parts in order, but I’m afraid that I’ll have to invest (eventually?) more than enough for the body. I think it’s better to think that they occur (*).

(*)More than half of the SWAT swamp is an “arigatha-arimizo-tripod swamp. In that sense, I think it’s a “shallow swamp” unlike BORG^^^

Top secret material obtained

What direction will SWAT take in the future? According to a reliable source^^, a new part related to “equatorial axis” is under development, which makes use of the high accuracy and load-bearing capacity of SWAT itself. Oh, and I’m looking forward to new products that will surprise you^^.

JILVA-170 and TOAST equatorial mount

Finally, there are two products that cannot be avoided when talking about the SWAT equatorial mount in the context of “The Greatest Legend”. They are JILVA-170 and TP-2(TOAST).

Although the product concepts and business styles are slightly different, these three products are all in the same position as “ultra-high-precision photographic equatorial mount with a single axis drive” and, aside from their history up to the present day, their origins are also the same.

The JILVA-170 and SWAT-310, the JILVA-170’s worm wheel is a whopping 170mm in size, and the difference is staggering. As a result, it is bulky.

I have never used TP-2, but I am an active user of JILVA-170. I would like to discuss the JILVA-170 in “The Legend of the Strongest Equatorial Mount” in the future.

conclusion

Thanks for reading this far!!

The SWAT equatorial mount was created by focusing on “single axis drive”. Of course, there is a direction to make full use of various electronic and information technologies, such as automatic introduction and IoT, but the SWAT equatorial mount, which is thorough in its basic functions to the point of being rugged, is sure to play an active role for a long time to come.

What kind of system will I set up with the SWAT Equatorial Mount and what kind of astronomical life will I spend? It’s all up to you to decide. I think this degree of freedom is the greatest attraction of the SWAT equatorial mount.

“Great equatorial mounts” gets astronomy fans fired up! So I’ll see you next time!

The SWAT-310 Equatorial Frame was interviewed by TV stations in Fukuoka, and the SWAT Equatorial Frame appeared as a blunt instrument in the drama “Sidekick” ^^

 


  • This article was prepared by Astronomical Reflections at its own expense and discretion, with equipment loaned by Unitec Corporation. All editorial responsibility rests with the Astronomical Reflections editorial department.
  • Please contact the manufacturer or distributor for product purchases or inquiries.
  • Astoronomial Reflexions assumes no responsibility whatsoever for any events that occur as a result of this article.
  • Images not otherwise noted are original, with all rights reserved by Astoronomial Reflexions.
  • The product specifications and prices in this article are correct at the time of writing (Aug 2019).
  • The version of the app Polarie U used in the article is 1.2.
  • We used DeepL for translation. Click here to read the original article in Japanese.