Sky-Watcher Star Discovery AZ GoTo Mount - First Experiences

Introduction | Mount Combined with Different Telescope Tubes | Using a 6" Tube on the Star Discovery GoTo Mount, Adaptation to Higher Loads | Accessories | First Comments | Useful Tips from the Manuals | Preliminary Conclusions | Links

On this page, I present (and will present) my first experiences with my AZ GoTo mount (since July 2016) and a few useful tips from the manuals. It has the long name Sky-Watcher Star Discovery AZ GoTo telescope mount and thus, is an azimuthal mount. Initially, I used the Sky-Watcher Heritage 100P and P130 (no longer in my possession) telescope tubes and the Skymax-102 OTA on this mount. In the meantime, I also use "with caution" my Sky-Watcher Explorer 150 PDS Newtonian tube on this mount, although it weighs more than the "accepted" 5 kg.

The Sky-Watcher Star Discovery AZ GoTo telescope mount seems to be identical to the Orion StarSeeker IV GoTo AZ Mount (I asked a dealer for this). The latter is, however, 100 EUR more expensive and is advertised as being able to carry a maximum load of up to 6 kg.

See also: Sky-Watcher Star Discovery AZ GoTo Mount Information | Sky-Watcher Star Discovery AZ GoTo Mount - General Experiences and Thoughts | Sky-Watcher Star Discovery AZ GoTo Mount - Adaptation to Heavier Loads

 

Introduction

After my unsuccessful experiment with a Sky-Watcher Virtuoso mount, I looked for an alternative, which would also allow to automatically track sky objects. On the advice of a dealer, I decided to go for a GoTo-mount, where motor tracking is "automatically" included in the package. The recommended azimuthal mount, a Sky-Watcher Star Discovery AZ GoTo telescope mount, also can carry more weight than the Virtuoso mount. At the beginning, I was not able to use the mount a lot, but I used already it with all my three small telescope tubes: the Heritage 100P, the Skymax-102 OTA and the Heritage P130 (all from Sky-Watcher). Meanwhile (April 2017) I gave the Heritage P130 away to a friend, sold the GSO GSD680 with the help of a dealer, and acquired a Sky-Watcher Explorer 150 PDS Newtonian tube. This allows me to use my GoTo mount with all my current telescope tubes, albeit the Explorer 150 PDS-Tubus only with caution because it is heavier than the listed maximum load.

I bought some accessories to make life easier for me; this is described in the Accessories section below.

Mount from one side

Mount turned around

Ditto with external power supply (Sky-Watcher Power Tank 12 V / 7 Ah)

 

Mount Combined with Different Telescope Tubes

For more photos see page Sky-Watcher Star Discovery AZ GoTo Mount Information.

Mount with Heritage 100P Telescope Tube (and with SkyWire GoTo Control via iPad)

Heritage 100P tube on mount (overall view)

Heritage 100P tube on mount, turned around (overall view)

Heritage 100P tube on mount (with tripod); SkyWire GoTo control lying on the ground, iPad lying on the table (both hard to see...)

Comment

Because of the low magnification of the Heritage 100P, its operation on the GoTo mount is the least problematic. Small alignment errors are easy to correct, and the object you are looking for is usually at least at the edge of the field of view in the eyepiece. In addition, the alignment can be corrected with the SkyWire control and the iPad App SkySafari, if the error is not too big. In some cases, when the error was too large to be corrected directly, I managed to move the position in several steps to a correct one, but this was a little tedious at times.

If you operate the 100P on the GoTo mount, you will not see more sky objects than without, but you will find more, and sometimes you can recognize that something is actually the object you are looking for, although you would not have thought so when controlling the telescope manually.

It also makes a big difference regarding the "search speed", whether you work with or without a GoTo control. With the GoTo control, you can always browse through your object list by entering the object names into the handbox or by tapping the objects in SkySafari again and again and without any problems and thus, run through a dozen of objects over and over again. Manual operation takes, of course, much longer, especially with difficult to find objects. You have to decide on your own what ultimately is more fun. For me, this changes from time to time... In any case, when using the GoTo control it is quite reassuring to know that you have found the object you are looking for and not one directly next to it, and that it looks this way and not differently...

Mount with Skymax-102 OTA

Skymax-102 tube on mount (overall view)

Skymax-102 tube on mount, turned around (overall view)

Ditto (detail)

The position of the red dot finder is not very useful - I have to find a better solution for this

Comment

The Skymax 102 OTA (tube) is the most problematic one to use on the GoTo mount due its high magnification (planetary telescope!). Small alignment errors, which are hardly disturbing at the 100P, mean that sky objects cannot be found, especially if you switch between opposite directions. Also correcting the position via the SkySafari app is more difficult, because the deviation between the target, which one wants to access, and the one, which one actually points to, must not be too big.

Here I still need a lot of experience, so that this matter does not end up in frustration only...

Mount with Heritage P130 Telescope Tube

P130 "compact" seen from the side

P130 in "working mode", overview

Ditto, seen from the other side

Note: The Heritage P130 is no longer in my possession.

Comment

The Heritage P130 tube weighs less than 4 kg and can therefore also be used on the Star Discovery mount. This is more or less the maximum that this mount can carry (think of the weight of the eyepieces!). Most 6" tubes (150 mm, about 6 kg) seem to be too heavy for this mount (but see below).

I have used the Heritage P130 tube on the GoTo mount the least, and I also did not record my experiences with it systematically. I, however, faintly remember that I experienced some frustration due to alignment problems with this tube as well. When I used the Heritage P130 on the GoTo mount in February 2017, all worked fairly well although the alignment was not perfect. I just used the hand box since I knew the object names by heart and slightly corrected the positions in the eyepiece after an object had been accessed. Thanks to the small alignment error, this presented no problem to me.

By the way, since the Heritage P130 tube is quite top-heavy, I utilized the long prism rail and suspended the tube relatively deeply. In this case, an "overhead movement" is, of course, impossible. I do not know whether the control would try to get to the target as quickly as possible using such movements...

Nevertheless, further attempts would have been needed to be able to judge this appropriately. This is, however, not possible, since the Heritage P130 is no longer in my possession.

Mount with Explorer 150PDS Newton Tube

Comments

The Explorer 150PDS Newton tube weighs about 5.5 kg "alone" and can therefore be used on the Star Discovery mount only with caution. More on this below.

Otherwise my first experiences with this combination are very good. In addition, this is just what I can carry quickly out onto the terrace. And I have sufficient routine now, I bought the Newton tube in 2017, with preparing everything for the observations, so that everything goes ahead quite quickly and smoothly.

By the way, when using the Explorer 150PDS on the GoTo mount, a more sophisticated finder like the Telrad or the Rigel finders is not needed, and I can do with a lightweight red dot finder (needed for the alignment stars).

 

Using a 6" Tube on the Star Discovery GoTo Mount, Adaptation to Higher Loads

Since my GSO GSD 680 Dobsonian telescope had become too heavy for me, I bought a 6" Newton tube (Sky-Watcher Explorer 150PDS), and all dealers listed its weight as 5 kg. This was the reason why I bought exactly this tube, since, according to the manufacturer, the Sky-Watcher Star Discovery AZ GoTo Mount can carry a load of up to 5 kg, and all other tubes, except for carbon tubes, were listed as being heavier. Shortly after having bought the tube, I went to the Sky-Watcher Website, and there I found a weight of 6 kg for the tube (BKP 150 DS). I was really embarrassed by this, since in this case I might have bought any other tube as well. When I measured the tube's weight myself, I found a weight of 5.5 kg, just the mean of the two weights that I had found... Having made these experiences, I am unsure, which technical data I can trust in, and in which I cannot trust... With its "pure" weight of 5.5 kg, the 6" Explorer 150PDS tube is beyond the 5 kg load, which the mount can carry according to the data sheet, particularly since an eyepiece and a viewfinder have to be added to the load. Now, the question was, whether my GoTo mount would tolerate 1-2 kg more weight than listed or not and how it would behave with this overload...

In the meantime, by the way, a variant of this mount is being sold by Orion (Orion Mount StarSeeker IV SynScan GoTo), which costs 100 EUR more and is reported to be able to carry a load of up to 6 kg. When I asked my astronomy dealer about this mount, he advised me that both mounts are identical. Thus, the technical data with respect to the load that can be carries seem to be somewhat arbitrary - as I also found in other cases... A mount that would be able to carry 6 kg would, of course, have been ideal in my case, but it looks as if the price difference between the Sky-Watcher and the Orion versions of the mount is based on factors that I do not know...

So I simply tried to use the Explorer 150PDS tube on the Star Discovery mount. During the first weeks or so, the horizontal drive slipped only at the first attempt to use the mount with the 6" tube. Furthermore, I sometimes heard a slight, recurring cracking in the vertical axis from time to time. Later, I also experienced for objects close to the zenith that the motor drive had problems with moving the tube in the horizontal direction. Assisting the GoTo control by pushing the tube with the hand was useful, but it is probably better in such situations to move the tube manually to approximately the right position and then leave the fine adjustment to the GoTo control.

All in all, however, I was unsure whether this would work in the long run and asked my Astronomy dealer (Karl Kloß, Teleskop-Spezialisten) whether the mount can carry higher loads without problems. He answered this question with a fairly definitive "yes" (there is no "fairly definitive", I know...) - at least if you adapt the mount a little to heavier loads. This requires that you increase the friction somewhat, so that the motors do not coast, but also do not have too much friction so that they drain the battery. I describe my attempts in this regard on the following page:

Since my "project" ended like the famous "Hornberg shootout," that is, without any decisive result, because I was not able to further tighten the corresponding nuts. I probably have not changed anything. I will now continue to see whether my 6" tube will work satisfactorily on the GoTo mount, or whether there are any problems. But so far, the problems are still so that I could live with them, and I therefore decided to go on with using the tube on the GoTo mount*. However, if there should appear any bigger problems, I will probably not touch the control again, but send it to the dealer for adjustment, because he has much more experience than me ...

At the end of August 2017, I received a request from a Czech star friend from Prague, as to which experiences I had gained with this combination in the meantime. Because of my "observation pause"* these unfortunately had not further grown, so that I was not able to tell him any news beyond what was already on my Website. Nevertheless, this inspired me to once again try out all my three telescope tubes on the GoTo mount, this time in daylight. All three tubes ran smoothly on the mount. When using the Explorer 150PDS tube, however, I was able to observe the following: It is possible that the tube bumps against the tripod legs when it is pointing high up (this also depends on how the Vixen rail is mounted). In such a case, the tube hits an obstacle and cannot move any further. I can not rule out that this happened to me, but that I did not notice the cause of the standstill in the dark. I also do not know whether the control makes the tube point high up when it has to move the tube around for longer distances. It is probably safer and also saves energy when you move the tube with your hands close to the target position for longer distances.

Status at the beginning of September 2017: I will continue using the 6" tube on the Goto mount.

*) By the way: From June 2017 to the end of September 2017, there was / will be a longer break in my astronomy activities (due to travel, etc.), so I was not really able to get enough experience with this combination.

 

Accessories

As "major" accessories, I purchased an external, portable power supply (Sky-Watcher 12V / 7Ah Power Tank) in order not to have to buy batteries all the time, and a SkyWire device made by Southern Stars (version with Lightning connector for newer iPads and iPhones). The latter allows you to command the GoTo mount instead of using the hand box with the iPad astronomy app SkySafari Pro. For this purpose, it has to be connected to the RS232 interface of the hand box. I also acquired a crosshair eyepiece (12.5 mm focal length, illuminated) for better alignment and a LED red + white flashlight with adjustable brightness to be able to read star catalogs, etc. All in all, it soon turned out that the mount was not the only investment necessary to enter the world of GoTo...

Sky-Watcher Rechargeable Power Tank (12 V/7 Ah). The 12 V cable for charging via car battery and for supplying the GoTo mount is stored in a timber (with caption); initially, I thought it would be missing (in the instructions it is listed, but not where it is ...)

Southern Stars SkyWire Serial Accessory

Ditto connected to iPad and hand box

Ditto, detail

Package content, batteries already installed in the illumination device

Illumination device with batteries and brightness control / on/off switch screwed in

Double cross hairs, illuminated

Flashlight with box, side view

On the top you can see the red-white switch (left) and the control for setting brightness and turning the light on or off (center)

Red light

Some Comments

Power Tank

After two days or so of observing, the first set of batteries (8 batteries) was exhausted. Thus, it soon became clear to me that I needed some power source other than batteries for the GoTo mount. If I would use the mount only at home, a 15 V power supply would be a potential solution, but since I plan to also use the mount outside in the landscape, a portable solution was required. The car battery might be used, but I may not use always use the car in such cases. I therefore decided to acquire a portable Sky-Watcher Power Tank (the 7 Ah version). Overall, it seems quite OK to me, but since it has a lead battery, charge times are rather long. The device is also quite heavy, thus carrying the equipment on your back on the way to an observation location may not be a good idea...

SkyWire Serial Accessory

I used this device only for a few times up to now. It allows you to control the mount with an iPad and the SkySafari software application. This is much more intuitive than using the mount's hand control and also reduces handling errors, as I found out (I have some difficulties with the handbox...). Another good point is that you can correct the mount's positioning to a certain degree, that is, as long as the target is not too far off in the viewfinder and on the sky map in SkySafari from the real target. In this case, I was able to iteratively correct or adapt the mounts target location as to the true target location so that I did not need to perform a new two-star alignment.

It is, of course, somewhat inconvenient that the SkyWire device needs a cable connection to the iPad, especially since you can stumble easily over cables in the dark... Wireless is definitely more comfortable, but it was too expensive for me.

Illuminated Cross Hair Eyepiece

For two-star alignment you have to center two stars in the eyepiece, one after he other. But it is somewhat difficult for me, to recognize when a star is exactly at the center of an eyepiece. I therefore acquired an illuminated cross hair eyepiece - illuminated because you cannot see the cross hair in the dark. My eyepiece has, however, a focal length of only 12.5 mm, which is rather short and already leads to fairly high magnifications for two of my telescope tubes. This makes aligning the mount hard, particularly for the P130 and 150PDS, and much more so for the Skymax-102, where the eyepiece already leads to a magnification of about 100 x (50 x for the P130, 60 x for the 150PDS). After some frustrating evenings, I resorted to using my 32 mm eyepiece, which allows for slower movements of the stars in the eyepiece. But I will have to give the cross hair eyepiece further tries...

LED red + white Flashlight

When searching for deep sky objects, you need to have more equipment as usual at your disposal and you also need to have sky maps and books available for finding out where to look (a little less with a GoTo mount, though...). Nonetheless, a red flashlight is a useful addition, particularly if you can also switch to white light when needed. The only gripe that I have with this flashlight is that I find the red light too low at times. But I read that you can already spoil your dark adaptation with red light that is too strong...

 

First Comments

No Built-in Circular Level, no Possibility of Alignment

While similar Sky-Watcher GoTo mounts are provided with a built-in circular level, neither the tripod nor the mount itself has any such alignment aid, although this would be very helpful. One can certainly argue about the usefulness of such a circular level, but it should at least be possible to place an external circular or other level on the device, in order to be able to align it horizontally. However, in the design of the mount, there are no planar surfaces on which the level might be placed. For the tripod, this would be possible, but because the mount must be screwed onto the tripod, I would never be sure that such an alignment will be maintained after the addition of the mount. In addition, I mostly leave the mount on the tripod for convenience reasons. Perhaps, the accessory tray (eyepiece holder) might be used for alignment, but I would not be sure that it indeed reflects the correct alignment...

The control unit of the mount does not have any planar surfaces...

...on which you might place a level

The base is completely uneven...

You might place a level on the tripod head - but only before you screw the control unit on it...

 

...or perhaps on the accessory tray?

 

It does not look quite even, though

Here, the level is not fully OK...

...but here it is. So which one is correct?

 

Useful Tips from the Manuals

Some Things to Observe when Doing the Alignment..

Eyepiece for the Alignment

Sky-Watcher notes that is is important to put the alignment stars at the center (or the same spot) in the field of view of the telescope's eyepiece and thus, recommends to either use

Actually, my cross-hair eyepiece (see below) also has a shorter focal length (12.5 mm), which makes it difficult for me to come up with a good alignment at telescopes with longer focal lengths, because the alignment stars move so fast. I therefore prefer to use eyepieces with longer focal lengths for the alignment process.

Sky-Watcher also suggest to defocus the telescope, because the larger, defocused star shape (a disk...) is easier to center than a sharp star.

Avoiding Mechanical Backslash

Since all mounts have more or less mechanical backslash on both axes, Sky-Watcher recommends the following:

Rules for Choosing an Alignment Star

Sky-Watcher recommends:

Can I Use Automatic Tracking only (that is, not GoTo)?

The Star Discovery mount has an "easy tracking mode" for doing just this. The steps to enable this mode are as follows:

  1. First, the mount must be set up at a proper "Home" position:
    1. Level the mount base
    2. Level the telescope tube and point it towards the true north (not magnetic north).
  2. Connect the handbox to the mount (if it was not yet connected).
  3. Turn on the power to the mount and start the initialization process of the SynScan handbox.
  4. In the last step of the initialization procedure ("Begin Alignment?"), cancel the mount alignment by selecting "2".

Now you can directly point the scope to the desired target using the handbox, and the mount will track the target automatically. If you want to track the moon or the sun, you have to set the respective tracking speed in the "Tracking" menu (otherwise the sidereal rate is being used). For observing terrestrial targets, you can also stop tracking in the "Tracking" menu.

 

Preliminary Conclusions

First attempts at using the GoTo mount with my different telescope tubes were encouraging on the one hand, but on the other hand, they were sometimes very frustrating. Sometimes, I quickly managed to align the mount well (using two stars), but sometimes not at all. In part, these differences can be attributed to the difference in magnification that can be achieved with the tubes - the Heritage 100P is the most benign in this respect because of its low focal length (and thus, magnification). In part, it may also have been a matter of how far apart the observed objects were in the sky. Let's see whether I can become better in this matter. First experiences in 2017 with different telescope tubes look quite promising.

Nevertheless, I have already been able to find and observe some deep sky objects with the GoTo mount, which were, of course, primarily "classics" (M 13, M 92, M 31, ...) that are easy to observe. I intend to describe my "deep sky experiences of a beginner" on separate pages, perhaps they may be useful for other beginners. Here are already first observations made in 2016 and 2017:

All in all, the GoTo mount has opened the way to the world of deep sky objects for me, also because I finally acquired the appropriate literature. As my experience shows, without this and a certain preparation for the observation objects, it just does not seem to work. Thus, in 2016 I was able to observe more such objects than in my whole life before. In addition, these experiences helped me to find larger deep sky objects without technology, but with literature, using the compact and thus, easily transportable Heritage 100P on my vacations!

I would not want to return the GoTo control any more. Nevertheless, I operate, particularly the 100P, but also the other two telescopes, manually much more often, especially when I want to watch something quickly and without a lot of preparation. I do not know, whether a point-to-solution would be good enough for me as well. I would probably miss automatic tracking. This one is not overly accurate, but it is sufficient to quickly show someone else sky objects at higher magnifications. In this case, the sky objects move very fast out of the field of view if there is no automatic tracking.

 

Links

 

An den Anfang   Homepage  

gerd (at) waloszek (dot) de

About me
made by walodesign on a mac!
11.12.2017