Sky-Watcher Explorer 150PDS Information (6" Newton)

Motivation | Look | Basic Data | Visited Sky Objects | Photo Attempts | First Conclusions | Links

On this page I provide some information about my 6" Sky-Watcher Explorer-150PDS Newtonian tube (150 mm/750 mm, f/5; purchased at the beginning of April 2017). By the way, "PDS" means "designed for Photography" and "Dual-Speed 10:1 ratio focuser."

About the Mount...

At the beginning, I used the Sky-Watcher Explorer 150PDS tube on the Dobsonian base of the Sky-Watcher Heritage P130, although this combination was a bit shaky and wobbly. Since I no longer own the P130, I now use the 150PDS only on the Sky-Watcher Star Discovery AZ GoTo mount . This mount can carry a maximum load of 5 kg (the identical Orion StarSeeker IV mount is advertised as being able to carry a maximum load of 6 kg). The 6" tube was advertised at online dealers as weighing about 5 kg. After the purchase, however, I found a tube weight of even 6 kg on the Sky-Watcher Website. My own measurements revealed a weight of about 5.5 kg - plus viewfinder and eyepiece. The whole affair definitely seems to be a borderline case, and only experience will show, whether this is indeed a workable combination in the long run.

See here my experiences that I made so far with "overloading the mount with a 6" Newton tube."

 

Motivation

Why did I buy the Sky-Watcher Explorer 150PDS tube and for what purpose? I bought this tube as a replacement for my 8" Dobsonian telescope GSO GSD 680, which is a very fine telescope but became too heavy for me. I therefore replaced the GSD680 with the Explorer 150PS tube and sold it later.

Thus, the Explorer 150PDS is currently the terminal station on a longer journey from 10" via 8" to finally a modest 6" aperture! Usually, however, such journeys go in the opposite direction, that is, in the direction of larger apertures...

When buying the 6" tube, I also hoped that it can be used on the Sky-Watcher Star Discovery AZ GoTo mount as the maximum possible option. Thus, all my telescope tubes would then be also usable on my GoTo mount. As written above, this mount can carry a maximum load of 5 kg. My own measurements revealed a weight of about 5.5 kg - plus viewfinder and eyepiece. I will see, whether this will indeed work in the long run.

Since there was only a small gap between the Explorer 150PDS tube and the Heritage P130, I parted with the latter and gave it away to a friend in April 2017.

 

Look

Unpacking

Outer package

Ditto

Ditto

Ditto

Opened package

Ditto

Styrofoam

Ditto

One of the Styrofoam pieces was damaged...

Package content

Content of accessories box

Ditto

Accessories

Tube with protective paper, oblique rear view

Ditto, oblique front view

Ditto, seen from above

Ditto, no paper, side view; note the Vixen-style prism rail

Ditto, oblique view from above

Detail: Focuser with 1:10 dual speed transmission

Looking into the tube

Ditto, here you can see the mark on the primary mirror

Accessories:

6 x 30 finder, 28 mm eyepiece (2"), 2" extension ring for visual observations, tools

Box weights and size:

NW = 7 kg, GW = 9 kg

80 cm x 39 cm x 34 cm
79 cm x 40 cm x 35.5 cm (my own measurement)

 

Explorer PDS150 Telescope Tube on Heritage P130 Rockerbox

Note: I do no longer own the Heritage P130 (and thus, its Dobsonian mount)

Explorer PDS150 Telescope Tube on Sky-Watcher Star Discovery AZ GoTo Mount

 

Basic Data for Sky-Watcher Newton Telescope Explorer 150PDS (in Comparison)

Telescope
Meade
Sky-Watcher Skymax/Heritage/Explorer
GSO Omegon
10" ETX 90EC 102 127 76 100P 114P P130 150PDS GSD 680 PS 72/432
Optical Design Newton
(Parabolic)
Maksutov-Cassegrain Maksutov-Cassegrain Maksutov-Cassegrain Newton (Spherical) Newton (Parabolic) Newton
(Parabolic)
Newton (Parabolic) Newton (Parabolic) Newton (Parabolic) Refractor
Primary Mirror Diameter 254 mm 96 mm (90 mm) 102 mm 127 mm 76 mm (3") 100 mm (4") 114 mm (4.5") 130 mm (5") 150 mm (6") 200 mm (8") 72 mm
Focal Length, Focal Ratio 1270 mm
f/5
1250 mm
f/13.8
1300 mm
f/12.7
1500 mm
f/11.8
300 mm
f/3.95
400 mm
f/4
500 mm
f/4.38
650 mm
f/5
750 mm
f/5
1200 mm
f/6
432 mm
f/6
Resolving Power (arc secs) 0.45" 1.3" 1.15" 0.91" 1.51" 1.15" 1.01" 0.9" 0.77" 0.58" 1.61" **
Limiting Visual Stellar Magnitude ca. 14.5 mag 11.7 mag 12.7 mag 13.2 mag 11.2 mag 11.8 mag 12.1 mag 13.3 mag 12.7 mag 14.5 mag 11.1 mag **
Light Gathering Power 1316.7 165.3 212.3 329.2 117.9 204.1 265.2 344.9 459.2 816.3 105.8 **
Maximum Practical Visual Power ca. 600 x 325 x 204 x 254 x ca. 100 x (152 x) 150 x (200 x) 170 x (228 x) ca. 195/220 x (260 x) ca. 225 x (300 x) ca. 300 x (400 x) 144 x
Optical Tube Dimensions (diam. x length) 35 cm x 119 cm 10.4 cm x 27.9 cm 11.6 cm x 27 cm 14.4 x 33 cm n.a. 11.5 cm x 37 cm* n.a. Tube collapsed < 37 cm
(14.5") long
18.2 cm x 69 cm
18 cm x 68 cm*
23 cm x 115 cm L: 39.5 cm with extended dew cap
Net Weight Basis 12.2 kg n.a. --- --- n.a. 1.3 kg* 1.6 kg 3.1 kg* -- 11.2 kg n.a.
Net Weight Optical Tube 17.2 kg n.a. 1.9 kg 3.4 kg n.a. 1.2 kg* 3.7 kg 3.25 kg* 5.0/6.0 kg
5.5 kg*
9.5 kg n.a.
Net Weight Complete 3.5 kg 1.75 kg 2.5*/2.8 kg 5.3 kg < 6.5 kg or 14 lbs. appr. 21 kg 2.06 kg

Dark Blue: Telescopes that I still own; italic and dark red: telescopes that I owned; black: for comparison; *) own measurement; **) corrected values

 

Visited Sky Objects

So far, I have visited (and documented...) the following sky objects with the Sky-Watcher Explorer PDS150:

 

Photo Attempts

First Moon Photos with the Camera Held to the Eyepiece

The following photos of the moon were taken at the beginning of April 2017 (April 1, 2, and 3; on April 3, it was half moon). They were taken using the 1:50 method, that is, with the camera held to the eyepiece. In this case, I used my Ricoh GR (28 mm equivalent) at ISO 1600 and underexposed to avoid flare.

I used a 16 mm and a 7 mm UWA eyepiece. With the latter, I was able to see the full moon, but not to "catch" it.

April 1, 2017

    

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

7 mm eyepiece (approx. 107 x) - 2000 pixels - 3200 pixels

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

April 2, 2017

7 mm eyepiece (approx. 107 x) - 2000 pixels version - SW

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version - SW

April 3, 2017 (Half Moon)

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

7 mm eyepiece (approx. 107 x) - 2000 pixels - 3200 pixels

 

7 mm eyepiece, section (approx. 107 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

Comparison of the Days

         

April 1, 2017

 

April 2, 2017

  April 3, 2017 (half moon)

April 6, 2017

    

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 107 x) - 2000 pixels

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

 

16 mm eyepiece (approx. 47 x) - 2000 pixels version

Photos with Atik Infinity

Photos taken with Sky-Watcher Explorer 150PDS (December 31, 2017), 600 x 600 section with 1:1 pixels in the large version:

         

M 15 (Pegasus), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

         

M 27 (Dumbbell Nebula in Vulpecula), unprocessed

 

Ditto, post-processed

 

Ditto, differently post-processed

         

M 56 (Lyra), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

         

M 57 (Ring Nebula in Lyra), unprocessed

 

Ditto, post-processed

 

Ditto, differently post-processed

         

M 71 (Sagitta), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

Photos taken with Sky-Watcher Explorer 150PDS (February 12, 2018), 600 x 600 section with 1:1 pixels in the large version:

         

M 35 (Gemini), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

         

M 36 (Auriga), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

         

M 37 (Auriga), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

         

M 38 (Auriga), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

         

M 42 (Orion), unprocessed

 

Ditto, post-processed

 

Ditto, post-processed and sharpened

 

First Conclusions

Since I own the Sky-Watcher Tube Explorer 150PDS only for nearly a year, it is too early for any definitive conclusions (see below). My first impressions are, however, very positive. I particularly like the dual speed focuser, which makes focusing much easier for me. And this scope is much easier to handle than the bulkier and heavier 8" GSO GSD 680 telescope. While the GSD 680 pushes me to the limits with its weight, I can carry and handle the Explorer PDS150 still fairly easily. At the beginning, however, I had difficulties with attaching the Vixen rail to the base - I needed three hands for this, or help from another person. In the meantime, however, I can do this on my own.

Sky-Watcher Tube Explorer 150PDS on the Sky-Watcher Star Discovery AZ GoTo Mount

In the meantime I have observed a number of sky objects with the 150PDS and used it mostly on the Sky-Watcher Star Discovery AZ GoTo mount, on the one hand to gain experience with this combination (see here my experiences that I made so far with "overloading the mount with a 6" Newton tube"), but also because I did not have a suitable Dobsonian base anymore. The base of the Heritage P130 would (mostly) have worked for this tube, but I had given this telescope away in April 2017... In the course of time, however, I have gained more and more confidence in this "overloaded combination" and worry now less about the durability of the mount. At the beginning of February 2018, I even purchased a Celestron StarSense AutoAlign module for Sky-Watcher (mounts) to automate the alignment and save myself from having to "creep" under the viewfinder.

Further experiences with the Sky-Watcher Star Discovery AZ GoTo Mount can be found on page Sky-Watcher Star Discovery AZ GoTo Mount - First Experiences.

Comparisons

I did a first quick & dirty comparison with the 8 "GSD 680 Dobsonian telescope using M 42/43 and M 35 as targets (about April 6, 2017). Since my eyepieces do not allow me to use both telescopes at exactly the same magnification, such a comparison is problematic, though. Overall and not surprising, the view in the GDS 680 seemed to be brighter and having more contrast to me, but the Explorer PDS150 was not bad either. Although I was decided to sell the GSD 680, because it was too heavy for me, this comparison made me a little bit uncertain again about this matter. But in the end, I parted from the GSD 680, as nice as the telescope was, and gave it to a dealer on sale or return to sell it for me (in the meantime, it was sold).

A few days later (April 9, 2017), I did a comparison with the 5" Heritage P130 Dobsonian telescope. Again, I was not able to operate the telescopes in parallel at exactly the same magnification. Overall and hardly surprising, the view was somewhat better in the PDS150 than in the P130, although I would not say that the differences were huge. On the whole, however, I could not see any advantages in owning both telescopes, although the P130 is certainly better suited to traveling. Therefore, I gave the P130 away to a friend in mid-April 2017.

Astrophotography

The Sky-Watcher Explorer 150PDS tube already shows its suitability for astrophotography in its name: "P" means "designed for astrophotography" (that is, it has sufficient backfocus) and "DS" means "Dual Speed," which refers to a 2" Crayford focuser with 1:10 dual speed transmission and the ability to carry up to 2 kg. Accordingly, I got into focus with the Atik Inifinity camera at this tube without any problems, and the first results are quite OK, even though I am sure that much better results are possible. See the examples above.

Astrophotography with a camera held or attached to the eyepiece (1:50-method, projection method) is of course also possible (moon, planets, sun with solar filter), as shown in the examples above. However, holding the camera with your hand to the eyepiece often results in vignetting and local blurring. Photography of deep sky objects is not possible this way because of the long exposure times that are required.

 

Links

 

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17.11.2018