Weight of the William Optics telescopes

[Thingo]

Hi all, after another few days of research I've narrowed in on a few telescopes from William Optics and I'm looking at a few different ones, namely the doublets: Zenithstar 103, Zenithstar 126 and potentially the triplet FLT-132.

The weight of these telescopes is....surprising. Can someone explain to me how this is possible and if it's at all accurate? Initially I was pretty interested in the 126, but with that weight I feel it gets too complicated to carry out in the park. Mount and counter weights would amount to ~20kg with the 126 while it would be around 15kg with the 103 for instance. 

Zenithstar 103, Tube: 4.36 kg

Zenithstar 126, Tube with Rings and Dovetail Weight：9.94kg

FLT-132, Tube: 9 kg

The 126 is more than twice as much as the 103! 

[Louis D]

Yep, tube weights go up rapidly in refractors.  You could look into fiberglass tubes to keep down the weight somewhat.  The length also goes up rapidly because longer focal ratios have to be used at larger apertures to keep false color at acceptable levels.  False color gets worse at larger apertures given a constant focal ratio and constant optical formula.  Mirrors don't have this issue, thus all the squat, giant f/3-ish Dobs with aggressive coma correction.

Here's a chart showing the relationship between refractor aperture and focal ratio and the level of correction for a given optical formula.  ED and APO variations are similar, but the colors start out more left shifted.

You can keep weight down by going with an alt-az mount to avoid counter weights if you're just doing visual work.

[Thingo]

That's interesting to see! And good point about the alt az mount. I'll keep that in mind. 

However, the point I'm trying to make with my post is that it's really odd that the triplet 132 can weigh less than the doublet 126 and that I question whether it's really correct. 

 

And by the way, I have contacted WO about this, but they don't respond...

Edited March 20, 2020 by Thingo

[Louis D]

20 pounds seems about right for a 132 triplet.  It's the 126 doublet that seems heavy at 22 pounds.  I'd expect it to be more in the 15 to 16 pound range.  It is slightly longer and has a bigger dovetail plate as well as a carrying handle, though.  I'd probably get the 125mm TS-Optics/Altair Astro FPL-53 doublet instead if weight and price are issues.

[joe aguiar]

I recommended he get the skywatcher 120mm ed it's only 5.1 kg or 11 lbs and  only 6mm less then the 126 wo

The sw ed120 comes with aluminium case 2 inch dielectric diagonal ep finder and bracket.  Only 2 downfall is dewcap not sliding and the focuser may or may not need to be upgraded

But the wo is ota only so if u were to buy case ep finder and bracket and diagonal that would equal at least the cost of the upgrade focuser 

What Louis says is correct too cause a doublet has to be longer to have the same color correction of a smaller triplet, so the extra length will add some weight but the triplet has extra lens but smaller tube so I guess both weights cancel each other out.

U would think tho still the 132 triplet should still be more than a doublet a d not less or same weight 

Joejaguar 

[joe aguiar]

I still prefer eq mount over alt az so I can polar align and easier tracking  but u decide if that's more import or less weight 

Joejaguar 

Edited March 20, 2020 by joe aguiar

[Stu]

8 hours ago, Thingo said:

Hi all, after another few days of research I've narrowed in on a few telescopes from William Optics and I'm looking at a few different ones, namely the doublets: Zenithstar 103, Zenithstar 126 and potentially the triplet FLT-132.

The weight of these telescopes is....surprising. Can someone explain to me how this is possible and if it's at all accurate? Initially I was pretty interested in the 126, but with that weight I feel it gets too complicated to carry out in the park. Mount and counter weights would amount to ~20kg with the 126 while it would be around 15kg with the 103 for instance. 

Zenithstar 103, Tube: 4.36 kg

Zenithstar 126, Tube with Rings and Dovetail Weight：9.94kg

FLT-132, Tube: 9 kg

The 126 is more than twice as much as the 103! 

What’s your interest, for visual or imaging?

[Thingo]

6 hours ago, Louis D said:

20 pounds seems about right for a 132 triplet.  It's the 126 doublet that seems heavy at 22 pounds.  I'd expect it to be more in the 15 to 16 pound range.  It is slightly longer and has a bigger dovetail plate as well as a carrying handle, though.  I'd probably get the 125mm TS-Optics/Altair Astro FPL-53 doublet instead if weight and price are issues.

Yes, it's the 126 doublet that is "too heavy". 

Here are the stats between the different scopes, the 126 is 1 cm longer retracted. The dovetail and the handle can't weigh 3-4 kg, can it? I'll have a look at that recommendation, thank you.  

 

	Retracted length [mm]	Fully extended [mm]	Weight [kg]	Focal ratio
Zenithstar 103	615	735	4.36	F6.9
Zenithstar 126	790		9.94	F7.7
GT 102	678	798	6.37	F6.9
FLT 132	780	1040	9	F7

[Thingo]

3 hours ago, joe aguiar said:

I still prefer eq mount over alt az so I can polar align and easier tracking  but u decide if that's more import or less weight 

Joejaguar 

I'm definitely opposed the alt az mount as well, but credit should be given for the lower weight. 

[Thingo]

3 hours ago, Stu said:

What’s your interest, for visual or imaging?

Focus is on observing of solars system and I want to be able to at least see something of dso's, but I don't want to exclude imaging.