William Optics Star 71 F/4.9 Apo: why discontinued?

[ollypenrice]

1 hour ago, steppenwolf said:

I think this is a backward step by WO - IMHO you DO need 5 elements to get a really flat field which is why the FSQ 85 doesn't do what it says on the tin! I do wish manufacturers would simply produce a high quality corrected set of optics and charge a fair price for it instead of this nonsense of selling too cheap and failing on QA. If you are into AP, you must have accepted it isn't a low cost option so imagers should be prepared to pay a sensible price but expect the QA to reflect that price - simples!

I know you had a poor 85 Steve, but it nearly does what it says on the tin! I'm not convinced that the image circle is 44mm though. It certainly won't cover full frame. No doubt about that, but how big is the Kodak full frame sensor? I've found various dimensions in mm on the net and it seems to need a 45.something circle to cover it. Sorry, I can't remember just what I worked out.

I totally agree on pricing. If you can't make it at that price (and that means make it consistently) then don't offer it at that price.

Tom and I both have older Tak FSQ106N fluorites. These go for a little over £2000, typically. However, they laugh at any amateur chip currently in production. They may not be perfect but I love 'em. (You get those 'dark lighthouse beams' on some bright stars which Greg Parker reckons come from pinching. I know nothing, except that they don't bother me.) I'd call the field very flat indeed over a paltry 35mm chip. If you're lucky enough to get your flight case stoved in and a £480 refund from Parcel Farce the scope starts to look positively budget!! More seriously, the FSQ106N is a very fine astrograph and is reasonably priced with a depreciation probability of around zero.

The Star 71, so near and yet so far. I hope they get it right next time but if Tak can't get 85mm to cover full frame with 4 elements...

Olly

[Jonk]

It certainly appears to be on sale in the US now - http://www.highpointscientific.com/william-optics-star71-four-element-f-4-9-imaging-refractor-w-2-5-focuser-a-wo71-ii

and is slightly more expensive than the MK1 (only by $80).

 

• Aperture: 71 mm
• Focal Ratio: f/4.9
• Focal Length: 350.2 mm
• Objective Type: 4 elements in 3 groups - patented 2-1-1 Configuration
• Lens ShadeRetractable
• Focuser: 2.5” Dual Speed Rack & Pinion
• Focuser Drawtube travel: 1.38" / 35mm
• Image Circle: 45 mm
• Type of Mount: Mounting rings with Vixen style dovetail
• OTA Tube Weight: 4.5 lb / 2.05 kg
• Tube Weight with Rings & Dovetail: 5.3 lb / 2.4 kg

[Davey-T]

Still claims to give pin point stars to 45mm imaging circle, will have to wait for some images to appear on CN.

Dave

[Jonk]

Of course it does, marketing!

They've removed an element and upped the price.

As you say, proof will be in the pudding.

[Davey-T]

Glad I got mine, perhaps they'll turn into collectors items

Dave

[Jonk]

I'll probably get the MK2 when it's been a month or 2 since release, to see what the early adopters think.

I'll be using a full frame DSLR to start with (this should show any issues), then once I've sold the other kidney, I'll get a ccd set up!

[FLO]

1 hour ago, Jonk said:

They've removed an element and upped the price.

As you say, proof will be in the pudding.

One less lens and a higher retail price should be welcomed because the Star-71 is an ambitious project. Multi-element lens cell design and construction is difficult, a number of big brands have tried and failed.

We are hoping they design in more serviceability than the previous model so those that do need re-alignment can be more easily adjusted. 

Steve 

[Jonk]

12 minutes ago, FLO said:

One less lens and a higher retail price should be welcomed because the Star-71 is an ambitious project. Multi-element lens cell design and construction is difficult, a number of big brands have tried and failed.

We are hoping they design in more serviceability than the previous model so those that do need re-alignment can be more easily adjusted. 

Steve 

So do I, the last thing we need, and you as retailers is constant returns. Adjustability in my opinion should be default, even on the most expensive kit.

You wouldn't buy a top of the range guitar without tuning pegs!

[geordie85]

Looking forward to this being released to the UK. Definitely going to be getting one 

[Jonk]

Some information from a US supplier:

 

The new William Optics Star71-II imaging telescope replaces the venerable first generation of this telescope introduced in 2014. The Star71 is an excellent, portable, high-quality apochromatic astrograph for the astro-imaging enthusiast.
How does this differ from the 1st generation Star-71 telescope?

• Mechanically, the two scopes are virtually identical.
• Optically, their performance is identical too. The key difference is that the first generation Star-71 had a five-element design out of which only one element used FPL-53 ED glass. This second generation has a new four-element design using two FPL-53 ED lens elements. William Optics retained the same optical design parameters and performance, but the new design is much easier to collimate during assembly.
• The new tube features a Vixen-style dovetail base for attaching finder/guider brackets.
• A soft padded carry case is now included as a standard accesorry. It was sold separately earlier.

Key Features

• 71mm f/4.9 imaging refractor telescope with 350mm focal length
• Two FPL-53 ED glass elements for color free apochromatic performance
• 4 element design. This is a new, patent-pending design and the optical configuration is not being disclosed at this time.
• Covers 45mm full frame imaging circle
• 2.5" dual speed R&P focuser
• Includes soft padded case, mounting rings, Vixen-style dovetail rail, and an M48 Canon EOS adapter
• Weight = 4.5 lbs / 2.05 kg (OTA only); 5.3 lbs / 2.4 kg (OTA with rings and dovetail)
• Focuser drawtube travel = 1.38" / 35mm
• Back focus = 71.3mm from 48mm Canon thread (see pdf attachment below for details)

Additional Information

• The focuser drawtube terminates in a male M48x0.75 thread. This telescope comes with a wide M48 female threded Canon EOS adapter ring. Similar rings are available from other suppliers for other brands of cameras. Note that this a not a conventional 2" focuser tube with locking thumbscrews.
• An optional 1.25" 90-deg dielectric mirror diagonal is available separately for those wishing to use this as a visual scope. This diagonal comes with a custom adapter that connects directly to the M63 female thread on the telescope's focuser tube. You cannot attach standard 1.25" diagonals and the telescope cannot reach focus with larger 2" diagonals.

Specification for ED Lenses

All William Optics refractor objectives are double tested and inspected by WO at their factory. These telescopes are free of coma and astigmatism. Since all individual lens surfaces are machine coated, sometimes you may notice visual imperfections which will not compromise the optical performance of the telescope. THe dimensions of scratches and points shall not exceed the following values:

• Scratches - Maximum Width: 0.025 mm
• Scratches - Maximum Length: 1/4 of total lens diameter
• Scratches - Maximum Quantity: Three
• Dots or Spot Points - Maximum Diameter: 0.4 mm
• Dots or Spot Points - Maximum Quantity: Three
• Accumulation of Defects - Limited Area: 0.8mm^2
• Accumulation of Defects - Total Area: 5.8mm^2