6 replies to this topic

[ngc4910]

Good afternoon,

 

today I received a 80/400 Celestron telescope, made by Vixen and labelled S-80+ "Fully Multi-Coated".

I wanted a rich-field refractor of this type for quite a while.

 

To my surprise, the coating on the lenses is vastly different from all other Vixen-made refractors that I have seen so far. It reflects in bright red, from all angles -- whereas typically MgF2 coated lenses from that era have a faint blue-ish reflection.

 

Looking online, I found pictures of the "S-80", but not of the "S-80+" . I wonder: Is the lens genuine, or has it potentially be replaced against an aftermarket lens?

 

If you own one of these -- especially the "Fully Multi-Coated" S-80+ variant, I'd be curious to hear whether it shows the same bizarre coating.

 

Pictures below.

Thanks

ngc

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[Lappe Lad]

Hi,

 

The SS80+ is the "ruby-coated" version, intended to cut glare off of water for spotting scope duty. That's what my old Celestron brochure from the mid-nineties stated.

Might not be ideal for maximum light transmission for astronomical observing. These coatings were quite common on some inexpensive binoculars at the time.

The green multicoated version was called the Rich-field 80. Original SS80 was magnesium-fluoride coated.

 

Robert

Edited by Lappe Lad, 27 September 2024 - 02:56 PM.

[ngc4910]

Thanks a lot Robert for the swift response!  I hope the "ruby" coating won't spoil sweeping the Milky Way then! If it does, I'll have to keep my eyes open for the non-ruby-coated version.

 

Cheers

ngc

[Lappe Lad]

I hope you find it to your liking; it's incredibly light-weight and compact.

Unusually good color correction for an 80mm f5, but that's because the very long 1.25" focuser cuts into the light cone from the objective, turning it  into a scope that's effectively operating well under 70mm aperture.

I flocked the inside of my unit's drawtube with emery cloth spray-painted with Krylon flat black. Big improvement in stray light control for daytime use, mainly.

 

Robert

[ngc4910]

Hi Robert,

 

 

Unusually good color correction for an 80mm f5, but that's because the very long 1.25" focuser cuts into the light cone from the objective

 

I read that too; that said, from the location of the field stop of my 26mm Plossl, when using a 90 degree prism diagonal, I can see the full lens (including the lens spacers). Off-axis, there is severe vignetting. But on-axis at least, it seems that (for this combination of eyepiece and diagonal) one gets the full amount of light.

 

What mount are you using with this telescope? I was considering to acquire some light Alt/Az mount for this telescope.

 

Cheers

ngc

[JOEinCO]

I can't speak to the ruby-coated slippers, but I have an old S-80 I've had for over 30 years that has gone on countless trips, both backpacking and airplanes. Love it. It still has a spot in the stable despite dozens of scopes coming through because of my obsessive buy-and-try nature.   

 

I'm sure your 80+ will serve you just fine.   

[Lappe Lad]

I use a video fluid head with an extra-long mounting plate that slides back and forth in a quick-release for easy balancing (Gitzo model #2380).

These fluid heads are an acquired taste among astro users. I like them for compact tube assemblies with built-in tripod mounting blocks.

 

Robert