29.05.2020 Vixen 90mm v Vortex Razor 85mm. Pt.2.

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I tried both telescopes on the sun at 50x using the same Baader solar foil, full aperture filter. The Vixen was clearly superior with a much sharper limb. Just finding the sharpest focus was a struggle with the Vortex. I certainly wouldn't bother to use the Vortex Razor for white light, solar viewing. Not even at a very modest 50x. The Vixen will easily allow over 100x with a Baader solar foil filter.

Given the problems with the floppy, eyepiece, rubber ring and the very stiff zoom collar. Then the optical quality just doesn't match the considerable asking price of £1400! Quality control seems absent if this is an average example. I have read glowing reviews of Vortex online. Even comparisons made with the considerably more costly Swarovski and Kowa 'scopes of the same aperture.

Later: 6pm. 62F, still bright sunshine but the moon was high in the SE. I compared the Vortex Razor with the Vixen again at several different powers provided by Meade 4000 eyepieces. The Vixen won each time. Small craters were clearly visible in the Vixen 90. Even though the bright sky made for poor contrast conditions. The Vortex seemed veiled and soft.

7.30pm : Over an hour later and the Moon was beginning to be interesting in the Vixen. Though the sky was still blue and the sun sinking behind the trees. In the Vortex the moon was washed out by the sky. Just like a badly baffled telescope. Or one without any baffles or blackening inside the tubes. I have been building my own telescopes for 60 years. I know when there is a problem!

A shooting forum member told how delighted he was to be able to clearly see his bullet holes in paper targets at 500 yards with the Vortex Razor 85mm. So I pointed both scopes at brightly sunlit trees at 500 yards. The Vixen was the clear winner at all powers in identifying small bare twigs against the sky and leaf detail.

Online and YouTube reviews repeatedly mention it being difficult to tell the Vortex and the leading, European and Japanese models apart. Seriously? Based on what level of personal experience? If the Vortex Razor 85mm can't even trash an elderly and damaged, Vixen 90mm achromat at only 50x, then what sort of comparisons are we talking about?

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29.05.2020 Vixen 90mm v Vortex Razor 85mm. Pt.1.

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Friday 29th 58F in bright sunshine. The following images were taken with my Lumix TZ7. Not through any telescope.

I still have some doubts about the true optical quality of the Vortex Razor 85mm. Yes, the view is impressively bright and sharp at 27x but it certainly gets softer with increasing power on the zoom.

So I set up my decades old, 90mm f/11 Vixen refractor alongside it on another tripod. As before, my target was the same, printed A4 instruction sheet with normal and bold black text and some drawings. Now looking crumpled after being caught by the wind.

I fitted a Baader 1.25" erecting diagonal to the Vixen to give them both the same correct left/right/erect view. The nearest useful power I had in 1.25" eyepieces for the 1000mm Vixen was a 20mm for 50x. I tried a no-name Chinese Plossl first and then settled on a secondhand, Meade 4000 series Plossl.

I set up both telescopes as closely together as possible and at exactly the same eyepiece height. Though I tried hard, I could not quite make a binocular out of the eyepieces. Because the telescopes got in each other's way. The Vortex was set to 50x on the zoom ring and this closely matched the Vixen. I was very careful to check the size of the A4 matched as seen through both instruments.

First I tried the target at 24 meters. Again, but it was too close to clearly separate them on image quality. So I put the target A4 on its own tripod outside the gate at 38 meters.  This is my longest sunlit line of sight while the telescopes remain inside the garden. I considered sunshine important to have good light [and some partial shade from a hedge] on the target.

The difference in the image colour was obvious as far as the normal, white duplicating paper of the target A4 was concerned. The Vortex was colder white with just a hint of violet. The Vixen rendered the white paper in a slightly warmer tone but still white.

I was surprised how the sun was already causing heat waves in the image. So that the text was not continuously sharp. It was slightly easier to read the bold text in the Vixen. Which, strangely, seemed less perturbed by the heat currents.

The Vixen is an old, Japanese made achromat. With absolutely no pretensions to being ED or APO. It has only a "middling" focal length rather than a classical F:15. So it is not as well corrected for false colour as instruments with longer focal lengths.

Vixen achromats have a good reputation but that is all. Mine is old and battered. Bought secondhand, years ago. I have no idea as to its true age. The objective is dusty inside and out with a small flake/chip from an accident caused during cleaning years ago.

My eventual, 38m target distance was well chosen to make reading the normal sized text really difficult.  It took real concentration to read the smaller text as it went in and out of focus in the warmth. In both 'scopes the text looked more like magenta than the target's normal, printed, jet black. The Vixen won on contrast and legibility.

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