Skylight F15 review in Astronomy Now

[dweller25]

Don't think the weight will be an issue but at 1524mm FL I would be thinking EQ6 minimum or maybe a G11.

[Helen]

I think it was on a Gemini mount at Kelling....

Helen

[Danny]

What about an altaz? It's not that heavy; it says on the Skylight website its only 9 kilos with that big dew shield attached and if that's brass then it would be maybe 7ish kilos without it?

[John]

What about an altaz? It's not that heavy; it says on the Skylight website its only 9 kilos with that big dew shield attached and if that's brass then it would be maybe 7ish kilos without it?

I've just picked up an Aztech Alt-az mount made by Ambermille Engineering - it has a quoted capacity of 20lbs on each arm (it's a sort of heavy duty Giro design) and from my 1st impressions I'd say that was conservative. It's currently got my ED102 F/6.5 on one side and my 127mm F/9.4 achro on the other (25lbs plus in total) and it seems hardly loaded at all

Might need a taller tripod though with an F/15 though ......

John

[philj]

I personally applaud Skylight / Richard for creating a traditional long focal length achro refractor.

They are not to everyones taste especially the younger folk who were not bought up with long fl refractors of the 60s and 70s. Quality scopes like these are a joy to use, despite their size and look elegant as well, if you just want function without form then buy a shorter / cheaper scope and leave these to folks who appreciate a little class with their glass:D

[russ]

There's certainly something very appealing about that refractor, it really does look a work of art. Would love a look through it. Also applaud Richard for bringing it to the market, especially as the demand can't be that high.

Only downside is the 8ft tall mount needed to get the eyepiece away from the ground. Oh and the price.

[Peter Drew]

The Skylight F15 or any long focus refractor will benefit immensely by the fitting of a "Hargreaves Strut", a rod or other section fitted between the objective end and the Dec axis. I have a 5" F15 triplet that is almost useless even on an EQ6 without a strut.

[brianb]

The Skylight F15 or any long focus refractor will benefit immensely by the fitting of a "Hargreaves Strut"

Not if the tube is stiff enough & the mounting of the tube to the mount dec axis is rigid. If I was getting wobble apparently caused by flexure in the tube or the mount/tube connection I'd probably try a Hargreaves strut. To say that a f/15 refractor is bound to need one is inaccurate.

[dogfish]

did Neil English not also buy one as he was that impressed with it ?

a little Victor Kiam me thinks

I saw Neil just before this scope arrived (I was buying his 12" Flextube) and he told me he was looking forward to its arrival. But he is a double star man, so that explains some of his enthusiasm.

Cheers, Martin

[crepitis]

I bought my Tal 100RS from Neil English and when I went to pick it up I had the opportunity to have a look at ( but not through, sadly) the Skylight scope which Neil had mounted on a Gibraltar Alt/Az mount.

It was a beautiful looking instrument and Neil was very enthusiastic about it, he did mention that he was writing a review of it. Neil was a thoroughly nice guy and his enthusiasm for refractors in general was very evident, I will have to pick up a copy of the mag ( or at least have a look through it in the newsagents ) and read his review.

[F15Rules]

I only came across this thread today so forgive me for joining in late:icon_confused:..

First point: what a marvellous hobby we have, where we can debate strongly held views in a civilised way:p...without coming to blows!

I have been fortunate enough to have correspondence with Neil English, though I have never met him. We got into contact over our love of all things achromatic, and especially the classic 60s/70s long focus F15s and more recently the Tal 100Rs/RSs operating at F10-classed as a long focus these days, but in reality only medium focus..

Second Point: Neil is a self confessed Double star-aholic, and he has extensively studied the theory of optics and their various aberrations..he has just written an absolutely fascinating article for Cloudy Nights which he was kind enough to email me: this is a review in some depth of Richard Days' Skylight Refractor, but it also goes into some very interesting details about just why long focus refractors are unbeatable on close doubles - fact: no apochromat, however expensive, unless itself a long focus instrument (I have never seen one over F9 myself), will be able to give the sharpness and stability of image (so vital for splitting close doubles) as a long (F15 or more) focus refractor, even an achromat. Note that I am not talking about false colour: although a long focus achromat will not be able to compete with an apo on colour correction, they do tend to exhibit much less colour -to an extent which might surprise anyone who has not looked through one..It is to do with the physics of lenses and how they work. I am a total ignoramus on this but Neil clearly is not, and I strongly recommend that any of you who like refractors or optics generally read his CN review..I believe he expects it to be posted within the next month, so if you search under Skylight you should find it once it is loaded up.

Final Point: on the subject of is the Skylight worth the money? This HAS to be a subjective argument: would I spend £2k on an apo scope of say F6-F7? No, thanks. Why? Because the appearance of how a scope moves me is quite important - I cannot get excited about a short, squat tube, however well built or finished it is. Would I spend £2k on a Skylight F15 "antique" (Richard would probably prefer "Classic"!) refractor? Almost certainly. And I bet there will be more of your out there that would take the opposite view to mine than would agree with me. And that is FINE! If you all wanted one, most of you would be disappointed, as these will never be mass produced, ever. So it is as well that most of us prefer other types of scope, whether cheaper, shorter, fatter, bigger, etc.

So, can I suggest we make room for artisanship and "difference" as shown by the Richard Days and Neil Englishs' of this world, and celebrate their enthusiasm and commitment - just as we celebrate the late Thomas Back or Al Nagler for their contributions to the quest for perfect colour corrections in the Apo community. After all, we all love looking at the same stars, nebulae, galaxies...just through different instruments!

clear skies to all (we can ALL agree on that!)..

best wishes,

Dave

[Astro_Baby]

Well I tried to sneak that beauty into next years budget on the basis that if nothing else it would make a tremedous room ornament and more in keeping with the decor and also more what the other half had in mind but yes you guessed it - I got the big 'you must be joking' reaction - sighs.

[skybadger]

I can't see the point of this scope. The Cooke scopes of the late 1890s were the best of this design and they were massive. Anything less than a similar mount and they are seriously undercooked. (pun)

Why would I spend so much money on something which is designed for a period where short f/ratios couldn't be achieved ? Given I can get this aperture in a F/7.5 APO why would I bother. Build quality is not a factor - Get a TMB. Otherwise get an antique. If you are doing it for the optics, at F/15, make them yourself.

Mikes penny worth.

[brianb]

Given I can get this aperture in a F/7.5 APO why would I bother.

Chromatic aberration isn't the only downside to a short focal ratio. Field curvature & spherical aberration are common faults with "fast" apos, even very expensive ones with impeccable reputations. Funny thing is, no-one thinks of parabolizing the surfaces in a refractor, whereas small reflectors with long focus spherical mirrors are universally looked down on, even when the difference between a spherical surface and a paraboloid is less than the manufacturing tolerance.

Optical glass "flows" very slowly under the influence of gravity, a scope with a 100 year old objective is going to need refiguring. And lens coatings hadn't been invented in Cooke's day, the light grasp of a genuine Cooke refractor is probably about 60% of that of a modern instrument made to the same specification.

[ollypenrice]

Certainly not a Gibraltar! It is barely adequate for an f5 Genesis for anything other than widefield - at which it and the Genesis excel.

I think the scope looks nice and it is clearly intended to be enjoyed in itself as well as for the observing it will provide. Nothing wrong with that in my book. I'd drive a Morgan if I could afford to, not because it would be a better car but because it would be more fun and just 'nice.' There would be a touch of history in

the using of the f15, too. You'd be getting the kind of view that a young EE Barnard might have enjoyed, or even a young Edwin Hubble.

However, I'm a bit surprized to see the website advocate the GM8. I have seen only two of these mounts down here and both were surprizingly poor with an assortment of defects not encountered on the cheaper EQ mounts.

Olly

[Danny]

Hi Folks,

Have you seen the Skylight website? He's reduced the scope's just in time for Astrofest to £1500 +postage. It looks like Neil English does have one of these scopes. I've seen some of his posts on CloudyNights over X-mas in the refractor forum and yes - it's on a Gibraltar mount.

I gave Richard Day a ring a few weeks back making some enquiries about their availability. Nice guy. He said hes currently building a few more. £1500 is blumming temptin if you ask me.

Danny