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Skywatcher Quattro f4 Imaging Newtonian telescopes

FLO

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MikeWilson

MikeWilson

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Hi Steve,

I've seen those. Scary prices!

I understand that they work by reflecting/folding the light path back and forth throughout the optical system so giving a more accurate colimation than a simple laser or cheshire. Got it. But will they help us accurately align the secondary mirror (i.e. in and out of the tube and twisted around)? I suspect that's where my issue lies. A misaligned secondary which thereby has perfect collimation along the path of the laser (center of the mirror) but not on the edges of the mirror.

And which pattern/style/type does one need for the Quattro?

All the best,

Mike

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FLO

FLO

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Oh yes - one more thing.. scope rings.. any news?

We are still expecting the tube-rings sometime next week Mike.

I'll let James answer the Catseye question (it was James' enthusiasm for his own Catseye Collimation tools that lead us to becoming the UK stockist :) ).

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James

James

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I understand that they work by reflecting/folding the light path back and forth throughout the optical system so giving a more accurate colimation than a simple laser or cheshire. Got it. But will they help us accurately align the secondary mirror (i.e. in and out of the tube and twisted around)? I suspect that's where my issue lies. A misaligned secondary which thereby has perfect collimation along the path of the laser (center of the mirror) but not on the edges of the mirror.

The Catseye Kits come with a sight-tube for accurate alignment of the secondary, a cheshire collimator and the Infinity autocollimator (which allows for the last extremely precise tweaks). There's various permutations but at it's simplest the Comboset Pro includes an autocollimator and a combined sight-tube/Cheshire.

I'm pretty poor at judging concentricity so the sight-tubes ability to be extended to a set length according to your focal ratio which tightly frames the secondary mirror makes it much easier to judge when the secondary is in exactly the right position.

James

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MikeWilson

MikeWilson

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The Catseye Kits come with a sight-tube for accurate alignment of the secondary, a cheshire collimator and the Infinity autocollimator (which allows for the last extremely precise tweaks). There's various permutations but at it's simplest the Comboset Pro includes an autocollimator and a combined sight-tube/Cheshire.

I'm pretty poor at judging concentricity so the sight-tubes ability to be extended to a set length according to your focal ratio which tightly frames the secondary mirror makes it much easier to judge when the secondary is in exactly the right position.

James

Very interesting. I currently don't have a Cheshire but I made a peep hole cap out of the 2" drawtube cap that came with the scope. It's not accurate but I got the secondary aligned 'good enough' to test (it was very far out out of the box as one would expect having been shipped around the world).

I then used an unbarlowed Revelation Astro laser to get the center spot collimated as accurately as I could. The edges are slightly off which I think may be caused by the secondary being slightly misaligned and then corrected for the center dot. The scope also is being held tentatively and not particularly securely by it's rings (and some cable ties for security!).

So I here are my first 'first light' test images.

3 x 3 min on 52Cyg/Veil Nebula (West Part). QHY8L.

No processing other than a single levels stretch. No darks but flats and bias were used.

post-18683-133877654188_thumb.jpg

100% crop of center

post-18683-133877654197_thumb.jpg

100% crop of bottom left

post-18683-133877654202_thumb.jpg

100% crop of top left

post-18683-133877654209_thumb.jpg

100% crop of top right

post-18683-133877654214_thumb.jpg

52Cyg (the bright star in the center) looks a little oblong when the image is stretched like this. I don't know why (but the effect is exaggerated here as I literally did a single levels adjustment clipping both white and black point severely).

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MikeWilson

MikeWilson

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We are still expecting the tube-rings sometime next week Mike.

I'll let James answer the Catseye question (it was James' enthusiasm for his own Catseye Collimation tools that lead us to becoming the UK stockist :) ).

James' review was very helpful and in fact having Google'd the Catseye Collimation tools I've found James does appear to be quite fond of them!

I suspect that I could really benefit from one of these tools. I'll need to have a think about this one!

All the best,

Mike

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MikeWilson

MikeWilson

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It's probably not obvious but I'm impressed with:

1. The light grasp - the equivalent exposure of a more or less similar composition of this target using my previous 150P would have required a 5 minute exposure.

2. The frame illumination - even without flats (let me know if you want a demo image) has *very* little vignetting on the ~APS-C sized CCD and 2" filters.

I'm looking forward to hearing Nadeem's report, particularly in how the optics compare to the venerable MN190.

Clear skies,

Mike

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blinky

blinky

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Yep That's a pretty good first light, looks like the collimation needs a wee tweak but nothin too bad - as Steve says F4 is very unforgiving of collimation! Cats eye tools look to be good but way out of my price range(around half the price of a new scope for what is really a couple of nicely machined tubes, though I don't doubt they allow for excellent collimation to be achieved).

I read a review on CN of the Rowe coma corrector and it seems the spacing has to be extremely accurate and the overall impression was it's not quite as good as the MPCC model ( I think the reviewer returned it for an MPCC) although if you need out focus (something I don't with my Altair model) then it's got to be worth a try.

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shaunster

shaunster

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I nearly ordered one today, however I managed to resist and just ordered a couple of smaller bits instead :)

The cost of collimation (hotech £130!) really puts me off as this is the only scope I would use one with.

Good first light there, how are you mounting it then Mike if the tube rings dont fit?

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Deneb

Deneb

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I'm looking forward to hearing Nadeem's report, particularly in how the optics compare to the venerable MN190.

Clear skies,

Mike

The Mirrors of the MN190 are of Low thermal Pyrex Glass with the secondary with BK7 Glass & top quality stuff, from what I understand the mirrors on the quattro's are probably just parabolic mirrors which get supplied with the SW DS models. Tell you the truth, I would find it hard for a quattro to beat the MN even in its optics, still two different beasts. If you was comparing a Intes Mak-Newt with a MN190, then that's something interesting to compare to.

Even I have an 8" Quattro, I certainly don't think it would be on par or near par with the MN190. I have seen third party companies which are advertising 8" Quattro like Astrograph Newts & with Carbon Fibre Models, with Pyrex Mirrors & BK7 optics & with baffles, just less then a grand (and come with Tube Rings :().

Yes maybe a tad too expensive, tell you the truth im thinking about buying one & doing a shootout between the 8" SW Quattro & the other third party ota. :)

Nadeem.

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FLO

FLO

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... from what I understand the mirrors on the quattro's are probably just parabolic mirrors which get supplied with the SW DS models.

We certainly hope so :)

A Skywatcher f4 parabolic mirror manufactured to the same standard as their f5 model would be very nice indeed!

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Macavity

Macavity

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A favourite reference on collimation is:

FAQ about Collimating a Newtonian telescope

Or, at least it gives some numbers. :)

I wonder sometimes. I sense, without Bob's knobs (or something) my GSO ain't going to achieve precision of a (very!) few millimetres. My next upgrade purchase? I remain a tad confused re. the idea that one (laser) collimates with the collimator clamped in ONE position. In brief, what happens when a real eyepiece / camera, manufactured to a different set of "tolerances" and precision is inserted? :)

I take personal consolation (again) in the idea that the TRUE dimension of the 1/2" Watec (and other) VIDEO chip is but 4.8 x 6.4mm. Maybe I don't even need a Coma Corrector? More questions than answers. :)

Aside: I use a Baader Mk.III laser collimator. Battery changes can be a pain, and certainly a job lot from "Poundstretcher" don't seem to last very long at all. :(

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blinky

blinky

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I would say if your chip is that small chances are you will get away without a coma corrector. Also, I bought new springs for mine from Bobs knobs but by far the best improvement was a £3 tube of clear silicon, works wonders......

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MikeWilson

MikeWilson

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I would say if your chip is that small chances are you will get away without a coma corrector. Also, I bought new springs for mine from Bobs knobs but by far the best improvement was a £3 tube of clear silicon, works wonders......

What's that for and how would one use it?

Cheers,

Mike

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Tim

Tim

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Just a quick heads up,

I didn't get long with clear skies tonight, but I was able to do a true side by side comparison of the Baader MPCC and RCC I coma correctors, with perfect spacing and in a canon 400D with an F4 scope.

Hopefully wont be too long before I get to examine the results and write up the findings :)

Cheers

Tim

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