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  • Newton 250CF f4.8 Newton 250CF f4.8

Newton 250CF f4.8

Product code: N250CF48

Quick Overview

The Newton 250CF f4.8 telescope with carbon fiber tube is the perfect telescope for long exposure astrophotography for those who have a mid-range equatorial mount (with load capacity up to 25 kg). It weighs just 11 kg and, thanks to a focal length of 1200mm and f/4.8 fast focal ratio, you can use it with EQ6 or AZ-EQ6 type mounts. The 250mm large diameter make it also ideal for those looking for a universal instrument with which to take pictures of the Moon and planets at high magnifications and for those who want an exceptional optical quality instrument for visual use.


Diameter is important: when we want to photograph the smallest details of the planets, using a large diameter telescope makes the difference. In addition, to record the weaker nebulae or galaxies, a fast focal ratio is recommended to avoid too long and too difficult exposure times. Telescope collimation and optics test included in the price!

Availability: available in 40 days from the order

Order €2,830.00
VAT 22% incl.
if you pay by bank transfer €2,745.10

Details

Newton 250CF f4.8 reflector, 250mm diameter, 1200mm focal length (f4.8), carbon fiber tube, OrionOptics (UK) UltraGrade optics lambda/10, 2" Hybrid-Drive focuser with 1:11 fine focus, PLUS support rings.

The Newton 250CF f4.8 telescope offers all of this along with other first-class features.



Carbon fiber tube, rigid and lightweight

Our Newton 250CF f4.8 telescope is made of a carbon fiber tube, lighter and more rigid than the classic aluminum tubes. By reducing the weight of the optical tube, the mount on which it is installed can deliver more precise tracking (essential for astrophotography). The high rigidity of the construction allows to maintain perfect alignment of the optics while the very low thermal expansion coefficient of the carbon helps to maintain the position of the focal plane during long exposures.

Built with the utmost attention to details, this optical tube features a beautiful glossy finish outside and matte finish inside, to minimize unwanted reflections.

 

 

 

 


Certificated optics lambda/10 Ultra Grade

Buying a Newton 250CF f4.8 telescope you are guaranteed of the utmost optical quality. The optics are in fact made in England by OrionOptics and are supplied with a Zygo optical report that certifies the high quality. Compared to other similar telescopes of same diameter, our Newton 250CF f4.8 offers higher brightness and contrast.

One of the parameters most commonly used to indicate the quality of a mirror is the correction in fractions of lambda (in simplified terms, the lower the value, the better the mirror quality): if cheap telescopes hardly reach lambda/4 and mid-range telescopes usually offer optics with lambda/5-6, our Newton 250CF f4.8 telescope is equipped with OrionOptics Ultra Grade optics with with lambda/10 optical correction! Other important technical values (which the majority of manufacturers of telescopes does not provide as too difficult to reach) are a Strehl ratio with typical values around 99% and RMS values of the order of 0.02PV.

What does all this mean? Better pictures, more contrasted and rich in details, that will allow you incredible performances.

 

 



Mirrors with 97% reflectivity for brighter images

Usually normal telescopes mirrors have a reflectivity that can hardly reach 90%. This means that, with a Newton telescope equipped with 2 mirrors, some 80% of the light reaches the CCD camera or the eye of the user. Our Newton 250CF f4.8 telescope is equipped with HiLux optical coating that increases the reflectivity to at least 97% across the visible spectrum! This feature allows the Newton 250CF f4.8 telescope to provide brighter images than other similar instruments of the same diameter.

Further advantage of the HiLux coating is the duration in time: in fact, thanks to the incredible protection that this coating provides to optics, your telescope will not show any decrease of performance that is usually known in cheap instruments, even after several years!




Precison mechanics for mirrors support cells

The best optics require high mechanical precision to deliver maximum performance and maintain (or make it easier) collimation. In order to do this, our Newton 250CF f4.8 telescope uses anodized aluminum primary cells made with high precision CNC machines. The 9 points mirror holder uniformly distributes the weight of the mirror throughout the cell. The cell is completely anodised not only to provide protection to the metal against corrosion but also to reduce the risk of scratches.

The primary cell has 3 fans (12V) which, when turned on, significantly reduce the risk of fogging and decrease the time of acclimatization of the primary mirror (the telescope provides the best performance when the mirrors temperature reaches the ambient temperature).

The precise collimation system allows to maintain the collimation longer compared to other telescopes. The collimation is also easier to perform thanks to the mechanical precision with which the cells are built.






Hybrid-Drive 50,8mm focuser

Often the Newtonian telescopes are provided with Crayford focusers suitable for visual use but not for astrophotography. In fact, during the long exposures required by astrophotography, this type of focuser can cause camera slippage moving the sensor out of focus. For this reason we have chosen to provide our Newton 250CF f4.8 telescope with the new 50.8mm Hybrid-Drive focuser that adds, under the focuser tube, a rack and pinion thereby maintaining in position even heavy cameras (capacity of up 8 Kg). Below the focuser there's also a locking screw: closing it, you will be sure that your camera will not move any more!

The 50.8mm Hybrid-Drive focuser presents the connection for 50.8mm and 31.8mm accessories (comes with a handy 31.8mm reducer). It also features a convenient 1:11 fine focus gear, particularly useful when you need to focus at high magnification (for example, when photographing the Moon or planets).

The focuser body has a low profile and the focus point exit from the focuser by 65mm. In this way it is possible to use many photographic instruments such as digital SLR cameras or CCD cameras with filter wheels or filter wheels. For visual use, a convenient extension built into the focuser allows for quick extraction of the focuser tube to reach focus with eyepieces (without requiring an additional extension).




PLUS system support rings:

Forget about the uncomfortable and weak support rings that are often found in cheap telescopes! Our Newton 250CF f4.8 telescope comes with beautiful aluminum anodized support rings, made with high precision CNC machines, which are part of the PLUS (Prima Luce Universal System). This system lets you maximum freedom in adapting the telescope to your requests, and at the same time, it has all the threaded holes, holes and slots suitable for connecting all the PLUS compatible elements.

For example, you can choose to install either a Losmandy or Vixen plate type, or you can use the holes in the upper part of the rings to install a telescope in parallel (through the guide rings PLUS compatible) or a second bar equals to one located below the telescope (to position where you prefer want guide rings or to allow the sliding Vixen + Losmandy dovetail clamp).




The security of your purchase: Q-certified

We often hear users are not sure about purchasing: the telescope is collimated? The operation has been verified? Does the focuser work?

For this, we have developed Q-certified, a comprehensive control system that we perform in our laboratory prior to shipment and delivery of the product you ordered. In fact, in addition to providing the Newton 250CF f4.8 telescope with a Zygo certificate on the quality of the optics, we test the collimation and the perfect functioning of all mechanical components.

In addition, we treat with care also ship carrying a sturdy packaging and giving the package to the courier service. We want to be sure that you will receive your new Newton 250CF F4.8 not only in the shortest possible time but also with utmost care.



NEWTON 250CF f4.8 reflector - equipment:

- NEWTON 250CF f4.8 optical tube (D: 250mm F:1200mm f/4.8)

Carbon fiber tube

50,8mm Hybrid-Drive focuser with 31,8mm reducer and 1:11 fine focus

Aluminum support rings, CNC machined, part of the PLUS system

Finder support shoe

 

 

M81 galaxy recorded by Filippo Bradaschia and Omar Cauz with NEWTON 250CF f4.8 and Atik 460EX mono camera.


Moon craters Ptolemaeus, Alphonsus and Arzachel recorded by Filippo Bradaschia with NEWTON 250CF f4.8 and Atik GP mono camera.

 




Sir Isaac Newton

Sir Isaac Newton (25 December 1642 – 20 March 1726/7 was an English physicist and mathematician (described in his own day as a "natural philosopher") who is widely recognised as one of the most influential scientists of all time and as a key figure in the scientific revolution. His book Philosophiæ Naturalis Principia Mathematica ("Mathematical Principles of Natural Philosophy"), first published in 1687, laid the foundations for classical mechanics.

from: Wikipedia

Technical specifications

Optical Design Newton
Optics Parabolic mirror
Diameter (mm) 250mm
Focal Length (mm) 1200
Focal Ratio 4.8
Field flattener/corrector Not included (optional)
Optical Tube Carbon
Secondary Mirror Obstruction 25%
Mirror Cell CNC 9 point
Focuser 2" Crayford, micrometric
Eyepiece holder 50,8mm with 31,8mm reducer
Weight 11
Hard/soft case No

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  1. davvero un ottimo strumento review by carlo ceglia on 9/7/2015
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    Partendo dall'estetica e dalla qualità della componentistica nulla da dire, il tele è fatto benissimo e tutti gli accessori in dotazione sono funzionali all'osservazione. Assenza di coma ed immagini nitide anche ad alti ingrandimenti. Focheggiatore buono anche se non particolarmente fluido e soprattutto problematico nell'inserimento degli oculari o del CCD, ma sono dettagli che con l'utilizzo vengono facilmente bypassati. Ho trovato un po' di difficoltà nella collimazione dello strumento, ma poi anche questa, con l'utilizzo, diventa semplice. Ho iniziato le mie prime riprese e sono rimasto davvero sorpreso dalla qualità ottica. Il telescopio, grazie alle ventole, raggiunge la temperatura facilmente.
    Che dire....un altro ottimo strumento riuscito ai maghi di PrimaLuceLab.

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