Note: The following TeleVue referred to as TV
TeleVue NP101
parameters
TeleVue NP101 parameters
packaging
TeleVue NP101 packaging
design and workmanship NP looks a bit like TV with other TVs similar to the TV85. . The internal structure is different from those small mirrors. It uses a four-piece design, which is called a Petzval structure. TV NP101 is an evolutionary version of four-inch, fast mirror and plan refractor, just like Genesis.
optics
Like other TV refractors, the NP101 objective lens group is embedded with a very thin objective lens holder.Almost as thick as the lens barrel. The curvature of the objective glass is very small, which is different from the kind of fast mirror we imagined. The reason is that it is actually a mirror with a focal ratio of F11, not F5.4. I will explain this later. In addition, similar to other TV mirrors, the optical axis of the NP101 is not adjustable, because the objective lens holder and the lens barrel are fixed by three (round cap) screws, which is the perfect optical axis once it leaves the factory.
The following explains what is the Petzval structure. Petzval combines a telephoto ratio objective lens (two-element lens like this one) and a focus reduction/plan lens, both of course in the front focus position. The Petzval structure objective lens can correct many inherent aberrations, the focal length can be shortened by half, and the length of the lens barrel is naturally shortened. The end result is a compact, corrected, four-inch lens with a fast focus ratio.
However, the Petzval mechanism does not correct chromatic aberration, only astigmatism and coma. The degree of chromatic aberration depends on the objective lens, which is why the previous Petzval fluorite Genesis is only a semi-APO (Semi-APO). In the Petzval structure, the fluorite is not in the objective lens, and the objective lens is just universal. But in this NP101, the objective lens is ED two-piece APO, and the focal ratio is F11, so in theory the chromatic aberration correction should be more perfect, but it is almost the same in practice.
Petzval objective lens looks past the past
tube
is almost the same as looking at many old TV tubes. The lens barrel part is still painted with pebbles white, while the retractable hood and focusing part are satin black. In addition, whether you like to screw on the metal objective lens cover or not, the NP101 does have to be screwed a lot, and the squeaking sound is much smaller, unlike the TV76.
The Petzval structure makes the NP101 shorter than the TV102 (discontinued) mirror body.However, it is much longer than the focal length of 540mm, reaching 640mm. TV officials claim that this mirror can be boarded with a soft bag, but in fact it has exceeded the length of the airline's limit (approximately more than 8 cm).
The weight is a little over 4 kg, which is okay, but the IS version is heavier (we will talk about it later). The typical flocking inside the lens barrel (a bit like black sandpaper) replaces the grating, allowing the 4-inch to be made very small. The position of the Petzval lens in the front of the focusing should not be touched by Zenith accessories.
NP101 internal flocking
focusing
is no longer the newest version of the gear and rack focusing with double-speed focusing Standard. The exterior of the new model is black, the CNC machining accuracy is better, and it is locked with two screws. Generally speaking, the new model is much better than the old model, and it is more stable, the load can be larger and there is no need to worry about the image shift problem.
new and old focus comparison
TV NP101 and NP101 IS difference
is for the Imagination Star, which also means "Span2sgpan", which means "IS". It is for visual use. The main differences between the two models are the following two points:
- IS version has a larger focus adjustment, mainly to match the CCD camera. The telescopic tube is also larger, with built-in fine focusing and four sets of screws Visual Back (for center correction),There is also a plate that can be fine-tuned so that the camera and the optical axis can be perfectly aligned.
- More importantly, Petzval's lens may be larger. In order to avoid vignetting (vignetting, mainly the edge of the field of view is dark and blurred), Petzval lens has this problem.
If it is a full-frame camera, the IS version is best. If it is a smaller format or occasional shooting, the normal visual version is fine.
The picture is the NP127 IS version
is on the shelf
is very different from the traditional refraction mirror. The TV hoop is connected to the dovetail plate with hexagonal screws. If you use the original TV dovetail, it can be used in your own Gibraltar U-frame or the dovetail slot of GM Prestige and Cinda. The effect is still better than TV’s own Gibraltar.
Dovetail close-up
accessories
NP101 accessories including a 20mm ceiling hoop, electrolyte membrane and a 20mm NP101 eyepiece A soft case, like the TV76, is very compact and portable and can be used on airplanes, but it is optional. Other accessories include starfinder, reduced focus, and all TV eyepieces, which can basically be used on this fast focal ratio mirror (all to be purchased separately).
The old version of NP101 has a hard case (box),The new models seem to be soft bags.
for daytime use
Do you think this mirror is a pure astronomical mirror? Wrong, the actual view of this NP101 is also the best I have ever seen. With a wider eyepiece, such as Pentax XW20 or Nagler 17, the bird watching effect is incredible. As for why the viewing effect is so good, it is due to the comprehensive quality of all aspects of the mirror, no chromatic aberration, coma, and completely flat field. Therefore, this mirror can completely replace the photographic lens, as a lens for shooting birds and wild animals.
Take pictures of tree branches and birds to see the excellent difference level
Photostar
There is no problem with shooting a single star in the back, even if it is not a deep shot of the star in the back of the version . No flat field lens and focus reduction are required. NP101 is already built-in. Of course, you can add it if you want to add it, so that the focus ratio can be faster. Some people may wonder which is better. My personal opinion is that if you want to save trouble and don't want to toss about accessories back and forth, it is better to buy a built-in TV such as a TV.
If you want to photograph the moon or other planets, what you actually need is a longer focal ratio, but NP101 can still shoot very sharp moons. The following photos are the moon and starry sky taken by NP101, which have not been processed and cropped. It can be seen that in the APS-C format, the shooting is not bad, the star points are a little bit fat, and the edges are a little vignetted. This IS version should not have this problem at all.
The moon photographed by NP101
The star points photographed by NP101
15u em2uspan4 15u em2uspan4 p0The chromatic aberration of the NP101 is still very slight, all thanks to the design of its native F11 focal ratio. field of view is very flat overall and is well corrected, especially with TV eyepieces such as Nagler or Ethos. Cooling A larger caliber like NP127, as the air between the first two pieces and the second two pieces may affect the cooling, and the speed will be slower. But this NP101 is fast, without this problem, like divergence or ball difference. star point test is similar to other TV mirrors, the correction is not enough, the others are fine. Moon/wood/Mars As a 540mm focal length, if you want to use a high magnification, you have to use a Barlow lens, but the test results prove to be worthwhile. If the seeing is suitable, the last 2.5mm Nagler can be composed of 216 times. At this magnification, this NP101 performs the same as other top 4-inch APOs, with high contrast and very sharp images. Looking at Jupiter is similar, the cloud belts, vortexes, and the Great Red Spot are clearly visible under high magnification, and the observation feels like a small detector. Many two-piece models are red, and the correction is poor, which will affect the observation of Mars. But this TV does not have this problem. The high-power lower polar crown, the big quicksand, and the Asidaria are all clearly visible. deep space TV’s products are suitable for deep space scanning,The experience of watching deep space on NP101 is naturally quite beautiful. First of all, the fast focal ratio, the large field of view and the flat field look very cool. Secondly, the star points are like diamonds hanging on the black flannel, not only the contrast is excellent, but also sharp to the edge. The last is the blessing of TV eyepieces, which can only be described as a spacewalk. I personally particularly enjoy the feeling that Nagler 17mm composes a 32-fold sweep of the Milky Way star cluster, and occasionally decompose the double stars, such as Betelgeuse, which can be easily disassembled. Summary TV NP101 is very expensive. Apart from this, it is difficult to find the obvious shortcomings. If only one telescope is selected, this one is also one of the main candidates. It's so comprehensive, it can be seen and taken stars, it can be viewed and it is very portable. Coupled with the TV brand blessing, the quality and service are naturally not to be said, and there is also a wealth of accessories to choose from. If it is the main competitor of Petzval structure, it might be Takahashi's FSQ106. Takahashi's star capturing ability may be better, but it is also heavier and more expensive. There are other FC100D (or TSA102 and TMB100) which may look at high-power planets a little bit better, but the portability is much worse, and the field of view is not so wide and flat (for a glance). So TV NP101 is still the most comprehensive one. I think so, and I highly recommend it.
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