Minimum magnification is limited by the telescope’s aperture. Here, the exit pupil should not be larger than seven millimetres. This is usually also the maximum diameter that the pupil of the human eye can reach. But this is only possible at night and in absolute darkness.

Focal length vs magnificationnikon

A practical example: if you are using a telescope with 200 mm lens aperture, the minimum useful magnification is around 28 times. If the telescope aperture was larger, the minimum magnification must be higher. For a smaller telescope, it is correspondingly smaller.

A telescope creates a focal point, depending on the curvature of the mirrors or lenses. With the focal length alone, a small level of magnification will be achieved. But in order to be able to look at the image, you additionally need an eyepiece. Imagine an eyepiece as a magnifying glass which enlarges the image at the focal point.

There’s something sartorially and excitingly perverse about seeing a shell-shaped cropped jacket—turtle-like, almost—made of jet-black dead-stock upholstery leatherette (cheap chic, defined), found somewhere in a warehouse. Same for a similarly constructed coat, built from cut-and-sewn vintage Helly Hansen jackets. Today in Paris, these weird—but convincing—examples of outerwear were worn with pooling, plasticky PVC trousers, or corduroys with flat fronts and double flies (two zips, at the thighs, not the crotch).

More magnification equals a better telescope? Beginners often think this, but it is not the determining factor, small or medium levels of magnification are usually more effective. Here you can learn how to calculate magnifications.

Focal length vs magnificationphotography

A telescope with an aperture of 100 mm would therefore have a optimum magnification of 142-times and a 200 mm telescope of 285-times.

Focal length magnificationformula

Maximum useful magnification is reached with an eyepiece exit pupil of 0.7 mm - 0.8 mm. It is not a precisely defined limit, more a guide for optimum magnification.

There are three important magnifications that every amateur astronomer can easily determine. Here we show you how you do this.

Focal length vs magnificationchart

Unfortunately, no telescope nor any other optical instrument is completely defect-free. Here we describe the most important image defects found in astronomical telescopes.

What isfocal lengthof lens

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Focal length vs magnificationreddit

Divide the telescope's aperture by the diameter of the maximum aperture of the eye’s pupil, to get the minimum useful magnification.

Focal length vs magnification vszoom

In theory, magnification is unlimited. However, since it is related to the aperture of the optics, there are limits. The exit pupil also plays an important role. This is the diameter of the beam of light that leaves the eyepiece and enters the eye. We’ll come to this again later.

Optimum magnification or maximum useful magnification is reached when a star no longer appears point-shaped, but as a tiny disk with diffraction rings. At this point, you are using all the optics’ available resolving power. This means that you can see many details that remain hidden at a lower or higher magnifications.

For example, if you have a telescope with a focal length of 1,000 mm and an eyepiece with a focal length of 5 mm, you'll get 200 times magnification.

This is the meta-mundane Fall 2017 vision of GmbH, the 8-month-old Berlin-based collective helmed by Benjamin Alexander Huseby and Serhat Isik. Think of this duo (the former, Norwegian-Pakistani and with a background in photography; the latter, German-Turkish and with training in fashion design) and their crew as something akin to Berlin’s Vetements. (Even the label’s name represents the pedestrian interchange of Vetements translating to “Clothing”—GmbH is the German abbreviation for a limited liability company.) However, instead of humorous subversion and post-Soviet blasé, GmbH’s brand of streetwear is harder, faster, and born out of the city’s techno clubs. And as a welcome bonus, everything they make has a low carbon footprint in mind.

Magnification depends on the ratio of the telescope's focal length to the focal length of the eyepiece. To calculate this, divide the focal length of the telescope (ft) by the focal length of the eyepiece (fe):

Focal length vs magnificationcanon

Each telescope has its own magnification limit. It is equivalent to 2 times the lens aperture. However, you cannot and should not use this upper limit every night. This is because you will only enjoy observing if the object is bright enough and the seeing is perfect. It is easy to find out for yourself whether it makes sense to operate at this limit: use an eyepiece with a 0.5mm exit pupil and pay attention to the seeing. How does the object appear? Is it blurred? Is it too dark? How are the conditions tonight?

“We want to make everyday clothes, inspired by nightlife, inspired by work uniforms,” said Huseby, wringing his hands (tonight’s Paris showcase marked GmbH’s second-ever collection, and first-ever formal presentation—nerves were natural). He then pointed at the models, one of which was his and Isik’s production manager, and another, the young woman in the leatherette bomber, their sales director. At Vetements, Demna Gvasalia did and continues to do the same with his inner circle. Huseby and Isik might not like this comparison, but it’s not to be taken as a negative. Rather, it is to point out that the concept (and weight) of a fast youth-fueled contemporary collective contributing to the fashion conversation is legitimate. Beyond one player, at least. Keep an eye on these two—GmbH is buzzy, and their output so far is worthy of the chatter.