Astronomy

Does anybody recognize this kind of prism?

Does anybody recognize this kind of prism?


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Supplemental to this answer to Did Edmund Scientific 4¼ inch Newtonians have 90° prisms as secondary mirrors in the 1970's? I was poking around a bit further and ran across this "1960's Edmund Scientific 'Space Conqueror', 3" reflector" with a prism diagonal at http://www.retrotechnology.com/glass/edmund.html

Question: Does anybody recognize what kind of prism this is? It doesn't look like a simple right-angle prism, but possibly something that has additional reflections and does some additional flipping or rotation.

Is there any chance that it isn't positioned correctly, it doesn't look like it is centered along the eyepiece holder's axis, but the image has a strong perspective component and we can't see the business end of the prism.


My guess is that it's not a prism (or at least doesn't function as one optically). It looks like it is a right triangle in one cross section. The diagonal face would be silvered to act as a star diagonal. If aligned correctly, the black plate it's glued to that attaches to the support arm would be perpendicular to the tube axis.

It looks like it's rough beveled on other sides, maybe to get an ellipsoidal cross section?


1. Gosky QHMN001

First up, the Gosky QHMN001 12吳 2mm is a fantastic monocular telescope for a smartphone. Looking through the scope, the picture quality is breathtaking. It produces ultra HD images that are very bright and crystal clear.

Coming with the purchase is a digiscoping cell phone adapter, hand straps, cloth for cleaning, lens protection, and a nylon carrying case. The digiscoping cell phone adapter is great. However, you must remove the case of most phones for a good fit.

Considering the hand straps coming with the purchase enhance stability and security, you’re easily able to take smooth video recordings with your phone, as well. This monocular has an excellent build quality. Not only is it waterproof and dustproof, but it’s also able to withstand vigorous weather conditions and impact with its shock-absorbing rubber armor.

It can zoom from 12x to 55x . Overall, the Gosky Skyhawk is easily one of the best options for your smartphone. We highly recommend it!

Users Say: “This telescope is majestic compared to what you see in the pictures. I was so excited and thrilled to open the box and see how large and well made this is! The telescope itself is very precise and you can see a long distance effortlessly. It is easy to focus and the tripod is dependable and made out of very thick material that will hold the telescope at the perfect angles every time. I love the fact that it will work with a camera or phone easily, yet you can look through it independently to see the stars or wildlife with the naked eye. This was well worth every penny we paid for it and will bring my son enjoyment for a long time to come.”

Tech Specs & Details

  • Zoom amount: 12吳
  • Waterproof
  • 82mm for clear picture
  • Dustproof
  • Made with shock-absorbing rubber armor
  • Comes with: digiscoping cell phone adapter, hand strap, straps, cloth for cleaning, lens protection, and nylon carrying case.

How to Choose Porro Prism Binoculars

Magnification

To satisfy users with different requirements, manufacturers release Porro prism binoculars with multiple magnification levels. However, there are models featuring a single, pre-selected magnification. That is why we recommend paying attention to this parameter while choosing a pair of binoculars in order not to be surprised after all.

Objective Diameter

The front lens of the binoculars is called the objective lens. Its size determines how much light is gathered and is referred to as its aperture size. The bigger the aperture, the more light it captures, which results in better image quality.

For instance, 10x50 Porro prism binoculars are capable of gathering more light than a 10x42 device. At the same time, both models have the same magnification. But a 10x50 binocular provides brighter images and guarantees a better viewing experience.

Field of View

Some binoculars are equipped with unique lenses and provide a &ldquowide field&rdquo of view. In such a way, these models may be better than binoculars of the same magnification. Field of view decreases as magnification increases, and vice versa. In other words, if a wide field of view is important for you, choose binoculars with lower magnifications.

On the contrary, if you don&rsquot care about the field of view, choose wide-angled devices. Large objective lenses provide a larger field of view. As a rule, Porro prism binoculars offer larger fields of view than roof ones featuring the same parameters.

Durability

Most people use binoculars in the open air. You may drop them, hit a rock, land in the mud, they may get wet, etc. You never know what surprises the weather prepares for you. Apart from standard weather protection, the best Porro prism binoculars feature impact and shock protection in the form of rubberized armor coatings. Moreover, they often add grip and texture for you not to drop them.

Weight

Weight is an essential characteristic you should pay attention to while choosing Porro prism binoculars. As a rule, binoculars&rsquo owners carry them around the neck all day. So, if the device is too heavy, you will feel the extra weight. In addition, heavy binoculars will tire your hands quickly, and they may shake spoiling the image. That is why it is recommended to choose the lighter binoculars you can afford.

Prism binoculars use prisms in the optical system to rectify an inverted image projected by the objective. They usually have a compact body because the prism shortens the optical path. We may distinguish 2 types of prism binoculars: Porro prism binoculars and Roof (Dach) prism ones.

Porro prism binoculars are more complicated than Roof prism optical devices. At the same time, Roof prism binoculars have a more complex light path and require greater optical precision in manufacturing. That is why they are more expensive. Speaking of Porro prism design, it is simpler and more light efficient. Moreover, the image you see features better contrast.

In general, Porro prism binoculars offer higher image quality and less light loss. As a result, the picture is clearer. However, thanks to a compact design and complex prisms, expensive roof prisms are frequently chosen for quality binoculars.

Average users who don’t have any particular requirements for a pair of binoculars should choose the devices from 7x to 10x power. People who buy binoculars for theatre visits should find something between 3-5x (it depends on the seats). If you are a sports fan, find something with 7x power. For long-range observations, get Porro prism binoculars with 10x magnification or higher.


Editor’s Picks —

Alex debuted last week in Prism & Pen with an impressive history of the real Marsha P. Johnson. This week, Alex ups the ante with a head-turning history of a famous early American who was loudly and publicly nonbinary in a way that feels almost contemporary.

The Public Universal Friend, as was the Friend’s chosen name, was born a Quaker in the colony of Rhode Island in 1752. For the first 23 years of the Friend’s life, the Friend lived as a traditional woman, although without getting married. The Friend attended the Quaker meetings of the area, but when the Friend was in the Friend’s early 20s, a group known as the New-Light Baptists caught the Friend’s attention.


BP 6.4 - Chrome Known issue. Elements not being recognized after spying

Issue:
Spied elements on a web application are NOT being recognized suddenly when it was working fine few days ago. I tried different websites to see if I encountered the same issue and it did.
The spying process works completely fine but when it comes to recognize that element, it cant find it. I compared the before and after attributes and they are exactly the same. This issue is not see in Win32 or thick appications or Internet Explorer. This is seen only on websites/web applications running in Chrome.

Troubleshooting steps performed:
- restart the machine
- used a different id for OS login and BP login ( to eliminate any issue with credentials/roles/premissions)
- reinstalled BP 6.4
- Re spied elements but got same result

BP support blogs mentions this issue and the possible solution:

Checked all possible solutions mentioned in this blog but the problem still persists.

Besides upgrading to 6.4.1 , does anyone else have a solution? or advice on troubleshooting directions?

Thanks for looking into it.

Nmanojnunna

New Member

Even we have faced the similar issue where all of sudden chrome unable to identify elements.
We could find that this is happening because of Chrome updated to 72 version.


What are the differences between the optical coatings?

Optical coatings reduce internal light loss and glare and ensure even light transmission, resulting in greater image sharpness and contrast. When you have your optics coated, your glass will have a less shiny, even dark appearance when looking into the barrel or tube. The glass may provide a greenish, bluish, or brownish tint due to the magnesium fluoride or calcium fluoride they are made from. This coating destructively interferes with certain colors or wavelengths of light, eliminating their reflection. Therefore, more light enters your optics and can pass through to your eyes.

Almost all modern consumer optics have at least some kind of coating elements, though there are different levels and qualities of coatings. Celestron has different levels of coating for optical tubes, binoculars, and spotting scopes. Here are the different coatings Celestron has on our products:

Coated: At least one of the major optical elements has a coating on at least one surface.

Fully Coated: All lenses and glass surfaces have a coating layer. For binoculars, this includes the long side of the prism.

Multi-Coated: At least one of the major optical elements in a fully-coated binocular has multiple coatings of anti-reflective compounds on at least one surface

Fully Broadband Multi-Coated: Predominately found in our binoculars and spotting scopes. Fully Broadband Multi-Coated decrease surface reflectivity therefore allows greater optical through-put across the entire visible light spectrum. Fully broadband multi-coated optics feature these types of coating on all optical surfaces throughout the entire instrument.

Fully Multi-Coated: All glass surfaces have multiple coatings and it is the best kind, resulting in light transmission of 90-95% for bright, sharp and contrast images.

Fully Multi-Coated XLT Coating: Only found in certain binoculars and spotting scopes (SkyMaster Pro and Echelon binoculars,TrailSeeker and Regal M2 Spotting Scopes). Fully Multi-Coated XLT Coating is an adapted form of Celestron’s proprietary StarBright XLT coatings. Celestron’s XLT coating further decreases reflectivity in fully multi-coated optical systems for higher optical throughput across a broad range of the visible light spectrum.

StarBright XLT: Predominately found in our telescope Schmidt Cassegrain optical tubes and the larger spotting scopes (C5, C90, and C70), the StarBright XLT coating outperforms any other coating in the commercial telescope market. The three major components that make up our StarBright XLT design is the Unique enhanced multi-layer mirror coatings, multi-layer anti-reflective coatings, and high-transmission water white glass.


NOTE: Some roof prism binoculars feature phase coatings because the light travelling through the roof prism assembly can diverge by wavelength as it transits the prism and emerge out of phase, thus producing a “muddy,” lower contrast image. By applying a special coating that compensates for this divergence, the contrast loss is eliminated, giving phase-coated binoculars brighter and more vivid images. Phase coatings are not applied to Porro prism binoculars as they are not necessary due to the more simple optical path through the prisms.

For information on Prism coatings, click here.

To Polar Align using a Computerized AZ mount with wedge, click here. To Polar Align.


There are two reasons why this might be occurring:

    Your system's OLEACC.DLL file is not properly registered - More information is available here on how to resolve this, but the solution boils down to the following:

  • Open a Command Prompt (CMD.EXE) with Administrator privileges
  • Navigate within that to the location of your OLEACC.DLL file (usually 'C:WindowsSystem32' directory)
  • Run the following command to re-register the DLL file: regsvr32 OLEACC.DLL

The window is created in the window hierarchy in such a way that it technically doesn't reside within the application you're attached to - Popups generated by certain web applications are not spyable using HTML mode. Instead, you'll have to create an entirely new object with new attaching logic to be able to spy this particular window. More information on this issue is available at the following resources:


2 Answers 2

It is convention and laziness (and I'm as guilty as anyone). In fact cgs units should not be used (according to the International Astronomical Union), in the same sense as Pluto should not be called a planet. Both were decisions made by the IAU. In the case of units, the IAU unambiguously endorsed the use of SI units, except for a short list of defined units common in Astronomy (like solar mass, parsec etc., although the electron-volt is also included).

So there you have it - the IAU has a policy, but most astronomers ignore it.

Of the main journals ApJ, AJ, A&A don't specify, but MNRAS does suggest using SI units and points to the IAU policy.

Interestingly, the American Astronomical Society machine readable table standards document also says it requires SI units, but then points to a table which includes gram as an allowable unit of mass, however the electrical units are SI (Teslas, Webers etc,)?

It's partially convention, but I think it's much more that Gaussian units are nicer to work with for a lot of the common problems in astrophysics. It's not that we prefer cm, g, and erg over m, kg, and J that's just to signal that we're using Gaussian units. To me, it's that Maxwell's equations have constants with intuitive physical meaning that we use all the time in astrophysics ( $c$ and $4pi$ ) instead of the permeability and permittivity of free space, which we never really think about in astrophysics.

For example, coming straight from Appendix C of Griffith's E&M textbook, the energy density in the magnetic field is $ U = frac<1> <8pi>int (E^2 + B^2) d au, $ with no $epsilon_0 E^2$ and $B^2 / mu_0$ to make the units of electric and magnetic fields different. Since we deal with electric and magnetic fields all the time (both because we observe them and because they are dominant forces in many astrophysical contexts, such as in radiative stellar atmospheres and interstellar gas), having their units be the same both makes the physics more clear and makes them easier to work with.

All that said, in a field that still uses magnitudes, discounting convention too much would be a mistake!


7 Comments

Great show. Helps put what we see out in the cosmos into everyday things. One thing you didn’t talk about though was dark matter and dark energy. Don’t both have temperature? But perhaps we can’t measure it…As Pamela would say “But….” does anyone have any theory’s? And if the universe ends in the big nothing….expands forever, wouldn’t the temperature eventually reach zero some trillion billion years in the future? Just some thoughts.

it is just a measurement of temperature like cm is for length

Did everyone read the excellent Science News article: “A new kind of gravity?” The author refers to a generalization of the concept of temperature to a holographic-like structure in space-time. This would be an alternative concept to dark energy . I’d love to hear astronomycast sort that article out for us.

I very much enjoy your show and am glad you are doing such a thorough coverage of topics relating to astronomy and other related fields.
My question/comment is this: In the show on Temperature, it was asserted that there was no theoretical limit to high temperature, but wouldn’t the theory of relativity come into play here? After all, if temperature is about motion, there is an upper limit to the speed of particles, even at the quantum level of their vibrations.
Of course, if we are generally thinking about average kinetic energy of the particles, then their relativistically increased mass would be part of the temperature, so in that sense there would be no upper limit on temperature, but if we are just thinking about their motion, then there is a limit.
I would love to hear what you think about this.
Best,
Rodney Ward
Science Teacher, 7th Grade
Framingham, Massachusetts

Sir,
My name is Akhil, from India. I think I can throw some light on your question. Sir, in particle accelerators, like cyclotrons, where there are electrones getting acceleratrd to a speed nearly 0.99999…. times the speed of light. It cannot be accelerated beyond that because the mass will reach to infinity. It stll receives energy but, with a very little change in speed. My point is, still we can give energy to a particle. That means. I think we can give heat to an object as much as we want, there is no limit on that.


Watch the video: Why incompetent people think theyre amazing - David Dunning (May 2022).