Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

Recommended Posts

Thanks for the link, really interesting. I guess it only gets more complicated when you sub-categorise scattering into different 'type', then we're back to reflect, refract etc. It's as simple or complicated as you want it to be, but it's nice to know it can be simple :icon_biggrin: 

Share this post


Link to post
Share on other sites

Antireflection coatings operate by destructive interference. 2 waves will destruct if 180 degrees out of phase - where is the scattering in this?

Besides just offering someones Youtube video what are your views and understanding on these optical phenomenon you post up?

Explain why this is all scattering. Explain the principal and theory behind the video you have posted.

  • Thanks 1

Share this post


Link to post
Share on other sites

Yes it's hard to see how interference effects are scattering. (Such as the anti-reflection effects Ronin mentioned, and of course common diffraction effects such as Airy discs.)

Share this post


Link to post
Share on other sites

The cool deranged dude in the video doesn't say interference is scattering. He writes and says at the beginning (00:31) that optics is the study of interaction of light with matter, but interference is interaction of light with itself, quite something else. Thus optics is indeed only various forms of scattering.

Edited by Ben the Ignorant
typo

Share this post


Link to post
Share on other sites
On ‎21‎/‎09‎/‎2017 at 13:51, Ben the Ignorant said:

The cool deranged dude in the video doesn't say interference is scattering. He writes and says at the beginning (00:31) that optics is the study of interaction of light with matter, but interference is interaction of light with itself, quite something else. Thus optics is indeed only various forms of scattering.

Interference is the interaction of light with the sides of an aperture (for example.)

Interference is definitely a part of optics (for example zone plates and other more fancy flat lenses), if he says otherwise he's wrong.

Share this post


Link to post
Share on other sites

I see how you could equate interference with diffraction because they often happen together, but they are two distinct things. Interference is waves adding up or canceling each other, which could occur in the vacuum of outer space where there is no material object to cause diffraction between the sides of an aperture.

And if interference is produced in the void of space, it's called a particle physics phenomenon, or a wave physics phenomenon, but not an optical one.

Share this post


Link to post
Share on other sites
13 hours ago, Ben the Ignorant said:

 

And if interference is produced in the void of space, it's called a particle physics phenomenon, or a wave physics phenomenon, but not an optical one.

I feel that the video is slightly confusing. In the video, 'optics' is defined as the study of how light interacts with matter. This interaction is then explained as 'scattering'. 'Scattering' is a huge subject of which there are a great many different cases to consider, this is all glossed over in the video.  To make sense of 'optics' when defined like this is difficult.

'Geometric optics' on the other hand has some  simplifying assumptions which although fall short of the complete picture of light, do in fact provide a useful approximation of what happens with lenses, mirrors etc. It is assumed that light propagates as a ray and that the size of any mirrors/lenses are large when compared to the wavelength of light.

With these simplifying assumptions, Fermat's Principle of Least Time describes geometric optics perfectly. This one principle describes everything. Geometric optics in a sense is in fact simple....

https://en.wikipedia.org/wiki/Fermat's_principle

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Similar Content

    • By Dippy
      Baader optical wonder solution is practically Isopropyl alcohol. Instead of £12 for a 70mL of it, buy a 1000 mL of Isopropyl alcohol for £22 (before pandemic it was only £5). They have also smaller bottles which will be cheaper of course. The Baader solution and Isopropyl alcohol don’t remove the toughest of fungi on optics, only a few of the less deep set ones can be treated with them. I have used both for cleaning eyepieces and on certain stage of cleaning several 8 to 12 inch mirrors. They both worked identical. When applied through an optical cleaning fabric, they remove ( dissolve) fatty oils and fingerprints on optical surfaces. I had cleaned a 12 inch mirror once which for some unknown reason had ice cream stain on it (cleaning followed standard operation procedure for cleaning coated aluminised mirrors).
    • By Corpze
      So, I have been testing three different kind of lasers, each one is supposed to be the "best" in each category or what you want to call it, the hotech and HG is almost the same, but whit the difference in how you lock it down.
      The Catseye is very different in how it works.

      I made a Youtube video of my thoughts

      https://youtu.be/ERF33hNVieQ

      What do you think? which one do you use?

      Regards, Daniel


       

    • By Astrofriend
      Hi,
      I spend a day here to analyze my master flats and what vignetting I have on my lenses and telescopes. It's very simple done but still interesting to set figures on it.
       
      It's done on a full frame camera and I use the values from the center and the corner of the sensor. The corner is 22 mm of from the center on a full frame sensor. I never liked to have strong vignetting in my optics, and in the future I want to go for bigger size than full frame.
       
      I have put together a page over the vignetting I got:
      http://www.astrofriend.eu/astronomy/projects/project-different-lenses-vignetting/01-different-lenses-vignetting.html
       
      Maybe interesting for some of you to have a look at.
       
      My telescope shall handle a medium format sensor of the size 48 x 36 mm with the setup I have now. My medium format optics already do it. Just missing the medium format camera.
       
      /Lars
    • By Lonestar2123
      Hello. I am using a Orion xt8 reflector telescope. I am wondering what optic / eyepiece set up I should be using for a mix of DSO and planets. I have a couple pictures which I have taken with honestly my cell phone on one of those (Omi cellphone adaptors for telescope) and they pictures don't come out to bad... but I am looking for something that I can actually put into the eye piece that will give decent looking pictures, or even one that I can hook up to my computer and look through it live. Price really is not the biggest issue but not really looking for something over $400. I know there might not be such a thing as I am describing. most of these pictures were taken with a 2x barlow and a 20mm The ones of mars I just took with a 5x barlo and the same 20mm. and I am unsure what this star formation I took a picture of is but It looked pretty cool and I am glad that I was able to take a picture of it.. But just looking for some help choosing what camera would be best.  (Obviously using the phone camera the objects appear so bright and there is no way to pull the actual detail of the planet into focus for me) But any help would be great :) Thank you for any feedback you have and I cant wait to become more active on this forum!











    • By MikeODay
      The Cat's Paw Nebula ( NGC 6334 ) in Scorpius 
      updated ( slight tweak to colour balance, a little brighter and tad more contrast )  

      ( please click / tap on image to see larger and sharper - a full size image can be seen here )
      ......
      original:

      ( please click / tap on image to see larger and sharper - a full size image can be seen here )
      ……………………...
      Also known as the Bear Claw Nebula, NGC 6334 is an emission nebula near the scorpion's tail in the Scorpius constellation. 
      Image details:
      Image centre ...... RA: 17 20 08.185  Dec: -35 52 30.91
      Field of view ..... 57' 37.8" x 38' 51.8"
      Rotation .......... 0.00 deg ( North is up )
      Resolution ........ 0.586 arcsec/px
      Telescope: Orion Optics CT12 Newtonian ( mirror 300mm, fl 1200mm, f4 ).
      Corrector: ASA 2" Coma Corrector Quattro 1.175x.
      Effective Focal Length / Aperture : 1470mm f4.7
      Mount: Skywatcher EQ8
      Guiding: TSOAG9 Off-Axis-Guider, Starlight Xpress Lodestar X2, PHD2 
      Camera:
      Nikon D5300 (unmodified) (sensor 23.5 x 15.6mm, 6016x4016 3.9um pixels)
      Location:
      Blue Mountains, Australia 
      Moderate light pollution ( pale green zone on darksitefinder.com map )
      Capture ( July 2018 )
      6 sets of sub-images with exposure duration for each set doubling ( 4s to 240s ) all at ISO 250.
      168 x 4 min frames plus ~10 frames each for the shorter exposures  
      Processing:
      Calibration: bias, dark and flat
      Integration in 8 sets
      HDR combination 
      Pixinsight July 2018
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.