Cela fait des décennies que ça existe ! Personnellement j'utilisais ce genre de truc il y a plus de 40 ans ! Les aigrettes (spikes) sont diffusées sur toute l'image, donc on ne les voit presque plus, par contre, il n'y a pas de magie : c'est une obstruction supplémentaire : cela ajoute de la diffusion et supprime le contraste (à ne pas utiliser en mode planétaire, lunaire, solaire)... Vous pouvez trouver quelqu'un pour imprimer en 3D sur Thingiverse... L'intérêt autre qu'esthétique (pour ceux qui n'aiment pas les aigrettes) et de pouvoir empiler des images avec des orientations différentes sans avoir des aigrettes dans tous les sens, ce qui est quand même très intéressant lorsqu'on photographie le même objet sur plusieurs nuits (voire plusieurs semaines ou années!).
@@ortizma13 The JWST has both spiders and the long arms that hold the camera away from the mirror.... that is why it has two sets of diffraction spikes... larger from the long arms and the shorter ones for the spider.
In other words, diffraction is happening at the edge of an obstruction and directs light perpendicularly to that edge. A curved spider vane and curved shapes will hence redirect (diffract) light all across the FoV and increase the halo around the stars rather than create well defined spikes.
The mirror of your telescope modifies the path of the light such that the image at the focal plane is (essentially) a Fourier transform of the "image" at the front aperture. So anything placed in that aperture, like the spider, modifies the Fourier transform of the image formed at the focal plane. Multiplying in the Fourier domain is convolution in the image domain, so your image gets convolved with the Fourier transform of whatever your support structure looks like. The shape of the diffraction modifiers is chosen so they spread the diffraction artifact into a shape that's less noticeable. They modify the shape of the diffraction artifact; they apodize it. Wikipedia has a decent article with some examples for different shapes: en.wikipedia.org/wiki/Diffraction_spike#:~:text=Support%20vanes,-Comparison%20of%20diffraction&text=No%20matter%20how%20fine%20these,used%20to%20image%20the%20star.
Now this makes a lot of sense, thank you!! I'm having trouble imagining how to apply a Fourier transform to a shape (and a cross would be like some sort of flat function with a Dirac in the middle, so infinite frequencies... That that's why we get infinitely long star spikes that just dissipate as they go? I need to research this!)
@@CuivTheLazyGeek Higher dimensional FTs follow a lot of the same patterns the 1D one does. Yeah, the FT of a cross is sort of another cross with a spike in the middle, the details depending on the thickness of the arms. The round central obstruction will spread that spike out a bit. Since stars are basically impluses, an isolated star is basically a picture of the FT of your spider. The papers other commenters have linked to seem to try to derive shape of the diffraction devices analytically. I don't think it would be too hard today to set up a problem with a Fourier optics model and optimize the device shape for whatever result you wanted. I might give that a try. Happy face stars? If you want some light reading, Joseph Goodman's Introduction to Fourier Optics is the bible. It's not light, but these lecture notes are pretty amazing too. They derive Fourier optics, but also ray optics as far field approximations of the angular spectrum representation: ethz.ch/content/dam/ethz/special-interest/itet/photonics-dam/documents/lectures/EandM/AngularSpectrumRepresentation.pdf
Has anyone replaced the open end of a Newt with an Optically neutral piece of glass with the Secondary Mirror suspended in the middle ? This would resemble an SCT of course but without the Optical “curve” . It would help to keep the Primary Mirror clean as well . Just a Newb question ./srk
In layman's terms: Imagine your spikey star image is a balloon with tentacle-like extensions. This gizmo simply squishes the 'air' (i.e. the light) from the tentacles back into the main body of the balloon so the balloon is rounder but also a little wider in diameter because the light that was filling the tentacles is now just expanding the rest of the balloon. You therefore loose resolving power. Others have explained it more technically in the comments if you are into Fourier transforms and such but that's essentially what it boils down to.
I have tried this, but the artifacts become very visible (and in my opinion a bit ugly). If you take longer subs they look even more strange and after stacking it sometimes looks awful. Though, you might want to use two of the four to have thinner spikes (since they will not overlap anymore). Also, during my tests, those things totally confused starexterminator that probably never had seen such strange stars before...
This cunning contraption was immensely popular among newt keepers a couple of years ago, but, in the end, the crowd abandoned it due to its degenerative influence on the image quality. I would recommend flocking spider spikes instead. I did it to my F2.8 newt, and those virtually light-years-long spikes became quite tolerable.
I wonder if someone makes curved spider veins to completely remove all diffractions? Either way thats a cool effect! And I wouldn't worry about bats, I would be more worried about robins showing up 😛
I believe nasa had a project named new worlds mission that uses a star shade that uses a similar concept to reduce difracction during star ocultations. It would be great to achieve something similar for the secondary of a Schmidt cassegrain.
In more mathematical terms, it redistributes the point spread function's intensity. I prefer to just use BlurXterminator post processing to do this mathematical function digitally, rather than physically increasing the obstruction and losing some information.
Thanks for the clarification about how this works! @boetschge: this video is just a test, unlike many other in depth videos about say, noise and astrophotography.
@@CuivTheLazyGeek You are doing a great job! The more your channel grows, the higher are expectations, of course :-) Just keep on doing your Thing, we love you!
I prefer my bat "appetizers" wrapped in bacon 🥓. Ha! But seriously, this sort-of solves your problem of needing to synchronize the spider vanes on your "double-barrel cuiv-scope".
Great video again, brilliant actually. I must have missed it but where can I purchase a new one piece spider for my 200mm Meade? I just cannot collimated that thing, I’m desperate. Bought it from “All-Star Telescope” and it showed up damaged, their answer is to ghost me, lol.
That thing is rubbish, IMO. Everything in the optical path contributes with its Fourier Transform shape to the final image. So adding things cannot improve, just change the shape (ie where photons end up landing) . The only way to get rid of diffraction patterns is having bigger pixels (so the pattern is binned in a pixel) and lower F/ (smaller Airy disk). Newton telescopes' users should just enjoy their spikes and put the money in sth else
I'm not really a telescope aficionado... but I do understand what's going on... (The comment from @ceoyoyo includes an excellent explanation.) (The little bats are effectively cancelling out some of the error created by the spider.) As for your closing question.... Assuming that those were designed specifically for that telescope and original spider... I would expect them to work best with those. The different spider will alter some of the optical properties that they are correcting. (But I have no idea how significant a particular change would be to the result.)
Interesting video and product! I'm literally just getting my new CYCK spider out of the box to fit it and I see this 😭 To be honest I would prefer perfect (if enhanced) spikes than this effect, the stars will be more compact overall. I think!
I experimented with it on several Newtonian telescopes, but the biggest issue is that something like Batman appears in the ghost of the huge stars. While it is possible to try this with M42 or IC434, the correction is challenging. However, if there are no nearby stars like Alnitak, excellent results can be obtained using BXT.
A physicist's point of view: The idea of apodization is so old that it was mentioned in the original "Amateur Telescope Making, Vol. II" by Albert Ingalls in 1937. If you check out his figure, the things even look similar. Also, the famous optician André Couder wrote about this kind of thing at the beginning of the 20th century. All that these things do is introduce more diffraction. Because of their irregular shape, the diffraction pattern is no longer all that nice and regular, but the energy is distributed throughout the image. In other words: these little masks will take out more energy from the central maximum of each star, distribute them around its edges, and also contribute ever so slightly to a brighter background. As you can clearly see in your first light image at 8:58, you get frilly edges on your stars instead of the spider vane cross pattern, but the fourfold-symmetry of the spider is still there because you have introduced four identical little baffles.
As this is just a mechanical means of altering the optical characteristics I am a bit surprised that no one has thought of this idea before, particularly the telescope manufacturers, who could have incorporated it into their secondary mirror spider designs. I don't use my Newtonian very much, and I am in fact considering selling it so I doubt I'll be buying these devices. To be honest I don't mind the diffraction spikes, though if I was imaging with a Newt all the time I probably would like the option to remove them for targets where they may be a bit overpowering. Finally Cuiv, I think the Frankenscope looks really awesome.
Thanks for the details! I know Vixen has some of their small visual scopes with curved spiders to avoid star spikes... But would be fun to have manufacturers providing these as an option
I’m guessing this is like a curved spider, which removes the spikes but “moves” the diffraction into a “blob” on the star, making the star less sharp. I’d rather have the spikes
I did look a dual reflector setup but am currently setting up a refractor setup instead. The thing with fast reflectors is the collimation and posible mirror shift moving the alignment of both scopes fov. Im to Lazy to deal with that😂 With the refractors i will have fixed optics
You can also get rid of the star spikes by using curved spider struts. You want the strut tangents to uniformly span a full 360deg angle range. It will still diffract, but the diffraction will not be concentrated in specific directions.
Yeah I don't know if it's a sign of me being very early in my astrophotography or showing my age but I rather enjoy the diffraction spikes, like you said it reminds me of the hubble photos I grew up with.
Hi Cuiv! Great video, again. -- The Fraunhofer (far field) diffraction pattern can be approximated with great accuracy by the magnitude squared of the spacial, Fourier transform of the obstruction (for a given wavelength of light). I think you're already familiar with Fourier transforms, which is why I bring that up. In other words, for all practical purposes, the obstruction geometry and it's diffraction pattern are essentially Fourier transform pairs (although there is a magnitude squared involved). Flat, horizontal obstructions will produce vertical spikes, and flat, vertical obstructions will produce horizontal spikes. The Batman shaped things work by (a) constantly being curved (i.e. removing the flat geometry) and also (b) having a varying rate of spacial curvature, which spreads the diffraction (hopefully somewhat evenly) across spacial frequency.
In other words, diffraction is happening at the edge of an obstruction and directs light perpendicularly to that edge. A curved spider vane and curved shapes will hence redirect (diffract) light all across the FoV and increase the halo around the stars rather than create well defined spikes.
i despise diffraction spikes. they are NOT naturally occurring, they are added artifacts to photos. yet people get so ANGRY about added artifacts to astro photos but gloss over these like they are 'cool'. well just go add some other lines dots and whatever you want then too since apparently it doesnt matter. the excuse that hubble had them is a bad one. i wont ever buy a newt for this very reason. because i dont have too. they HAD to with the hubble to get it feasible. it wasnt because they thought it was 'pretty'. its a negative aspect to the design. its called a flaw, not bonus material.
Ah Batman to the rescue lol, it kinda reminds me of being at a star party & a guy with a 20" Dob & the bat sign tried making the bat lamp on a cloudy night, it didn't work but it was funny all the same. I have seen curved spider vanes used to get rid of diffraction spikes maybe someone on Ali Express could make some he he. Clear skies
Decades ago, I saw a picture of a scope made in Russia that had spider veins that were shaped like half circles. Someone claimed that they still produced diffraction but the curved shape allowed the pattern to be essentially spread out and "cancelled". I don't know if the word "cancelled" is the right word, but they seemed to work. I suspect that regardless of patent issues, the curved veins may be mechanically problematic especially in larger scopes. I'm going to have to take a look at this Japanese company's web site.
Idk if you ask me the refraction spikes add very nice colors to blue and orange stars. If I started astrophotography from scratch I would take the reflector route because I love how those spikes look on bright stars as they also add very nice blue and orange colors.
Nah! It's a gimmick... On with the video. OK sorta... I think it mushes out the sharpness. There's no free lunch. And I'm biased anyway... I like spikes. Reminds me of Christmas! 😉👍
Newtonian spikes can be very distracting on any target with bright stars around. Pleiades can be just too much, so is Alnitak with the Horsehead nebula.
@@CuivTheLazyGeek They Look Incredible,lol..But I Dont Use It All The Time,Just When Wanting The Brighter Stars Standing Out..Ive Got Clear Skies For The 1st Time In 4 Months😂🤣😂I Dont Know What To Do,lol..Besides Catch The Borealis,lol….
I thought they would help eliminate the spikes, but not work as well as they did. Remember that some spiders used curved veins to (or try to) eliminate the spikes, therefore they're due to the veins being straight and across the FOV. "Jingle bells, Batman smells, Robin laid an egg, The Batmobile lost a wheel, the Joker got away, hey" Geek On, Cuiv!
I use a refactor and I personally do not care for the star spikes from Newtonians, but it is the signature of a Newtonian scope. I do prefer the normal Newtonian spikes over the small stars with 4 stub spikes this device generated. Have you looked curved spiders?
I personally love the star spikes. And in my terrestrial photography, I love the sun-stars, and lightbulb-stars at night photography. My favorite is 10 spikes, but I only have one lens with ten aperture blades, fortunately not rounded blades. (I even like ten sided bokeh balls.) I’ve been doing some ultra-wide Astro-imaging lately with camera lenses, and the star spikes help differentiate the stars from the globular clusters and any small fuzzy nebulae.
Cool! This is very timely. My 10" reflector is arriving this week. I'll custom order these so I have the option of removing the diffraction spikes. Thank you!
BTW you missed one potential benefit. If you are imaging with a Newt/DK/RC/etc and you don't have a permanent set-up, it's virtually impossible to get the diffraction spikes to line up over more than one session. The apodizer should allow you to combine imaging runs over several nights with a Newt.
You make a very key point. And that is why I don't use a Newtonian for imaging since my image data often are taken over several nights... even years, locations, different scopes, and setups. I could never understand why people will add fishing line, etc. to a SCT to create diffraction spikes! I use either refractors or SCTs to AVOID those diffraction spikes. Perhaps people think that having those diffraction spikes makes their images like the professional big observatories that use giant reflectors and do have those spikes ;-) There are other ways to eliminate those spikes on reflectors.... curved vanes is one way. I also use Hyperstar setups and if you run the camera cables from the camera and an angle down to a point where they can exit near the corrector through the dew shield you can also mostly eliminate the spikes. If you run them horizontally on a Hyperstar setup out the side near the forward edge of the dew shield you will get the spikes.
what? I regularly shoot over multiple nights (while reassembling the whole rig), and never had this problem. Spikes will be aligned, just like everything else, during stacking.
"it's virtually impossible to get the diffraction spikes to line up over more than one session" Sure it's possible and done a million of times. Plate solve to find previous imaging angle and adjust camera current angle to match. Friggen MAGIC!
No, actually the diffraction spike angle doesn't change between nights, at least after star alignment - it will only change if you physically rotate the tube and thus the spider - only the orientation of the spider wrt the stars is important, the orientation of the camera won't be an issue!
The images are already manipulated in many ways. The regular spikes are not real and neither is the noise, the brightness, the apparant size of stars, or the 2D representation of a 3D object. Even our eyes manipulate images, as can be seen by optical ilusions. Scientific observations are done all the time with corrective optics where the mirror is physical bend into a differnt shape. I believe it is all up to the photographer how the image is captured, as long as it is not misleading.
So glad you decide to try these out. I got one for my Kasai Trading Ginji 200/4 Newt, and another for my VMC260L, but have yet to try out imaging with them.
This kind of makes me wonder what kind of effect you would get if you had a spider that rotated slightly after every image, but you were able to keep the secondary mirror still.. I assume the diffraction spikes would cancel out in stacking?
@@CuivTheLazyGeek Yea, that's what I was thinking, kind of like satellite trails. But of course the problem would be trying to implement something like this without vibration, or the secondary mirror moving, but I'm sure there are probably some people a lot smarter than me could find a way to do it with some gears and a belt.
Hey Cuiv nice video as usual, I'm considering the apertura carbon star 150 but I'd like to know if it has major issues or after a quick collimation is ready to go. What are your thoughts on that scope? Thanks 😊
BTW it's "apodizer", not "apotizer". The original paper is "Apodization of the flat mirror support of a Newton telescope" by Temich et al. I think the StarWorks site is using automatic translation.
Also "apo" just means "far away". I presume apochromats are named so to emphasise they have even less colour than achromats. So, to me "apoodizer" just means they are removing the aberation, in this case the diffraction spikes. Doesn't really mean "it's like a refractor" to me.
I did some research on these things a while back. Basically that shape is a dissected circle and what it does is to scatter the light that would normally get concentrated into diffraction spikes. I thought about using them but I would have to print them myself since I use the smaller Skywatcher 130p-ds and nobody seems to make them to fit small scopes like that. Honestly though, if it makes my stars look weird, I would rather have the clean spikes
These bats should have been marked closer to the diagonal mirror, perhaps at Newton 200 mm they should be printed larger in linear size, and the effect is similar to a radius spider, when light waves are reflected and cancel each other out due to the interference effect, a local calm with small ripples is created, which the main mirror no longer sees
@@CuivTheLazyGeek In more detail and "scientifically" you can find out here about the calculation of the shape of the spider and its influence on the final shape of the stars www.telescope-optics.net/spider.htm
My solution to the diffraction from the spider vanes has been to 3D print a curved vane spider. Like these apodizers, it's almost magical how well it works. In both cases, the overall diffraction increases, but it is distributed across the image and reduces the contrast just a little bit. Maybe not quite a refractor, but getting close.
They need to use 2 arcs to hold the secondary. We use one arch with our hyperstars to remove the single diffraction spike cause by cables. By routing the cables in an arch it removes the spike.
I don't understand all the love for diffraction spikes here. They are literally destroying data behind them. I would get rid of them in a heart beat if I can afford a 12" $500k commercial refractor. I just don't know if I like the weird stars you got with this addon.
@@CuivTheLazyGeek didn’t know that. I will seek the Aussies wit and wisdom on the subject. But I agree. The remind me of NASA photos and thus seem almost…. Important.
Have you seen a RASA? The camera is mounted on front. Power and data cables coming off it cause diffraction spikes. Some people orient them at 90 degrees.
The reason why the bat spider vanes work is because they create interference pattern waves that cancel out each other. Think of a pool and a wave generated on one end. If you create another wave that is opposite of it in the reverse direction, you can cancel the original wave out. The interference modeling to figure that out is even more interesting than the result.
Hi Cuiv, Jaime from Chile again. If you going to 3d printing your own apodizing devices, make sure to scale acording to your telescope . The total length should be according to the following simple formula: Main mirror diameter minus secondary mirror diameter divided by 2. Then at the moment of placing on the spider, make sure you consider to fit the Device starting from the edge of the secondary mirror to eliminate the spikes because they are placed right on the light path of the telescope. Hope this information will help you. Greetings from BelloCielo - Chile 🇨🇱
Removing spikes is considered as crime to humanity. The best spikes that I ever got were with the "amazing" spider of my Skywatcher 150PDS and my DSLM having Alnitak on the exposures. The spikes in fact went through the full image. I love diffraction spikes!
@@CuivTheLazyGeek Star Spike Police is on it's way to Tokyo. 😄If you are nice and remove those evil things and they are able to confiscate then they are going to be pleased and won't arrest you. 😁
It works completely off of sound mathematical principles. Bahtinov mask is another kind of mask that redistributes intensity of light using similar concept.
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Cela fait des décennies que ça existe ! Personnellement j'utilisais ce genre de truc il y a plus de 40 ans !
Les aigrettes (spikes) sont diffusées sur toute l'image, donc on ne les voit presque plus, par contre, il n'y a pas de magie : c'est une obstruction supplémentaire : cela ajoute de la diffusion et supprime le contraste (à ne pas utiliser en mode planétaire, lunaire, solaire)...
Vous pouvez trouver quelqu'un pour imprimer en 3D sur Thingiverse...
L'intérêt autre qu'esthétique (pour ceux qui n'aiment pas les aigrettes) et de pouvoir empiler des images avec des orientations différentes sans avoir des aigrettes dans tous les sens, ce qui est quand même très intéressant lorsqu'on photographie le même objet sur plusieurs nuits (voire plusieurs semaines ou années!).
Removing Newtonian star spikes may be considered a crime
Indeed, I love those spikes and shouldn't be removed ever. If you want without them then buy a refractor :D
Agreed. Though the JWST could use a few of those
@@ortizma13 The JWST has both spiders and the long arms that hold the camera away from the mirror.... that is why it has two sets of diffraction spikes... larger from the long arms and the shorter ones for the spider.
AFAIK it's illegal in at least 6 states.
@@czejczej Refractors are much more expensive and they are annoying when having it on the horsehead neb:D Also looks weird on fainter stars
Spider vane,
Spider vane,
Does whatever a spider vane does.
Batman fell into the dark
Bane was born into the dark,
But Cuiv...he chose the dark.
:D
In other words, diffraction is happening at the edge of an obstruction and directs light perpendicularly to that edge. A curved spider vane and curved shapes will hence redirect (diffract) light all across the FoV and increase the halo around the stars rather than create well defined spikes.
The mirror of your telescope modifies the path of the light such that the image at the focal plane is (essentially) a Fourier transform of the "image" at the front aperture. So anything placed in that aperture, like the spider, modifies the Fourier transform of the image formed at the focal plane. Multiplying in the Fourier domain is convolution in the image domain, so your image gets convolved with the Fourier transform of whatever your support structure looks like.
The shape of the diffraction modifiers is chosen so they spread the diffraction artifact into a shape that's less noticeable. They modify the shape of the diffraction artifact; they apodize it.
Wikipedia has a decent article with some examples for different shapes:
en.wikipedia.org/wiki/Diffraction_spike#:~:text=Support%20vanes,-Comparison%20of%20diffraction&text=No%20matter%20how%20fine%20these,used%20to%20image%20the%20star.
Now this makes a lot of sense, thank you!! I'm having trouble imagining how to apply a Fourier transform to a shape (and a cross would be like some sort of flat function with a Dirac in the middle, so infinite frequencies... That that's why we get infinitely long star spikes that just dissipate as they go? I need to research this!)
@@CuivTheLazyGeek Higher dimensional FTs follow a lot of the same patterns the 1D one does. Yeah, the FT of a cross is sort of another cross with a spike in the middle, the details depending on the thickness of the arms. The round central obstruction will spread that spike out a bit. Since stars are basically impluses, an isolated star is basically a picture of the FT of your spider.
The papers other commenters have linked to seem to try to derive shape of the diffraction devices analytically. I don't think it would be too hard today to set up a problem with a Fourier optics model and optimize the device shape for whatever result you wanted. I might give that a try. Happy face stars?
If you want some light reading, Joseph Goodman's Introduction to Fourier Optics is the bible. It's not light, but these lecture notes are pretty amazing too. They derive Fourier optics, but also ray optics as far field approximations of the angular spectrum representation:
ethz.ch/content/dam/ethz/special-interest/itet/photonics-dam/documents/lectures/EandM/AngularSpectrumRepresentation.pdf
I used to have Goodman's book, but a brief scan of my shelves didn't find it....
Has anyone replaced the open end of a Newt with an Optically neutral piece of glass with the Secondary Mirror suspended in the middle ? This would resemble an SCT of course but without the Optical “curve” . It would help to keep the Primary Mirror clean as well . Just a Newb question ./srk
Would be nice! There's also Schmidt Newtonians and Mak-Newts :)
I don't like it.....Just make the telescope with the curved spider viens to eliminate the spikes.
You can call them "Bat-inov Masks". You're welcome.
In layman's terms: Imagine your spikey star image is a balloon with tentacle-like extensions. This gizmo simply squishes the 'air' (i.e. the light) from the tentacles back into the main body of the balloon so the balloon is rounder but also a little wider in diameter because the light that was filling the tentacles is now just expanding the rest of the balloon. You therefore loose resolving power. Others have explained it more technically in the comments if you are into Fourier transforms and such but that's essentially what it boils down to.
The layman explanation, I LOVE this, thank you!
Blurxterminator should sort this out
😂😂 Love it, you make such charismatic videos, long live the Cuiv….👍🏻
Glad you like them! I had fun with this one!
I didnt care for now what appears like diamond 💎 stars i rather have rhe spikes
I have tried this, but the artifacts become very visible (and in my opinion a bit ugly). If you take longer subs they look even more strange and after stacking it sometimes looks awful.
Though, you might want to use two of the four to have thinner spikes (since they will not overlap anymore).
Also, during my tests, those things totally confused starexterminator that probably never had seen such strange stars before...
Aha, I should try BXT and SXT on this!
This cunning contraption was immensely popular among newt keepers a couple of years ago, but, in the end, the crowd abandoned it due to its degenerative influence on the image quality. I would recommend flocking spider spikes instead. I did it to my F2.8 newt, and those virtually light-years-long spikes became quite tolerable.
The spider veins on my Newt (used for the test) are actually already flocked, but now I need to test that with the CarbonStar!
We just need secondary mirrors held,floating in place, by electromagnets.
@@CuivTheLazyGeek well done, mate 🙌
@@WilliamBlakers Astro-Biscuit uses piano strings for that purpose… it works incredibly well!
@@shusiman no, they didnt, hes got rid of them
"Kind of cool and ridiculous at the same time" is definitely where the fun happens in this hobby. 😆
I wonder if someone makes curved spider veins to completely remove all diffractions? Either way thats a cool effect! And I wouldn't worry about bats, I would be more worried about robins showing up 😛
Vixen does! On their smaller VMC90 and VMC110 scopes! Not sure if they're still making them though
I believe nasa had a project named new worlds mission that uses a star shade that uses a similar concept to reduce difracction during star ocultations. It would be great to achieve something similar for the secondary of a Schmidt cassegrain.
The diffraction is not removed. Just spread out more evenly into the background with a loss of contrast result. You don't get nothing for nothing!
Thanx for your Comment. What you are saying is exactly what happens. Sadly, Cuiv is not that informative.
In more mathematical terms, it redistributes the point spread function's intensity. I prefer to just use BlurXterminator post processing to do this mathematical function digitally, rather than physically increasing the obstruction and losing some information.
Thanks for the clarification about how this works!
@boetschge: this video is just a test, unlike many other in depth videos about say, noise and astrophotography.
@@CuivTheLazyGeek You are doing a great job! The more your channel grows, the higher are expectations, of course :-)
Just keep on doing your Thing, we love you!
I think the diffraction spikes add a bit of artistic flare, especially on the large stars.
Couldnt this help with your frankenscope? That way the 2 spiders wouldnt have yo be perfectly aligned?
Correct! But the small star stubs are bothering me haha
@CuivTheLazyGeek I definitely understand that. Are you going to try the custom version?
What does blur exterminator do to the strange stars created by the bat wings?
I'll have to test!
I have seen worm style spike killers. Old way is use curved vaines.
Yep, the small vixen VMC scopes have those!
This is blasphemy! Removing defraction spikes from a Newwt...... in Gretta's tone "how dare you" hehehehehehe
It looks like the spikes were not removed, but rather replaced by the spikes from the bat-thingies. So you just have different spikes.
Technically it is overlapping existing spikes inversely... True method is making mask with 4 holes just around the spikes without any obstruction.
I prefer my bat "appetizers" wrapped in bacon 🥓. Ha!
But seriously, this sort-of solves your problem of needing to synchronize the spider vanes on your "double-barrel cuiv-scope".
Great video again, brilliant actually. I must have missed it but where can I purchase a new one piece spider for my 200mm Meade? I just cannot collimated that thing, I’m desperate. Bought it from “All-Star Telescope” and it showed up damaged, their answer is to ghost me, lol.
That thing is rubbish, IMO. Everything in the optical path contributes with its Fourier Transform shape to the final image. So adding things cannot improve, just change the shape (ie where photons end up landing) . The only way to get rid of diffraction patterns is having bigger pixels (so the pattern is binned in a pixel) and lower F/ (smaller Airy disk).
Newton telescopes' users should just enjoy their spikes and put the money in sth else
I'm not really a telescope aficionado... but I do understand what's going on...
(The comment from @ceoyoyo includes an excellent explanation.)
(The little bats are effectively cancelling out some of the error created by the spider.)
As for your closing question....
Assuming that those were designed specifically for that telescope and original spider...
I would expect them to work best with those.
The different spider will alter some of the optical properties that they are correcting.
(But I have no idea how significant a particular change would be to the result.)
Interesting video and product! I'm literally just getting my new CYCK spider out of the box to fit it and I see this 😭 To be honest I would prefer perfect (if enhanced) spikes than this effect, the stars will be more compact overall. I think!
Enjoy the CYCK focuser! It's working well for me!
I experimented with it on several Newtonian telescopes, but the biggest issue is that something like Batman appears in the ghost of the huge stars. While it is possible to try this with M42 or IC434, the correction is challenging. However, if there are no nearby stars like Alnitak, excellent results can be obtained using BXT.
A physicist's point of view: The idea of apodization is so old that it was mentioned in the original "Amateur Telescope Making, Vol. II" by Albert Ingalls in 1937. If you check out his figure, the things even look similar. Also, the famous optician André Couder wrote about this kind of thing at the beginning of the 20th century.
All that these things do is introduce more diffraction.
Because of their irregular shape, the diffraction pattern is no longer all that nice and regular, but the energy is distributed throughout the image. In other words: these little masks will take out more energy from the central maximum of each star, distribute them around its edges, and also contribute ever so slightly to a brighter background.
As you can clearly see in your first light image at 8:58, you get frilly edges on your stars instead of the spider vane cross pattern, but the fourfold-symmetry of the spider is still there because you have introduced four identical little baffles.
Great video! I loved the energy. You had me laughing 🤣. Thanks!
Glad you enjoyed!
Amazing how two telescopes on the same mount allow you to test out and compare different hypothesis right away, so cool!
It's a lot of fun!
As this is just a mechanical means of altering the optical characteristics I am a bit surprised that no one has thought of this idea before, particularly the telescope manufacturers, who could have incorporated it into their secondary mirror spider designs. I don't use my Newtonian very much, and I am in fact considering selling it so I doubt I'll be buying these devices. To be honest I don't mind the diffraction spikes, though if I was imaging with a Newt all the time I probably would like the option to remove them for targets where they may be a bit overpowering. Finally Cuiv, I think the Frankenscope looks really awesome.
Thanks for the details! I know Vixen has some of their small visual scopes with curved spiders to avoid star spikes... But would be fun to have manufacturers providing these as an option
Thank you for being a such a knowledgeable resources, you've taught so many people so many things
My pleasure! Although to be fair I was just having fun in this video :)
I’m guessing this is like a curved spider, which removes the spikes but “moves” the diffraction into a “blob” on the star, making the star less sharp. I’d rather have the spikes
you can reduce the spikes quite a bit by flocking the spider vanes.
True! Although in my case (for the SW Quattro) they are already flocked!
👍👍👍👍👍👍👍
I have a Newtonian scope precisely because I love diffraction spikes. No bat-scope for me.
I did look a dual reflector setup but am currently setting up a refractor setup instead. The thing with fast reflectors is the collimation and posible mirror shift moving the alignment of both scopes fov. Im to Lazy to deal with that😂 With the refractors i will have fixed optics
You can also get rid of the star spikes by using curved spider struts. You want the strut tangents to uniformly span a full 360deg angle range. It will still diffract, but the diffraction will not be concentrated in specific directions.
Yeah I don't know if it's a sign of me being very early in my astrophotography or showing my age but I rather enjoy the diffraction spikes, like you said it reminds me of the hubble photos I grew up with.
Bat Scope, Spider Vanes, any other superheroes? Your laugh is more like that of a Bond villain.
But I love my spikes, last week i glued strings on my refractor objective
Hi Cuiv! Great video, again. -- The Fraunhofer (far field) diffraction pattern can be approximated with great accuracy by the magnitude squared of the spacial, Fourier transform of the obstruction (for a given wavelength of light). I think you're already familiar with Fourier transforms, which is why I bring that up. In other words, for all practical purposes, the obstruction geometry and it's diffraction pattern are essentially Fourier transform pairs (although there is a magnitude squared involved). Flat, horizontal obstructions will produce vertical spikes, and flat, vertical obstructions will produce horizontal spikes. The Batman shaped things work by (a) constantly being curved (i.e. removing the flat geometry) and also (b) having a varying rate of spacial curvature, which spreads the diffraction (hopefully somewhat evenly) across spacial frequency.
In other words, diffraction is happening at the edge of an obstruction and directs light perpendicularly to that edge. A curved spider vane and curved shapes will hence redirect (diffract) light all across the FoV and increase the halo around the stars rather than create well defined spikes.
That is fascinating, thank you so much! I need to figure out how to do Fourier transform of shapes, I'm used to functions :)
@@CuivTheLazyGeek maybe you are supposed to put the bat signals along the full length of the spider vanes?
@@CuivTheLazyGeek You can draw a monochrome image and use SiriL to perform the direct and inverse transforms
So, destructive interference?
i despise diffraction spikes. they are NOT naturally occurring, they are added artifacts to photos. yet people get so ANGRY about added artifacts to astro photos but gloss over these like they are 'cool'. well just go add some other lines dots and whatever you want then too since apparently it doesnt matter. the excuse that hubble had them is a bad one. i wont ever buy a newt for this very reason. because i dont have too. they HAD to with the hubble to get it feasible. it wasnt because they thought it was 'pretty'. its a negative aspect to the design. its called a flaw, not bonus material.
Well... at least now you know how to align the spikes from the two scopes ... remove them, and the problems is solved. :D
👍😎🇦🇺🐈⬛
Ah Batman to the rescue lol, it kinda reminds me of being at a star party & a guy with a 20" Dob & the bat sign tried making the bat lamp on a cloudy night, it didn't work but it was funny all the same. I have seen curved spider vanes used to get rid of diffraction spikes maybe someone on Ali Express could make some he he.
Clear skies
Decades ago, I saw a picture of a scope made in Russia that had spider veins that were shaped like half circles. Someone claimed that they still produced diffraction but the curved shape allowed the pattern to be essentially spread out and "cancelled". I don't know if the word "cancelled" is the right word, but they seemed to work. I suspect that regardless of patent issues, the curved veins may be mechanically problematic especially in larger scopes. I'm going to have to take a look at this Japanese company's web site.
The smaller Vixen VMC scopes actually use curved spider veins!
“The next steps would be… “ i was expecting you to say dress up like batman while using the telescope at night 😂
A circular disk of glass might help. ;)
Mmmmmh hahaha
You know what else is cool and ridiculous at the same time?
Bicycle choppers.
Idk if you ask me the refraction spikes add very nice colors to blue and orange stars. If I started astrophotography from scratch I would take the reflector route because I love how those spikes look on bright stars as they also add very nice blue and orange colors.
Yep a lot of people (and tbh me too) love diffraction spikes!
The evil laugh cracks me up! As always, good video Cuiv!
No idea how those veins work but I think you mean the ‘Bat Wing’ that could fly!
Nah! It's a gimmick...
On with the video.
OK sorta... I think it mushes out the sharpness. There's no free lunch. And I'm biased anyway... I like spikes. Reminds me of Christmas! 😉👍
Fully agree in the end :)
This is apparently not available in the US. Is there another source?
And Here I Am Using Fishing Line On My Sct To Get Those Spikes😂❤❤
Newtonian spikes can be very distracting on any target with bright stars around. Pleiades can be just too much, so is Alnitak with the Horsehead nebula.
They do look really good haha
@@CuivTheLazyGeek They Look Incredible,lol..But I Dont Use It All The Time,Just When Wanting The Brighter Stars Standing Out..Ive Got Clear Skies For The 1st Time In 4 Months😂🤣😂I Dont Know What To Do,lol..Besides Catch The Borealis,lol….
Mmmm appetizing 😋
Yummy!
I thought they would help eliminate the spikes, but not work as well as they did. Remember that some spiders used curved veins to (or try to) eliminate the spikes, therefore they're due to the veins being straight and across the FOV.
"Jingle bells, Batman smells,
Robin laid an egg,
The Batmobile lost a wheel,
the Joker got away, hey"
Geek On, Cuiv!
Always geeking on!
I use a refactor and I personally do not care for the star spikes from Newtonians, but it is the signature of a Newtonian scope. I do prefer the normal Newtonian spikes over the small stars with 4 stub spikes this device generated. Have you looked curved spiders?
Curved spiders are fun! The smaller Vixen VMC scopes have them
I personally love the star spikes. And in my terrestrial photography, I love the sun-stars, and lightbulb-stars at night photography. My favorite is 10 spikes, but I only have one lens with ten aperture blades, fortunately not rounded blades. (I even like ten sided bokeh balls.) I’ve been doing some ultra-wide Astro-imaging lately with camera lenses, and the star spikes help differentiate the stars from the globular clusters and any small fuzzy nebulae.
I actually do like star spikes as well, but I just needed to test this :)
Cool! This is very timely. My 10" reflector is arriving this week. I'll custom order these so I have the option of removing the diffraction spikes. Thank you!
Note that there may be an impact on contrast, etc. so there's no free lunch!
Used them a while ago but switched back to normal spikes... feels better to see spikes on my pictures. :D
Yep, they're off the scope for me too!
You always bring a smile to my face. Thanks
BTW you missed one potential benefit. If you are imaging with a Newt/DK/RC/etc and you don't have a permanent set-up, it's virtually impossible to get the diffraction spikes to line up over more than one session. The apodizer should allow you to combine imaging runs over several nights with a Newt.
Never had this issue with multiple nights.
You make a very key point. And that is why I don't use a Newtonian for imaging since my image data often are taken over several nights... even years, locations, different scopes, and setups. I could never understand why people will add fishing line, etc. to a SCT to create diffraction spikes! I use either refractors or SCTs to AVOID those diffraction spikes. Perhaps people think that having those diffraction spikes makes their images like the professional big observatories that use giant reflectors and do have those spikes ;-) There are other ways to eliminate those spikes on reflectors.... curved vanes is one way. I also use Hyperstar setups and if you run the camera cables from the camera and an angle down to a point where they can exit near the corrector through the dew shield you can also mostly eliminate the spikes. If you run them horizontally on a Hyperstar setup out the side near the forward edge of the dew shield you will get the spikes.
what? I regularly shoot over multiple nights (while reassembling the whole rig), and never had this problem. Spikes will be aligned, just like everything else, during stacking.
"it's virtually impossible to get the diffraction spikes to line up over more than one session"
Sure it's possible and done a million of times. Plate solve to find previous imaging angle and adjust camera current angle to match. Friggen MAGIC!
No, actually the diffraction spike angle doesn't change between nights, at least after star alignment - it will only change if you physically rotate the tube and thus the spider - only the orientation of the spider wrt the stars is important, the orientation of the camera won't be an issue!
Dare I say we should improve/revive the Schmidt Newtonian design.
That type of scope looks intriguing to me. Especially with no coma corrector needed. Too expensive though.
That looks like fun! We could also use Mak Newts!
@@Neanderthal75 the Meade SN6 was $200 when Meade cleared them out
Interesting effect, but makes stars look odd. Why artificially manipulate the images? Not my cup of tea.
The images are already manipulated in many ways.
The regular spikes are not real and neither is the noise, the brightness, the apparant size of stars, or the 2D representation of a 3D object. Even our eyes manipulate images, as can be seen by optical ilusions. Scientific observations are done all the time with corrective optics where the mirror is physical bend into a differnt shape.
I believe it is all up to the photographer how the image is captured, as long as it is not misleading.
Yep, as ancientcolors says, star spikes are manipulations in and of themselves, and reduce contrast in the image :)
So glad you decide to try these out. I got one for my Kasai Trading Ginji 200/4 Newt, and another for my VMC260L, but have yet to try out imaging with them.
Hope you have fun testing this!
Okay cool but how do I do the opposite, I want super thin and long spikes :)
Just add more spokes. But they must be exactly parallel to those of the secondary support.
this is why you should buy an obsession
Does yours have curved spider vanes? I haven’t seen such in the Obsession range…..
@@wessmith6196 I don't actually have an Obsession, that's out of my price range. But I have seen such 12.5" classics with curved spider vanes.
It would be interesting to measure contrast drop
This kind of makes me wonder what kind of effect you would get if you had a spider that rotated slightly after every image, but you were able to keep the secondary mirror still..
I assume the diffraction spikes would cancel out in stacking?
Probably be rejected by pixel rejection algos! That's a cool idea!
@@CuivTheLazyGeek Yea, that's what I was thinking, kind of like satellite trails.
But of course the problem would be trying to implement something like this without vibration, or the secondary mirror moving, but I'm sure there are probably some people a lot smarter than me could find a way to do it with some gears and a belt.
Hey Cuiv nice video as usual, I'm considering the apertura carbon star 150 but I'd like to know if it has major issues or after a quick collimation is ready to go. What are your thoughts on that scope? Thanks 😊
Overall good, review coming Friday!
It'll be great, if you still have it, to test out this scope with the starizona 0.75 coma corrector 😊
Witchcraft I tell ya!
In the history of all the iterations of batman, there was at least one batmobile that could fly. :)
Good to know!
BTW it's "apodizer", not "apotizer". The original paper is "Apodization of the flat mirror support of a Newton telescope" by Temich et al. I think the StarWorks site is using automatic translation.
Also "apo" just means "far away". I presume apochromats are named so to emphasise they have even less colour than achromats. So, to me "apoodizer" just means they are removing the aberation, in this case the diffraction spikes. Doesn't really mean "it's like a refractor" to me.
Thanks for this! This makes sense :)
I did some research on these things a while back. Basically that shape is a dissected circle and what it does is to scatter the light that would normally get concentrated into diffraction spikes. I thought about using them but I would have to print them myself since I use the smaller Skywatcher 130p-ds and nobody seems to make them to fit small scopes like that. Honestly though, if it makes my stars look weird, I would rather have the clean spikes
Cuiv, never a dull moment visiting you! Keep up the great laziness.
Thanks so much Melvyn, cheers!
These bats should have been marked closer to the diagonal mirror, perhaps at Newton 200 mm they should be printed larger in linear size, and the effect is similar to a radius spider, when light waves are reflected and cancel each other out due to the interference effect, a local calm with small ripples is created, which the main mirror no longer sees
Thanks for the explanation! This is super cool though
@@CuivTheLazyGeek In more detail and "scientifically" you can find out here about the calculation of the shape of the spider and its influence on the final shape of the stars www.telescope-optics.net/spider.htm
My solution to the diffraction from the spider vanes has been to 3D print a curved vane spider. Like these apodizers, it's almost magical how well it works. In both cases, the overall diffraction increases, but it is distributed across the image and reduces the contrast just a little bit. Maybe not quite a refractor, but getting close.
They need to use 2 arcs to hold the secondary. We use one arch with our hyperstars to remove the single diffraction spike cause by cables. By routing the cables in an arch it removes the spike.
Yes appetizer
I don't understand all the love for diffraction spikes here. They are literally destroying data behind them. I would get rid of them in a heart beat if I can afford a 12" $500k commercial refractor. I just don't know if I like the weird stars you got with this addon.
Been using these on my 250p for a while now, they’re amazing!
Haven't seen you this energetic and positive in a long time :)
It's just fun to test things like that haha
I bought a Maksutov-Newtonian, so I did not have to deal with spikes.
I've always been curious about Mak Newts!
@CuivTheLazyGeek I think they are the best do it all scope out there. They are not the greatest at any one thing, but really good at everything.
Thank you, Cuiv, for your hard work! I enjoy your videos!!
I dont think the Batmobile flies.
Further serious and in depth research confirms this, although there is a flying vehicle called The Bat in The Dark Knight Rises!
As a refractor guy I envy the spikes and am left wondering why someone would want to remove them.
monofilament fishing line cross in front of your lens bubba :)
@@MatthewHolevinski nice!
Never thought of that. Thanks brother.
Technically they're bad for contrast (check Dylan O Donnell video) but yeah they do look gorgeous!
@@CuivTheLazyGeek didn’t know that. I will seek the Aussies wit and wisdom on the subject.
But I agree. The remind me of NASA photos and thus seem almost…. Important.
@Cuiv, can we get an in depth review of the carbonstar?
Friday
@@CuivTheLazyGeek Great!
@@CuivTheLazyGeek would love to hear if it works well with the 2600 duo!
Interesting. I wonder if these will work on something like a RASA
Does a RASA have spider vanes ?
@@WilliamBlakers and where wil he place them, glued them on the glas
Have you seen a RASA? The camera is mounted on front. Power and data cables coming off it cause diffraction spikes. Some people orient them at 90 degrees.
It could be interesting to 3D print a cable funnel with an integrated bat shape!
Great video looking forward to a update . Thank you
The reason why the bat spider vanes work is because they create interference pattern waves that cancel out each other. Think of a pool and a wave generated on one end. If you create another wave that is opposite of it in the reverse direction, you can cancel the original wave out. The interference modeling to figure that out is even more interesting than the result.
I really need to look into Fourier transforms of shapes :)
I actually doubt that these simple curved spider vanes are manufactured precisely enough to create cancellation of sub-micron interference patterns.
I like the spikes.
To be honest, I do too - but I needed to test this out!
Thanks Cuiv.
Hi Cuiv, Jaime from Chile again. If you going to 3d printing your own apodizing devices, make sure to scale acording to your telescope .
The total length should be according to the following simple formula:
Main mirror diameter minus secondary mirror diameter divided by 2. Then at the moment of placing on the spider, make sure you consider to fit the Device starting from the edge of the secondary mirror to eliminate the spikes because they are placed right on the light path of the telescope.
Hope this information will help you.
Greetings from BelloCielo - Chile 🇨🇱
Woohoo, thank you for those details, outstanding!
Removing spikes is considered as crime to humanity. The best spikes that I ever got were with the "amazing" spider of my Skywatcher 150PDS and my DSLM having Alnitak on the exposures. The spikes in fact went through the full image.
I love diffraction spikes!
Hahaha I hope I don't get arrested!
@@CuivTheLazyGeek Star Spike Police is on it's way to Tokyo. 😄If you are nice and remove those evil things and they are able to confiscate then they are going to be pleased and won't arrest you. 😁
This will not work...bet
It works completely off of sound mathematical principles. Bahtinov mask is another kind of mask that redistributes intensity of light using similar concept.
And it worked!