Question about telescope optics for someone who knows what their talking about.?
I have an idea for a telescope design that could be somewhat revolutionary. Surely someone must have thought of this before but I've never heard of it.
My understanding is that you can't increase the surface brightness of an object with a normal telescope. An increase in aperture results in an increase in magnification. More light is gathered, but, it's spread over a larger area.
What if you took three or four refracting objective lenses and using mirrors, arranged them so their focal points converged at the same point. I'm not an expert in optical design, but I could guess there could be problems with making sure the light rays would be parallel when they reached the focal point.
Could there be some way to accomplish this? It sounds very expensive, but if it could be done I think you could gather enough light to see galaxies and nebulae like no one has ever seen before. increasing the surface brightness enough would allow you to see colors and details more like those in photographs.
Maybe the lenses would have to shaped very strangely and precisely for this to work. Perhaps insanely long f ratios would be required. Maybe that's why it hasn't been done on a large enough scale for me to have heard of it. Or maybe it just isn't possible. Does anyone know? Does anyone understand WTF I'm talking about?
2014-11-08T01:26:09Z
I meant using prisms and/or mirrors.
2014-11-09T00:47:01Z
I understand aperture doesn't directly affect magnification, I'm not sure how to properly word the problem I'm referring to. I read about it maybe 10 years ago in sky in telescope magazine and the details are bit hazy from all the meth I've done since then.
michel2014-11-08T06:26:02Z
Favorite Answer
yes it has been thought of by myself for a start , first of all aperture does not increase magnification , only the focal length of the objective divided by the focal length of the eyepiece does that , but the larger the aperture the more potential there is for suitable magnification , below I have included a picture of 2 telescopes , they are unique to the market in that they are twin self triangulating telescopes , so as you rack in and out to focus they continuously alter their angles centralising on the object chosen , because of this feature they are capable of magnifying 510 x as close as 30 metres without getting double vision , one is an apochromat triplet the longer one an achromat doublet , mirrors have been chosen to fully erect the image , rather than prisms , if prisms were used 2 for each lens the light would have to travel through an extra 12" of glass to each eye piece and even with the best prisms there would be a substantial loss of light , by using the best dielectric mirrors on the market 99.99% reflective 8 per twin scope 4 per lens , the final reflectivity measured on a spectrometer comes to 99.96% therefore it has suffered no discernible light ( unlike prisms ) however it is easier to mount 4 prisms than 8 mirrors , these mirrors have to be calibrated exactly , and bear in mind sooner or later they will require cleaning , which is why I had to come up with a system of being able to remove and replace without having to collimate them again , which I have tried and tested , bearing in mind that if I magnify 510 x as close as 30 metres the field of view is only 2" diameter , and since from centre to centre the lenses are 9" apart each telescope would be looking at a different house brick , which is why these triangulate , now if we take the same set up and mount a twin upon a twin , so far we would have 16 mirrors but 4 eyepieces so then we would have to use more mirrors to bring it down to 2 eyepieces 8 more mirrors totalling 24 mirrors , it could be done but there are probably easier ways of getting what one requires however you sound like someone taking after myself whereby you are more interested in what you are actually looking at , rather than getting a panoramic view of surroundings , the trouble being nobody builds long focal length apochromats , that is why my F15 achromat beats my F11 apochromat even though they are both 127 mm
"An increase in aperture results in an increase in magnification. More light is gathered, but, it's spread over a larger area."
Not quite. The larger amount of light gathered means smaller detail can be resolved. This does mean indirectly that higher magnifications can be used.
"increasing the surface brightness enough would allow you to see colors and details more like those in photographs."
Well, if they've got the photos like that, obviously they're doing it, aren't they? No human eye will see like a long-exposure photo. The photos you see of galaxies look like whirlpools of light, but bear in mind we're in the middle of one and it doesn't look like that from here.
I know the issue you're referring to, and I suspect the problem would be that the mirror to bring the light paths from two telescopes together would necessarily obstruct the light paths partially or totally, undoing the benefit.