Maximum magnifications and what next?

[hms_furious]

Hi all, 

I have a 150p and a 127mak. I have a nice focuser in the 150 and a 2" diagonal on the 127mak.

I have the baader 8-24 zoom and the accompanying Barlow. 

I also have a baader solar filter for the mak and a 1.25 baader neodymium filter. 

How do I calculate what mm eyepiece equals what magnification each scope and also what it's maximum useful magnification is? 

Given the equipment, what eyepieces do you also think would be useful to get the most from these scopes? 

Anything else you think would be useful? 

[Mr Spock]

With the 150mm you have 650mm focal length. Divide that by the fl of the eyepiece and your 8-24 gives x81 to x27.

The 127 is 1500mm focal length, so you will have x188 to x63.

Both are probably kept to a maximum of around x200.

[johninderby]

Just use the Televue calculator and enter your scope details and select Magnification and it will show you what each focal length eyepiece will give which magnification.

https://www.televue.com/engine/TV3b_page.asp?id=212&plain=TRUE

[vlaiv]

Maximum useful magnification depends on couple of things:

- seeing on particular night - telescope can deliver magnification but it is atmosphere that blurs the detail and there is not much point going with higher mag

- your visual acuity - how sharp is your eyesight? Some people have sharper eyesight and can use less magnification to see what is there to be seen, while others need more magnification to comfortably observe (similar to font size on computer screen - some people are fine with small letters while others prefer larger font for easier reading). For 20/20 vision we can say that threshold magnification is about x100 per mm of aperture. Below that - you won't be able to resolve detail that is still there - above that you'll see all there is to be seen and additional magnification will just make it easier to see but also more blurred once you increase magnification too much. If you have different acuity - just multiply x100 with given number. For example - if you have 20/10, or twice as sharp vision as 20/20 - you can use only x50 per mm of aperture to fully resolve image, and if you on the other hand have 20/30 vision - then you need x150 per mm of aperture to fully resolve image.

Just two additional notes - above is for perfect telescope and your visual acuity after corrective measures. If you wear eyeglasses - it is your acuity with glasses - not without.

- collimation and quality of optical figure of telescope. Collimation is important and optical figure as long as telescope is diffraction limited - has the least impact on usable magnification.

 

[Mr Spock]

16 minutes ago, vlaiv said:

then you need x150 per mm of aperture to

x22500.00 for a 150mm? I think your calculations are a bit off 

[vlaiv]

6 minutes ago, Mr Spock said:

x22500.00 for a 150mm? I think your calculations are a bit off 

Indeed - that should be 1.5 per mm of aperture or x150 per 100mm of aperture

What is few orders of magnitude difference between friends

[Mr Spock]

[ecuador]

9 minutes ago, Mr Spock said:

x22500.00 for a 150mm? I think your calculations are a bit off 

Yeah, that's absurd! I'd never use more than 10000x on a 150mm.  

[Roy Challen]

4 hours ago, hms_furious said:

Hi all, 

I have a 150p and a 127mak. I have a nice focuser in the 150 and a 2" diagonal on the 127mak.

I have the baader 8-24 zoom and the accompanying Barlow. 

I also have a baader solar filter for the mak and a 1.25 baader neodymium filter. 

How do I calculate what mm eyepiece equals what magnification each scope and also what it's maximum useful magnification is? 

Given the equipment, what eyepieces do you also think would be useful to get the most from these scopes? 

Anything else you think would be useful? 

I think what you have is fine. Getting the most from your scopes isn't just about maximum magnification.