Astrological Telescope

SethJ

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#1
So I see some really big telescopes for looking at the stars. I can't discern the power however because they don't express it like a spotting scope, like 20-60 power...

it's all in weird 700mm x 1500mm-400nm some weird designations.

So this is a two part stupid idiot question,...

1) Whats the equivalent of like 150x in one of those telescope? (NEVERMIND< I FOUND THE STUPID IDIOT answer)
2) Wouldn't that be able to see a target pretty well at extended ranges?

lmao,..maybe I'm full on retard,....but couldn't you get a big ass telescope to spot targets with? I prolly wouldn't do it in public,,...but when I'm out shootin by myself it might be worth trying if I could figure out the damn power ratings lol.

 
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Nik H

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Jan 22, 2014
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#3
Astronomical telescopes are generally specified by the size of the objective and an F stop ratio. To determine the magnification, you also need to know the eyepiece size.

Example: a 130mm f8 refractor with a 20mm eyepiece delivers 52X (130*8)/20.

Beware of scopes that claim a certain magnification range. They are junk. The rule of thumb is 40-50X per inch of objective...maximum. That figure is for tier 1 APO or Fluorite based refractors.

The problems with using an astronomical scope for target shooting are:
  1. Physically very large and very heavy
  2. Require an image erector as the image is upside down.
  3. Very expensive - a very good astronomical refractor and mount is $5,000 min. A tier 1 is 2x that.
Buy a Kowa TSN-82SV for $1,100...be done
 
Jun 13, 2008
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#4
Quoted from a post of mine on SniperCentral, so some may be elementary for you, but you get my drift:


In fixed-distance competitive shooting, most of our scope use is for observing mirage, not for seeing exactly where on the target our shots are impacting. In fact, a lot of F-Class riflescopes have enough magnification to spot shots themselves.

Anyhow, what I'm getting to is that you are largely wasting anything above 25x on a highpower range. As you increase power, field of view decreases. With decreasing field of view comes a decreased awareness of what the wind is doing...you don't have as much ability to see what's coming your way.

You also can't scope as many neighbor's targets up and downwind of you to see what the conditions are like before you fire.

Example: Moderate to Stiff wind at 10:00, no flags, cloudy, 800 yards...what do you do? One GOOD answer is to wait a bit and watch the first 1-3 shots on the targets around you. If they all end up on the right side of the bull, then chances are, the conditions are worth more than you (and they) think.

Most elite highpower shooters are using spotting scopes with magnification at 18x-25x, and don't worry with any more. Less, and it can become hard to determine location of holes at long range. More, and mirage becomes so dense that you can't see holes, and your FOV is so small that you don't get a good sense of wind on the WHOLE range...just the little tunnel you're lookin' at right then.

now then, scope:

You want and NEED a 45-degree angle scope body. Period.

I recommend either the Celestron Regal F-ED scopes, or the Pentax PF ED. Both offer good durability and waterproofing, ED glass, fine adjust focus, rotating mount band, et cetera...but the biggest thing they offer is their American standard 1.25" eyepiece mounting sockets.

This is huge, because it allows you to purchase any standard 1.25" astronomical eyepiece, either fixed, or zoom, and plug it right in for a completely different scope performance from the one you had in before. Eyepiece do not receive as much credit as they ought to, because they can make or break the image faster than just about anything else.

Scopes like the Kowa, Zeiss, Leica ("The Big Three") use PROPRIETARY bayonet mounts for their scopes, so that only their eyepieces will fit. This way, they sell more shtuff, see?

Lower end scopes have fixed eyepieces that cannot be changed for anything else, and are generally not high quality anyhow. Trust me, I've been there and done that...no good for serious work.

There are literally hundreds of eyepiece available. MOST are not waterproof, and this is a feature you MUST have on a highpower range.

The Pentax XW series 1.25" eyepieces and are recognized around the world as some of the absolute best available. Just trundle over to any birding or astronomy forum and see. They are a far better EP than most of the proprietary ones available for The Big Three's scopes. Among other good features, keys are: waterproof, offer 70-degree field of view (excellent), and fixed 20mm eye relief (excellent) for easy use with shooting glasses.

Put one of these suckers in a Celestron or Pentax ED-glass scope, and prepare to be amazed. For cross-course shooting, I use a Celestron Regal 65 paired with the Pentax XW 20 eyepiece.


To determine end magnification of your scope with an eyepiece:

Focal length of scope / Focal length of eyepiece = Magnification in powers.
Example: Celestron Regal ED 65 = 386mm Focal Length
Pentax XW 20 = 20mm Focal Length

386mm/20mm = 19.3x Magnification

The Vixen Geoma-II scopes accept 1.25" EP and have received good reviews as well.

-Nate
 

Nik H

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#6
And if you go Kowa, which is a fine idea, go big or don't.

PROMINAR. 77 or bigger.

It's a big deal.
Most excellent post @natdscott. I agree with many of your points.

The PROMINAR 77 is nice...very nice but depending on where you are in the shooting hierarchy may be overkill. Most people would never even consider that kind of coin on a spotter. I am always amazed at how many people complain about their spotter but would never consider anything more than a couple of hundred dollars budget.

Regarding the Pentax XW, they are regarded as good astronomical eyepieces with good detail but that is all. I have tried a number of eyepieces in astronomical applications as I am a pretty serious astronomer. Been doing it for over 30 years and am fortunate enough to own 3 of the finest refractors available today. I would pick any Televue over a Pentax but you are talking a significant increase in cost that may have diminishing returns in a shooting application. However, I seldom run 1.25" eyepieces except for low focal length eyepieces providing high magnification. The Televue Ethos,Nagler and Panoptics are in a class of one. Nothing can touch them.

Just my 2 cents on the astronomical end of things. Don't want to derail the OP's subject
 
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Jun 13, 2008
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#7
Indeed. The reason (only) I did not go with a Televue is that they are about as waterproof as a piece of newspaper. Given how I have to employ my Pentax XW, it really has to be 100% waterPROOF.

As you know, that's sorta a rare attribute in astro EP.

And yeah...back on rails.. lol
 
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Nik H

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Jan 22, 2014
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#8
Indeed. The reason (only) I did not go with a Televue is that they are about as waterproof as a piece of newspaper. Given how I have to employ my Pentax XW, it really has to be 100% waterPROOF.

As you know, that's sorta a rare attribute in astro EP.

And yeah...back on rails.. lol
Yes about the waterproofing and Televue. However, I don't try to look at the planets when it is raining...LOL
 
Dec 26, 2013
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#13
I'd love to see some of the video you get on steel with that thing! But like has been said before, that's a lot of coin to be dropping. I have a friend with a Cabelas Krotos and I'm actually pretty impressed (however kinda off topic) but interesting thread.
 
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