Guide :Optics : 675x5 EQ Reflector Telescope

Focusing the Barlow lens

I have a 3x barlow lens that I can't see anything out off. This telescope was given to me. The 22x lens works fine. There is a tube that goes with the barlow lens, not sure what this is. Thanks for any help.

Research, Knowledge and Information :


How to Use a Barlow Lens | eBay


How to Use a Barlow Lens. ... A Barlow lens does not create a higher ... Using a telescope without a Barlow lens takes less practice than focusing with a Barlow ...

Barlow lens focusing - Getting Started Equipment Help and ...


Sadly, although things were looking good to begin with, fatigue, a strong breeze and vibrations meant that I wasn't going to see a great deal of Jupiters sh...
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Barlow lens - Wikipedia


The Barlow lens, named after Peter Barlow, ... A standard Barlow lens is housed in a tube that is one Barlow focal-length long, so that a focusing lens inserted into ...
Read More At : en.wikipedia.org...

Meade Instruments #126 1.25-Inch 2x Short-Focus Barlow Lens


Amazon.com : Meade Instruments #126 1.25-Inch 2x Short-Focus Barlow Lens : Barlow Lenses : Camera & Photo

Barlow Lenses | Focus Camera


4-element fully multicoated barlow; 2.5x magnification; Can be used with 1.25" and 2" eyepieces; Brass compression rings securely hold eyepieces without marring the ...
Read More At : www.focuscamera.com...

Meade #128 1.25" 3x Short-Focus Barlow Lens # 07278


Product Details. Meade Series 4000 #128 3x Short-Focus Barlow Lens (1.25") #07278 is a compact "shorty" type Barlow that triples the magnification of your 1.25 ...
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How to Pick a Barlow - Astronomics


The Barlow lens was invented in 1834 by English physicist and mathematician Peter Barlow ... Focusing Aids. ... How to Pick a Barlow. Informational Links.
Read More At : www.astronomics.com...

Astromania 1.25" 3x Short Focus Barlow Lens for Telescope ...


Amazon.com : Astromania 1.25" 3x Short Focus Barlow Lens for Telescope Eyepiece : Camera & Photo

Meade 1.25" Short Focus 3x Barlow Lens - 07278


Meade 1.25" Short Focus 3x Barlow Lens. The Meade #128 Short Focus 3x Barlow lens triples the magnification of any eyepiece when inserted into the telescope's ...
Read More At : www.highpointscientific.com...

Suggested Questions And Answer :


Hey guys! My brothers chipped in to get me a telescope for my birthday. It's a celestron sky prodigy 70. I took it out a few times with zero experience except for what I picked up from reading the owner manual. Please excuse my language as I do not know any common terminology nor am I very good at trig but I at least know the terms relating to math( if thats what it really is talking about). So, when I look through the lens I get a nice sharp and crisp image with the factory provided lens. I know this is an entry level telescope but I want more magnification. So I bought an x-cel lx 2x Barlow lens and a 24mm-8mm zoom lens. I know the max magnification is 165x and the focal length is 700 so that puts my strongest eye piece at a little over 4mm meaning a 5mm is pretty much what I'll get out of it. I tried the Barlow and the zoom lens a smidge over 8 (9 I hope it was at) and the image is very soft. Then again I am in Los Angeles and looking out of my window through a fairly heavy marine layer. But the image comes out sharp if I use my factory lens, or just the zoom, or my already provided 24mm with the Barlow or the zoom at a lower magnification with the Barlow. My provided 9mm with the Barlow produces a blurred image and I tried to focus but it still seems blurry at best. I think I'm safe to say a 9mm on a 2x Barlow is still within the max effective range of zoom? I'm wondering if I shouldn't expect much out of the telescope or if I should return either the Barlow or the zoom lens or both and get some higher quality object specific lens instead. Or maybe I'm not focusing correctly? Or a zoom should not be used on a Barlow? Any insight would be very helpful.


Hi, I can see you'r statring a interesting journey in amateur astronomy. Which can be really amazing but also disappointing, because usually people are expecting too much (specially after viewing beautiful astronomy pictures on internet).Before we go back to your question lets go over some basics here:Your telescope has a F10 aperture (Focal lenght / Diameter).So to be able to see the maximum amount of details from it, the smallest eyepiece you need is a 10mm (eyepiece mm = to f number of thetelescope).Then it's easy to find the maximum useful magnification: 700mm (focal lenght) / 10mm (eyepiece) = 70x Ok but why does the manufacturer say that it can be at a max of 170x... they are not really lying, if you get a smaller eyepiece it will make the image bigger but will show no additional details than a 10mm one. But the image being bigger it can make details easier to see.That for the questions about magnification an image quality.The more pieces you put between you eye and the telescope mirror, the dimmer and less contrasty the image will be. Especially after you go higher that the maximum useful magnification.Hope this helps. And enjoy wathching the stars and planets, it is a always a beautiful sight.
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I've just purchased a used TAL 1 telescope complete with eyepieces and Barlow lens. However I can only get objects into focus by moving the focuser to it's limit and then physically lifting the eyepieces part-way out of the eyepiece holder. I don't think this is a collimating problem and my searches on the internet turned up a possible cure - a focuser extension tube (11/4"). Your assistance will be appreciated.


Yes, the "back focus" is too short. That extension should work.
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Bushnell Telescope 78-4678


A telescope like that has a very narrow depth-of-field, so you need to focus very, very slowly to be able to see any image. Try focusing on something bigger (like a spot on the moon) and adjust the crosshair accordingly. The two eyepieces gives different magnification.
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I have a makusutove 150 1800 telescope and I cant seem to get it to focus correctly - it seems as though the mirrors are focussing the light behind the viewing lens. I can get a focussed image if I hold the viewing lens about 4 inches behind the telescope. how can I adjust this telescope to enable a focused image with the viewing lens in the holder?


You do not have enough BACK-FOCUS, you need an extension tube for the focuser like this one:http://www.skiesunlimited.net/index.php?CategoryID=132Buy the correct size for the focuser hole--
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I can target moon or planet in view finder and see same using just the 45 degree mirror;but, when I put in lens the object of course is blurred.My question is...How do you focus???...I had a telescope previously and you had a knob to turn on lens to focus...Lens that came with scope had none and additional barlow 2x is same type lens I know to add...But can't figure out how to focus...Please help....David


The knob on the back of the tube is the focuser-- put in the eyepiece with the largest number written on it and try again.It's harder to focus at HIGH magnification the sweet spot is very tiny.Go here and download a manual:http://www.celestron.com/c3/downloads.php
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Can't see anything through the lens?


Put the diagonal into the telescope-- then put the eyepiece that has the LARGEST number written on it. This is the lowest magnification. DO NOT USE THE BARLOW 2x multiplier !!Take the scope outside during the day time and practice focusing on a distant object. The moon should be the first night time target you try to see.
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Wont focus correctly


TOO MUCH magnification. Put the eyepiece with the largest number written on it into the telescope. DO NOT USE the 2x barlow. Try Jupiter with lower magnification.
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