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Different size eyepieces or barlows


miken4247

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Hey people I'm totally new here and recently just got in to astronomy, would you say it's better to have a variety of different size eye pieces or fewer but with multiple Barlow's like a 2x,3x and 4x as from what I've seen this would give the same as the higher powered lenses, thanks in advance for your recommendation

Mike

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Hello and welcome to SGL

Personally I prefer separate eyepieces. If you are going to use some sort of Barlow then make sure it is a high quality one , or a powermate as otherwise you risk the cheaper ones producing inferior sharpness/ transmission. I prefer separate eyepieces , because I consider the sharpness of a quality single eyepiece probably better than a barlowed one. The eye position at the scope is also changed due to the Barlow length and possible extra weight . To my personal preference and eyes I just consider the experience of a quality single eyepieces, better than a barlowed ones. 

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Unless you choose carefully barlows can make getting the right level of magnification at higher mags because it effectively doubles the ‘gaps’ between your various fl’s. E.g- if you’ve got. 1200mm fl scope with 10 & 7mm eyepieces plus a 2x Barlow- you get 120x, 171x, 240x and 342- that’s a big jump between 240 & 342- so if you want something around 300x you’ve either got to go for an 8mm native with the 2x Barlow or a 12mm with 3x Barlow- either way you end up with an eyepiece that’s pretty close to one you’ve already got....you could go for a 2.5x Barlow...but you’ll almost certainly end up with some duplication....It’s almost certainly possible to get a good spread of mags but it makes my head hurt trying to avoid duplication, so I’ve not gone down the Barlow route

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I opted for for 4 wyepoeces and a barlow. I have a TAL barlow which are fairly well regarded but not the easiest to get hold of.

I mainly use it with smaller focal length EP's because it maintains eye relief and is generally a more comfortable experience than a very short focal length single EP.

My smallest eyepieces are 9mm (111x mag) and 6mm (167x mag). So with the barlow I also get 222x and 333x with the same eyepieces and to my eyes the image is not significantly degraded other than the unavoidable dimming.

In actually fact I can also get 250x because the barlow can be unscrewed into two pieces and screwed into the eyepiece as a 1.5 barlow (quite a few barlows do this)

 

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You're going to get a lot of different answers to this question, Mike!  It's often a matter of personal taste.

My own preference is for a Barlow or Barlows because of the increased flexibility.  It can also mean reduced cost as one Barlow can be used with many eyepieces and so much increase the range of focal lengths.

Others will point to the loss of transmission in adding a Barlow because of the extra elements.  Years ago, before the advent of multi-coating, this was a very valid point, and it may be that this maxim has simply continued to this day. The loss of transmission still makes a small difference, but these days is relatively minor  -although it can still be seen on careful examination of very low contrast objects.  Having said that, many of the most highly regarded ranges of eyepieces actually contain a Barlow (known as a Smythe lens in this case), and this means more elements in the eyepiece anyway!  You can usually tell these by all the eyepieces in the range having a constant eye relief.

Eye relief (how close you need to get to the eyelens) is an important consideration, especially if you have astigmatism and wear glasses at the scope or add a Dioptrx to correct the astigmatism.  Either way you need extra eye relief to be able to see the whole field of view and to avoid being uncomfortably close to the eyelens.  Generally, the shorter the focal length the less the eye relief.  A Barlow, either a separate one or incorporated in the eyepiece, mitigates this problem as the eye relief increases slightly.  An additional consideration if using a Dioptrx is that they can be fitted only to a limited range of eyepieces, so one doesn't have so much choice. 

It's also possible to have too much eye relief resulting in blackouts.  This means that a Barlow with a long eye relief eyepiece may not be as suitable.  The answer to my mind is to choose an eyepiece with suitable eye relief in the first place.  This will differ from person to person,  depending on the shape of one's face/eye sockets plus the style of glasses if used.  For instance, those who don't need glasses may prefer 12 to 15 mm eye relief, whilst with glasses or a Dioptrx that same person might need 20 to 23 mm.  It's also important to treat the quoted eye reliefs with caution as the useable eye relief can be reduced by a number of factors, including in particular how deep the eyelens is recessed.

 

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In the garden I use separate.

In school we now have a zoom and barlow, very convenient.

On hols, or grab and go, I take 2 or 3 EPs and a 2x barlow.

I don't know if that helps, but it gives you an idea of the options. :)

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I like both worlds!  A barlow can greatly increase your power range at minimal cost, and they are good. A 17.5mm Morpheus for example, when barlowed at 2X makes a stunning 8.75mm (~9mm), Also, many top end eyepieces incorporate a barlow into their design anyway, so there's no reason not to use one. They can offer high power views in comfort when a similar powered eyepiece would have minimal eye relief. On the other hand , there's a good argument for minimal glass when observing the Moon, planets and binary stars, but high end minimal glass eyepieces are often just as expensive as the complex multi element designs. A barlow, or selection of barlow's can greatly reduce the cost of having to buy multiple high end designs, as well as enabling simpler designs to really prove their worth.

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I agree with Mike, barlows are a great asset, particularly if you are financially challenged most of the time!   I also have a Morpheus 17.5 (best eyepiece I've ever owned or used).  I have used it with a x2 Ultima barrow to great effect since I've had it.  I recently bought a used Celestron X-Cel LX x3 barlow to use with it, and it too make a fabulous combination, giving me just over x150.  I've saved myself around £300 by using my barlows - including the money I spent on the used X3 barlow.  I also use  both barlows to extend the range of my Baader Mk111 zoom.

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