2 x Barlow lens.

[Guest]

I have never really given 2 x Barlow lens any great reverence. I was of the opinion that they add more glass elements and thus reducing the incoming light of a celestial object. Making it too dim to resolve any detail. Having owned several over the years. I now have in my armoury a 2 x Celestron Ultima Barlow lens. Recently I have been observing Saturn with the 82° Explore Scientific eyepieces; 4.7, 6.7 & 8.8 mm. 

Using a Vixen 115mm refractor these eyepieces gave pleasing views of the planet. But introducing the Barlow with the 4.7 & 6.7mm eyepieces made the object scale larger. Yes there was some dimming. But the Cassini division and darkness inside Saturn's rings became more obvious. So I have to say that barlow's do have their place in an accessory collection. 

[Ags]

I have been thinking about completing my eyepiece collection with a 2x barlow.  I have the following eyepieces: ES 24/68, Nirvana 16/82, Speer WALER 10/82, ES 6.7/82. A 2x barlow would give 120 magnification in my ST80 for solar observing, and also give 12 and 8mm options for planetary observing. 

[Guest]

5 minutes ago, Ags said:

I have been thinking about completing my eyepiece collection with a 2x barlow.  I have the following eyepieces: ES 24/68, Nirvana 16/82, Speer WALER 10/82, ES 6.7/82. A 2x barlow would give 120 magnification in my ST80 for solar observing, and also give 12 and 8mm options for planetary observing. 

It's not just the magnification. The Barlow gives a different type of image. If I used a 5mm Eyepiece and compared it through a 10mm Eyepiece with 2 x Barlow the views are different. Try putting a wanted request for the Celestron Ultima. They are discontinued. But come up used. They are good quality in my opinion. 

[Rob Sellent]

1 hour ago, Grumpy Martian said:

So I have to say that barlow's do have their place in an accessory collection. 

I agree. I find a good Barlow a handy tool to have in the eyepiece kit.  It'll increase magnification, extend eye relief, make a lower power ep into an easier to look through high power ep, makes a standard 24mm 8mm zoom run to 4mm (handy for splitting stars or adjusting high magnifications) and in my own case, takes nothing away from the view. 

Do you think the more contrasty view you saw, Grumpy might have come about by having better eye-relief with the Barlow or that to some extent it 'corrected' the field of view? 

[John]

I would go for a Focal Extender / Tele Extender / Powermate if you can.

These devices deliver the image amplification but don't change the focus position and eye relief and don't vignette eyepieces with large field stops. With the Powermates in particular, apart from the increased magnification, you simply can't tell that they are in the optical train.

Such devices do tend to cost more than a barlow lens though.