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What Barlow to use


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With what lenses? You're really limited to 250-300x in the UK for 99% of nights, so if you're already at that, there isn't much point in going any further. I have a Celestron Ultima x2 (very good Barlow) and it only ever gets used in imaging with the DMK21....

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Assuming a FL of 1216mm (is this right for your 'scope) a x2 Barlow will give you eyepieces of 7.5mm, 12.5mm, 15mm, 24mm, 25mm and 42mm (I assume the 42mm is a 1.25" eyepiece?). Which gives you a mag range of 30-160.

An x3 would give 5mm, 8.3mm, 14mm, 15mm, 25mm, 42mm which is 30-240.

Depends what you want to do most - see things up close or wider field. Up cl;ose is good for splitting doubles, planetary nebula (although the higher the mag, the fainter they are) open and globular clusters, wider for DSOs such as galaxies...

Barlow or another "good" quality eyepiece... up to you....

HTH.

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Given Arad's calculations, and the fact that it is an f/8 scope, I would say the 3x Barlow would serve you best. Get a medium-quality Barlow, unless you have an unrestricted budget, it will be fine. Later you can go for eps with wider FOV, but as long as you are happy with the view through the Kellners, go with it. I used a pair of Kellners for years in an f/8 scope.

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I'm assuming that you have the 2x and 3x Tal barlows? In which case, these are both excellent quality and will both be of benefit.

I have a 2x and 3x Barlow and which I use depends on the seeing on any particular night. If it's very clear and steady, I can be found using the 3x to get up to almost 300x magnification. If it's not so good, that I might sturggle with half that thru the 2x Barlow.

Best bet is to experiment and see which is best for you on any given night.

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Ok and thanks all for those tips will do some browsing for Barlows taking in that it,s the splendour of the Cosmos that i,m hooked on so imaging is goin to be baby....as....there is a televue Powermate x2.5 on Ebay..not quite sure what the phrase Powermate is..so...can someone throw some tried and tested makes at me !!Televue is out the range of my pocket and the wifes purse at the moment..and she,s a sure shot with a dinner plate !!Anyways...Thanks all..Rob :D

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