Barlow lens. Advantages and disadvantages?

[Marmot]

Hi

i am hoping that someone can help me by giving a bit more detail on the pros and cons of a Barlow. Obviously they increase magnification, but I assume there are some disadvantages otherwise everyone would half the size of their eyepiece collection merely by purchasing a Barlow. I also wonder if their are any advantages apart from the increase in magnification?

 

I am asking this question to help me decide, weather it is better to achieve a certain mag by using an eyepiece on its own or weather I can use a Barlow without noticing any difference.

 

Thanks in advance.

[paulgrover68]

I'm no barlow expert - I have a TAL 3x and a SvBony 2x. I use these with my stock skywatcher eyepieces for primarily looking at the moon and planets with my achromat.  I was genuinely surprised with the quality of the SvBony, considering it cost less that £20 and is mainly plastic.  The TAL one is great - even with a 6mm eyepiece the view is very serviceable, but very dependent on viewing conditions. 

Like with everything you introduce into you optical train, you're reliant on the quality of each component. So putting a cheap barlow in front of a posh eyepiece will inevitably have an impact.  The advice I was always given was eyepiece alone will always be better -  although I doubt my eyes are trained enough to see the difference.

[Marmot]

Thanks Paul. That sounds much as I thought. I felt that it may be better to try to view with an EP alone rather than introducing something else.

 

[MarkAR]

Supposedly more glass between the eyeball and object is not a good thing but for the average observer it'll be really difficult to see the difference.