What barlow should i get?

[mih]

I recently bought a 6 inch reflector, 750mm focal length and i want to get a barlow lens to get better observations. I have 2 eyepieces, one 9mm and one 25mm. My question is should i go for a 2x barlow with the 9mm eyepiece(about 160x magnification) or 3x with the 9mm(about 250x magnification)? I know that a 6inch can handle about 300x. Is the 2x barlow enough or should i get a 3x?

[petevasey]

You could compromise and get a 2.5x Televue Powermate.  They give a better image than a standard Barlow, but of course they are relatively expensive.  There's a wide choice at The Widescreen Centre - worth a browse.

Best of luck,

Peter

[Waddensky]

20 minutes ago, mih said:

I know that a 6inch can handle about 300x

In theory, yes. But it also depends on the atmospheric conditions. Here in NL, seeing rarely allows me to go much over 200x.

What kind of objects would you like to observe with the barlow? For planets, 150-200x is often sufficient in my experience. Very close double stars may require more magnification, maybe some planetary nebulae too, but I can't think of any other objects that benefit from magnfications up to 300x (but maybe others have other experiences!)

[John]

I use the Baader Q-Turret 2.25x barlow. Simple design but very nice optics

 

[mih]

2 hours ago, Waddensky said:

In theory, yes. But it also depends on the atmospheric conditions. Here in NL, seeing rarely allows me to go much over 200x.

What kind of objects would you like to observe with the barlow? For planets, 150-200x is often sufficient in my experience. Very close double stars may require more magnification, maybe some planetary nebulae too, but I can't think of any other objects that benefit from magnfications up to 300x (but maybe others have other experiences!)

Yeah, i have heard that 300x is in the perfect conditions, that's why i am a bit sceptical. I think i should go with the 2x or 2.5x, i mainly observe planets. Is that enough for some deep sky objects too?

Edited May 25, 2020 by mih

[John]

11 minutes ago, mih said:

Yeah, i have heard that 300x is in the perfect conditions, that's why i am a bit sceptical. I think i should go with the 2x or 2.5x, i mainly observe planets. Is that enough for some deep sky objects too?

300x is the max theoretical useful magnification. In practice what is actually useful is more often 150x-250x.

Deep sky observing is usually done at low to medium magnification.

 

[Waddensky]

16 minutes ago, mih said:

Yeah, i have heard that 300x is in the perfect conditions, that's why i am a bit sceptical. I think i should go with the 2x or 2.5x, i mainly observe planets. Is that enough for some deep sky objects too?

Most deep-sky objects require less magnification than planets, so with a 2x barlow in your stable you have 30x, 60x, 83x and 167x magnifications available. That's a nice range to choose from. A 2.5x barlow will give you a higher magnification on your 9 mm eyepiece (208x), but with the 25 mm essentially gives you the same magnification as your 9 mm alone - so no nice 'in between' magnification.

[mih]

1 hour ago, Waddensky said:

Most deep-sky objects require less magnification than planets, so with a 2x barlow in your stable you have 30x, 60x, 83x and 167x magnifications available. That's a nice range to choose from. A 2.5x barlow will give you a higher magnification on your 9 mm eyepiece (208x), but with the 25 mm essentially gives you the same magnification as your 9 mm alone - so no nice 'in between' magnification.

Ok, so I should probably get a 2x. I'm just starting out so i am a bit of a noob, Thank you guys!

Edited May 25, 2020 by mih