General post about Barlow x2 or x3.

[Parky1972]

Hi.

I'm a Newbie, and this is my first 'propper' post.

So please excuse if it's a question that's been asked a million times or in the wrong area.

My question.

I have a Helios 6inch scope.

Lens diameter 150mm.

Focal Length 750mm.

Using the Sticky about lenses, and doing some crude mental maths.

It looks like the scope I've bought is an F5.

It came with a Barlow x2, a Plossl 10mm and a Plossl 25mm.

Is there any point in me getting either a 32mm or 40mm lens or indeed a x3 Barlow lens?

Obviously, I want the best and largest image I can get with the scope we have.

Thanks.

Jason.

[John]

I would think of adding a 32mm plossl and a 7mm BST Explorer eyepiece. With the 2x barlow you would then have a decent range of magnfications for an investment of around £50-£60.

The 7mm eyepiece with the 2x barlow lens will give you 214x which is as much power as can be used under out typical observing conditions. The 32mm eyepiece will give you 23x and a wide field of view which is nice for scanning star fields and the larger deep sky objects like M31, the Andromeda galaxy.

[ronin]

Slight correction to John but get the 8mm BST Explorer, they don't make a 7mm:D:D:D

On it's own that will give 94x and with a 2x barlow 187x

Although not the theoretical max may be the practical maximum.

The stock barlow may be the weak point in the system.

[Parky1972]

Now, this is where my limited knowledge falls down.

I'd have assumed that the best thing to do would be to increase the magnification.

so a x2 barlow with something like a 40mm lens would give an x80 magnification.

But I'm now guessing it doesn't work like that? LOL!

To give you an idea what I want to look at..

I'd like to see a good images of the major planets. Saturn, Jupiter, Mars etc..

The Moon ( Obviously ) and some galaxies etc..

What I'm likely to see however.. I'm not sure.

I live in Stretford. Which is about 4 miles as the crow flies from the centre of Manchester. About a mile from Trafford Park and the Trafford Centre.

So in about as light polluted area as I could possibly be in.

Again.

Thanks for your help.

Jason.

[John]

If you are in a really light polluted area then your deep sky viewing is going to be rather hampered I'm afraid, especially galaxies and nebulae.

You might be better off sticking to the planets, the Moon and binary stars for which higher powers are more useful.

Applying too much power does not lead to the best images of anything - smaller but crisp and contrasty images are best in my view.

[Parky1972]

Thanks.

So you would recommend getting an 8mm Plossl and 32mm Explorer BS?

Is a x3 Barlow worth getting or am I wasting my money?

As for the light pollution, without throwing everything in the car and taking a drive out somewhere, there's not much I can do about that.

Thanks for your help.

Jason.

[rwilkey]

I think you mean the 32mm plossl and 8mm BST Explorer, a great combination, I do not recommend a 3x Barlow, a 2x is sufficient, although you do not get the best quality when packaged with the telescope, but it's a start.

[Parky1972]

Ok.

Thank you.

Now all I need is a clear sky.

Anyone help with that?

Jason.