What len's to buy for a 8inch dob?

[uklee6]

was reading around and apparantley a 2x /3x barlow is a good lense to buy and is there anything else i could buy to improve my viewing?

don't know anything about len's what would buying one of these lenses do?

thanks

[wookie1965]

It depends on what you want to look at and how much you want to spend.

[John]

Eyepieces are quite a complex subject in their own right but this piece was designed to cover the basics and will help you understand the different sorts that are available and what they can do for you:

[Eastridge]

If you have further questions having read the above it helps if you let us know your budget and whether you wear glasses to view ( if so you need greater 'eye relief' which we can explain further if need be) . Also you say 8" dob, the exact make and model would be even more helpful as that should enable us to know exactly how 'fast' yoour scope is ( it's f number) as that has a big impact on what eyepieces work well with it.

[Lenny147]

Go go far wrong with a TAL x 2 Barlow if you can find one

It would double the mag of any of your EPs by the way

[blusky]

You won't go wrong if you get a 30mm, 12mm and a 2x Barlow.

That won't blow your budget, and at least should give you an idea what you like. I recon you can get all 3 second hand for under £100. A moon filter will be a must too.

My wife is a big fan of the 30mm with a god eye relief - to occasionally look at M42, the Moon and carbon stars.

Although I have a TAL Barlow, I swear by the Orion (not Orion Optics UK) 2x Barlow. In a combination with a 12mm Plossl it beats the dedicated much more expensive 5mm planetary.

PS Some people advocate for a 20mm EP, it doesn't add much value for me, it's the 1st on the list to be sold. The next item to go is the red filter

[E621Keith]

was reading around and apparantley a 2x /3x barlow is a good lense to buy and is there anything else i could buy to improve my viewing?

don't know anything about len's what would buying one of these lenses do?

thanks

When you say lens, i think what you want is eyepieces rather than barlow. The term lens is usually only used for describing photographic lens.

An eyepiece is the thing you put at the end of the telescope focuser to look through. It determines the magnification.

A barlow lens is a amplifier for your eyepiece. It increase the magnification of your eyepiece by the factor stated on the barlow.

What eyepieces you need depends on your scope and your budget.

How much do you want to spend? Individual eyepiece can cost from £30 to over £1.5k.

[JamesM]

The key thing to remember about any magnification, is that different eyepieces will effectively attempt to stretch by different degrees the fixed amount of light that enters your scope. You will notice that as magnification increases, so the image it projects to your eye gets progressively darker in addition to sharpness - all as a consequence of stretching the light. John's recommendation above of the link, "Eyepieces - the very least you need" will certainly help you calculate the limits of what your own scope can muster and so it then becomes a matter of budget and whether you want additional benefits, such as a wider field of view to accompany a given magnification. The BST brand of eyepieces seem popular and are also modestly priced but on your travels you will also notice some very exotic glass that can cost more that a scope and cost is linked to design, coatings and the control of undesirably aberrations (e.g where stars do not remain sharp across the whole view). One view to take might be think that eyepieces remain with you for the longer term whereas you are likely to change your scope over that period, so I would always recommend buying the best that you can afford. Like may things, the extra you pay can be disproportionate to the difference that it makes but for many, that little extra contrast or sharpness can make all the difference and so it's down to personal choice.

It is possible to buy used eyepieces which have the benefit of being sold at a lower price, such that you can then sell them on for as much as you paid for them as you decide to upgrade. However, I would only buy from a reputable site such UK Astro Buy & Sell when you know the particular brand and size you want. Most astronomers selling kit on usually look after their kit very well so there are bargains to be had once a little research has been done first.

James