I'm coming at eyepieces from the wrong direction, so......

[the lemming]

Now that I've done a bit of research on this site and with help and advice from you chaps I now know haw to phrase my question about eyepieces.

Rather than ask questions about what size millimeter eyepieces to get, I now realise this is confusing because my telescope will have a different capabilities in relation to people offering advice on which size to get.

So, with this in mind my question should be what zoom/magnification ranges should I try to aim for?

What magnification range should I try to get for looking at planets such as Jupiter?

What magnification range should I try to get for star clusters and stuff like Orion's Belt?

And what magnification range for other stuff that I can't describe because of my limited knowledge and vocabulary?

[the lemming]

Agggg.

I was trying to add more but my Tablet screwed up and posted the OP.

I was going to finish off with what magnifications should I try to achieve for close up, mid range and wide angle?

That way I can do the maths and choose the size of eyepieces to meet my needs.

Cheers

[Bart]

I'd say the mags you should go for are

60, 100, 150 , 180 and 220

I use 180 up for planets, and 180 down for the clusters, nebs and galaxies.

Of course, your scope's abilitities will have a bearing on the above. These are not precise numbers but are close enough.

Barry

[cantab]

Sticky over in GSGH&A

Makes a good start. The calculation from focal ratio is clever IMHO since it falls out that you get magnifications related to your scope's aperture.

[John]

I'd add a lower magnification to Barry's selection - something around 30x for the larger deep sky objects and to act as a "finder" eyepiece. 220x might not see much use to be honest. Remember that a barlow lens can be used with eyepieces to get further focal lengths so you don't need to buy as many eyepieces.

[the lemming]

I'd add a lower magnification to Barry's selection - something around 30x for the larger deep sky objects and to act as a "finder" eyepiece. 220x might not see much use to be honest. Remember that a barlow lens can be used with eyepieces to get further focal lengths so you don't need to buy as many eyepieces.

I do have a Barlow which will help as well.

As I am new to all this it is the ???x magnification ranges that I want suggestions for. At the moment I have a 10mm and 25mm eyepieces which give me magnifications of, provided my sums are right:

10mm - 65x and 130x (with a barlow)

25mm - 26x and 52x (with a barlow)

[Moonshane]

everyone is often guilty of thinking they need lots of eyepieces to match apparent gaps in their collection (me included) but we all have certain eyepieces that we use most of the time and some we use occasionally. often the eyepieces are used only to step to others; sometimes the jump is made ignoring the middle ones. I do find that a good range at the higher power end is useful as seeing conditions change, although often you don't see any more detail if honest, with more power and sometimes the reverse is true.

I'd broadly agree with above comments.

[Capricorn]

Forget where I read it but it was suggested that you use a factor of 1.6 based on a start of an eyepiece equal to the scope f number.

So if the scope if f/5 get a 5mm eyepiece, then multiply that to get an 8mm, then again multiply by 1.6 giving 12.8 so either 12mm or 13mm, just carry on multiplying and stop at around 30mm or 32 mm.

Seems to give 5, 8, 12, 20, 32.

Which isn't a bad collection for most things.

Haven't tried for an f/7 scope and suspect that they get long pretty fast.

7 would give 7, 11, 18, 30.

[8kids]

When I first got my scope back in March I had the same eyepiece agony as you. In the end I chose a Baader zoom which has served very well so far. The thing it has helped me with is nailing down my most used magnifications. So armed with this info I'm patiently waiting for my chosen eyepieces to turn up on the used market.

So far I've bagged a Nirvana 16mm, I'm just waiting for the other 50 or so to make an appearance.

[Stu]

It's probably also worth factoring in the field of view obtained with each magnification too. Eyepieces have quite a range of apparent fov, roughly speaking from 40 to 100 degrees and this makes a big difference to how much sky is seen at the same magnification.

For instance, in my 4" scope, an 18mm BGO gives x38 and just over 1 degree field of view, whilst the 17mm Nagler gives slightly higher mag at x41 but with just over 2 degree field of view. Makes a significant difference to how larger objects are framed, or even whether some of the larger clusters and nebulae will fit.

Cheers

Stu

[Stargazer_00]

Divide focal length by eyepiece to get mag

Divide focal length by mag you want to achieve to get the eyepiece size you need to buy.

Simple Math that can be done in your head at the scope

Helps when shopping for scopes to know what your current eps will give.

[Bart]

John, you're right, a low mag is a definite must, both for those nights when you feel like wandering through the sky and as a finder. Its one of my most used EPs. The high mag is one not used an awful lot but when the opportunity arises you're glad you have it. I recently used aES 16mm 68" (I'm probably one of the few) barlowed, giving x230, to get two Jovian moon shadow transits within a couple of hours, plus the GRS simultaneously, and it was one of those moments where you're supposed to lie back and have a cigarette!!! Not that I'm condoning that kind of lark, cough!!

Barry

[LukeSkywatcher]

For a skywatcher 130mm scope, i would ensure you have:

6-8 (high power),12-15 (medium power) and 30-32mm (low power) EP.

That really should cover you.

I have a skywatcher 130P scope and i use an 8,15 and 30mm Vixen NPL with it. They cost about £30 each.

Brilliant EP's and dont break the bank:

http://www.firstligh...-eyepieces.html

The 30mm EP is my workhorse. I love relaxing and scanning the skies with it.

[cs1cjc]

I agree with the 1.6 factor suggested by Capricorn, but I would start from the other end. To me 2" eyepiece are a pain - just too big and too heavy on the whole. So I would start with the widest possible 1.25" eyepiece, a 24mm or 25mm wide angle. Divide down by 1.6 or so from there to give perhaps 16mm, 10mm, 6mm, and perhaps 4mm but this is likely to be little used. Then if you really want you can get a 2" eyepiece of up to about 35mm at the top.