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Eyepiece for Sky Watcher Sky Max 127 Mak


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Hi, I'm new here so apologies as I know this has been covered, but I'm wondering if someone could give me a pretty basic answer to the above question. I'm a beginner, I got my scope in October. It cam with 10 and 25 mm eyepieces. I have heard people say that the 10 is not very good but the 25 is passable? I have nothing to compare it to so I wouldn't know. Only dimly aware of what I was doing I then bought a Vixen 8mm eyepiece and a moon filter. Only got to use it once on Jupiter before the bad weather but was a tad disappointed (probably wasn't doing something quite right). Anyway, if I were to invest in say two more eyepieces for under £100 what should they be? Also, at the risk of incurring the wrath of the knowledgable, what is a plossl and do I need one ???

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Half suspect that the 8mm was too much power for the scope, you would be close to 187x and that is not going to be usable too often.

The 12mm and 15mm BST Starguider should be a better option if you wanted magnification. If you were not overly bothered then the 15mm and the 18mm.

The 15mm will give 100x and that is OK for Jupiter maybe a bit more for Saturn,.hence the 12mm giving 125x

When Mars becomes a convenient object with regards time then you may have to try the 8mm again.

Edited by ronin
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Hi Inky, and welcome to SGL.

I have the same scope, and I had the same issues with mine. The 25mm is useful as it's a long eye relief EP, but neither that nor the 10mm are all that good, and I no longer use either of them. I got the Revelation set, five plossls for just over £100, and while that may not have been the best thing to do, they're still better than the stock EPs that came with the Skymax. My C9.25 came with a Celestron 25mm plossl, which far surpasses the Skywatcher one.

Plossl? (There are no silly questions on here. Astro terminology is not self-explanatory.) Here's Wiki's piece on EP designs : - click. You don't *need* an EP of any particular design, but plossls are common, good and popular.

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Thank you all for your replies. Are the BST ones any good, I saw them advertised but wasn't sure? Also, is there much difference between say a 12 and a 15. Would I not be better off getting say... Well I don't know, but two numbers that are further apart !

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Hmm. You shouldn't have much difficulty getting Jupiter in focus. It'll be fairly small in a 5" scope no matter what you do, but if you can't see Jupiter's moons or equatorial bands then I'd say you're doing something wrong.

Re: EPs, a 12 or 15mm would be a useful addition, but what surprised me was how useful a 32mm EP is, especially for larger DSOs. It's worth bearing in mind that eg the Andromeda galaxy appears as wide as six full moons.

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The bst,s are good but maks do take sometime to cool down.Also the focal length is 1500mm so using an 12mm in yours would be the same as me using an 8mm in mine which is about the best unless seeing is very good.My bruv has an sct with a focal length of 2000mm and could not understand why he could not use the same high power as I could,maybe on the moon though.So a Bst 12mm I would recommend as the highest and at£49 won,t break the bank

Good luck and stick with it

Jonn

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How about a zoom eyepiece?

I bought the Seben 8-24mm one second hand for £25 for my 127 mak and despite the low price tag it's always the eyepiece that comes out of the box first.   There's a review of it here.

It doesn't perform too well at the lower focal lengths so an 8mm BST explorer would be great for more detailed planetary views.

The Seben brand is far from respected here but actually that particular one is actually a rebranded Skywatcher 8-24mm and is a lot of eyepiece for not a lot of money.

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I also have the 127 mak and the 10mm and 25 mm aren't very good and I replaced them pretty quick.

Plus I have the 8mm vixen and it's about as low as you can go with the 127 and I have had some good views of Saturn and Jupiter with it when the condition have been good.

It's worth having In your set but the condition will not always be that good to be able to use it.

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I've had my SW 127 Mak for a couple of weeks now, my SW planetary 5mm ep was way too powerful for the scope & made the image too dark & hard to focus.

So, I decided to buy a ep to replace my stock 10mm & went for the 9mm x-cel as it gives 60o fov, as this helps with a non motorised tripod & has good eye-relief, which I prefer.

I've been getting sharp views of Jupiter with plenty of contrast, The only problem is the exit pupil is small, so I get some blackouts. The 12mm should stop this happening.

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Is there much between the BST, Celestron Xcel LX and the Vixen NPL eyepieces? They are all within about £15 of each other. What would you go for ?

Bst / starguiders . The x- cels are as good as , but cost more.
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Ok depending how much is left in the bank on Monday I think I'm going to go for a 12mm bst to get the ball rolling. Any sugestions what I should get after that mm wise (or brand wise)?

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Have you tried the stock 25mm on DSOs or the Moon?

The Orion nebula & star clusters resolved well, I'm still waiting to try it on the Moon, before choosing my next eyepice.

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I've tried it on the moon and I thought it was ok but I have absolutely nothing to compare it to (well apart from the 10mm). They both seemed to do a job but I don't know any better. As I mentioned I then bought a 8mm Vixen and probably expected too much. But I have only used it once and may not have let things cool down etc. I've just ordered a 12mm am thinking about maybe an 18 and possibly a barlow. But still do t really know exactly why lol

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My advice would be to wait until you have tried your 12mm out & see if you like the fov, eye relief & image.

Use the stock 25mm on some DSOs, the scope will work on the brighter ones, you will see distortion towards the edge.

If I'm correct, the stock 25mm should give a similar tfov, as a 18mm 60o & should fit whole moon in. If you are after a larger field go for lower magnification eyepiece.

I think a 2x barlow, would make the scope too slow at about f24.

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Unfortunately telescopes & plain english do not mix, it's all mathematical.

Here goes, to get magnification, you divide telescope focal length by mm of eyepiece, so a eyepiece of 25mm in a 1500mm focal length scope will be 60X magnification, 1500/25=60

The f-stop is the amount of light that enters the eyepiece, the smaller the f-stop the more light, so a f5 lets more light in than a f12.

The 127 is about f12, this is the focal length divided by aperture, so 1500/127=11.81. If you use a 2X barlow it doubles the focal length so the scope wold become 3000mm, making the f-stop f24.

The afov starts getting complicated, as you need to work in arcsecconds. A 25mm 50o eyepiece will show the same magnification as a 25mm 60o eyepiece & the object will the same size, but you will see more sky. So in theory you can use a smaller eyepiece with a larger fov, as a larger eyepiece with a smaller fov & see the same amount of sky, with higher magnification.

stellarium is free software & will give a visual idea of what you will see.

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Thanks for that reply. I knew the first part, learnt something in the middle and was lost by the end, but every little helps! I think you're saying that with a wider field of view you can afford to up the magnification because you're looking g at a bigger canvas so to speak? I've just ordered a 12mm EP so that will be good for maxish magnification but what sort of EP is good for different things? I've got my head around working out the magnification and the upper and lower limits of what's practice for any one scope, but what I don't understand is whet you would use a 15mm as opposed to an 18, or a 25 or anything else. Is there really that much difference between say a 15 and an 18 as to mean you would need both? Or, to put it another way, if you had three or four EP what size should they be?

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Yep, the canvas is a good way of explaining it, better than my way.

Have a play with the 12mm, if im correct it has a 60o fov. See if you like the eyepiece, then go for one in the same series. While you are out use the stock 25mm, I'm sure it is 50o.

If you find that you are looking at DSOs more, go for a 25mm 60o as you will still be able to see the moon.

But, if you spend more time on the moon, then a 18mm 60o eyepiece should frame the moon nicely, but may be a bit tight on a non motorised mount.

The 15mm may be useful, if you wanted something in between, maybe for star clusters or closer views if the moon if the 12mm is too powerful.

Unfortunately eyepieces are a personal preference.

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