Best EP

[Stargazer 2013]

Stellarium won't work on my old laptop but should work on my newish pc..Yes I had it installed many years ago,great software.

btw I used to live in Rutland,Great little county

[Bart]

Wow...Best EP? Thats a meaning of life question.....

[Stargazer 2013]

Wow...Best EP? Thats a meaning of life question.....

It was a question about what's the best eye piece to use out of a 10mm or a 25mm !!

[Bart]

That'll teach me not to read the post properly in future. Apologies all round!!!

Barry

[David55]

I have 200p skywatcher and find x200 to be the optimum magnification for planets from my location in rural essex. An important thing to look out for is the eyepiece's field of view as planets will move quite quickly from one side to the other unless you've got an automatic tracking mechanism . Manually steering the scope disturbs the image, making it that much more difficult to pick out surface detail.

[acey]

I'd recommend starting with the 25mm, whatever you're viewing, then go up to the 10mm. If it still looks like it could take more magnification then try the 10mm with barlow. If you're bothered about the speed at which things move across the field of view then remember that the higher the power, the faster they move. If you think you need a high power eyepiece for planetary viewing then save up for a very good one, e.g. an 8mm TeleVue plossl (about £65).

[Charic]

stargazer 2013..........I`m a BST Starguider user ( I also have the same lenses as you!)  I would keep using the  the 25mm  for now , as that lens isn't too bad,  and buy  either an  8mm or 12mm BST Starguider for your planetary work. The 8mm blows the supplied 10mm away.   Both the 8mm & 12mm lenses could be 2x Barlowed,  producing the equivalent of  4mm & 6mm EPs.

[Stargazer 2013]

Thanks for the replys

Again too much cloud..Tonight there is shooting stars but unable to see..I will test my x2 barlow lens with a 10mm to see more detail on the moon..

[ardbeg74]

Hi Stargazer,

David55 mentioned the EP field of view so thought i'd share stats for different eyepieces to give you an idea of what the magnification and field of view would be like through your scope. 

Not suggesting you buy that make of EP, was just ones i was looking at for myself.

Couple of things to note. Exit pupil, this is the diameter of the circle of light coming out the eyepiece. If this is bigger than your pupil   (which is generally between 7-4mm depending on dark adaption, age, health etc ) then some of that light is wasted as it cant get into your eye.

So from below we can see that the 40mm EP would give you the largest FOV but the image wouldnt be as bright unless your pupil was 8mm. 

Max magnification for the scope is a strange one, im still coming to terms with how that really applies to viewing. I was way over my max on friday but got the best views of jupiter yet. My understanding is that you can exceed this and you will get a bigger image, but you wont see any greater detail. ( in my head i see this like zooming in on an image till you can see the pixels) If anyone has a better explanation for this then please correct me. 

Anyways if you want me to re-run it for a specific set of EP's just let me know the website or the focal length and field of view.

Objective diamater.........130 mm

Maximum usable mag.........130 X

Focal length...............650 mm

F-Ratio....................5.00 

Resolving power............0.92 arc seconds

Star Magnitude limit.......12.57 

Brightest eye piece........35.00 mm

Eyepiece for max mag.......5.00 mm

EP             FOV_ep Mag      FOV_scope  exit pupil surface brightness

Vixen NPL 40mm 40     16.25 X  2.46 deg   8.00 mm    128.00 %

Vixen NPL 30mm 50     21.67 X  2.31 deg   6.00 mm     72.00 %

Vixen NPL 25mm 50     26.00 X  1.92 deg   5.00 mm     50.00 %

Vixen NPL 15mm 50     43.33 X  1.15 deg   3.00 mm     18.00 %

Vixen NPL 10mm 50     65.00 X  0.77 deg   2.00 mm      8.00 %

Vixen NPL 8mm  50     81.25 X  0.62 deg   1.60 mm      5.12 %

Vixen NPL 6mm  50    108.33 X  0.46 deg   1.20 mm      2.88 %

Vixen NPL 4mm  50    162.50 X  0.31 deg   0.80 mm      1.28 %

If you are interested in the theory or math ( just division , multiplication and one log ) it can be found on this great site:

http://www.rocketmime.com/astronomy/Telescope/telescope_eqn.html

All the best

Mark

[fondofchips]

Hi guys..Fantastic forum by the way.I just bought a

Skywatcher Explorer 130P  and have the normal 10mm and 25mm eye pieces,I wanted to know what is the best EP to view Saturn/Jupiter? I have a x2 Barlow coming soon and would it be too much of a magnification with  x260 ?  I just need to find these planets

I noticed you put "I just need to find these planets" on your post.

As a fellow newbie I found finding even brighter objects difficult at first.

The initial setup advice is to align the findercope with the telescope on a distant object in daylight.

This alignment is OK for the moon but not accurate enough for more distant objects.

So I have practised aligning the finderscope on any bright distant object, only takes me a couple of minutes now & finding objects is much easier for the rest of your observing session.

Clear skies,

Fondofchips.

[Stargazer 2013]

Yes when I said I need to find these planets I meant it could be difficult with the scope I have and also being completly new tothis it's going to be difficult,It;s really frustrating because of all the cloud cover..Thanks ardbeg74

 

[lestergibson]

To help you understand the different types of eyepieces try this link

http://www.swindonstargazers.com/beginners/eyepieces.htm it's a 

beginners guide to eyepieces, and there are other links to further

articles all about eyepieces, it's a great site, you will learn a lot from

it, I certainly have. 

 That was a great article; very informative.

[Caldwell14]

It has to be said that although you can push things a little higher most of us in the UK find 200X times is about the useful limit on Jupiter on most occasions, often much lower, perhaps 160X 

[todd8137]

Asking about eps is like asking about cars they all drive ,some better than others hope you find what you looking for. Pushing the mag ro far is always a bad idea

Pat

[Paul73]

On the subject of finding the planets.

I was struggling as a newbie to using a scope & finder (which point of light I am looking at in the finder scope?). Saw articles about TelRads. Liked the idea. Then realised that I could get much the same effect by punching a 1/4 inch hole in the bottom of a long tin can (I used an old tennis ball can) and blue tacking it to the side of the view finder. By looking through the hole at the bottom I had a patch of sky about 3 x the arc of the view finder nicely outlined and by getting the star / planet roughly in the middle I was close enough to catch it in the proper view finder. £40 saved.

NB. Blue tac isn't an approved fixing so tethering the can with a bit of string stops it falling onto anything expensive when you knock it off!!

The more I use it the less I need it. Should be able to bin it in a week or two as my scope handling skills increase.

Paul