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Desperately need help/advice please!


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Hi all.

Having spent years looking at the night sky and wanting a telescope to view it with, I have finally taken the plunge and got myself a 2nd hand Skywatcher 200p. The reviews on this scope were really positive, But now I have it I realise how important the correct eyepieces are and here lies the problem. The scope came with a 28mm eyepiece that looks pretty cheap and has no brand but it gives a good view of the moon, so I was really happy with that. Wanting something else I looked at a few sites and got a Celestron x-cel lx 7mm eyepiece and I can't see anything through it at all. Is there a reason for this? Have I got an eyepiece that doesn't go with the scope? I'm a complete beginner at this and I really don't want to make another expensive mistake when buying another eyepiece. Any advice on what pieces to buy that would give me good views of the planets and moon would be great please, I have read the pinned eyepiece section but to be honest I still don't know what to get.

Many thanks.

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Hey jonny, I'm not sure what to say about your celestron ep but it dosent sound right. I have 200p skyliner And I have the stock ep's tht came with the scope a 25mm and a 10 mm and these give grate views of the moon Saturn Venus ext. I've also recently bought a x2 Barlow which increases the magnification of the ep's I'm hoping to upgrade my ep's soon but I'm saving up for an eq3 skyscan to get in to astrophotography so tht comes first lol good luck with your scope clear skys. Stu ~

Sent from my HTC Desire HD A9191 using Tapatalk

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Hi and welcome to the forum !

You have a great scope and the new eyepiece is excellent so don't panic. A common mistake with these scopes is to use both eyepiece adapters (ie: the 2" and the 1.25" ones) at the same time. Skywatchers are unique in that you don't do this - you use either the 2" or the 1.25" in the drawtube. Using both at once moves a 1.25" eyepiece to a position where it won't come to focus.

I hope that helps.

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That sounds like your problem. In principle, any eyepiece should be able to come into focus in any telescope assuming you have the right amount of travel in the focuser. There are some cases where this isn't possible, but that's rare. When you "can't see anything" it's almost bound to be a focusing issue.

Regarding good eyepieces for planets. Pretty much any eyepiece is a good planetary eyepiece. Sure, some will be slightly sharper than others but overall there is little difference so long as the eyepiece is from a reputable company. The reason why this is the case is because most aberrations tend to occur off-axis (around the edges of the field of view). WIth planets you're viewing an object that's in the field centre where the view is usually sharp. So even if you're using an eyepiece with astigmatism around the field edges, that doesn't effect the view of the planet in the middle of the field. Some people do prefer some eyepiece designs or brands over others for planetary observing but this is, for the most part, a personal preference. If you are on a budget then you could stick to Plossls and be happy in the knowledge that you'll be getting good planetary views. Plossls are cheap because they have only 4 glass elements and a modest (but quite acceptable) 50 degree apparent field of view.

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You couldn't be missing the object due to not having the finder quite aligned could you? An alignment that's good enough with the 28 mm eyepiece might be noticeably off with the 7 mm eyepiece.

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Hi Jonny,

You don't say where you are, but I am sure that there will be an astronomy group near you where you could take your scope along and ask advice. Your scope and eyepieces are fine, it's just trying to identify where the issue is. There aren't that many bits to go wrong!

If both mirrors are fine, a bit of dirt won't make much difference. If could be a collimation, finder or drawtube issue. Whichever it is it Is solvable.

A word of warning, don't expect to see Hubble like pictures through the scope. Hubble has a lot of advantages over us Earthbound mortals.

Best of luck.

Simon

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Your 7mm eyepeice should give you 143x magnification in your 1000mm focal length scope. This should allow you to easilly see the moon surface, planets will be small but straightforward to discern, and nebulae and clusters will be plainly visible.- galaxies will apper as faint smudges. The focal ratio is f-5 which does favour higher quality eyepieces - but nonetheless all the above should come to focus with good sharpness and contrast. I've done this with an 8mm eyepiece in a 200P many times.

You may have an inward focus problem as suggested above, or possibly an alignment problem with the finder scope (which needs to be more accurate the higher the magnification). Make sure there is nothing between the draw tube and eyepiece (ie no extender or barlow). Align the finder in daylight on a distant objects (eg tip of a church spire 2 miles away) making sure it is dead center of both eyepiece and finder. Finally check collimation of the secondary and primary mirrors.

It helps to pay attention to prevailing conditions - no cloud, fully dark (no moon), good transparency, etc, and try to look at a high object. If you still can't see anything at all then the eyepiece may be faulty (are you sure it's not been opened and lenses rearranged?). Once you find an object you may need to realign the finder on it in the dark for greater accuracy. Using a high power for the first time often proves difficult but the 7mm X-Cel should have no problem with your scope. HTH :)

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Thanks for the quick reply's by everyone. Having read through the replies I think I may have been using both the adapters at the same time for the 7mm one as suggested by John, So hopefully if it's a clear night tonight I can give it another go and have better luck with it. The Celestron eyepiece that I have got comes in a variety of mm's (2.3, 5, 7, 9, 12, 18, 25) What is the different mm's used for and how many of these would you need to have a decent set? There is an astronomy club close by so I will be joining that.

Thanks again for the reply's.

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Hi JonnyF

The different focal lengths (mm) of eyepieces give different magnifications. The smaller the eyepiece focal length the higher the magnification. The actual magnification is given by the focal length of the scope divided by the focal length of the eyepiece.

If you look in the primers & tutorial section there is advice on eyepieces, but generally it is recommended to get a low power eyepiece, a high power one (your 7mm covers this) and then something in between. What tends to happen is that you have a low & medium power eyepieces plus a selection of high power ones - high power viewing is generally limited by the seeing (atmospheric turbulence) so having several high options allows you to find the best one for a particular night/object.

But you don't have to jump in straight away - use what you have and see what you feel is missing.

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The smaller the (mm) the higher the magnification, use a high (mm) to locate objects then work your way down to the higher power EP's as conditions allow, you won't always be able to use the highest power EP you have if the seeing conditions are not good..Most DSO's Gallaxies will be a small grey smudge when found and viewed through low power (high mm) EP, this grey smudge will get bigger and the view may improve depending on the quality of the EP and the seeing conditions allow.

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Imho it's not really worth going much higher than a 5mm eyepiece - this would give you 200x magnification which is very workable on a clear night with good transparency. Higher mags have been used but the occassions on which it's possible are few in UK conditions. Also over 200x magnification with an f-5 scope your collimation needs to be spot on, and good quality eyepieces costing in excess of the £150-£200 range are a must for good observing. The times I view at 200x or more magnification in any year can be counted on one hand. :)

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I'd agree that higher than a 5mm will get used infrequently...

If you're still stuck, take some pictures of the eyepeice in the scope (during daylight) and post them up and we can make sure that there isn't anything daft going on.

If you have trouble adding pictures to your post , there is a guide here >>http://stargazerslounge.com/topic/154704-sgl-how-to-attach-images/#entry1561785<<

Rest assured we can get your sorted :)

Cheers

Ant

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Hey jonny, I'm not sure what to say about your celestron ep but it dosent sound right. I have 200p skyliner And I have the stock ep's tht came with the scope a 25mm and a 10 mm and these give grate views of the moon Saturn Venus ext. I've also recently bought a x2 Barlow which increases the magnification of the ep's I'm hoping to upgrade my ep's soon but I'm saving up for an eq3 skyscan to get in to astrophotography so tht comes first lol good luck with your scope clear skys. Stu ~

Sent from my HTC Desire HD A9191 using Tapatalk

Stu - I don't know much about A/P but from what I read you will need something better than and EQ 3 to use a 200p Skyliner (unless the Syncscan means something I'm unsure about) - most people would suggest an NEQ5 or EQ6 If possible and then your talking £6-700 I would guess

perhaps I've got this completely wrong but it may be worth posting your thoughts in the astro photography section to get some feedback - hope I haven't misled you but it might be worth doing some research on the forum just to put your own mind at rest.

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Am really pleased I found this forum, everyone has been really helpful so thank you all for taking the time to reply and help me. Have had the scope for a month but the weather conditions have meant that chances of getting out and using it are few and far between. Hopefully it's clear tonight so I can give the suggestions a go after the football!

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Have got perfectly clear skies here so I have just been out trying the suggestions on the moon and the 7mm now works superbly. It was because I was using both adapters but with just the one I got onto the surface with the 7mm and also took some decent photos! One thing I have now noticed though is that the finder scope and the telescope don't line up, When the moon is in view through the telescope it's to the far left of the finder scope. But I can live with that for now and that problem is for another day!

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Yup - as per what Knobby says just move the scope so the moon is dead square in the eyepiece - then adjust the finder so the center of the moon is in the middle of the finder. That will give a basic alignment but won't be accurate on planets and stars. So you will have to repeat the process on a star for higher accuracy.

First - start with a lower power eyepiece (around 20mm or more) on a star. Center the eyepeice and then finder. Then pop in your 7mm and it will still be way off - so try with a 15mm and adjust, then a 10mm and adjust, then finally the 7mm and adjust. Now you'll have it bang on for all your eyepieces. :)

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