Eyepiece sets

[Andy_E]

What a headache this must be causing you!!! There's some excellent advice throughout the thread which should hopefully be helping you on your way to a decision. Why not simply buy one new EP for the time being? try it out for a couple of weeks and see how you get on with it. If you do, then you can invest in one, maybe two more in the knowledge you have a set you will really enjoy. If not, then there's always the S/H market!

This way you will help not over complicate things which could get in the way of simply enjoying the night sky, which is first and foremost what it's all about. Stick with your £15 bargain and only upgrade when you feel like you've rung everything you can out of it. If you're like me, you'll find that your equipment is amazing on clear nights... it's only when the cloud rolls in that you start to question your set up as it sits in the corner .

[cowmoon]

Well andy at least i'm glad I came and asked for help before I bought anything, even if I am more undecided now than when I came in. Anyway, I feel like i'm almost there and i'm thinking just buying one lens and maybe a barlow would be best for now. Its just whether that lens would be the 9mm wide angled, the seben zoom, the 8mm BST or soemthing else. The 9mm has the benefit of being half the price and a nice fov. For its price isnt the 8mm BST out of the picture if the Seben performs better at 8mm?

Something like the 9mm wide angled and a barlow is starting to feel like the best option for now as Its not too expensive and the general consensus seems to be against zooms, the only problem being that the heritage comes with a 10mm so one of them would probably end up with not much use. So i'm back to just looking for a single lens then, probably between 7 and 12mm, any more suggestions on specific EP's and should I get a barlow to go with it or forget that for now?

[Schorhr]

I agree, if you can afford it, always go for a eyepiece instead of a barlow. But to stretch the budget there's nothing wrong with using a achromatic glas lens (not single plastic lens) barlow.

But both the 13gbp and 30gpb variants perform similar, so either get a cheap one or don't get one at all.

I can go to the basement later and check the barlow with my 76/700 if I can get in focus.

I *think* I remember that it was no problem with the short version barlow. Therear different types though. The 76/700 reflector telescopes should all be the same build/length wise.

Does yours have a 1.25" or 1" Focuser(inner tube diameter)?

The 10mm of the heritage is not so good (but usable and better then most enty level kit eyepieces).

So getting the 9mm would not hurt anything, plus you can barlow it if you get larger aperture.

Oh, and if you like to tinker, by changing the distance of the eyepiece's bottom element you can increase the magnification. There is even the "Astrozoom" to mod these eyepieces, but the adapter costs more then a set of these eyepieces ;-)

The 6mm eyepiece would be nice, not the maximum magnification but still 0.65mm exitpupil(image not too dark) 116x --- be aware that planets are still pretty tiny at 116x --- The 6mm will not be an advicable combination with a barlow on your telescope, as the small amperture can't handle that high magnifications.

[spaceboy]

I knew I would be stirring the water mentioning a zoom over fixed focal lengths but I will hand on heart say at this point in time it would suit you best and it is an eyepiece that you will find handy in grab and go situations.

I admit to having the Meade 8-24 zoom which could be argued to be better quality that cheaper brands but most budget eyepieces on the market appear to be a rebadged of one or another anyway so there is no saying the cheaper brands are any the less good a performer. As always in this game do your research and be aware that eyepieces perform differently depending on the type and focal length of telescope.

In this case the Seben 8-24 appears to be a bargain and has had some praise from fellow members. The 8-24 would be a better choice over the 7-21 in that the x2 barlow will open up more focal lengths. Regards what barlow to get I would recommend you get the best you can afford as this is something that will always come in handy (more so if you find you want to dabble in webcam imaging) no matter how often you change out your eyepieces.

It is always down to you at the end of the day but I know how hard it can be to make up your mind when starting out and you are up against such a vast array of accessories to pick from. My advice to a beginner over everything is that if you have a budget stick to it!! or at least buy used until you have made up your mind that late nights in a cold garden looking at faint and fuzzies is for you.

[Charic]

skies_unlimited, Sky`s the limit, offers a service whereby you can purchase  lenses, and the ones you dont like, you send back for a full refund. I think you get two weeks to test? I was going to take a TMB & BST, but by references to this site and the web, have decided to stay with the BST Starguiders.The contact is Alan @ sky`s the limit.

[Reeny]

.......................... Anyway, I feel like i'm almost there and i'm thinking just buying one lens and maybe a barlow would be best for now. 

.......................... So i'm back to just looking for a single lens then, probably between 7 and 12mm, any more suggestions on specific EP's and should I get a barlow to go with it or forget that for now?

I repeat - a decent barlow is likely to pull the focal point beyond the adjustment stop on the rack & pinion focusser.

If my telescope is the same as yours, the photo below will show you what I mean.

The focussing tube nearly touches the secondary mirror - and will block some of the incoming light.

Work out what magnificatioin the barlow will give you - and get yourself a second eyepiece instead.

 

[Reeny]

BST Starguiders only come in 25mm / 18mm / 15mm / 12mm / and 5mm

Giving you 28x / 39x / 47x / 58x / and 140x

I would still go for the 12mm and the 5mm

If you need to save money - get a cheaper 10-12mm size which is less critical for optical quality than the higher magnification EP's.

If you need to buy one at a time, get the 12mm first as a good allrounder to keep.

[spaceboy]

Sorry Reeny I admit to overlooking this in your post and indeed you are better informed than me to the capabilities of this particular scope. Whether a different x2 barlow would have the same problems god only knows but it could become expensive to find out so maybe a barlow would not be useable?? but I would still vouch for a zoom eye piece on this occasion..

[Andy_E]

BST Starguiders only come in 25mm / 18mm / 15mm / 12mm / and 5mm

Giving you 28x / 39x / 47x / 58x / and 140x

I would still go for the 12mm and the 5mm

If you need to save money - get a cheaper 10-12mm size which is less critical for optical quality than the higher magnification EP's.

If you need to buy one at a time, get the 12mm first as a good allrounder to keep.

There is also an 8mm... I own one . Lower power EPs are more demanding as it becomes harder and harder to control optical abbreviations with wider FOVs.

I agree the 12mm would be a good mid power EP to start off with.

[Reeny]

The stock 20mm eyepiece is quite good. So no need to change it just yet.

The best clear image at maximum magnification achievable so far is 116x - using a 9mm and a 1.5x magnifying lens = 6mm equivalent.

With that set-up I saw the mountain peaks inside the craters on the moon. They were pin sharp.

And I even managed to resolve the two dark coloured bands around Jupiter (although they were very distant, and a bit blurry)

The maximum of the scope will be around 140x mag using a better quality BST 5mm ED eyepiece.

I'm tempted to get one for myself now to see what it can do.

[Reeny]

There is also an 8mm... I own one

The 8mm is not available at the moment in the Ebay shop.

That would give 87.5x mag.

Excellent for crisp views of the moon.

[Andy_E]

Just as a heads up, there is a 11mm televue plossl on ebay at the moment... you WILL NOT get a better quality EP in this price range... worth a look.

[cowmoon]

Reeny is this not a lot shorter than the one youre using? Theres no length measurement I can find for it but it doesnt look as long as the one in your picture.

Just measured the focuser, Schorhr, and its definitely 1.25".

Spaceboy I thinks its been an overall good suggestion even if its led to a harder decision my end, I think partly the reason why its hard is that i dont actually have a set budget. The limiting factor, and why I didnt just go and buy a £200 scope, is more my level of interest.  I'd be concerned i'd find a few objects in the sky, think cool ive seen them and then not really bother again. If after using this scope I just want to see more then i'll know it probably wont be a waste of money to upgrade in the future. Even if this scope may not show me much it will give me a good idea of what i'd be getting into.

How about this in combination with this for now to start with? Thats only £40 together and with the 20mm I have it gives me a decent range of magnifications to start with. Any thoughts on better Ep's for around the same price (£25)? Any opinions on getting the 6mm and just forgetting the barlow for now? For example I could just get the 6mm and then a 9-15mm with the money saved instead. What eyepiece would compliment a 6mm, would a 9mm still be useful or would going up to something like 12mm be better? 

Thanks again everyone for the very helpful replies, i'm sure i'll have my head wrapped around this soon enough.

[cowmoon]

I missed all those replies after Reeny and i've gone back and re-read all the posts. To make it easier i've now set a budget of £50 with no intention of spending more until after the new year or I buy another scope.

The way I see it that basically gives me a number of options and i'd like to know which you would go for given the choice:

• Seben zoom £56
• BST 5mm £50
• BST 12mm £50
• Wide angled 9mm with 2x barlow £40
• 6mm wide angled and 9/15mm wide angled £50
• 2 other lenses with a total of £50

[Reeny]

It could be worth a try for £15.

The Barlow is shorter where the sleeve slides inside the chrome focusser tube.

But - that won't change where the focal point is.

You could still be hitting the stop to get it focussed in.

That one from amazon will be a single element 2x barlow.

I did see it advertised and considered getting one myself to try.

But I already have a very similar one (£10 second hand)

And I can't use it becasue of the poor optical quality.

The Revelation 2.5 three element Barlow works if you grind down the black plastic lock ring on the focusser by 3 or 4mm.

That allows you to go beyond the focus stop.

But the single element 2x barlow does not work at all.

It would have been binned if the 1.5x magnifier which unscrews from the end hadn't been useful.

Photos below.

 

If you decide to go for the £15 barlow - let me know how you get on with it.

[Schorhr]

I can try later perhaps, I have the short seben barlow and a ts and another brand 76/700

[Reeny]

I would be interested to know if the Seben will work.

The problems I have encountered are:

- Needing to reduce the width of the lock ring assembly to get the 2.5x to focus OK.

- Blurry images using the 2x single element Barlow (maybe I got a bad-un)

Hopefully the focal point is OK, and the images pin sharp.

[Schorhr]

Results:

6mm 6deg Eyepiece: 76/700 focuser-tube reaches about 2-3cm into the telescope-tube when focusing on an object about 400m away (sadly, furthest point I can aim at on balcony)

With 2x Seben/Orbinar barlow (15-18€): About the same

With 3x Meade Barlow (19€): Only about 1cm

http://http://www.ringohr.de/tmp6//barlowbarlow.jpg

;-) ;-) ;-)

3x and 2x combined does work, but reduces the contrast; I find the 2x work well on the 76/700, the 3x increases the contrast noticably.

Of course just the 3x could also be an option for you, along with your existing 20mm.

I can understand the probing-interest thing, that's why I got that telescope used as well a few years back.

Sorry for beeing so pushy :-) Just in retrospect, the other telescope would have had the least compromises.

9mm and 2x:

Not too bad;

9mm on 76/700 -> 0.98mm exit pupil (good) -> 77.7x magnification (Good for smaller objects, will be nice for the ring nebula, dumbbell nebula, moon, will show a tiny saturn when it's up, and perhaps you can make out the two bands on Saturn, it's moons should be obvious... Orion nebula can be stunning under dark sky)

x2Balor = 145x, 0.49 exit pupil (a bit too low but okey on brighter planets, usualy 0.5-0.6mm is considered the usefull magnification limit)-> Moon will be amazing. Saturn rings (when it's up) may show the cassini division despite the barlow contrast loss; Jupiter will be nice to view, depending on the conditions perhaps more then just the two center cloud bands, too dark for most other things though)...

I will post a few possible upgrade paths in a bit, I am currently trying to make a easy-diy, low budget zoom out of the 66deg eyepieces, I will post info shortly

[cowmoon]

Will look forward to that Schorhr. Do you know if these are these Plossl?

[Naemeth]

Will look forward to that Schorhr. Do you know if these are these Plossl?

No, they are modified achromats. Not worth that price either - they are simply the eyepieces that come with most Skywatcher scopes

[cowmoon]

Okay thanks Naemeth. Will keep looking.

[Schorhr]

Wrong link above

http://www.ringohr.de/tmp6//barlowbarlow.jpg

About the DIY zoom:

http://www.ringohr.de/tmp6//PipeZoom.png

This is a budget solution. The idea came to me after I tested the barlows for you and I had my "reading glasses telescope" (for a school class I'm teaching) laying next to my telescope...

Those pipes are versatile, at least if you don't have a 3d printer ;-) ;-)

Here you see the "professional" version with a 6 and 9 66deg eyepieces, HR Planetary and many more

http://vangestel.de/astrozoom/produkte/zoomkulare

(translated: http://translate.google.com/translate?sl=de&tl=en&js=n&prev=_t&hl=de&ie=UTF-8&u=http%3A%2F%2Fvangestel.de%2Fastrozoom%2Fprodukte%2Fzoomkulare )

I just remembered Seben/Orbinar has a cheapo-zoom, too

http://www.ebay.com/itm/Seben-Zoom-Teleskop-Okular-7-5-22-5mm-1-25-31-7mm-SZ1-Astronomie-/360718254656?pt=DE_Foto_Camcorder_Okulare&hash=item53fc7bc240

I suppose it's a Kellner (40 deg)zoom eyepieces but I have no clue as I don't own one!

A kellner is one of the better eyepiece types that come with cheap department-store telescopes.

Back to eyepiece and upgrading:

IMHO a good overview eyepiece is at least as important as a high-magnicication eyepiece.

A 20mm Kellner is not too bad, but a 30mm Plössl shows the maximum field of sky, a 20mm Erfle has a wider aparent field of view then a Kellner, but still can't show as much as the 30mm Plössl.

24/25mm Wide angle eyepieces are much much more expensive then the Plössl though.

9mm and barlow is a bit much, but it can be done.

The 15mm and the 3x barlow would be another solution, so you'll have:

15/5mm (47x/140x) - and 20/6.6mm (35/106).

Maybe more versatile and saves you from double eyepieces if you buy a telescope that comes with a 10mm eyepiece. Plus you don't magnify higher then you should with the 76mm telescope.

If you decide on the heritage later, the bst/tmb eyepieces will perform better regarding sharpness of the outer field. The 66deg won't be completely sharp (outer 10, 20 percent but that doesn't bother me that much as the usable field is still large and the eyepieces are a good deal).

A 150/1200 or even 200/1200 telescope with the aperture ratio of f/8 / f/6 won't be as critical regarding cheap eyepieces.

[cowmoon]

Looks like a fun little diy project indeed!

I just read on my eyepiece "H20mm" does the H mean its a Huygenian EP? If so does that make any difference to your suggestion? I like the idea of the 15mm with a 3x barlow but is there any major downside to using barlows I should consider like loss of light?

Hopefully those are my last few questions for now, thanks for all your help.

[Schorhr]

Yes, most likely.

Huygens will have around 30 degree aparent field of view, but it may be larger for the 20 degree eyepiece.

You could calculate it for a distance and mesure it, or just compare the view on the moon.

If it's 30degree, the moon should fit well into the view twice, h&x shouldfit, m81&m82 should fit nicely (but are small faint fuzzies)...

If it's only 30degree it's not a good eyepiece :-( But hey, it's not horrible either.

A 20mm30degree eyepiece will show almost 1 degree of sky (2xfull moon diameter), a 20mm66degree eyepiece almost 2 degree of sky. While they have the same magnification and same exit pupil, the wide angle eyepiece shows almost double.

Actually, the 9mm66deg will have a much higher magnification but shows about the SAME as the H20.

Just a wide angle view. BUT: Also darker (smaller exit pupil).

So even though in theory it sounds like it would be better to use the wide angle eyepiece, faint objects may be too dark to see allready. Many deepsky objects look best with 2-3mm exit pupil, but of course the eye recognizes larger faint areas better then small ones, so it really depends on the object and sky conditions.

The field of a Huygens is like looking through a paper towel roll, a Plössl like looking through a toilet paper roll, and a wide angle eyepiece like looking through the "O" shape you make with your thumb and index finger ;-) (sorry for that rough and inaccurate comparison).

Barlow:

A budget barlow will

-decrease contrast

-Introduce chromatic errors, color fringe/seams around bright objects

-"loose" some light;

Of course more glass will block some light, but coatings keep that to a minimum. What really makes the image darker is not the barlow but the higher magnification <> smaller exit pupil.

Anything under 1mm exit pupil will be dark, under 0.5/0.6 even too dark for planets and contrast gets lousy.

BUT: A 4mm Plössl is almost impossible to use comfortably due to the short eye relief, so even with all the barlow's downside it can be a valid solution. And seriously, I have those two barlows, they are much better then the plastic-y telescope kit barlows made completely out of plastic.

The 3x color fringe is more obvious though. It can cause you to miss fine details such as the cassini division in Saturn's rings.

I'm not sure what to suggest now if it's a hyugens.

2 eyepieces and barlow won't kill the budget I hope, and even if you don't like the barlow anymore soon, 10-15gbp won't be to much of a catastrophy later on.

Worst-case scenario: You sell it for 5-8gbp to another beginner or use it to experiment with a webcam and imaging.

The seben has gotten more expensive then when I bought it, on their webshop it's still available for 13€/11gbp. I think they have an english section too, not sure if their regular shipping makes sense for a single item though.

If you just want to spen 50gbp, I think I'd say 20mm 6mm (66degree eyepiece) even though there is a gap inbetween, but you have a nice planetary eyepiece and a overview eyepiece.

But a 30mm Plössl would do too.

IF you want to use a barlow, accepting the down sides of the 3x barlow, 20 and 15 would make more sense then 20 and 6 with the 2x barlow, as barlowed 6mm is too much for your telescope (but you can try) ...

You can see with a limited budget there is no direct answer.

IF you want to view the moon and planets, high magnification should be your main focus.

If you want to view deepsky objects, the overview and mid range eyepiece are importaint. They don't magnify as much but show a brighter image and thus some fainter objects.

If you want an allround solution, you either have to spend more to buy three eyepieces or try the barlow approach.

Also I am not sure if the 15mm 66deg ep has a barlow element if you want to tinker with that approach.

If your budget is 50gbp, ad another 70gpb for the telescope, test it and send it back or sell it, the resale value is good ;-) Another approach.

[cowmoon]

Someone has very kindly just offered me a set of 9mm, 12mm, 15mm and 20mm revelation plossls for around the price I was looking to spend. I think that has basically made my decision very easy . Thanks for all your help Schorhr and everyone else, i've learnt a lot going through all this so hopefully i'll get some clear skys along with the lenses soon and get to try it all out.