Selecting an eyepiece

[Mowbs]

Hello.

Apologies because I know there are millions of posts on EP's and I read one a few days ago that I can't find now that explained all about them. I'd really appreciate a link if anyone knows what I'm talking about.

Anyway, having recently taken delivery of a Skywatcher 200p EQ5 goto and having very limited use of it so far, my thoughts have turned to accessories, and mainly eyepieces.

I have the standard 25mm, 10mm and 2x Barlow that came with the scope and I would like to build up a nice collection of quality EP's. I read in a post that Baader Hyperions we're not particularly suited to such a fast scope.

I would really appreciate any advice and thoughts on this, I would happily pay around £100 for an EP if it would make a significant difference over say a £50 one, maybe even more for one that I would use most of the time.

Thanks

[Reeny]

I have the Dobsonain version of the 200p

But it is difficult to advise because each persons viewing habits are different.

Have a look at the Maxvision 68-degree eyepieces from Explore Scientific.de

http://www.explorescientific.co.uk/en/Eyepieces/

The 16mm is the shortest focal length they do - so try to get a matched set of sizes up to 16mm, and a Revelation 2.5x Barlow (which is nearer to an actual 2x magnification).

The 24mm and 16mm = £130 delivered / the Revelation Barlow is around £36 delivered

24mm = 50x

24mm = 100x barlowed

16mm = 150x barlowed

The 11mm 82 degrees give me just over 200x mag (£90 from USA)

Also look at the BSTs.

You can make up a fully matched set of 6-eyepices for less than £300 (and you should only need 4 or 5 anyway)

http://stores.ebay.co.uk/Skys-the-Limit-Astro-and-Optical/BST-Starguider-ED-/_i.html?_fsub=2568750014&_sid=53377064&_trksid=p4634.c0.m322

[Bart]

Can't really go wrong with the Maxvisions at the moment

[ronin]

I have the set of BST's and really they are worth considering for your scope.

As said above the complete lot will be just under £300, and from reports they work well at f/5, so you would get use from the whole lot at one time or another.

As they are one set they are reasonably parfocal so minimal focus adjustment when swapping.

The next ones up in cost that come with good reports are the Celestron X-Cels, they are £65 and from everything are of more or less identical performance, they do have an "advantage" of one extra eyepiece at the lower end. After that you are in the £100 a piece or above market, at least for the ones that people use and there is feedback on.

[Mowbs]

Thanks for the suggestions, I quite like the look of the Celestron X-Cels. I like the the fact that they also do a matching Barlow. I was looking at a 3x Barlow but I'm probably getting carried away by numbers there.

Does anyone have any experience of these eyepieces in a similar scope?

[wookie1965]

Have a read through these they may help.

The BST Starguider's are very good but the X-Cel's get very good reviews on here aswell.

http://stargazerslounge.com/topic/43171-eyepieces-the-very-least-you-need/

http://www.swindonstargazers.com/beginners/eyepieces.htm

[Mowbs]

Thanks Wookie, the first link is the one I was talking about in my original post.

Doesn't look like the clouds are going to clear anytime soon here so I'm going to make myself a cup of tea and read those two links in my bed.

Many thanks

[Reeny]

It's crystal clear up here at the moment.

The Barlowed 16mm on Jupiter is going to be the weapon of choice tonight.

I would have preferred not to use a Barlow - but the MaxVision range is limited.

The 8mm BST is going to be a good-un on your 200p EQ5 at 125x, along with the 5mm to push towards 200x magification.

I would be looking to split the 12mm with a 2x Barlow to give you 166x

and a Barlowed 8mm will give you 250x magnification.

There are far too many choices.

But 3-eyepieces and your current 2x Barlow will give you 83x / 125x / 166x / 200x / 250x.

Then you would need to add a 25mm at some point to replace the usable Skywatcher eyepiece.

Good luck with the lucky dip.

[Reeny]

Well

By the time I finished off the work I was doing an hour ago  - it has clouded over.

Oh dear - I shall try again next week.

The forcast is rubbish over the weekend

[wookie1965]

Same here got the scope out let it cool then cloud started rolling in waste of time looking forward to try and find M82 to see if i could see the nova.

[Mowbs]

I got up a little earlier this morning just in case (and that's not like me ) I'd love to see Saturn. But it's as cloudy as it's been since I got my scope. Friday has a poor weather forecast but there might be a slim chance for tonight. That could just be me not understanding BBCs graphics.

Thanks again for those links Wookie, they made great reading and I think I'll go back and read them again. I must admit at the moment I'm much wiser but more confused. I started looking at the Televue EPs and thought I'd maybe like to invest in in one of them for a well used size but I should really wait until I have a better understanding of what I'm doing and the sizes I'm using the most.

I will most likely buy 2 or 3 Celestron X-Cels for the time being but that gives me another question... Would a good quality Barlow make a worthwhile difference?

[wookie1965]

Stick to 3 good quality eyepieces for the time being low mid and high mag then in future get a good quality Barlow. Saturn is a bit low at the moment but the rings are in a very good position to see them if you haven't seen it before it will blow your mind my first time was a wow moment.

[Mowbs]

After a night and a full morning of researching and drooling over my screen I crumbled and ordered 3 Celestron X Cels in 7mm, 9mm, and 18mm. I'll see how I get on with those for the time being. I fancy ordering a Maxvision to cover the lower end but maybe I should wait until I've at least seen the Celestrons and maybe even a star or 2

Thanks to everyone above for helping me with the decision     

I'm still not sure about the Barlow though, does anyone know if I would see much of a difference between my standard Skywatcher one and something like the Celestron?

Anyone know of an eyepiece that can penetrate thick cloud?     

[Mowbs]

Sorry Wookie, I must have written my last post as you were typing. I've done just as you said too, the 18mm was as low as I could go with the Celestron X Cel but I still have the 25mm that came with the scope. I'll definitely look into the Barlow

[Mowbs]

And I haven't seen Saturn yet, I'm really looking forward to that one. I work away from home for a month at a time so I really hope that I don't miss to many of the best viewing nights. I'm sure It'll all come round again anyway

[Reeny]

...........does anyone know if I would see much of a difference between my standard Skywatcher one and something like the Celestron?

The short answer is yes - but use your current Barlow first to see what you might need to match your final choice of eyepieces.

I have a Skywatcher 2x Barlow and it is terrible.

You should be able to unscrew the magnifier lens from the end to use it at 1.5x (screwed directly into the eyepiece filter threads).

That is all mine is good for.

The Revelation Barlow I have is excellent, and will correct minor edge distortion on the MaxVisions.

It must be a built in comma corrector or something.

However, the magnification is not 2.5x.

That is the only problem I have with the Revelation.

It is exactly the same magnification as the Skywatcher 2x (although I suspect they are both 2.2 or 2.3)

Use the 2x Barlow for now - then upgrade once you have all the information you need to choose a new one.

Money is normally best spent on the correct eyepiece.

I am only using the Revelation because I had it already.

[Reeny]

PS - don't screw anything like a filter into the 10mm SW eyepiece, or the empty Barlow barrel.

The threads are not machined properly.

I lost a good moon filter by fitting it into the empty Barlow threads - and wrecked it completely.

[Mowbs]

Aaaaaargh, Help!

My attentions have turned to the Maxvision's and I feel like I need to make an order before they're all gone!

If I have the Celestrons in 7mm, 9mm and 18mm should I get a 24mm, 28mm and a 34mm Maxvision just to round off my collection? Would I be better with a 20mm rather than the 24mm since the barlow will duplicate the 12mm I already have, I have read that the 24mm is very good. There is also a 24mm 82o, does anyone have experience of this one? Should I just get the 20mm and the 24mm? And the 40mm?

I really appreciate the advice and feel like I couldn't buy anything now without running it past the good people at SGL.

[bingevader]

The exit pupil would be a little over the magic 7mm for a 40mm EP in your 'scope, so theoretically, not all the light might reach your retina, unless you're observing from very dark skies where a little light loss won't hurt much.

The 34mm would be bang on and at 30x magnification would make for a good low powered EP if that were to be your thing!

I have the 24mm 82^o but haven't had much chance to use it since Christmas. On the few occasions I have however, I've thoroughly enjoyed using it. Took a little time to get used to positioning my eye comfortably and there's a touch of field curvature round the edges, but I prefer the contrast it gives over my TV plossl. It is a fair bit more expensive than it's 68^o equivalent which everyone who has seems to love!

Cheers

[Reeny]

On the 200p dob, I find the 24mm and the 16mm too close together

= 50x and 75x at the 1200mm Dobsonian focal length.

In hindsight I should have gone for something longer to match the 16mm.

I would try the 34mm (2-inch fitting) = 30x magnification.

Or the 28mm (2-inch fitting) = 36x magnification.

And not bother with anything else - Just go straight from one of those, onto your 18mm (at 55x mag)

There is no need to buy everything in the sweet shop.

Try your 25mm Skywatcher against the 18mm Celestron to see what I mean.

The view won't be that different.

[Mowbs]

Are you talking about using 2" EP's Reeny?

That's a whole new avenue I haven't looked into.

[bingevader]

Oops sorry, I thought you'd realised. The 28mm and 34mm 68^o and the 24mm 82^o Maxvisions are all 2" fittings!

BTW, I know we all have varying observing habits, so I'm not disagreeing with Reeny, but I use all my EPs and don't find the gaps between them too close.

However, if you're on a budget or intend to gradually build up a set then choose those that will best fit your needs.

Cheers

[Mowbs]

Ahhhhhh, I see. I didn't know that.

Are there any disadvantages to using 2" EP's? I'll have to do a search on that.

As for EP's I don't mind investing a bit if I'm going to get some use out of them and they seem to resell for a reasonable amount if my telescope ends up in the obsolete equipment cupboard with my multi gym, karate outfit etc. etc.

I'm sure the scope would also make a great clothes horse

I think I'll buy 2 initially and see how I go from there. I just wish I had some to try out last night. The 82 degree (where do you get the symbol?) 24mm definitely appeals to me, are there any disadvantages with that over the 68 degree other than the price?

[Reeny]

There are no disadvantages using a 2" EP apart from the fiddle about when swapping over the Skywatcher adapters.

I got the 24mm maxVision which is great for general use, observing the double cluster, finding nebula etc.

But I needed something wider after that.

I should have gone for the 28mm.

The 82 degree 24mm will give a wider view over the 68 degree 24mm - so that may be enough to get Andromeda (and the wider objects) successfully into the viewfinder.

It will be a 2-inch fitting - but worth the hassle.

Also - get yourself some plastic screws to prevent the razor sharp chrome versions marking the eyepiece barrels.

Can't remember the sizes - but they are on Ebay, and look like this.

Get them now before the new EP's become scarred for life.

[bingevader]

2" EPs tend to be bigger and will then need the 2" adapter, so it's a little bit of a fiddle if you want to go over to 1.25" unless you buy a 1.25" to 2" adapter.

I've not used the 68^o (it's the x² sign in the bar just above the reply box), so I can't really give a comparison. I went for the 82^o because it was a 2" EP and so would fit in with the other 2" EPs I have (it's on the limit of what I'm able to afford for an individual EP, so seemed a good investment).

You won't get all of the Andromeda galaxy in the FOV. I can't get it all in the 32mm either, it's huge! But it is a very pleasing sight in both EPs!

Cheers