confused about what eye pieces to purchase

[Zane]

Hey all, I'm currently in the market to purchase some eyepieces but am lost as to what types I should get, I'm using a skywatcher 10" f4.72 with a 2 inch single speed focuser, I have a 28mm 2" orion eyepiece which is quite wide as you could immagine. I would probably be looking to get a kit of 1.25" pieces with a 2"-1.25" adapter with a nice range of views but honestly don't know where to start.
Does anyone have a suggestion about where I should start with my first kit?

[Allan]

Hi Zane. We will need some more information to best help you out.

What is your budget? What objects do you prefer to observe? Do you observe using glasses?

Those are some of the important factors, otherwise we will just be throwing around guesses for you.

[Zane]

Hi Allen, I don't wear glasses, I am interested in viewing the planets, moon some brighter galaxies, clusters and nebulae, I don't mind spending a bit extra if the quality is worthwhile. I am more interested in astrophotography but want to show my friends and family what can be seen through the scope.
I will also be adding another scope down the track and having interchangeable eyepieces would be the way to go

[janoskiss]

I'll interpret your willingness to spend a "bit extra" as you want bang for buck good quality EPs: not super cheap but not very expensive ultra-wide ultra-everything big brands either.

Here is what I'd recommend as the general game plan:

1) Low-power widefield / finder EP
It sounds like you're happy enough with the 28mm Orion EP, so let's start with that as your widest field / high-power eyepiece.

2) Deep Sky workhorse, Lunar, low power planetary
The next one to look at is a deep sky "workhorse" EP and mid-low power planetary. The former implies something with roughly around 2mm exit pupil, which for your scope is achieved with an approx 9.5mm, or let's say 10mm EP.

If you were going for an ultra wide (80-deg FOV or more), a 9mm would be ideal there. But on a sensibly restricted budget it would be better to go for somewhat less FOV (more in the 60-70 degree range) but with better optics than the same money would buy you in an ultra-wide. That means, e.g., 12mm 60-degree, 11mm 65-degree, or a 10mm 70-degree EP. All these also very nicely frame the Moon which will fill most of the FOV.

The 10mm/70-deg combo would be an excellent choice if you can find a good one. Pretty close to ideal for the human eye to tease out the most detail on fainter deep sky objects and still a big immersive 70-deg FOV.

Unfortunately the only EP I can unreservedly recommend there is the Pentax XW-10, which is ridiculously expensive (especially since the AU$ took such a dive; it is also a ridiculously good EP though).

But there are less expensive alternatives around that offer good performance. The Baader Hyperion 10mm is one I know of (you can easily find it for under $AU200). It also has provisions for camera attachments and some other tricks you can play with its "modular" design. Both the XW and the Hyperion are big heavy EPs, if that matters to you (it does to me; I prefer pocket-friendly lightweight EPs).

Another excellent choice here is the Pentax XF 12mm 60-deg. This is optically superior (in terms of contrast, sharpness and transmission) to just about any other similar TFOV widefield except the XW 10mm (and by all reports the Nikon NAV SW 10mm, but those are even pricier than the XWs) --- in all respect but one that is: it's only slight issue in a scope like yours is slight field curvature visible near the edge of the FOV. Your eyes might be able to accommodate it though (you've got to try for yourself to see).

But there are lots of and continually improving EPs coming out of China (and some from elsewhere) that I have not kept up with recently. So there are no doubt other options you might like to consider. (Same comments apply below.)

3) Higher power DSO, mid-power planetary/lunar
You'll want something with roughly 40-50% more magnification here than #2 (if AFOVs are about the the same). There is a clear winner here for me: the Pentax XF 8.5mm. It's optically as close to perfect as they come: superb on everything from DSOs to planets, and performs flawlessly at any f-ratio. Unlike the 12mm XF it has no field curvature issues at all. It's optically up there with the XW-10 or XW-7, with just 10-degrees less FOV, much less bulk and weight, at 1/3 to 1/2 the cost. If you shop around you can still find these for not much over $AU200 (or equivalent in $US or JPY).

But if you're not happy with "only" a 60-degree FOV, you might look for a 7mm widefield. Can't recommend any bang-for-buck ones off the top of my head. I used to use the XW-7, and don't know of any less expensive ones directly comparable. If you get the 10mm Hyperion, it possibly can be fiddled with to turn it into a 7mm (with the modular design spacer rings and what not), but you don't want to have to disassemble and reassemble your EP every time you want to change focal lengths. Maybe two Hyperions could work here.

Note about the Hyperions and their "modular design" feature (that lets you change the focal length): when you reduce the focal length from the default, the edge-of-field performance tends to degrade, especially in faster scopes. Conversely, when you increase the focal length the edge of field performance tends to improve.

4) Higher power eyepieces mostly but not exclusively for planets
Here I'd recommend several more tightly spaced focal lengths so you can select the magnification to best suit the seeing conditions:
6mm, 5mm, 4mm planetary EPs. I used to own some TMB planatery EPs around these FLs and they were quite good performance for low-cost, wide field (60-ish-degree), comfortable eye relief EPs. Fairly nice and light too. There are apparently similar EPs around from other manufacturers (also some TMB clones) these days, but I cannot vouch for them. If they perform anything like the original TMBs, they'd be well worth looking into, even in longer focal lengths.

That should about cover it. (And just in case you're wondering, no you don't really need anything between 28 and 10-12mm. But if you were to insist, 19mm Panoptic is nice. Second hand, the cost should be very reasonable.)

On Barlows
I have not mentioned barlows because some people are afraid of or just plain don't like barlows. I am not one of them.

Barlows do several things for you that individual focal length EPs cannot. For one thing, you can fine tune the magnification by adjusting the EP-to-barlow-lens using a simple extension tube. (In fact that's exactly how the Hyperion modular design variable FL works.) Secondly, good barlows combined with high quality simpler design EPs can give you exceptionally good high-power views of both planets and DSOs without giving up the comfort of longer eye-relief; e.g., A 12mm ortho in a good barlow makes for an excellent planetary EP.

Unfortunately the barlow I would recommend is no longer in production (AFAIK). I have not found anything else to be as good in 10 years (inlcuding televues, powermates, ultima shorty plus, you name it). It was the Japanese Orion Ultrascopic 1.25" fully-baffled 2x long Barlow (was sold under other brands too). There was also a 2" version, which used to be the University Optics' 2" barlow, that they've since replaced with a GSO I believe. (The whole UO range took a turned to poopoo some years back.) These barlows control reflections and light scatter like no others and yield very high contrast. They also eliminate abberations of most eyepieces (even cheap and nasty ones) - almost like magic. But I believe that is a simple consequence of the fact that they are longer than most other barlows. If you can find one second hand, jump on it.

On Geese and Ganders and my personal favourites
Eyepiece selection is a very personal thing and even ones own preferences shift over time. Here is my current collection that I am very happy with and use it in the same type of scope you have:

* 30 mm Ultra-Wide (fairly inexpensive big Chinese piece from Andrews) - this is not great on its own in this fast scope. Lots of edge of field abberations. I rarely use it that way. However in the 2" UO Barlow it becomes an excellent 13-14mm ultra-wide that is abberation-free sharp edge-to-edge. Even on the Moon it's perfect. Much preferred to my old Nagler T6 13mm. Just to be clear: I don't recommend this EP. When I bought it years ago, it was a bargain on special for <$70. Now it's closer to $200 and it's not worth it.

* 35 mm Orion Ultrascopic: this is an unnecessary luxury item, not really needed, nor exactly well suited to an f4.7 because it yields 7+mm exit pupil, but it's probably the world's widest TFOV 1.25" EP.

But here are the ones that get used most, and 99+% of the time I'd be happy with only using these:

* 25mm Antares Elite: my default low-power/finder eyepiece. (The Antares Elites are no longer made, but Parks Gold Series is still around and it's practically the same.)

* 15mm Antares Elite: low-mid power DSO EP; frames the full disk of Moon nicely with loads of detail to impress your non-astro friends.

* 8.5mm Pentax XF: mid power DSO and low-mid power planetary/lunar. This is the ticket! If you find one for under $AU200, don't even think about it. Just get one. Or two.

* 1.25" Orion Ultrascopic 2x barlow: combined with the above for higher powers. (Using extension tube to get to any desired magnification.)

So just the latter three EPs (the two Antares and the XF) combined with the Ultrascopic barlow make a very good comprehensive set. They are not particularly wide FOV EPs (52-degrees for the Elites, 60-degrees for the XF), but they are optically excellent, brilliant performers in the fast scope and very comfortable to use, compact and light. These factors are much more important to me than more FOV mostly in my peripheral vision. (And I've gone through many widefields, LVWs, Panoptics, Naglers T4/T5/T6, Pentax XWs etc etc in the past 12 or so years.) But that's just my personal preference. Others have different preferences and that's fair enough.

[Zane]

Thanks Steve for the very detailed suggestions I now have a list to go by I can't wait to get my hands on some decent ep's and see the differences that they make :eyepop:

[janoskiss]

I suggest if at all possible go along to astro club observing night or better yet a star party and look through as many EPs as you can. My preferences in EP selection are not likely to match yours. But the basic idea to have one low power EP, one general purpose DSO EP, one somewhat higher power DSO, and several higher power planetary EPs is pretty general. To summarise more clearly/succinctly:

Go for exit pupils of 6mm, 2mm and 1.4mm for your three lowest power ones (these are rough rule-of-thumb numbers, not set in stone), and have several more in the 200x-300x range. (Whether you achieve this with individual EPs or combination of EPs and barlow is up to you.)

Good luck.

Note:

Exit Pupil = Eyepiece Focal length divided by Telescope f-ratio

[Zane]

Im heading to the perth astrofest on the 12th of March so I will be looking at heaps of set ups and asking questions, I've just been looking for some of those ep's you listed but having trouble finding any in Australia, I've only ever browsed 2 sites they were bintel and myastroshop, both unfortunately don't offer the pentax range. What other sites could I find the pentax ep's sold in Australia?

[Kunama]

You can buy the Pentax eyepieces from Barry Gooley at Kokusai Kohki.
The XF8.5 is a lovely eyepiece, I have a pair that I use regularly in mono and recently in binoviewer mode, you could try a 'Wanted' ad in the IIS classifieds.
They sell for about $165 in near new condition.

[janoskiss]

That's a good tip Kunama. I did not know about that dealer. Looks like a fantastic international online shop in Japan (there aren't enough of those). The XFs work out at $AU210 + shipping, so maybe $AU240 or so total. You can probably find them locally for that price; possibly at AEC (Astro & Electronics Centre in SA).

[janoskiss]

OMG! How about those Nikon NAV-HWs for $1250 a pop?! :eyepop:

[janoskiss]

I got so distracted that I forgot why I came to this thread. Zane, I just remembered I saw some great budget deals at Astro Pete's astro cafe. See my post in Stonius' thread:
http://www.iceinspace.com.au/forum/showpost.php?p=1233277&postcount=5
For your scope I'd recommend pretty much the same set (because there is no 10mm in the Saxon SWs.)

[Zane]

Ok will do thanks. Wow these eye pieces are rather pricey I'm glad Ill only have to buy a few and still be able to use them on other scopes down the road. But it's similar to golf, my other passion, a massive outlay in equipment when starting out and slightly less outlay per year of membership ;)

[Zane]

Those saxon super wide angle ep's sound great, should I also consider an f4 or f5 coma corrector and a set of filters?
Sorry for all the questions just getting started again after 15 years :question:

[janoskiss]

They're very good for the money. They are not as good as the original Vixen LVWs that cost 2.5x as much, especially at f/5. They can be improved by increasing the barrel-objective separation (and focal length) with a spacing ring like the Hyperions have, though I'm not 100% sure about the threadings on these (i.e., whether they are standard 2" filter threadings).

You can also remove the barlow group at the base of the EP completely and stick the objective group into a long barlow and get a very capable but ridiculously huge EP that becomes an Ultra-Wide!! (80 degree FOV instead of 68). It's same idea as the Antares Speers-Waler ultra-wides use, which already looked kind of ridiculous at only 1.25". I described this ages ago (shame I could not take any photos at the time):
http://www.iceinspace.com.au/forum/showthread.php?t=6558&highlight=Stratus
If it does not work well enough you need to add a barrel extension to the barlow. It's a fun experiment but you end up with an eyepiece the size of a small refractor. :P

Re coma correctors, the cheapest one around is probably the one from GSO. Don't know how well they work but when I start imaging with my 10" f/4.7 tube I'll probably get one to try.

PS and on filters, don't worry about them yet, they're not so important (mostly you'll observe without them). Recipe for filters is the same as for most other gear: try out other people's first and see how you like them.

[simmo]

Hi Zane,

Not sure if you're familiar with the term parfocal eyepieces but hosting friends and family it might be worthwhile looking for when selecting.

I'm not sure of the brands/lines of eyepieces that are parfocal as I use orthos which are not however I did come across the term while researching before buying what I have.

I'll leave other people with more experience with parfocal eyepieces to comment further or it could be more detective work for you.

Simmo

[Stonius]

Thanks for the advice guys, looks to me like I'm probably looking at something in the area of the Baader Hyperions. I'm thinking I'll get an 8 and 13mm (& maybe a 24mm) to start with, then complement it with a barlow because it would give you 4 eyepieces for the price of two and it can be used with astrophotography.

The 4 element Barlows seem to be the better ones, but do they really make all that much difference? There's cheap ones and then there's really expensive ones and nothing in between. And even then, Teleview have the normal 2x, or the powermate 2.5x for another $100. Is it really going to make that much of a difference?

Markus

[MattT]

Big question this one.

Knowing what I do now....the best value IMO are the Explore Scientific 82º series. As Zane has a 28mm I'd start with the 18 82 and 11 82 with a 2" 2x barlow. The ES aren't cheap, specially now the Oz$ has sunk to pitiful levels.

Barlows...I have a few and use them a bit. My favourite is the 2" ES 2x Focal Extender. ...why??? It takes the 18 82 which is a 2" eyepiece and also will take any 1.25" eyepiece with the supplied adaptor...versatile in other words. The GSO 2xED is pretty good too...not quite up to the same standard as the ES though.

Save buying a coma corrector for later on. They need to be set up correctly to get the best views. When they are...you won't want to be without one.

It's a voyage of self discovery in reality, one in which budget rules.

Where to get these...http://agenaastro.com/eyepieces/shopby/explore_scientific_82_deg/explore_scientific.html

No one in Oz sells these postage isn't that expensive.

Hyperions I would never buy for a Newtonian....not for any scope actually.

Matt

[Zane]

Thanks for the info there Matt, after looking closely at my current eyepiece I realise its just a standard skywatcher 28mm in an orion box that came with the scope. I have been thinking of the saxon super wide angle pieces would be perfect for me though having nothing to compare them to of similar quality leaves me uninformed on an experience level though. There is an astrofest happening on the 12th of March I hope to look through some different ep's but being a free public event I would imagine the people putting their scopes on display may be hesitant to allow swarms of people to use their finer quality ep's! All this information here is a huge help I've been watching numerous videos on youtube learning about eyepieces, filters, barlows etc it's all overwhelming at first but making sense eventually

[mickeytg]

So I have the following scope Saxon Velocity 1309EQ2 Reflector Telescope and am looking for new eye pieces as well. Currently have the standard pieces that came with the scope but am looking to upgrade. I have a good budget of no more than $1k to get various types. Mainly viewing planets such as Venus, Saturn, Mars and Jupiter to start with. Any suggestions?

[janoskiss]

@mickeytg There is no need to go to such great expense. It's an f/6.9, 5.2" Newt with a 1.25" focusser and a light duty EQ mount. For planets you could go 7mm and 5mm with decent eye relief and high contrast (TMB planetary and the better clones would be excellent), or get a 14-15mm Plossl and a barlow. Best to stick with lightweight EPs for that setup otherwise you'll get too much vibration at high powers.

But seriously, if you have $1k to spend, just get yourself an 8" f/6 GSO Dob and a good EP kit. It'll knock your socks off especially on planets compared with the 130mm Saxon.

[mickeytg]

Thanks for the advice, might look into that then!;)