what have zoom eyepieces ever done for us?

[Mr niall]

Hello there,

i was wondering what the consensus is on zoom eyepieces? I've got a new SW Mak 127 (amazing!) and I guess my next upgrade will be eyepieces. I've been looking through a few older threads here and people seem to suggest 3 eyepieces is the way to go. I think about 24, 16 or 14 and an 8. Of course, two would be cheaper.....

people seem to recommend BST eyepieces universally and that would cost me about £130 ish for the 3. But, then again the baader Hyperion zoom would do all that too I guess? But is the quality the same or less? Or higher? And I know the Meade 4000 is about £85, that would be cheaper? But is it less good? And do you have to refocus every time you change focal length on a zoom eyepieces (not that it matters, just wondering)? 

I don't know - I'm guessing what I'm saying is that if it were you, and you could only have one, would you have the three or the single zoom?

thanks!

[Alfian]

I chewed the very same idea over a week or two back. The baader zoom has a good reputation and has a wider fov than most. Some zooms at the lower eg 24mm end  have only a 40 degree fov. There are a lot of zooms at various prices that look very similar but if you look at the specs carefully they are not. ( though some are the same) Its a bit of a minefield to work out.  However the one zoom that people seem to agree is  OK is the Baader. 

[vlaiv]

I'm in a similar sort of situation, deciding on new eyepieces (I really need to change whole lineup apart from 6mm BCO, for that particular eyepiece I'll decide later based on comparison between it and tv nagler zoom and delite 7mm).

Question for me was whether to get couple dedicated fixed focal length eyepieces for planetary or to go with TV Nagler zoom 3-6 - I've chosen zoom. There are other eyepieces that are probably better optically for a given focal length, have larger AFOV, but idea of having one eyepiece that I can dial in to right magnification on a given evening, with more than decent optical characteristics just seems like the way to go.

I based my decision in part on F/ratios of scopes that I'm using for observing (F/6 dob, F/6 apo), range 3-6 mm ideally covers high range of powers (1-2 x aperture in mm)  that one would expect from these instruments.

I also considered Baader Hyperion Zoom, but one of my limits for new eyepieces it that they should have > 60deg AFOV, unless for very special purpose / special characteristics (like BCO and TV zoom). Reviews of Hyperion Mark III just put me off in this regard with 42deg AFOV on max fl setting. Now that mark IV is out and quoted 48deg on 24mm it does still look interesting if I find couple reviews confirming this AFOV, but I'll have to re-read the reviews to check how it behaves in faster scopes (but not ultra fast like f/4.5, still not seeing myself with ultra big dob :D, 8" is enough for now).

Now from time to time I tell myself - "You don't have to use it full range, limit usage to 8-20mm if AFOV is bugging you that much" :D.

Your scope is slow, so I believe that performance of hyperion zoom will be good, and idea of having variable mag range to dial in as needed really appeals, if you can get past narrowish AFOV on longer focal lengths, then I think it would be good choice.

[John]

I've owned a few zooms over the years including the Baader 8-24. I tend to use them for outreach but prefer fixed focal lengths for my own use. The exception I've found are the high power (and high cost !) Tele Vue Nagler Zooms which really can compete with top quality fixed focal length eyepieces. I tended to use the Baaders as 8-20 zooms because the field of view just got too restricted and a little fuzzy at 24mm for my taste. To balance this their field of view at 8mm is wider than the specs say - probably more like 65-68 degrees.

I suppose it's a matter of balancing a few small compromises in optical performance against the convenience of being able to change the magnification at will.

Each person might reach a different conclusion on that

I may well get another Baader 8-24, a Mk IV this time because I still do quite a bit of outreach and its a very nice tool to have for that

I would not want to solely rely on the Baader zoom for my mid focal length eyepiece choice though. 

PS: you do need to re-focus just a little each time you change the focal length. Just a small touch on the focuser is usually enough.

 

[Alien_Photons]

If you don't have many eyepieces a zoom is a great buy. I had 127 Mak and used a 7mm vixen LV a 32 Televue plossl and an APM zoom for everything in between. Its a great arrangement. don't worry about the field of view so much, the sharpness is more important. A sharper smaller view is better than a bigger blurry one.

[ronin]

I would tend to opt for the 3 eyepieces rather then a zoom. I can understand a zoom for outreach (partially) and for being able to put one in your pocket and hop on a plane. For my own use just could not see it. Although it may cover the range of focal lengths I would think it wasier to take one out and put another in. With a zoom the options are take it out change focal length anf put it back - so much the same, or try to do it in-situ. I would expect the in-situ action to cause the scope to move and so the target gets swung out of view - especially if you are doing it while in a 127 Mak.

Another odd "advantage" is if the zoom breaks then you have no eyepiece, if one eyepiece breaks then you at least have 2 others.

If I recall from some time back the notorious Seban used to produce a zoom tht many people said was fairly good. Always a bit odd as Seban were known primarily for items to avoid, but the zoom apparently was reasonable.

With a zoom and a 127 make sure you get a range that is sort of long focal lengths, short ones will deliver a narrow view as a zoom tends to be narrower to start with, you could be down at 2/3 of what a BST would deliver.

Get the zoom and the BST's - problem solved.

[Mr niall]

Thanks everyone, good advice as always - forgot to ask, can anyone confirm the BSTs are a good buy? Anyone tried the Meade 4000?

[Piero]

Possibly it's just me but when I read the title I thought this was going to be a thread of complaints against zoom eyepieces. 

Glad to read in your thread that you are actually more interested in hearing opinions about zoom eyepieces!  

 

>> i was wondering what the consensus is on zoom eyepieces?

Here you will get mixed opinions. Not sure this will help. Zoom eyepieces seem like a personal thing, a bit like binoviewing. Some like them, others don't. Possibly the best advice I can give you is to get a decent one in the second hand market, so that if you are not happy with it, you can just resell it possibly losing the shipping costs only. 

 

>> I've got a new SW Mak 127 (amazing!) and I guess my next upgrade will be eyepieces.

I feel the next upgrade comes when you feel you want something different and to expand your focal lengths. Yes, three eyepieces is technically what one would need, but as you can see in the thread `show me your eyepiece case`, this is not generally the case!   Your telescope is considered a slow one. This has the advantage that many (also cheap) eyepieces will work reasonably well (=minimal distortions) on your telescope. 

 

>> people seem to recommend BST eyepieces universally and that would cost me about £130 ish for the 3. But, then again the baader Hyperion zoom would do all that too I guess? 

I don't have experience with the BST, so maybe other members will comment on their performance with your telescope. Regarding the zoom, yes, a zoom can replace a few focal lengths, which also means that you don't swap eyepieces while observing. Zoom eyepieces often have a variable field of view, with the lower magnification having the smallest fov. For this reason, a few people combine a low power eyepiece with a zoom. It's a nice combo. 

 

>> But is the quality the same or less? Or higher?

A lot depends on the zoom. Some zooms are cheap and might show aberrations, others (Pentax, Baader) are of good quality, others (Leica, Zeiss) can be on par with (or better than..) many eyepieces, even high end ones. Televue has a 3-6mm zoom (they also had a 2-4mm) which is meant for planetary observation using fast or short tubes (e.g. refractors, fast-ish newtons). In my opinion the "Zoom market" is still little explored. As I said in the beginning, I suggest you to get a good zoom in the second hand market and use it for a while. Only after this test, you can see if you like the idea of the zoom and potentially invest in something better, or turn back to fixed focal length eyepieces.

 

>> And do you have to refocus every time you change focal length on a zoom eyepieces (not that it matters, just wondering)? 

For some people this matters quite a lot actually. That's a reason why they tend to buy a full set, so that the eyepieces are nearly or completely parfocal (=they reach focus at the same distance = no need to refocus). High end zooms are nearly parfocal throughout the zoom range. Not sure how the "click zooms" are, but my bet is that they are close to be parfocal.  

 

I'm guessing what I'm saying is that if it were you, and you could only have one, would you have the three or the single zoom?

Tricky question this one. Thinking of me, I would get (as I did) a very good zoom in any case. I love the principle, its comfort, and the views are just stunning. I knew what I wanted though. It took me a very long time while I asked a very large amount of questions before pushing the button. No regret at all. Said this, if money is a concern and I had a slow telescope, there are some fixed length eyepieces in the second hand market which can be acquired for less money than a zoom I feel. Economically speaking, in my view a zoom becomes effective when getting three wanted eyepieces cost more than the zoom, assuming that the quality of the views is comparable. 

 

Hope this helps, 

Piero

[Peter Drew]

If I had to have just one eyepiece it would have to be a zoom, it would drive me nuts to have a fixed magnification. As I don't have to have just one I use a Baader Hyperion zoom for my longer focus telescopes and a TV Nagler 3-6mm zoom for the shorties. You do still need to have a good wide field low power eyepiece to compliment them. 

[Dave In Vermont]

First off, all 8mm - 24mm Zoom EP's will give you a narrow F.O.V. when compared with fixed-length EP's. It's part of their optical-design. If I couldn't live with this, I'd sell my 2 Zoom EP's - a Baader Mark III Hyperion & a Vixen LV.

I like them for the sheer convienence of not carrying around a bag-full of fixed-length EP's. And newcomers at informal outreach-work in the parks, people love 'em! I tell them to try 'skydiving-on-the-Moon!'

I find them to be a very useful tool in my astro-arsenal.

Enjoy!

Dave

[Pondus]

2 hours ago, Mr niall said:

And do you have to refocus every time you change focal length on a zoom eyepieces (not that it matters, just wondering)? 

The Hyperion zoom is Close to, but not quite parfocal all the way.

'Zooming' does not knock the target out of view anymore than focusing do. Its not an issue.

I`ve used it as my only eyepiece for some years, but lately I have started adding fixed eyepieces.

 

Rune

PS I find focusing/defocusing as a good method to relax my observing eye during longer sessions.

[Charic]

1 hour ago, Mr niall said:

Thanks everyone, good advice as always - forgot to ask, can anyone confirm the BSTs are a good buy? Anyone tried the Meade 4000?

Yes & Yes !

On my setup, the BST Starguiders are good, and on trying the Meade 4000 series, I  personally discounted them and Tele Vue Plössl's in favour of my GSO Revelation Astro's,  because they work,  the images are clear, and their cheap as chips, but as they say, each to their own. Not only that, someone better than I at EP assessments, rated the GSO's highly, in comparison to Brandon and Tele Vue  so with that, and from my own experience with them, their keepers for a while longer, but should I sell them as a set, someone is in for a treat?

I was also of the opinion, and it was my sole intention to have/own a Plössl set  from the outset? I have the Revelations now, but nothing in my signature is as comfortable as the BST's, for my eyes, on my f/6 scope.
Your scope being much slower may not need anything fancy in the way of  expensive or fancy optics, just find something you feel comfortable with. The Plössl collection was intended for my Planetary views, with their narrower field of view, as I don't need much field except for the Moon.  But having acquired a 6mm William Optics SPL (Super Planetary Long eye-relief) and now the full set, do I need the Plössl's anymore?

Not sure I need anything else as I write this text, but not sure I'll sell anything just yet, except my Tele Vue ( Thats just sold !) oh and a Meade 4000..........if I can find it?

 

Edit: Think I sold it already (Meade 4000 ) Yes, double checked, both sold.

[Littleguy80]

1 hour ago, Mr niall said:

 

Thanks everyone, good advice as always - forgot to ask, can anyone confirm the BSTs are a good buy?

 

I have the 8, 12 and 18mm and am very happy with them. They've proven a good upgrade from the eyepieces supplied with my scope. I did a lot of reading around and asking questions before settling on them. It's also worth keeping an eye out for second hand eyepieces. I managed to pick up the Explorer Scientific 68 24mm eyepiece for less than half of it's new cost from the SGL classifieds. Very nice eyepiece that I would never have bought from new due to cost. AstroBuySell is another good site for secondhand Astro gear. Most of my filters have come there at very good prices. 

[Louis D]

No one has mentioned one advantage that zooms have over fixed focal length eyepieces, you can nearly instantly adjust your magnification depending on sky conditions.  Thus, if the atmosphere settles down for a few seconds, you can dial up the power while observing planets to see additional detail.  If you overshoot, just dial it back a bit.  Swapping eyepieces takes far longer than the atmosphere remains stable.

No one has mentioned the discontinued Speers-Waler 5-8mm varifocal zoom.  It's not a true zoom.  It's actually an 80 degree AFOV eyepiece with a variable extension Smyth lens.  I've had one for years and prefer it to the TV 3-6mm zoom for multiple reasons.  If you see one come up used, grab it.

[John]

7 hours ago, Louis D said:

No one has mentioned one advantage that zooms have over fixed focal length eyepieces, you can nearly instantly adjust your magnification depending on sky conditions....

I did mention that in my post but maybe did not emphasise it enough ?

It was on deep sky objects that I found the Baader zoom a little dissapointing though. It's light transmission on galaxies was slightly but noticably lower against other quality eyepieces

 

[Louis D]

6 hours ago, John said:

I did mention that in my post but maybe did not emphasise it enough ?

 

17 hours ago, John said:

the convenience of being able to change the magnification at will.

Is this the comment you were referring to?  I guess I was emphasizing not only that you can change the magnification at will, but do it rapidly as well based on sky conditions.  Someone who hasn't used one may not realized the speed difference in changing magnification between a zoom and fixed focal length eyepieces.

I actually like using them in binoviewers the most because changing two eyepieces and getting them parfocalized again is a royal pain.  The other option is to get a "power switch" type of device.

[John]

5 minutes ago, Louis D said:

 

Is this the comment you were referring to?  I guess I was emphasizing not only that you can change the magnification at will, but do it rapidly as well based on sky conditions.  Someone who hasn't used one may not realized the speed difference in changing magnification between a zoom and fixed focal length eyepieces.

I actually like using them in binoviewers the most because changing two eyepieces and getting them parfocalized again is a royal pain.  The other option is to get a "power switch" type of device.

Yes that was the comment.

Having used predominently fixed focal length eyepieces, some par focal and some not, some 1.25" fitting and some 2" for over 30 years now I find changing them over and a slight re-focussing just part of the business of observing now.

If it was massively inconvenient then I guess everybody would have moved to zoom eyepieces ages ago and the fixed focal length ones would have gathered dust on the dealers shelves

Now if someone could come up with a zoom that delivers a consistent, say, 60-70 degree AFoV across it's range and be at least as good as premium fixed focal length eyepieces then that would be very interesting. Leica have (arguably) done that with the ASPH 17.8 - 8.9mm zoom. The slight drawback is that it's a £700 eyepiece.

 

 

[Littleguy80]

28 minutes ago, John said:

The slight drawback is that it's a £700 eyepiece.

No one said it had to be cheaper than buying the equivalent set of fixed focal length eyepieces 

[John]

24 minutes ago, Littleguy80 said:

No one said it had to be cheaper than buying the equivalent set of fixed focal length eyepieces 

The OP talked about a budget of £130 for 3 eyepieces ?

[Louis D]

54 minutes ago, John said:

Leica have (arguably) done that with the ASPH 17.8 - 8.9mm zoom.

If they could extend the range to 5mm - 40mm (8x) and have a 70 degree field throughout with long eye relief for under $2000 with Delos/XW or better correction, I'd be all over it in a heartbeat.  Weight wouldn't matter because I'd just have to counter balance once and forget about it.

[Littleguy80]

Just now, John said:

The OP talked about a budget of £130 for 3 eyepieces ?

Indeed, I was thinking more of comparing the £700 zoom to 3 equivalent premium eyepieces rather than the OP's budget. £700 in that context might not be a bad price. A thought for another thread, I guess

[Highburymark]

Zooms come into their own when used for lunar, solar and planetary observing - for all the reasons described above. I have 3 and love them all. Nagler 3-6 for fracs, Pentax XF for solar and Leica ASPH for just about everything. Alternatives like the  Baader and Vixen are also excellent.

£700 is far too much to fork out for any eyepiece. I bought a new Leica ASPH for just over £400 a couple of years back. Think I was very lucky to find it for that price. With a good Barlow it offers a range of 4.5mm-18mm and fovs between 60-80 degrees, long eye relief and views that match those of Delos or XW equivalents. Still a lot of money, but also cheaper than two XWs.

[DirkSteele]

Those of us who have been in this hobby for long enough probably have a slightly unflattering opinion about zooms as once upon a time were rather compromised designs. However that is not necessarily the case anymore. There are some good models at a variety of price points.

 

For me they come into their own when travelling and weight considerations are of paramount importance. Though generally closer to home observing I prefer fixed focal lengths. The Nagler Zoom for high powered work has one huge advantage. Those moments when suddenly the image settles and its clear Mother Nature has just given you a window to the stars, you can dial up the magnification in seconds to take advantage. By the time an observer switches eyepieces, that moment will have likely passed.

[Louis D]

One more advantage to zooms, the wow factor as you zoom into the lunar surface.  If you manage to keep focus at the same time, it feels like you're crashing into the lunar surface.   Kids in particular get a kick out of the efffect.

[iPeace]

Great topic. Most of the grass has been mown, as we say in Dutch, so there's little to add in general terms.

A zoom is convenient and a lot of fun to use - one of my guilty pleasures as a seriously dedicated casual astronomer. And the good ones work very well for me - Baader Mk IV, Pentax XL. Cannot vouch for others.

If you should find yourself using a particular setting more often than others, that would be a good time to seek out an alternative in that particular focal length. In Dutch, this last point would be called kicking in an open door.

But seriously, the point is that you can get more of whatever type of performance you like at a fixed focal length - and spend as much as you like in the knowledge that you're not spending on the ability to zoom.