zoom eyepeices vs fixed eyepeices

[travaler]

Hi guys,

typical of beginners I find myself looking at eyepieces for beyond what came with my telescope. my question is about practicality of a zoom lens vs say buying a 9mm and a 15mm fixed eyepieces or buy a good quality zoom lens. I have no plans at the moment taking photos of any kind. I’m still dealing with my training wheels looking around our Aussie night skies! There’s just so much see, I need more sets of eyes.

thanks for any advice guys!!!

 

Keith

 

[AlexK]

Hey, Keith. I had a chance to enjoy your beautiful Southern skies in 2012 driving through Queensland bushes and then from the scuba diving boat (yes I had my 4" Astroscan with me there too!) for 7 nights along the GBR in November (remember the Eclipse?). Good times...

To have your question answered properly you should post your current instruments you plan to use these EPs with. And your interests in astronomy. Because that might dictate your choice. The common practice is to add that info to your forum signature (see mine?).

In my opinion, a quality fixed EP would be a better bang for the buck in general. A quality zoom EP is fun to use on Moon and planets indeed (folks call it the landing illusion). But for deepsky I would rather get the widest AFOV EP you could afford (it makes views really breathtaking as if you are floating in space between stars). I have three 100 - 110 degrees eyepieces and would never even think going back to the keyhole-like EPs (all zooms I know about have quite narrow AFOVs).

But surely you can try zoom EPs fun in some cheap variants instead. They are not stellar but many folks found the $70 Meade zoom not so bad that you immediately want to get Televue $400 one instead.

Perhaps, you have an idea to just save on the EP set to have fun while you are waiting for your AP rig/experience building up? As the visual gazing is not your thing at all? Then a zoom might be feasible, because it might be helpful for imaging targets pointing and framing later as a single piece of equipment. Just figure if the cheap 8-24mm would work for that task, or you must go for 3-6 instead. I'm personally got the illuminated reticle 9mm Meade Series 4000 fixed EP, as that what AP folks are using for guiding and framing planning work.

OTOH, if you've got some spare dough (folks considering AP hobby usually do ), just go for best of the best TV Ethos 101 deg EPs (and their zoom) as I did. And see for yourself. They worth their price in the weight of gold (well, silver at least  ) so you will have zero problems reselling them later to fellow colleagues in the hobby.

Edited January 14, 2021 by AlexK

[Pixies]

Some threads for you:

 

 

 

 

 

[Jiggy 67]

All the above threads are worth a read for the detail but on a personal level, I wouldn’t be without a zoom, they work really well for targets such as double stars when constantly changing ep’s can be a pain. I would recommend buying one even before you start searching fixed ep’s. Just make sure you get a decent one, the Hyperions are excellent 

[travaler]

9 hours ago, AlexK said:

Hey, Keith. I had a chance to enjoy your beautiful Southern skies in 2012 driving through Queensland bushes and then from the scuba diving boat (yes I had my 4" Astroscan with me there too!) for 7 nights along the GBR in November (remember the Eclipse?). Good times...

To have your question answered properly you should post your current instruments you plan to use these EPs with. And your interests in astronomy. Because that might dictate your choice. The common practice is to add that info to your forum signature (see mine?).

In my opinion, a quality fixed EP would be a better bang for the buck in general. A quality zoom EP is fun to use on Moon and planets indeed (folks call it the landing illusion). But for deepsky I would rather get the widest AFOV EP you could afford (it makes views really breathtaking as if you are floating in space between stars). I have three 100 - 110 degrees eyepieces and would never even think going back to the keyhole-like EPs (all zooms I know about have quite narrow AFOVs).

But surely you can try zoom EPs fun in some cheap variants instead. They are not stellar but many folks found the $70 Meade zoom not so bad that you immediately want to get Televue $400 one instead.

Perhaps, you have an idea to just save on the EP set to have fun while you are waiting for your AP rig/experience building up? As the visual gazing is not your thing at all? Then a zoom might be feasible, because it might be helpful for imaging targets pointing and framing later as a single piece of equipment. Just figure if the cheap 8-24mm would work for that task, or you must go for 3-6 instead. I'm personally got the illuminated reticle 9mm Meade Series 4000 fixed EP, as that what AP folks are using for guiding and framing planning work.

OTOH, if you've got some spare dough (folks considering AP hobby usually do ), just go for best of the best TV Ethos 101 deg EPs (and their zoom) as I did. And see for yourself. They worth their price in the weight of gold (well, silver at least  ) so you will have zero problems reselling them later to fellow colleagues in the hobby.

thanks Sub Dwarf for the tips. I know I'll be making an ass of myself on this fourm. OK . i'm using a skywatcher 12" Dob with GOTO and wifi. I have at present  10mm; 25 mm plosals oh forgive my spelling Dang!! and a 5 mm Celestron. though I like to gaze around the sky for planets, but it's deep sky  stuff that drews me when I look up. 

[John]

I use fixed focal length eyepieces most often with my 12 inch dob. I do have a couple of zooms but those tend to get more use in my refractors. With the big dob I love very wide angle eyepieces and zooms, with the exception of the immensely expensive Leica ASPH zoom, don't give very wide views at lower powers.

 

Edited January 14, 2021 by John

[Owmuchonomy]

My 7.5 to 21mm zoom earns its living when solar viewing.  It's an excellent device for defeating seeing issues during daytime viewing.  Small adjustments can help get round the ever changing solar view affected by the elements.  Dark sky observing for me requires a handful of fixed focal length EPs, I don't get an advantage with my Lunt zoom.  The other slight problem with the zoom EPs I have owned (particularly Baader) is the poor eye relief.  The best investment I made was in the TV Delite options; marvellous EPs if you have the budget.

Edited January 14, 2021 by Owmuchonomy

[davyludo]

I'm yet to be lucky enough to use something like a 12" dob, but here's my thoughts.

I know zooms aren't for everyone, and I believe the extra glass in them can impact views of DSOs. I recently got one though (the Baader Hyperion) and I really really like it. My fixed eyepieces aren't particularly expensive (compared to what is available), so I can't compare it to views through them. But it's been a real joy to use, and it's also been useful in helping me understand what fixed lengths would be useful. 

You can play about with the zoom on different targets, see what works best and note down what focal length has been useful. For me, never thought about getting a 12mm fixed. But from using the zoom I can now see a 12mm fixed would be a great addition to my kit. 

[Second Time Around]

This is a question that comes up often, and views are split.  

Personally, I'm a fan of zooms for medium to high power use.  I have a range of fixed focal length eyepieces, but use zooms much more often. 

I agree that fixed focal length eyepieces may be slightly better corrected when compared with a zoom at the same magnification.   But that's not always a fair comparison as that magnification may not be the optimum for a given object.  This is because one of the many advantages of a zoom is to be able to dial in precisely the best focal length.  For instance, this may be 13mm or even 13.1mm, which may actually show more detail than shorter or longer fixed focal length eyepieces - even higher quality ones.

Because you have an infinite range of focal lengths, zooms work out at particularly good value for money compared with a set of fixed focal length eyepieces.  This is especially so if you eventually use binoviewers, that require pairs of identical eyepieces.

I have the Svbony 7-21mm and the Baader 8-24mm.  The latter is easily my most used eyepiece.  I use it on its own or with one of 3 Barlows:  a dual amplification 1.5x/2x, the matching 2.25x, or a 2.7x.  On rare occasions I add an extension tube for even higher power.  These plus a wide field eyepiece as a finder does me for most of my sessions, even though as I've said I have other fixed focal length eyepieces.   

I particularly like the ability to very quickly increase the magnification to make use of brief moments of good seeing.  It takes more time to swap out an eyepiece, and the opportunity may then be missed.  You can't see anything if you haven't got an eyepiece in the focusser!

Zooms also enable the field of view to be varied to frame an object to get the prettiest view.  For this reason I particularly like them for clusters.

Many of those who post here and advocate fixed focal lengths are experienced observers.  It's so easy to forget what it was like as a beginner!  A zoom eyepiece enables beginners to easily learn what difference a change of magnification makes on all the various classes of object.  It also shows them what focal lengths would be most useful to their eyes, their telescope, and their observing conditions.  They then have the option of buying/not buying the most appropriate fixed focal length eyepieces for them.  For these reasons I'd always recommend that beginners buy a zoom as their first eyepiece.

[Louis D]

17 minutes ago, Second Time Around said:

A zoom eyepiece enables beginners to easily learn what difference a change of magnification makes on all the various classes of object.  It also shows them what focal lengths would be most useful to their eyes, their telescope, and their observing conditions.

However, the focal lengths marked on many zooms are not very accurate and should only be used as guidelines, not gospel.

[Second Time Around]

Just now, Louis D said:

However, the focal lengths marked on many zooms are not very accurate and should only be used as guidelines, not gospel.

As usual, Louis makes a good point.  However, they're a good starting point and a good way to learn.

[F15Rules]

Some very good points made above in favour of both fixed length and zoom eyepieces.

I'm a refractor only user, so not really qualified to advise the owner of a large Dob.. but if you are a newcomer to the hobby, I do think that unless you have a large budget available to buy premium wide field eyepieces suited to large Dobs, it's worth considering a decent zoom eyepiece to compare with your fixed length units.

Two nights ago, I had a session with my 5" Apo refractor for which I had prepared several optically excellent eyepieces, a Baader Genuine Ortho, a  Televue T2 Nagler, and a Baader Morpheus. I didn't expect to use any other eyepieces that night apart from a 30mm 68 degree widefield.

I'd decided to observe M42 and some double stars in Orion, my favourite constellation. However, within about 30 minutes, while observing Alnilam (the lowest star of Orion's Belt here in the UK, but the highest as seen from Oz) I became aware that something had changed in the seeing..a quite clear split of Alnilam and it's companion (which is a fairly close double star at 2.4" separation), had become much less clear within less than a minute. 

Looking up from the eyepiece I saw that a very fine misty haze had descended, but oddly, a breeze had got up, and the seeing had deteriorated. Then, a few minutes later, just as quickly, the sky cleared, the haziness disappeared, and the sky became very transparent - in fact the best seeing I've had in my location for some months!

At this point, I decided to get out my old Carton Japan zoom eyepiece, which adjusts from 7mm to 21mm focal length. Over the next hour or so, there were more variations in the seeing (I think we have a micro climate going on here, but that's another story). But while using the zoom, I was able to dial in adjustments instantly as the seeing came and went, much faster than if I'd been using only the fixed length eyepieces.

From about 11pm the seeing really settled down and I was able to go back to the fixed eyepieces, which do offer wider, and very slightly sharper views.. but the zoom enabled me to make the most of my couple of hours session, spending more time viewing and less time "faffing about" switching eyepieces in and out.

As I say, there is room for both types, and until you try both types you'll never know👍😊

Dave

[travaler]

The level of respectful response here is astonishing, thanks to everyone who has responded to my question of Zoom Vs Fixed eyepieces. So –  It appears to come down to practical value at a beginner level to buy a quality Zoom, there were a few examples of brands to look for. On the other side of the choice, is a fixed eyepiece that can bring a wider field of view and therefore see more. I also noted there seems to be personal opinions about which works best for personal reasons about the topic generally, this tell me I need to draw from my own experiences over time just as everyone who has responded to my question has done. Wow, my little head is spinning right from the quality of advice so far!

skywatcher 12" Dob with GOTO and wifi. I have at present  10mm; 25 mm plosals oh forgive my spelling Dang!! and a 5 mm Celestron. though I like to gaze around the sky for planets, but it's deep sky  stuff that draws me when I look up. 

Edited January 14, 2021 by travaler

[AlexK]

In this particular case, I would agree on a zoom feasibility with Steve. A 12" 1:5 light bucket is very forgiving on the EP optics quality/issues. Also, as the OP's instrument has the GoTo feature, the advantage of an ultra wide fixed field for manual tracking, finding objects, and starhopping is of a significantly lesser importance as well (when the GoTo actually works ). I see the point about experimenting with the "best magnification" as well, but aside from aesthetics of "clusters views framing" the best magnification for the desirable DSO observations, Keith has mentioned, is always close to the D/5-6mm, which for that collapsible 12" on Keith avatar now is 50x-60x, thus a 25 - 30mm EP would work best for DSOs with it.

Edited January 14, 2021 by AlexK

[Tiny Clanger]

4 minutes ago, travaler said:

The level of respectful response here is astonishing, thanks to everyone who has responded

This is a little oasis of decency and politeness amid a sea of internet sites awash with trolls, pompous opinionated oafs and shouty dogmatic know it alls isn't it ? I learned when I was searching for info before buying my first 'scope that if a search came up with a link to a thread here, it would always be helpful and reliable.  There is a vast reservoir of knowledge here just waiting to be asked for .

Having said that ... I have not a clue about zoom EPs ! 😀

Heather

 

[travaler]

15 minutes ago, AlexK said:

In this particular case, I would agree on a zoom feasibility with Steve. A 12" 1:5 light bucket is very forgiving on the EP optics quality/issues. Also, as the OP's instrument has the GoTo feature, the advantage of an ultra wide fixed field for manual tracking, finding objects, and starhopping is of a significantly lesser importance as well (when the GoTo actually works ). I see the point about experimenting with the "best magnification" as well, but aside from aesthetics of "clusters views framing" the best magnification for the desirable DSO observations, Keith has mentioned, is always close to the D/5-6mm, which for that collapsible 12" on Keith avatar now is 50x-60x, thus a 25 - 30mm EP would work best for DSOs with it.

I'm having an issue at the moment when I look up at the sky of late, a strange senation runs in my hands, they seems to move on their own, it only happens on cloudy nights. I've been told by experts in the field of astronomy that its cloud rage! Hmm Cloud rage hey? is this a thing? oh have I started another topic! oops..

Edited January 14, 2021 by travaler

[AlexK]

2 minutes ago, travaler said:

I'm having an issue at the moment when I look up at the sky of late, a strange senation runs in my hands, they seems to move on their own, it only happens on cloudy nights. I've been told by experts in the field of astronomy that its cloud rage! Hmm Cloud hey? is this a thing? oh have I started another topic! oops..

LOL! Just drive over the rim and into The Bush. I've found there are almost always pristine night skies up there during the AU summer last time visiting , and almost no city lights to bother you. An astronomy Paradise.

[Spile]

My decision to get the Baader Zoom/Barlow combination was based on quality, price and convenience.

This is my total ocular collection (apart from the two supplied) and I do not plan (I know, I know) on getting any more.