3x Eyepiece Collection for a Beginner

[RJC]

Hi All,

I am trying to plan a budget friendly way of upgrading stock eyepieces with a decent range that will allow me to cover most bases to get started.

How does this sound for a 3 EP collection to go with my standard stock 10mm and 25mm EPs?
(I also have a 2x Barlow)

1) StellaLyra SuperView 15mm £39
2) SVbony 7-21mm zoom £50
3) Astro Essentials Super Plossl 32mm £29

If there is something better that I’m missing in this price range, please let me know

[Stu]

1 minute ago, RJC said:

Hi All,

I am trying to plan a budget friendly way of upgrading stock eyepieces with a decent range that will allow me to cover most bases to get started.

How does this sound for a 3 EP collection to go with my standard stock 10mm and 25mm EPs?
(I also have a 2x Barlow)

1) StellaLyra SuperView 15mm £39
2) SVbony 7-21mm zoom £50
3) Astro Essentials Super Plossl 32mm £29

If there is something better that I’m missing in this price range, please let me know

Apologies if it’s in your signature, I can’t see that on my phone, but knowing the scope you are planing to use it in would help to give best advice. Also what targets are you going to focus on, or just a broad range?

[Bugdozer]

I have that Astro Essentials eyepiece and it's very good with my scope. However I notice your 15mm eyepiece is right in the middle of the range covered by your zoom - if you're on a budget, do you really need both? 

[Second Time Around]

We also need to know whether you wear glasses when you observe, and also how dark your skies are.

Finally, what 2x Barlow do you have?

[RJC]

Hi All,

apologies for the lack of information.

Scope: Sky-Watcher StarTravel 120
Ideally observing a bit of everything
I don’t wear glasses
Barlow is SVbony 2x

Thanks

[Second Time Around]

Could you please post a link to the Svbony Barlow you bought as they have several models?  The reason I ask is that some of them can be used at 1.5x as well as 2x.  This  adds versatility, and also give a wider field of view at a given magnification with nearly all zoom eyepieces.

I agree with Bugdozer that the 15mm wouldn't be a good buy if you get the 7-21 mm Svbony zoom, the latter being something that I'd definitely recommend.  Good choice!

It looks as though your scope comes with a 45 degree diagonal, that's great for terrestrial viewing.  This won't be as good quality as the rest of the scope, and will literally be a pain in the neck when observing objects high in the sky!

So I'd forget about the 15mm eyepiece and buy a 90 degree diagonal instead.  Sybony do a cheap model, but the optical alignment of a diagonal is important.  I'd therefore go for the slightly more expensive Celestron at £45.  It's worth spending a bit more on a diagonal as you'll be using it all the time.  Go to https://www.firstlightoptics.com/diagonals/celestron-90-prism-diagonal.html#:~:text=Celestron's Prism Diagonal slides into,chance of a cricked neck!

Edited January 8 by Second Time Around
Added price of Celestron diagonal

[RJC]

Thanks @Second Time Around for the help with this.

I can confirm the Barlow that I have is able to do 2x and 1.5x magnification. I actually bought it for that reason after seeing a review online about that feature.

I have also been wondering which diagonal to go for so this is a great help also!

[Second Time Around]

That's great about the Barlow being a dual 1.5/2x model!

Finding objects, especially for beginners, can be difficult.  So I'd also go along with your idea of the Astro Essentials 32mm Plossl.  This will give the maximum field of view with the 1.25 inch drawtube of your scope. 

Compared with the Plossl, a shorter focal length eyepiece with a wider apparent field of view can do the same.   The extra magnification will also darken the sky background and therefore show more stars, especially in towns and cities.  However, it will be from quite a bit to much more expensive than a 32mm Plossl. 

 

[RJC]

Thanks so much! I’ll start my online shopping

[Naughty Neal]

 The Svbony zoom though will only give approx. a 40 degree fov at 15mm where as the superview 15mm will be 68 dregrees.  

I feel for the similar money then a better fixed FL ep then the superiew  would be the Svbony  65 degree 18mm uff for a nice low- medium  power 33x ep , the uff can be had for approx.  £51 - £52 delivered via Aliexpress https://www.aliexpress.com/item/1005005538661261.html?spm=a2g0o.order_list.order_list_main.5.21ef1802lokEfN

The above would give a wider view as well then the superview.

The 32mm plossl giving a very  wide view  19x would be complemented quite well with the UFF.

 

The graph below shows the 15mm surplus to requirements.

 

 

 

 

 

 

 

 

 

Edited January 9 by Naughty Neal

[Naughty Neal]

The same view with the Svbony zoom at the 16mm position (green) and 21mm position (yellow) . 

The 16mm is 39.4 degrees fov and the 21mm 37.6 degrees according to Ernest review.

 The yellow fov circle of the 21mm zoom being too close to the white 15mm circle in the above post, also the red circle of the 18mm uff being further enough out to warrant it over the 15mm superview.   

 

All five of the below FL increases all fall within the 1.3 - 1.4 x range of recommended FL's  without being to close to be over lapping.

%
SvBony Zoom 7-21	21	37.6	1	4	4	Diffr	Diffr	Diffr	Coma, Ast. -3%
zoom...	16	39.4	1.4	4	6.5	Diffr	Diffr	Diffr	Coma, Ast. 0%
zoom...	12	43	2	3	4.5	Diffr	Diffr	Diffr	Coma 0%
zoom...	9	48	2.5	6	8.5	Diffr	Diffr	Diffr	Coma, Ast. 0%
zoom...	7	53.5	3.3	6	7	Diffr	Diffr	Diffr	Ast.,Coma +4%

 

 

 

Edited January 9 by Naughty Neal

[Naughty Neal]

 

Here the five fov's of the Svbony zoom using Ernest's measurements.

 

1. Here 

Edited January 9 by Naughty Neal

[Naughty Neal]

Using the typical 1.3x or 1.4x mag spacing increase in ep power,  then the 18mm uff and the zoom both fit in quite well.

There is alittle bit of overlap but not too bad  between the 16mm/18mm and 21mm FL's. 

 

[Second Time Around]

Neal is of course correct that a 15mm/68 degree eyepiece will give you a wider field of view.  However, it will only be at that one focal length and multiples thereof with the Barlow.

Instead, I'd very much recommend a zoom eyepiece as your workhorse.  One zoom eyepiece will cover multiple focal lengths and so is really excellent value for money.

Despite having high quality fixed focal length eyepieces,  I use my zooms a lot more often.  The zoom plus a Barlow lens and a low power, wide field eyepiece to find objects is often all I (and many others) use the whole evening.

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 better quality ones.

I especially like the ability to increase the magnification to make use of brief moments of good seeing (a steady atmosphere).  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 focuser!

Zooms also make it quick and easy to reacquire an object if it drifts out of the field of view by zooming out to a lower power without having to change the eyepiece.  This is especially useful when showing objects to others.

They 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 in future 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. 

[Naughty Neal]

 

 

 

And finally a graph with the view of all four ep's in one  place , the Lt blue ring being the 15mm superview.