36 replies to this topic

[GolgafrinchanB]

My svbony 9mm 66 degree long eye relief eyepiece (I believe these are colloquially known as "goldline"s because of their small gold band) arrived today and I wanted to do a bit of a comparison with my much nicer 8mm Delos.

 

First off, some clarifications and justification:

 - I bought the goldline for outreach. I bought the Delos earlier for planetary work. I have zero affiliation or relation with either brand.

 - Unsurprisingly, the $400 Delos performed better than the $25 goldline. The interesting question here is how and by how much did the Delos outperform.

 - I feel that comparisons like these are useful for beginners asking the question "what am I missing if I don't buy premium eyepieces?"

 - Today's tests were done using an AT72EDII and were far from exhaustive. I'm confident there are differences I missed.

 - I've read reports of the 9mm goldline performing the best of its lineup, so I'd caution about trying to translate my results to other focal lengths in the series. I do not own any others for testing.

 - I didn't get a chance to compare performance on Jupiter tonight, which would be good to test at some point due to the low contrast detail available in its cloud bands.

 

Let's get into the comparison. The main differences I observed were eye relief, clarity in the edge of the FOV, AFOV itself, sensitivity to eye placement, and internal reflections when viewed outside of the telescope. The main similarity I noticed was clarity (tested only at f/6) and brightness in the center 60% the FOV, which was a welcome surprise.

 

Eye Relief: I believe the advertising on this one. The goldline claims 16mm and the Delos claims 20mm. Both were achievable, but the Delos showed the full FOV without having to poke my glasses to the rubber where as the goldline required that I first push my glasses up my nose and second place the glass all the way against the eyepiece. The goldline has enough eye relief to be usable and not too frustrating, but the extra 4mm of the Delos is appreciated. Additionally, the flip up eyecup on the goldline feels a bit small. It seems to do the trick, but I worry it will attract a lot of eyelash smudges on the lens. The Delos solves this problem completely with their adjustable eyeguard (my favorite design is twist-up, which neither compared eyepiece has).

 

Clarity at edge of FOV: This was probably the most stark difference between the two eyepieces (aside from the obvious price, weight, and size). The outer 10-25% (estimating this stuff is hard) of the goldline has strong astigmatism and even some false color rainbow effect when a bright object like the moon is placed on the outer edge. It seems to me that this eyepiece may as well be 55 or 60 degrees AFOV instead of the listed 66 because those outer few degrees aren't very usable outside of recognizing that something bright exists. The Delos on the other hand is sharp right until a star literally touches the edge.

 

AFOV: I was pleasantly surprised to find that the AFOV was actually similar to the listed 66 degrees. I was expecting it to be smaller. By holding one eyepiece up to one eye and another up to the other eye, I was able to confirm that the AFOV of the Delos is the biggest (72 degrees), followed by the goldline (66 degrees), and then followed by my DeLite (62 degrees). That said, see the clarity comment regarding usable AFOV.

 

Sensitivity to eye placement: I actually consider my Delos to be one of the fussier eyepieces I regularly use regarding eye placement (this is compared to my DeLites and Plossls which are both really easy) but the goldline was worse here when using glasses. I think this was mostly due to difficulty positioning my eye with the shorter eye relief fighting against my glasses. I regularly got some kidney beaning using the goldline. The Delos blacks out when I mess up, but at this point I've gotten extremely consistent with using that eyepiece and my eyeball knows exactly where to go.

 

Internal reflections noticed outside of telescope: When I view through both eyepieces at a distance outside of any telescope with an off-axis light in the room, the goldline shows a bunch of internal structure illuminated by the light where as the Delos shows extremely little internal structure. I didn't notice this observing, but suspect that under the right conditions such as off-axis light hitting the eyepiece in a reflector this could cause issues in the goldline which are better mitigated in the Delos.

 

Clarity and Brightness in the center 60% of AFOV: This was pretty incredible for me. Now, perhaps a sharper eye would be able to see differences here, but I narrowly split castor into 2 and noticed no difference in the view between the eyepieces when it was centered. I was also able to find all the same stars in both eyepieces BUT this is from my bortle 9+ home so more testing may be required on brightness from a dark sky. I think this is an important lesson for beginners though, a decent budget eyepiece can perform practically on par with premium eyepieces for centered objects. Differences tend to come about off axis, under difficult conditions or difficult targets, or in the other areas I elaborated on above.

 

Hopefully this is helpful for somebody someday. I found myself looking for stuff like this when I was first considering premium eyepieces and hope to contribute to the next person wondering what improves and what stays similar. P.S. there are other kinds of premium eyepieces with different benefits such as extremely wide AFOV. I like this comparison in particular because both eyepieces have very similar claims of reasonably wide AFOV while accommodating eyeglasses.

 

I'm also curious to hear what other optical aberrations people notice in their goldines that I missed. I'll probably try to see if I can notice them in mine.

[T1R2]

I got the full set of Goldline's and I thought the 9mm was the worst, it had very noticeable Edge Of Field Brightening, SAEP (kidney beaning / blackouts) very hard to hold the exit pupil when viewing the moon and even though the 6mm has SAEP on bright objects like the moon, its fine on DSO's, I learned to move the terminator of the moon away from the center fov and closer to the edge and the orange glare goes away, The 6mm was also perfect edge to edge in my f6.5 AR127.  I thought the 20mm and 15 were also pretty good in my f13 refractor but still had a tiny amount of astigmatism.  

[quilty]

Hi Golgafrichin,

to me you're most welcome with such a comparison.
I purchased the goldlines for 59€ each and think compared to other eyepieces they're well worth the price.
To me the best one in that line is the 15 mm.
I like the 9, too, the only downside to me is that kidney disease. But I learned easily to deal with soon. (@ those 110%ic purists: No, I' m not on a waiting list for a replacement kidney to it. Not yet :-). It makes an orange tint unlike the other specimen.
Long ER is a bit euphemistc I'd say they're medium ER.

Now, honestly, is there any detail which the Delos reveals and which is hidden in the 9 goldline?

All the goldlines do well in all my long fl scopes but in the short 102 f/4.5 frac as well. They were my best value/price ratio ep purchases ever.
I now prefer the Baader Hypers but not for better detail but for larger FOV (extended) and longer ER.

I think the general ep design is similar, sort of an Erfle upper part and a Smyth group for the 6 and 9

A severe downside is that ring of fire at high bright/dark boundaries in the FOV in the 6 mm only (like the terminator). which excludes it to lunar observations.

At correction at the field edges: I never really paid attention to. I think when it's significant I won't miss it. Like I do for coma and fc in the Meade 2080.
But when I'm not annoyed by the view through the goldlines, rather completely satisfied, to me that edge performance is no issue to me, rather an academic one
I'd prefer neither if they were stopped to an FOV size wich is well corrected. Some outer field imperfections don't at all reduce the joy of a wide angle view both, at observing and at finding a target.
sharp vieving occurs in the very center anyway (eyewise)

PS: In order to justify the Delos' price (500?) it's supposed to display 20 times the detail the 9 goldline does, sort of :-)

Edited by quilty, 15 April 2025 - 09:24 AM.

[Ernest_SPB]

Eye Relief: I believe the advertising on this one. The goldline claims 16mm and the Delos claims 20mm

According to my measurements 14.5 mm vs. 20 mm

 

Clarity at edge of FOV: This was probably the most stark difference between the two eyepieces (aside from the obvious price, weight, and size). The outer 10-25% (estimating this stuff is hard) of the goldline has strong astigmatism and even some false color rainbow effect when a bright object like the moon is placed on the outer edge.

Actually in F4 scope at the edge FOV "goldline" represents aberration spot in size 20'x30' when Delos 4'-5' (plus 10'-12' dark blue tail)

 

AFOV: I was pleasantly surprised to find that the AFOV was actually similar to the listed 66 degrees. I was expecting it to be smaller. By holding one eyepiece up to one eye and another up to the other eye, I was able to confirm that the AFOV of the Delos is the biggest (72 degrees), followed by the goldline (66 degrees), and then followed by my DeLite (62 degrees).

According to my measurements 64.9° vs. 72°

 

Internal reflections noticed outside of telescope: When I view through both eyepieces at a distance outside of any telescope with an off-axis light in the room, the goldline shows a bunch of internal structure illuminated by the light where as the Delos shows extremely little internal structure.

It is not a good way to check internal reflections. Main trouble of 9mm "goldline" - a glare on a mount of its "Barlow" lens (filed component inside barrel). 

Edited by Ernest_SPB, 15 April 2025 - 05:17 AM.

[SeattleScott]

I think you pretty well summed up the differences. I don’t have these specific eyepieces, but you rated the Delos higher in the areas it would be expected to be clearly better.
In the center of the field, the Delos should do better on planetary due to better management of stray light when looking at bright objects. But on DSO, the views through cheap eyepieces are typically similar to premium brands in the center of the field. Generally I find the view to be a little crisper in premium eyepieces, but I can generally see the same stars and the same details in cheaper eyepieces. Even comparing premium brands, there can be subtle differences in clarity and contrast.

But when we buy premium brands, it is mostly for the wider AFOV or longer eye relief, the better edge correction and better control of stray light. So the Delos is 16x as expensive. I don’t think anyone can realistically argue that the Delos is 16x better. But if finances aren’t much of a concern, and stargazing is a serious hobby that one is willing to invest in, it could make sense.

That being said, a used LVW would probably only set one back about $150, and would provide premium performance and better ER with similar AFOV. Granted it wouldn’t go as wide as a Delos. And maybe the Delos is a hair better optically (I haven’t compared them). But it would clean up the edges, control the glare, improve the eye relief a bit, basically fix all the problems with the Goldline for far less than $400. Pentax XL are also 65 AFOV and similar price. So there are different options at different price tiers.

[Jon Isaacs]

 

But when we buy premium brands, it is mostly for the wider AFOV or longer eye relief, the better edge correction and better control of stray light. So the Delos is 16x as expensive. I don’t think anyone can realistically argue that the Delos is 16x better. But if finances aren’t much of a concern, and stargazing is a serious hobby that one is willing to invest in, it could make sense.

 

Perfection is not measured on a 0-1 scale but rather how close to perfect it comes.  

 

Jon

[CrazyPanda]

I didn't notice this observing, but suspect that under the right conditions

 

The Moon with a long enough focal length telescope to produce a real image of the Moon that is physically wider than the field lens of the 6mm and 9mm Gold Lines will cause substantial glare all around the exit pupil. Or if any part of the Moon is just out of field, (e.g. when viewing the terminator), it will also cause glare on one side.

 

Here are the 6mm and 9mm Gold Lines in my scope aimed at a full Moon:

 

 

See the bright rings around the exit pupil? That is from unbaffled beveled edges of the field lens:

 

 

If any bright light source illuminates those bevels, it means any time your eye's entrance pupil encapsulates any part of that light, it will manifest as a veiling glare over the field of view.

 

In reality ANY light source (including sky glow) will illuminate those bevels at the same intensity as the exit pupil and can produce an additional source of glare that reduces contrast. And because deep sky viewing is generally done when your entrance pupil is dilated, it has a greater chance of encapsulating part of those glare rings.

 

In addition to those sources of glare, the interior of the eyepiece has shiny surfaces that can produce secondary glare depending on how your eye is positioned. Flocking the interior of the eyepiece can make a difference, but the primary source appears to be those bevels.

 

To use those 6mm and 9mm gold lines requires you to not only avoid SAEP, but also avoid letting your pupil drift over those glare rings when aligning to the exit pupil. Sometimes those two tasks compete with one another and there's literally no good place to hold your eye, and you have to accept some SAEP or some glare.

 

Interestingly, there is a variation of the 9mm gold line made by Aquilla. This has an internal field stop that limits the FOV to about 50-55 degrees or so. While this does not fix the glare, it 100% fixes the SAEP.

Edited by CrazyPanda, 15 April 2025 - 09:45 AM.

[quilty]

sorry, I just use to use the 69, or the other way round :-)

The question to me is: can I find any issues trying hard? Are they inavoidingly annoying at use? Do I need to try hard to avoid them? Or can they easily be ignored?

To me the latter applies except for the ring of fire in the 6

[GolgafrinchanB]

First off, it sounds like I really need to give these 2 a test against Jupiter and the Moon. I know these are especially important targets due to their combination of beauty and tendencies to reveal flaws in optical systems. I started too late for Jupiter last night and the clouds rolled in before the Moon made it high enough. I used a nearby streetlamp as a proxy for the moon, but it sounds like there are some effects which may be present in the real thing - I just need to test. I'll update with a comment here when I find the right conditions to test these (the moon is getting harder this week as a non-morning person).

 

Thanks everyone so far for adding details! I wanted to respond to a few.

 

 

According to my measurements 14.5 mm vs. 20 mm

...

According to my measurements 64.9° vs. 72°

Your measurements are well within the margin of error of my measurements as well. i.e. when I said I have no compelling evidence that the numbers differ from the advertised 16mm and 66 degrees, that is in part because I have no way of measuring to an accuracy of more than plus or minus 3mm and 5 degrees or so. Since both the advertised values and the values you measured are within the margin of error of my crude methods, I personally can't help corroborate your numbers nor can I help disprove them. OK, that's the technical side - for the non-technical response: thanks for measuring them more precisely than me! That's sweet to know

 

As for various comments about value - I want to be very clear, I believe the difference in value between these 2 eyepieces is a very personal decision and there's no correct answer in this case. Correct value answers only show up when one product is unambiguously superior and cheaper, but in this case the Delos was superior while the goldline was cheaper. Because there are real differences in quality and price (and also an entire market of options beyond these 2), only you can decide what is the right combination of features for your price point. I'm simply trying to help people better understand what they are and are not getting for their money (and I think these discussions are fun). I personally plan to continue using my Delos for personal use and begin using my goldline for outreach, but I would 100% support a wide range of other value decisions since it is so personal.

 

 

Here are the 6mm and 9mm Gold Lines in my scope aimed at a full Moon:

...

See the bright rings around the exit pupil? That is from unbaffled beveled edges of the field lens:

...

I only quoted a portion of your comment for brevity, but I'd like to thank you for your whole well thought out response and accompanying images CrazyPanda. This is a super useful addition to the comparison and covers a bunch of holes in what I was able to test / thought of testing. Heck yes!
 

Lastly, some of these comments are my first introduction to the relationship between kidney beaning and SAEP. That's a sweet thing to know about and I plan to research some more to better understand it myself.

 

Thanks everyone, and let's keep it coming if there's more to contribute!

[GolgafrinchanB]

I've come back to update this with a comparison on Jupiter tonight. I was unable to notice any difference between the 8mm Delos and the 9mm goldline on Jupiter within the center 50% of the FOV. The issues stated above about eye relief, AFOV, and edge of FOV of course still apply to Jupiter. The limited usable AFOV especially matters on Jupiter as I found myself needing to adjust my Dobsonian (this time tested on a 10" f/5 dob instead of the 3" f/6 frac) about twice as often on the goldline to keep Jupiter in the usable field. Compare this to the Delos which allowed me to place Jupiter at the very edge, enjoy it for the full drift to the other edge, and then re-adjust with basically no difference in view quality from touching the edge and the middle.

 

As a note, my old GSE mirror has a known slight TDE based on star tests and seeing was only so-so today. I was able to make out the GRS during moments of decent seeing, but not continuously (both eyepieces). This limits my ability to comment on limiting resolution since the rest of the optical system is getting in the way of testing the super sharp stuff.

 

The moon comparison will come a few weeks later because I refuse to wake up early.

[quilty]

When you (like me) are used to Schmidt Cassegrain scopes (classical ones) such edge performance diffs at eyepieces are rather neglible.
The same applies to short achros and uncorrected Newts

Edited by quilty, 21 April 2025 - 04:39 AM.

[Jon Isaacs]

When you (like me) are used to Schmidt Cassegrain scopes (classical ones) such edge performance diffs at eyepieces are rather neglible.
The same applies to short achros and uncorrected Newts

 

That's not my experience. In short achro's (and ED/apps), the field curvature of the objective is added to the off-axis astigmatism of the eyepiece. With a Newtonian it's the coma added to the off-axis astigmatism.

 

Eyepieces that are sharp across the field in fast scopes help a lot.

 

That said, the 9 mm Goldline has been around for more than 20 years. It was first introduced as the 9 mm Orion Expanse but has been around in its generic form for nearly as long. I believe it was the first affordable short focal length wide field.

 

It's actually pretty well corrected in a fast scope, it's a negative-positive eye piece (Barlow like negative lens in the barrel.)

 

I had one for several years, it was the last non-TeleVue eyepiece in my main case, it sat between a 12 mm Type 2 and a 7 mm Type 1.

 

Using the 9 mm today, the scattered light and EoFB (Edge of Field Brightening) are quite apparent but I still had some wonderful planetary views.. 

 

Eyepieces that don't get used, they don't look like this 9 mm Expanse clone.

 

 

Jon

 

 

 

[quilty]

Eyepiece SA might add to a Newt's or SC's coma, yet it doesn't annoy me. Coma does, sometimes.
And it may add or substract to/from a short frac's SA. I own only one short achro. And none of the goldlines degrade the view noticeably, the 6 does only due to exceeding the maximum power

[Mike W]

I've come back to update this with a comparison on Jupiter tonight. I was unable to notice any difference between the 8mm Delos and the 9mm goldline on Jupiter within the center 50% of the FOV. The issues stated above about eye relief, AFOV, and edge of FOV of course still apply to Jupiter. The limited usable AFOV especially matters on Jupiter as I found myself needing to adjust my Dobsonian (this time tested on a 10" f/5 dob instead of the 3" f/6 frac) about twice as often on the goldline to keep Jupiter in the usable field. Compare this to the Delos which allowed me to place Jupiter at the very edge, enjoy it for the full drift to the other edge, and then re-adjust with basically no difference in view quality from touching the edge and the middle.

 

As a note, my old GSE mirror has a known slight TDE based on star tests and seeing was only so-so today. I was able to make out the GRS during moments of decent seeing, but not continuously (both eyepieces). This limits my ability to comment on limiting resolution since the rest of the optical system is getting in the way of testing the super sharp stuff.

 

The moon comparison will come a few weeks later because I refuse to wake up early.

I think you'll find the 30UFF and the Delos a perfect combo in a Dob or any scope actually. Drift time in a Dob is crucial!

[GolgafrinchanB]

I think you'll find the 30UFF and the Delos a perfect combo in a Dob or any scope actually. Drift time in a Dob is crucial!

Oh, I'm super happy with my 8mm Delos and 30UFF "main pair" so to speak (as well as my 15mm Delite which I use with friends who aren't ready for Delos placement + smaller exit pupils as well as solo for certain "just right" sized targets). This post was more about testing and learning the differences between those premium eyepieces and the highly-recommended budget counterparts. I have no intention of switching from my Delos to the new-to-me goldline as my primary eyepiece or anything.

 

FWIW, my current budget lineup for star parties with kids involved is:

9mm goldline (this post)

12mm X-Cel lx

25mm plossl

2x orion shorty barlow (for when I'm feeling like a spicy 6mm x-cel lx, which drifts a bit fast for star parties)

 

One of the 9mm goldline or 12mm X-Cel lx may leave my service eventually since they serve pretty similar roles, but we'll see.

[quilty]

Try the 15 mm goldline. You'll like it, the best from the series

[Jon Isaacs]

Try the 15 mm goldline. You'll like it, the best from the series

 

Maybe at F/12. The scope here is F/6 and the 15 mm and 20 mm Goldline's show a lot of off -axis astigmatism.

 

Jon

[quilty]

It does well at f/4.5, too.

[CrazyPanda]

It does well at f/4.5, too.

The 15mm gold line absolutely does not do well at F/4.5.

 

*Significant* astigmatism throughout most of the field.

 

The 9mm gold line does reasonably well at F/4.5, but not the 15mm or the 20mm.

[Jacques]

The 15mm gold line absolutely does not do well at F/4.5.

 

*Significant* astigmatism throughout most of the field.

 

The 9mm gold line does reasonably well at F/4.5, but not the 15mm or the 20mm.

The 15mm doesn't do well even at F9. The 6mm on the other hand is surprisingly very good (at least at F9)

[quilty]

The 15mm gold line absolutely does not do well at F/4.5.
 
*Significant* astigmatism throughout most of the field.
 
The 9mm gold line does reasonably well at F/4.5, but not the 15mm or the 20mm.

it does.

[CrazyPanda]

it does.

 

Prove it.

[John Huntley]

At some time in the past I've owned quite a few of those 66 degree eyepieces. Some were branded Skywatcher UWA (bit misleading) and looked identical to the gold lines. Others bore Orion or Telescope Services branding and seemed to have better quality coatings. 

 

I used them mostly in scopes around F/10 and they worked well enough. Some ghosting from when observing bright targets, eg: Jupiter and the 6mm, 20mm and 9mm seemed well corrected at that focal ratio. The 15mm was the one that I least enjoyed using although it was still OK in the slower scopes I owned back then.

 

When I got an F/6 newtonian and an F/6.5 refractor I started to see more correction errors in the outer field with the 20, 15 and 6mm. The 9mm held up quite well though.

Edited by John Huntley, 22 April 2025 - 06:46 PM.

[starfinder123123]

The main thing for me with these eyepieces is the ghosting when observing Jupiter and Moon.

Otherwise, they are not bad for the price.

[GolgafrinchanB]

Can someone who has experienced it describe precisely what "ghosting on Jupiter and the moon" looks like and what conditions make it worse? I ask mainly because I didn't notice anything on my Jupiter test in the 10" f/5 and I'm wondering if I should be adjusting some variables or looking carefully at some part of the image.