Upgrading eyepieces - advice on 100 degree eyepiece?

[James9]

Hello All, 

I am an intermittent observer, depending on my work and general life stresses. Upgrading kit comes close to being a stress so I would like some help ! A new job on the horizon will also give me a more time for hobbies.

I have a Nexstar 130 SLT (f/5), a steal from a pawnbrokers for £200. When I opened the box, it contained the SkyQ Link wifi module ! Albeit I think the version 1, it is grey and not orange around the clip.

My 'best' eyepieces are Celestron AstroMaster Telescope Accessory Kit:

• 15 mm Kellner Eyepiece - 1.25” - Decent enough for me to use.
• 6 mm Plossl Eyepiece - 1.25” - I find very difficult and uncomfortable to use. Like looking through a straw.
• 2X Barlow Lens with T-threads - 1.25”

(As also have Celestron 25 and 9mm eyepieces and an unbranded "Super 10mm" eyepiece (Skywatcher? I still have a Celestron Travel 70 scope, one of my previous rungs on the ladder)).

 

In the next 2-5 years, with sufficient growing experience and enjoyment permitting, I would like to upgrade to whatever the Celestron Nexstar 8 (f/10) variant (or last generation, second hand) is around then. I would like to keep the same, better eyepieces I will hopefully begin investing in now. 

I also have a Canon 5D camera, used mainly for travel and some night landscape Astro but would like to leave the door open to taking a variety of astro pictures through the scope.

 

I am looking at buying 1-2 eyepieces for £200-550 total and I have been drawn to wide (and even wider) angle eyepieces.

Initially, I looked at the Panorama II that seems to have got good reviews in 2018 but with some niggles.  

I read the Hyperions are good but poor at f/5 so wouldn't do me any good for the next few years.

I am currently considering my best bet is the the APM 13 XWA and either the APM 20 XWA or the APM 5 XWA. Tempted by the 5mm so I can get high magnification on my f/5 with the 2x barlow and then use it on it's own on the f/10. But maybe the 7 or 9 mm would be better?

I don't wear glasses but the 6mm has made me gun shy and would like a comfortable viewing experience for the what I buy. Interested in everything, would like to see larger images of the planets and better views of DSOs than my current set up. 

 

I have tried to do my research but I'm still an improving/advanced beginner and my head is genuinely aching after 2-3hours so I will have to have some water and a lie down! Any feedback or oversights I am making would be appreciated. I am hoping these purchases would be for life so would like your help to get them right. 

Thank you for reading!

Edited December 1, 2022 by James9

[Louis D]

Avoid the Panorama II and Meade MWA lines.  Both closer to 80 to 90 degrees in AFOV and suffer from significant SAEP (kidney-beaning).

Don't overlook the other 100 degree variants on the APM XWA line.  Astronomics has their Astro-Tech 100° line in the US, and then there's the Stellarvue Optimus line in the UK.  There are more brandings out there, but I can't remember their names offhand.  Eye relief in the shorter focal lengths will be much better than in your 6mm.

[Elp]

I don't think you need to go to the extreme of 100 degrees (your wallet will thank you). I use plossls so going from the standard 50 degree which I find restrictive to 60 degrees with a BST Starguider is a bit more liberating. The sweet spot seems to be my WO swans/UWA at around 70 degrees. At the higher end my ES 82 degrees and Meade UWA 82 degrees are great (the latter being discontinued and hard to find). As you're not using glasses they'll all work great.

OVL Nirvana's are equivalent of the ES range I believe but cheaper.

[Ratlet]

I'm going to second ELP on the starguiders.  They are quite liberating compared to the bog standard eyepieces (although I quite like my plossl if I'm sketching).  I'm pretty new and can't comment on the wide FOV, but I think given that by and large they eyepieces you've got so far are pretty poor, jumping straight into 100 degree eyepieces might be an over reaction. I'm using an F5 Newtonian, 130mm so broadly similar scope to you.

Personally, I'd test the water with something less extreme and cheaper than the Wide angle stuff.  The jump from even my plossl at 48 degree to a Starguider at 60 is impressive and like ELP I find it imressive.  It's plenty wide, excellent eye relief and looks delicious at F5.

I can tell you that the 8mm BST Starguider is amazing at F5.  Heck, I've managed to go 6 months using almost exclusively the 8mm starguider and a 32mm plossl.  I've got a barlow and an 8-24mm zoom but those almost never get used.

[Louis D]

You might look into the new Svbony 3-8mm zoom.  It's been getting good initial reviews on CN, has a 60 degree AFOV, and comfortable eye relief.

[James9]

Thanks for the replies so far!

I am very tempted by the Svbony 3-8mm (SV215) for the travel scope. At the very least, I would learn what focal lengths I like on each of my current scope and develop me a little further. But it won't be delivered in the time I am in the UK to collect it over Christmas. So it is one for the future. 

You may have talked me down from the 100 degrees, I wish I had the opportunity to use one on my scope as I am still tempted. But I have also seen the APM may also have some issues on my F5. I was briefly tempted by some 70-82 degree eyepieces but I think the below is good for where I am right now.

I like the comfort that there seems to be with the BST Starguiders (21m lens diameter and 16mm eye relief). I should upgrade my Celestron Barlow to the BST Starguider Barlow to match the same quality as the eyepieces?

Current thoughts to buy: 

• 25mm BST Starguider
• 15mm BST Starguider
• 5mm BST Starguider
• 2x BST Starguider barlow for 12.5mm, 7.5mm and 2.5mm (2.5mm will give comfortable max usable magnification in both my current scopes)

Option: drop the barlow and 5mm and get the 3.2mm and the 8mm instead? I could use my existing 2x Celestron Barlow when needed I suppose, if that wouldn't cause too much of a degradation.

Any further comments will be gratefully received!

Thanks

 

Note: I have just seen FLO give 15% off if I buy 4, so the 4th one is effectively heavily discounted. Recommendations for the best option for 4 would be appreciated. 

Edited December 2, 2022 by James9

[Don Pensack]

A 21mm eye lens and 60° field translates to an eye relief of 18.2mm on the Starguiders.

It could be 16mm from the edge of the lens out if the eye lens is strongly concave, but I don't recall that is the case with the Starguiders.

That might explain why many people can use them wearing glasses.

[bosun21]

I’m going to rock the boat and recommend getting the Nirvanas. They are very well received eyepieces with 22 degrees more FOV than the Starguiders. I generally recommend the Starguiders, however with you stating that you want them for life, I’m inclined to opt for something better. If you don’t mind spending a bit more then the Baader Morpheus eyepieces are better still. Good luck with whatever you choose.

[apaulo]

i too would agree about the baader morphs for life long  use.  id say money well spent but shop around for prices.

[Louis D]

4 hours ago, Don Pensack said:

A 21mm eye lens and 60° field translates to an eye relief of 18.2mm on the Starguiders.

It could be 16mm from the edge of the lens out if the eye lens is strongly concave, but I don't recall that is the case with the Starguiders.

That might explain why many people can use them wearing glasses.

Due to a couple of different eye lens sizes and 3mm to 4mm eye lens recession due to the eye cup design, I measured the usable eye reliefs as below:

The AstroTech Paradigm is the same as the BST Starguider.  The discontinued Meade HD-60 line is much more eyeglass friendly across the line.

My thoughts on the two lines are in the following thread:

 

[Louis D]

3 hours ago, apaulo said:

i too would agree about the baader morphs for life long  use.  id say money well spent but shop around for prices.

I'd also recommend the Pentax XWs.  The 1.25" ones are $30 cheaper than the Morpheus right now in the US.

[Louis D]

10 hours ago, James9 said:

Current thoughts to buy: 

• 25mm BST Starguider
• 15mm BST Starguider
• 5mm BST Starguider
• 2x BST Starguider barlow for 12.5mm, 7.5mm and 2.5mm (2.5mm will give comfortable max usable magnification in both my current scopes)

Forget the 25mm BST in a fast scope, it's not sharp in the outer field.  You're just as well off to get a 32mm Plossl for widest field of view in a 1.25" barrel and save a few bucks.  The 25mm BST also requires quite a bit of in focus, so it won't come to focus in my Dob with a low profile focuser and GSO coma corrector.

The 12mm BST is much better corrected in the outer field than the 15mm, and yields a more usable power across more scopes.

The 5mm is a good choice for highest power in the f/5 scope, but will be all but unusable in the f/10 scope due to the super high power and tiny exit pupil.  The 8mm might be the better compromise choice if it will be used in both scopes.  8mm is about as short of a focal length you'd want to use in an f/10 scope.

Despite owning 6 different 1.25" Barlows (with some duplicated for dedicated binoviewer usage to reach focus increasing that total even more), I've never been a fan of Barlows.  They're clumsy to use in practice as compared to dedicated focal lengths and can cause vignetting, focus, or exit pupil issues.  I have no experience with any current day 1.25" Barlows.  Everyone one of them in my collection dates to the 1990s and was made in Japan.  I've found they had better polish, coatings, and stray light control than today's crop of sub-$100 Barlows.

You won't really need a Barlow in the SCT due to the long focal length.  I consider them merely a stop-gap measure for shorter focal length scopes like your 130 while you accumulate more focal lengths.  After which, you won't find yourself using one much at all.

[Elp]

A Barlow does allow you to effectively double the amount of lenses you have but I find I don't use it and prefer to use the individual powered eyepieces. Even then I probably only use a 30mm and perhaps a 9mm, most of the inbetweens and higher powers don't get used much.

Edited December 2, 2022 by Elp

[cajen2]

2 hours ago, Louis D said:

I'd also recommend the Pentax XWs.  The 1.25" ones are $30 cheaper than the Morpheus right now in the US.

It's the opposite in the UK: the Morpheus are £50 cheaper 

I have 2 XWs and 3 Morphs. Both are excellent but for me, the Morphs just shade it.

[Don Pensack]

3 hours ago, Louis D said:

Due to a couple of different eye lens sizes and 3mm to 4mm eye lens recession due to the eye cup design, I measured the usable eye reliefs as below:

The AstroTech Paradigm is the same as the BST Starguider.  The discontinued Meade HD-60 line is much more eyeglass friendly across the line.

My thoughts on the two lines are in the following thread:

 

That doesn't compute, Louis.

 

If the 5mm Paradigm is a measured 58°, and the eyepiece has a 22mm eye lens, the eye relief is 19.86mm

Subtract a 3mm depth for the lens from the eyecup, and you have 16.86mm effective eye relief, not 12mm.

I don't see how it could be 12mm effective eye relief unless the eye lens had a 5mm concavity to it, which I know it does not have.

You measured 3mm depth, which points to a fairly flat eye lens.

 

And the Meades had the same lens diameter with a wider apparent field, which means LESS eye relief, yet you have a longer eye relief on the Meades.

The 4.5mm Meade cannot have a longer eye relief than 17.9mm at 63°.  14.0mm effective eye relief seems about right.  But that should be shorter than the Paradigm.

Something doesn't compute.

Either your eye lens measurements are wrong or your apparent field measurements are wrong.

 

 

[Louis D]

I just used the flashlight method to measure the distance from the top of the eyepiece to the point where the projected light cone was smallest.  12mm to 14mm is definitely how they view in practice.

Geometry doesn't entirely define usable eye relief or all of the original Morpheus would have the same usable eye relief, but they don't.  The shortest focal length ones have the tightest eye relief despite having the same eye lens diameter and AFOV as all the rest.  I see a similar pattern with the HD-60s going from 9mm down to 4.5m in both measurements and in practice.  In particular, the 4.5mm is quite difficult to use with eyeglasses.  Conversely, the Paradigm/BST Starguiders view remarkably similarly across focal lengths in both eye relief and AFOV by comparison.  This is more similar to the Pentax XL/XW lines which all view pretty much the same across focal lengths in both eye relief and AFOV.  All I can surmise is that there are at least two schools of design for these types of long eye relief and wider AFOV eyepieces that leads to the differences or constancy in eye relief (and AFOV in the HD-60s).

If I could ever get the upper assembly removed from the Paradigms, I would remeasure the usable eye relief.  However, I can't get the upper casing to unscrew from the main barrel as others have done.

[Pixies]

13 hours ago, Louis D said:

The 12mm BST is much better corrected in the outer field than the 15mm, and yields a more usable power across more scopes.

I agree. Go for the 12mm rather than the 15.

[Don Pensack]

18 hours ago, Louis D said:

I just used the flashlight method to measure the distance from the top of the eyepiece to the point where the projected light cone was smallest.  12mm to 14mm is definitely how they view in practice.

Geometry doesn't entirely define usable eye relief or all of the original Morpheus would have the same usable eye relief, but they don't.  The shortest focal length ones have the tightest eye relief despite having the same eye lens diameter and AFOV as all the rest.  I see a similar pattern with the HD-60s going from 9mm down to 4.5m in both measurements and in practice.  In particular, the 4.5mm is quite difficult to use with eyeglasses.  Conversely, the Paradigm/BST Starguiders view remarkably similarly across focal lengths in both eye relief and AFOV by comparison.  This is more similar to the Pentax XL/XW lines which all view pretty much the same across focal lengths in both eye relief and AFOV.  All I can surmise is that there are at least two schools of design for these types of long eye relief and wider AFOV eyepieces that leads to the differences or constancy in eye relief (and AFOV in the HD-60s).

If I could ever get the upper assembly removed from the Paradigms, I would remeasure the usable eye relief.  However, I can't get the upper casing to unscrew from the main barrel as others have done.

After I posted, I realized I'd forgotten to mention that the geometric calculation only defines the MAXIMUM eye relief possible, not the actual.

The reason is that not every eyepiece uses the entire width of the eye lens for the the field.

This is likely to be the case with the Morpheus eyepieces, which would all have 23-24mm of eye relief if the entire eye lens were used to field the image.

Another good example is the TeleVue Delites, which do not utilize the entire eye lens for the field.

My guess is that utilizing a certain size of lens a couple places in the stack saved on manufacturing costs, even though the eye lens on the Delites could have been a lot smaller.

That must be true of the Starguiders as well.

[bosun21]

On 02/12/2022 at 20:36, Louis D said:

I'd also recommend the Pentax XWs.  The 1.25" ones are $30 cheaper than the Morpheus right now in the US.

Not the case in the UK Louis. The Pentax are £50 more expensive per eyepiece.

[cajen2]

On 02/12/2022 at 23:05, cajen2 said:

It's the opposite in the UK: the Morpheus are £50 cheaper 

I have 2 XWs and 3 Morphs. Both are excellent but for me, the Morphs just shade it.

There's a strange echo in here! 😄

1 hour ago, bosun21 said:

Not the case in the UK Louis. The Pentax are £50 more expensive per eyepiece.

 

[bosun21]

Didn’t see your post, I’m even getting clouds in my vision 😂

[Guest]

16 minutes ago, bosun21 said:

Didn’t see your post, I’m even getting clouds in my vision 😂

That's called glacoma lol

Edited December 4, 2022 by Mike Q

[bosun21]

2 minutes ago, Mike Q said:

That's called glacoma lol

My eyesight is actually sharp. I only need to use reading glasses, otherwise it’s all good through the eyepiece.

[Guest]

43 minutes ago, bosun21 said:

My eyesight is actually sharp. I only need to use reading glasses, otherwise it’s all good through the eyepiece.

In the same boat here, but the eye doctor says i am at risk for glacoma, so i get checked yearly for it.  No worries yet he says. 

[James9]

Wow, thanks everyone. That is a lot to digest. I started planning to buy 1-2 long term eye pieces, switched to shorter timeframe for what I have now and I am now moving back towards longer term..!

My takeaways are:

• Barlow's, while they have a use of effectively doubling your number of EPs, aren't popular! So I will use my existing Celestron in a pinch but try to plan not to rely on one.
• I gather the Nirvana's are just rebranded cheaper versions of the Explore Scientific's? When I said I was tempted by 82 degrees before, it was the Explore Scientific's I was looking at. I discounted the Explore Scientific's on cost so curious about the Nirvana's now. 
• Going back to my original plan of 1-2, the Baader Morpheus could be best life long eyepieces. 
• 32mm plossl is better for widest field of view, which seems a common choice.

Latest thought based on everyone's comments:

1. 32mm Celestron Omni Plossl - any other recommendations gratefully received, if there are better cheaper ones.
2. 9mm OR 12.5mm Baader Morpheus. A life time purchase for now and future use. Ratlet and Elp use 8-9mm with a 30-32 exclusively, but Pixie's and Louis recommend the 12.5mm (at least over the 15mm). A 12.5mm might be better for long term than f10? I am leaning towards the 9mm, at the moment. 
3. 5mm Starguider for my current scope, knowing it will be no good on an f10. And slumming it down to 2.5mm for max mag with my barlow when needed 😁 I considered the 4mm Nirvana but 2x barlow down to 2mm is outside the useable magnification (x325, above the upper rule of thumb limit of 307). I could plump for the extra cost of the Nirvana if this is still a useable magnification in practice? Though the AFOV appears very similar, maybe it isn't worth it?

 I put the links in to make sure we are talking about the same products! 👍

Thanks for your continued input!

Edited December 4, 2022 by James9