738 replies to this topic

[Jon Isaacs]

Thank you Don. While not considering a large fast Dob, a smallish fast Newtonian such as imagers use, as a widefield scope would be a test for some eyepieces, there seem to be several F4 ones made.

 

I have had my 12.5 inch F/4.06 for about 25 years.  But F/4.06 is not F/3.17 like Tay's 24 inch.  

 

Jon

[Starman1]

Thank you Don. While not considering a large fast Dob, a smallish fast Newtonian such as imagers use, as a widefield scope would be a test for some eyepieces, there seem to be several F4 ones made.

If used visually, those inexpensive f/4 newtonians will, unfortunately, require coma correctors and expensive eyepieces.

Plus, the obstruction percentage of the secondary grows as the aperture shrinks.  My 6" f/5 had a 33% secondary.

As I see it, 6" though 10" f/4 newtonians are imaging scopes, not visual ones.

[25585]

If used visually, those inexpensive f/4 newtonians will, unfortunately, require coma correctors and expensive eyepieces.
Plus, the obstruction percentage of the secondary grows as the aperture shrinks.  My 6" f/5 had a 33% secondary.
As I see it, 6" though 10" f/4 newtonians are imaging scopes, not visual ones.

So does the % of CO start to decrease from 12" aperture, and is that enough, or is 14" or 16" a better CO%:aperture better yet? Many 16" commercial Dobs are F4 to F4.5. Larger secondaries do provide fuller illumination, maybe slightly more forgiving collimation as well?
 
Your 16" having both shorter FL than your 12" as well as more aperture seems paradoxical, or specialist maybe, in a way, as exit pupil is boosted from two different aspects. I wonder how many others have upsized aperture and downsized FL in one scope as you have. 

Edited by 25585, 14 May 2025 - 04:36 PM.

[Starman1]

Keep the scope f/4 and use commercially available secondary sizes:

A 6" aperture will have a 43.3% secondary to keep edge illumination to 70%

A 12" aperture will have a 21.7% secondary

A 16" will have a 19.4% secondary

A 20" will have a 17.5% secondary

A 28" will have a 16.1% secondary

etc.

 

My 12.5" f/5 had a secondary of 20.8%

My 16" f/3.75 has a secondary of 21.9%

If I got a 20" with approximately the same focal length, the f/ratio would be f/3.1 and the secondary would be 22.5%

The secondary size does creep up if keeping the focal length the same as you increase size, but not by great amounts.

Short focal ratios make sense with large scopes, but not with small ones.

[saemark30]

Would you still recommend Morpheus now that Nagler T7 series are out?

SImilar eyepiece relief but slightly wider field and Japanese glass with excellent polish.

[rgk901]

Would you still recommend Morpheus now that Nagler T7 series are out?
SImilar eyepiece relief but slightly wider field and Japanese glass with excellent polish.

I'd think that would be a financial decision.

[Neanderthal]

I'd think that would be a financial decision.

For me, there's more to it than that, for example I am not a fan of adjustable eyecups - too much hassle when switching between eyeglass/non-eyeglass wearers. There are other reasons I won't get into but that's a biggy for me.

[Starman1]

Would you still recommend Morpheus now that Nagler T7 series are out?

SImilar eyepiece relief but slightly wider field and Japanese glass with excellent polish.

T7s are almost twice the cost, 1.8x the weight, made in Japan, have a slightly wider apparent field, work down to shorter f/ratios, and have infinitely-adjustable eyecups.  4 focal lengths (so far)--two 2", two 1.25".

Morpheus are cheaper, lighter, made in China, have a slightly narrower apparent field, work down to f/4, have 4 different heights for the eyecups.  6 focal lengths, all 1.25".

 

I think we may be comparing apples and oranges here, and I like both.

[rgk901]

t7 are 3x cost if considering used morphs too

Edited by rgk901, 19 May 2025 - 11:13 AM.

[Procyon]

Would you still recommend Morpheus now that Nagler T7 series are out?

SImilar eyepiece relief but slightly wider field and Japanese glass with excellent polish.

Only one way to find out. Get both and spend a few nights out with them. It'll cost you a bit for shipping, resale, etc but I've always found that was best way to really find out. Worst way is to get the Morpheus than have the T7 in your thoughts when you go to sleep lol. Especially if you find some picky thing about the M for some reason. Your thought of is this worth 2-3x more will be much clearer as you 're switching between eyepieces in front of the scope, trying it on various objects. But my view is that of an eyepiece junkie a bit, I'm sure 95% of the people who get a Morpheus will be more than happy about it. I'd be too, great eyepieces.

Edited by Procyon, 19 May 2025 - 01:34 PM.

[25585]

Would you still recommend Morpheus now that Nagler T7 series are out?

SImilar eyepiece relief but slightly wider field and Japanese glass with excellent polish.

 

Morpheus have easy eye placement. Delos and T4s I find not so easy there, as a glasses wearer. 

[HellsKitchen]

Just came in from viewing the last quarter moon with my 130mm newt and 4.5mm Morpheus. This was 1st light for the 4.5mm, and I hate to say it but am not impressed with the scatter control. 

 

While the image itself was sharp and pure, very nice infact, there is a lot of glare when panning away from the moon. Even when it's 3* away from the fov, glare appears. Some of this is probably the moonlight reflecting off inside the ota and the unblackened edge of the secondary mirror, but overall, not pretty. The limb of the moon also had green fringing near the edge of the FOV. Quite a bit of kidney beaning too, but I have to add the M43 extension to get better eye placement, and being 4am I was a bit fatigued.

 

Looking through the bottom of the EP at a light, there's lots of bright concentric rings.

 

I had a 3mm Delite with me aswell, and that eyepiece showed far less scatter. Was a night and day difference. I will have to compare to mynother Morpheus, Delites and  Pentax XW, and try another scope aswell.

 

But yeah, this isn't going to be a lunar eyepiece.

Edited by HellsKitchen, 19 May 2025 - 04:23 PM.

[Starman1]

That's my opinion too, The shorter focal lengths of Morpheus aren't great lunar eyepieces.

I use a 7XWA, 6 Ethos, and 3.7mm Ethos for that.

Planets are less of a problem.

[JoeBlow]

The 4.5mm is super sharp and contrasty on planets. But scatter is noticeably worse compared to other premium eyepieces.

[HellsKitchen]

I took a look at Saturn too with the 4.5mm in the 130 newt. It actually looked real sharp in steady moments. The thin ring was easy to trace and so was the thin black shadow across the globe.

 

Tonight I'll compare the 4.5 to my 4 and 5mm Delites and 3.5mm Pentax XW on Sirius to test the internal reflections. I think I'll wait for the moon to move into the evening sky, waking up at 4am on work mornings is no bueno. 

 

I feel that its strength will be on the deep sky. I know I am very fond of the 12.5 and 17.5 for that purpose.

 

For Lunar I'll have my Delites. I would like to try a Delos and have yet to try my 3.5mm Pentax. 

Edited by HellsKitchen, 19 May 2025 - 07:19 PM.

[25585]

I am not a lunar or planetary observer, but find my Pentax eyepieces do well on the Moon.

[rgk901]

there is a small spot within the exit pupil where majority of the glare goes away...but it's a small spot and you have to hunt for it.

I will, one day, take it apart and airbrush some Musou black all over the inners and see what happens.

Edited by rgk901, 20 May 2025 - 07:09 AM.

[JoeBlow]

I am not a lunar or planetary observer, but find my Pentax eyepieces do well on the Moon.

I've noticed the same.

[HellsKitchen]

Just came back inside from comparing my 4.5, 6.5, 9mm Morpheus, 5mm Delite and 3.5mm Pentax XW on the moon. Using the 130mm F/5 newt. 

 

The 6.5 and 9 Morpheus felt like an extension of the excellent 12.5 and 17.5. The 4.5, however, seems to be a different animal. It's not as comfortable to use as the rest of the line. Eye placement is more difficult, I get kidney beaning, and it also has obvious EFOB compared to the other Morpheus and also the Delite and XW. All the Morpheus had significantly more scatter than either the Delite and XW when moving the moon just outside the FOV, and even when a part of the moon is in the FOV, there is scatter present which was distracting. Where the 6.5 and 9 differ though is the comfort, they just "fit" my eye, I could hold the exit pupil, and there was no EFOB or kidney beaning. They feel like a natural extension to the 12.5 and 17.5, whereas the 4.5 is something else entirely. 

 

The Delite and XW have much better scatter control. The XW had just the most minimal glow as the moon was moved outside the FOV. The Delite had essentially none. Like the 6.5 and 9 Morpheus, I found both the Delite and XW much more comfortable than the 4.5 Morpheus once I got the eyecup dialed in.  All eyepieces had the green and blue fringing when moving the lunar limb to the edge of the FOV. 

 

That being said, the 4.5 Morpheus IS sharp and has a nice neutral tone. The colours were pure and crisp. Shadows nice and black. Good resolution of tiny features. The Delite I feel is still a tad more crisp, but, the difference really is small. 

 

Even if you've never used a particular eyepiece before, the first time you use it, you just "know" if it's going to be a keeper or not. I did not get that same feeling from the 4.5 Morpheus as I did from the others. I would like to try a Delos...

Edited by HellsKitchen, 20 May 2025 - 04:17 PM.

[JoeBlow]

Were the comparisons only made on the moon? I don't have issues with eye placement on the 4.5mm Morpheus when viewing planets and DSOs. I do sometimes see EOFB, enough to be kinda distracting, but other times not.

[HellsKitchen]

Were the comparisons only made on the moon? I don't have issues with eye placement on the 4.5mm Morpheus when viewing planets and DSOs. I do sometimes see EOFB, enough to be kinda distracting, but other times not.

 

Yeah. The EOFB I consider significant, I mean it really stood out compared to the others. So did the Kidney beaning. I'll try it on some DSOs with the M43 adapter, but as it is, this eyepiece is not likely to see a permanent home in my case. 

[rgk901]

Yeah. The EOFB I consider significant, I mean it really stood out compared to the others. So did the Kidney beaning. I'll try it on some DSOs with the M43 adapter, but as it is, this eyepiece is not likely to see a permanent home in my case.

the brightening was seen on the moon?

I too see it sometimes but don't ever remember seeing it while that flashlight is illuminating the view, that be pretty bad for sure
..interesting

Edited by rgk901, 21 May 2025 - 10:33 AM.

[TayM57]

I thought the 4.5 Morpheus was actually excellent on the moon, owing to its sharpness. 

 

A Televue Delite 5mm would probably be better due to better scatter control, but it is also much narrower. 

 

No such thing as a free lunch it seems. 

[HellsKitchen]

the brightening was seen on the moon?

I too see it sometimes but don't ever remember seeing it while that flashlight is illuminating the view, that be pretty bad for sure
..interesting

 

 

No, it wasn't on the moon. I had it panned well away.

 

 

 

I thought the 4.5 Morpheus was actually excellent on the moon, owing to its sharpness. 

 

A Televue Delite 5mm would probably be better due to better scatter control, but it is also much narrower. 

 

No such thing as a free lunch it seems. 

 

It's sharp alright, it really is, with a nice neutral tone too.  However the scatter control in the Delite is superior, it's legitimately a night and day difference.  I've been put off the 4.5mm Morpheus , so I'll be looking elsewhere for this focal length. Perhaps a Delos will be closest to what I'm looking for. It'll have to be second hand though.

Edited by HellsKitchen, 21 May 2025 - 02:41 PM.

[25585]

I have two 9mm Morpheus, and when not binoviewing with both, use one in a 2x Barlow, instead of the 4.5mm, much comfier.