Baader Morpheus range - General chat

[Louis D]

4 hours ago, Barry-W-Fenner said:

Well after a look around I have just managed to get an M48 2" 20mm spacer ordered from Fleebay, Coming from China for £3.67...

I look forward to its arrival and trying out the CC & Morpheus combo!

Baz

Well, for that price it's worth trying out.  I think I paid about $25 for my 25mm spacer ring, so about a buck a millimeter.  Adapter rings and spacer rings are probably the most overpriced astro gear there is.

You can always pull an eyepiece up out of the eyepiece holder and retighten it to see if the additional spacing improves coma correction with a too short spacer ring.  You can't push an eyepiece further into the holder with too long of a spacer ring, so there is that advantage to the 20mm ring.

[Barry-W-Fenner]

Out of interest, what is the preferred mode to use these EP's in? 1.25 or 2"? Is there any advantages to using the morphs in  2"  mode.

I tend to use mine in 1.25 via the 2" to 1.25" click lock. However I Have considered
taking this out and just just my 2" click lock. With the 20mm spacer ring I Have just ordered I assume I should be able to achieve
focus OK in 2" mode. 🤔

[Barry-W-Fenner]

4 hours ago, Louis D said:

Well, for that price it's worth trying out.  I think I paid about $25 for my 25mm spacer ring, so about a buck a millimeter.  Adapter rings and spacer rings are probably the most overpriced astro gear there is.

You can always pull an eyepiece up out of the eyepiece holder and retighten it to see if the additional spacing improves coma correction with a too short spacer ring.  You can't push an eyepiece further into the holder with too long of a spacer ring, so there is that advantage to the 20mm ring.

Yeah this is true, I could pull the EP up slightly. Or the Chinabay seller had 3mm and 5mm rings for a couple of quid, I could pick one of them up 👍

[Louis D]

48 minutes ago, Barry-W-Fenner said:

Out of interest, what is the preferred mode to use these EP's in? 1.25 or 2"? Is there any advantages to using the morphs in  2"  mode.

I tend to use mine in 1.25 via the 2" to 1.25" click lock. However I Have considered
taking this out and just just my 2" click lock. With the 20mm spacer ring I Have just ordered I assume I should be able to achieve
focus OK in 2" mode. 🤔

When used in 1.25" mode, they're mostly parfocal with Pentax XL/XW, AstroTech AF70, ES eyepieces, and many others that focus at or very close to the shoulder of the eyepiece.  Using the 2" mode would require racking the focuser outward to compensate and would also result in poorer coma correction with the GSO CC.

[Don Pensack]

On 17/08/2021 at 19:03, Louis D said:

I will agree to disagree with Don on the spacer length again.  I use a 25mm spacer to good effect with my range of eyepieces.  Most focus within 5mm of their shoulder and I get 95%+ of the coma corrected out without messing with the spacing on most of my eyepieces.  As I stated above, my 12mm NT4 is the only one needing parfocalization because it focuses 20mm from its 2" shoulder.  That's just too far off to work well with the GSO CC.  The uncorrected coma is intrusive without parfocalization.

Different eyepieces focus at different points.  I've had sets of eyepieces that focused 1.2-1.4" apart at times.

They will focus that far apart in a coma corrector too.

It's why I suggested parfocalizing your eyepieces with the in-most focusing eyepiece, since that one has its focal plane the farthest from the bottom of the eyepiece

and needs to be closer to the CC lens.

How close is that?  It would depend on how far in the eyepiece focuses.

The size of the spacer in the GSO Coma Corrector that would be added would depend on how much infocusing that eyepiece needed, and whether or not you wanted that eyepiece

to focus the CC + eyepiece ensemble perfectly when sitting in the CC without any parfocalizing ring.

The key is to achieve the correct placement of the CC in the light cone of the scope and that will be done when the focal plane of the eyepiece is the working distance from the CC lens.

I described a method for determining what that spacer length should be in my previous post.  It could be short, or, as in your case, it could be longer.

With a few eyepieces, that spacer might be quite short or even removed.  I have had eyepieces with focal planes 0.5" to 0.7" above their shoulders that required a lot of infocusing.

 

[jetstream]

I  use the Paracorr II that will work with just about any eyepiece regardless of focus position.Had a great chat with senior Mr Nagler years ago who told me how to do it and I developed a lot of respect for him and Televue out of that conversation.

I also went down the path some are considering and figuring out, in this thread- and thankfully I saved up for the PCII and purchased one.

[Louis D]

5 hours ago, jetstream said:

I  use the Paracorr II that will work with just about any eyepiece regardless of focus position.Had a great chat with senior Mr Nagler years ago who told me how to do it and I developed a lot of respect for him and Televue out of that conversation.

I also went down the path some are considering and figuring out, in this thread- and thankfully I saved up for the PCII and purchased one.

Do you have any issues with vignetting of some 2" eyepieces in your PCII?  I've read some reports that certain eyepieces don't play well with it.

[jetstream]

25 minutes ago, Louis D said:

Do you have any issues with vignetting of some 2" eyepieces in your PCII?  I've read some reports that certain eyepieces don't play well with it.

I'm not sure really- Im usually too busy checking objects out to think about this stuff. I can check the 42mm LVW and 30ES 82 at some point- thing is I dont use these in my dobs, I have, but just playing around with the exit pupil thing.

I really like the PCII.

[Don Pensack]

With some people reporting vignetting on the 17mm Ethos in the P-II, I looked for it.

It certainly wasn't severe if it is there at all.  I'm not as sensitive to vignetting, I guess, as some people, since I regularly used a 41mm Panoptic in an 8" SCT

and eyepieces that yielded up to 1.3° at f/5.5 in the same scope.

I didn't find either the 17 Ethos or 21 Ethos had notable vignetting.

Currently, my largest field diameter eyepiece has almost exactly the same field diameter as the 21mm Ethos, and I see no vignetting in that eyepiece.

That would not carry over to a larger field diameter such as those in the 31mm Nagler, 30x82ES, 41mm Panoptic, 40x68 ES, 35mm Panoptic, 34x68 ES, 36mm Hyperion.,

all of which have larger field diameters.

[jetstream]

5 hours ago, Don Pensack said:

I didn't find either the 17 Ethos or 21 Ethos had notable vignetting.

I see no vignetting in the 17E or 21E to my eyes using the PCII.

[badhex]

Thanks to almost 100% cloud cover on almost 100% of the days since my Morpheus 4.5mm arrived, I have not had chance to play properly with it yet. I did set up in the day in my ZS73 briefly and found that eye position was a bit tricky - getting blackouts when moving around. I do not really experience this with the 5mm BST in daytime which only has a 0.09mm larger exit pupil.

I suspect my pupils were constricted a lot due to daylight and I need to play with the eyecup and eyecup extension (I need the extension on the 17.5mm to get the correct eye position) but I guess I'll need to wait to use it at nighttime for best effect. 

[Barry-W-Fenner]

On 21/08/2021 at 11:40, badhex said:

Thanks to almost 100% cloud cover on almost 100% of the days since my Morpheus 4.5mm arrived, I have not had chance to play properly with it yet. I did set up in the day in my ZS73 briefly and found that eye position was a bit tricky - getting blackouts when moving around. I do not really experience this with the 5mm BST in daytime which only has a 0.09mm larger exit pupil.

I suspect my pupils were constricted a lot due to daylight and I need to play with the eyecup and eyecup extension (I need the extension on the 17.5mm to get the correct eye position) but I guess I'll need to wait to use it at nighttime for best effect. 

Lets hope you can try this EP out soon under a clear dark sky, The 6.5 & 4.5 are both definitely where the eye position are a bit more fiddly in my opinion, Especially the 6.5 for some reason. 

[Barry-W-Fenner]

Any updates for the folks that have recently purchased a new morpheus? Have you had time to test yet, would be interested to hear thoughts, particularly on the 12.5.

My coma corrector arrived, however the extension ring hasn't yet.  Looking forward to giving it ago.

Fitted some nice handles to the 300p tube while the sky has been cloudy..

[Sargares]

@Barry-W-Fenner I’ve had a good bit of use the last week with the morphs I have in the 250p. Really enjoying them a lot. I’m also really really enjoying the APM 30mm uff which is very flat and crisp right to the edge although does seem to have less eye relief than the Morpheus and you do notice the 8 degrees or whatever it is less field of view. 
 

the Morpheus do seem to go off very slightly at the edges. The 9 seems slightly better than the 17.5. But it’s really the very very edges. 95% of the field of view is perfect. They’re contrasty, comfortable and easy to use. They’re not parfocal but it’s close. Will have more info when I grab the 6.5 and 12.5 in a few weeks.

[Louis D]

I've measured the Morpheus 9mm to have a 78° AFOV both via projection and image photography.  The 14mm comes in at 77°, and the 30mm APM UFF comes in at 72°.

Usable eye relief was measured to be 20mm, 18mm, and 16mm for the three, respectively.

Your observations about AFOV and ER match up pretty well with my measurements.

[Don Pensack]

Ernest Maratovich (apologize if name spelled wrong) has measured the Morpheus at:

http://astro-talks.ru/forum/viewtopic.php?f=32&t=1483#p41976

4.5mm--78°

6.5mm--79°

9mm--78°

12.5mm--78°

14mm--78°

Within the margin of error, that matches Louis' figures.

The weakest one at the edge at f/10 is the 12.5mm and 14mm, but, based on his figures, essentially perfect.

At f/4, the14mm is worst.

in my coma-corrected 12.5" f/5.75 (the CC-corrected f/ratio), even the 14mm is pinpoint at the edge and a star stays point-like past the field stop.

I've used these in scopes from f/3.45 (CC-corrected) to f/8 (refractor) and would say their "critical f/ratio" is about f/4.5 and that they are not well corrected below that f/ratio.

So the f/4 figures don't indicate flaws in the eyepieces, merely their use at too short an f/ratio for the design.

In other words, not the best design for the ultra-fast scope.

 

As for effective eye relief, the eyepieces in question are all usable by me with glasses on.

If wearing glasses, what do I have to do to see the field edge? 

These are all just compared on my 4" apo on a distant land target:

17.5mm Morph--glasses 2mm away from rubber,   MFR eye relief 23mm, maybe 20mm effective

14mm Morph--glasses touching rubber, pressure light , MFR eye relief 18.5mm, maybe 17.5mm effective (pressure compresses the eyecup)

12.5mm Morph--glasses just touching rubber, no pressure, MFR eye relief 20mm, maybe 18mm effective

30mm APM--glasses just touching rubber, no pressure,  MFR eye relief 22mm, maybe 18mm effective (top lens recessed a couple mm)

22mm Nagler T4--glasses touching rubber, pressure moderate,  MFR eye relief 19mm, maybe 17mm effective

20mm Pentax XW--glasses touching rubber, pressure moderate,  MFR eye relief 20mm, maybe 17mm effective

 

It took me a while to realize exactly how much eye relief I actually needed to see the entire field of view in an eyepiece with glasses on.

And, I suspect like many glasses wearers, I don't really need 20mm of "effective" eye relief--17 to 18mm will do.

The only figure where I disagree with Louis is the eye relief of the 30mm APM.  I couldn't see the entire field at 16mm effective eye relief, yet it's easy to do so.

 

Hope those impressions help someone looking for a long eye relief eyepiece.  I should note I have fairly deep-set eyes and the distance my glasses are from my eye exceeds

the width of my little finger, so those whose glasses sit closer to the eye might find all of those eyepieces to have even more eye relief than I found.

 

 

 

 

[jetstream]

5 minutes ago, Don Pensack said:

Ernest Maratovich (apologize if name spelled wrong) has measured the Morpheus at:

Excellent reference Don, love that chart, thanks

[vlaiv]

18 minutes ago, Don Pensack said:

Ernest Maratovich (apologize if name spelled wrong) has measured the Morpheus at:

Would you care to comment apparent issues with those results?

To quote parts of that post that are important:

Quote

in columns F4 and F10 - sizes of evaluated/measured aberration sport in angular minute; F4 - in condition of "fast" 1:4 optics; F10 - in conditions of "slow" 1:10 optics. My experience shows that if aberration spot is less then 10 angular minutes - quality of image could be evaluated as perfect.

For comparison - naked eye moon is 30 arc minutes. Average person can't resolve below 1 arc minute.

How does one see image as being perfect if spot is less than 10 angular minutes? That is say 9 minutes of arc, or about 1/3rd of the full moon. That is considerable dot and not pin point star. Star needs to be 1-2 minutes of arc in size so that we say it is point like.

Some of results are shown as 60+ minutes of arc in that table - that is 1° or more. That is one's fingernail width at arms length or size of Jupiter at x80 magnification. I would be seriously surprised to see star that big in any eyepiece.

If we assume that there is error in units for some reason and that we are talking about arc seconds instead of arc minutes - well, again things don't add up as most of spot diagrams would be up to 1 minute of arc or just above that - and that is point like so all eyepieces would be essentially perfect.

[globular]

I think his arc minutes are relative the the eyepiece AFOV, not the TFOV you'd get when used in a telescope. 
So to convert to the language you are using you have to divide his figures by the magnification you'd get by putting the EP in your telescope.

Or as he puts it:
"Note : I hope it's clear that in order to determine how these aberration spots will affect the resolution of the telescope, you need to multiply the spot size by 60 (converted to arc seconds) and divided by the magnification given by the eyepiece in the telescope. For example, an aberration spot with a diameter of 20 ang. minutes when transferred to objects of observation in a telescope with a magnification of 100x will smear stars up to a diameter of 20 * 60/100 = 12 arc. seconds"

These numbers still seem quite large.  I think he tries to address this in a further note:
"Note that the real resolution of the eyepieces can be noticeably better than these numbers, since the resolution is influenced not so much by the total size of the aberration spot, how much energy distribution is in it. If there is a sharp peak in brightness in the aberration spot (this is especially typical for spherical aberration and coma), and the aberration halo is dim, then the resolution can be three to four times better than the full spot size."

When I first saw this table a year or so ago I didn't really take the numbers on face value.... but figured someone measuring using the same technique across different EPs should result in a useful guide to the relative quality of the different EPs.

Edited August 29, 2021 by globular

[vlaiv]

9 minutes ago, globular said:

I think his arc minutes are relative the the eyepiece AFOV, not the TFOV you'd get when used in a telescope. 
So to convert to the language you are using you have to divide his figures by the magnification you'd get by putting the EP in your telescope.

Or as he puts it:
"Note : I hope it's clear that in order to determine how these aberration spots will affect the resolution of the telescope, you need to multiply the spot size by 60 (converted to arc seconds) and divided by the magnification given by the eyepiece in the telescope. For example, an aberration spot with a diameter of 20 ang. minutes when transferred to objects of observation in a telescope with a magnification of 100x will smear stars up to a diameter of 20 * 60/100 = 12 arc. seconds"

I'm talking about AFOV and not TFOV.

AFOV is what we see with our own eyes irrespective of telescope and magnification used.

Moon is 30' in size when we view it with naked eye (no magnification). You can clearly resolve features on the moon and moon is quite "big" in the sky - far away from anything resembling point source.

If I were to see 1° "star" at the edge of the field - I would be very surprised. That is twice diameter of full moon in the sky.

Here is simple experiment for you - take five pence and put it 1m away from you. Look at the size of it.

According to above linked table - that is the size of star at the edge of FOV in Baader Hyperion Zoom at 16mm in F/4 scope. Can you see that being true or would you say that such assessment is somehow flawed?

 

 

[globular]

I agree with you @vlaiv:
 

37 minutes ago, globular said:

When I first saw this table a year or so ago I didn't really take the numbers on face value.... but figured someone measuring using the same technique across different EPs should result in a useful guide to the relative quality of the different EPs.

I was just pointing out the notes he made to accompany the table in case you hadn't seen them.

[vlaiv]

@globular

Do you know how are these values measured in the table?

I think I know fairly simple method for measuring same thing. It does involve quite a bit of gear to be used - but it's not expensive and most astrophotographers should already have some or all of it.

1. One artificial star

2. Camera and fast sharp relatively long FL lens. Many people have Samyang 135 - but any other lens that is sharp at say F/4-F/8 in similar FL will do.

I borrowed the idea from @Louis D who did wonderful set of comparison photos thru the eyepiece. Only difference is that I would advocate using large lens instead of phone camera because phone camera can act as aperture stop and reduce aberrations created by eyepiece.

That way one can actually take a photo of star in center, mid field and at the edge of different EP / Scope combinations and post these instead of numbers. That way we can actually see what the star image looks like.

[globular]

No, @vlaiv I don't know.  Hopefully Don will be back with an answer.

I would hope, however, that they were done on the eyepiece alone.  As soon as you do something like your idea then you are measuring both the EP and the lens (and the camera).  But with only the EP changing between each tests it would give a nice relative performance. (And wouldn't be far off absolute performance I'm sure).

I like your idea though... you should do it.  Just need someone with a huge EP collection to collaborate with 😉

[vlaiv]

2 minutes ago, globular said:

As soon as you do something like your idea then you are measuring both the EP and the lens (and the camera).

Indeed - both scope and lens will contribute, but these can be minimized with careful selection. Long focal length is the key for lens and large aperture for telescope.

Long focal length of lens means that lens aberrations will be small compared to eyepiece aberrations, and large aperture of telescope will make airy pattern small compared to eyepiece aberrations.

[Louis D]

I believe Ernest uses a telescope with micrometer eyepiece to look into the exit pupil of the eyepiece to measure the aberration spot sizes.

I also believe he always uses the center of the lens and moves the eyepiece across its central axis to take measurements so lens edge aberrations do not figure into the equation.