MONO & BINO VIEWINGWITH THE
BAADER MORPHEUS 17.5MM EYEPIECE
by: William A. Paolini, February 26, 2018

Fig 1: The Baader 17.5mm Morpheus configured with the eye guard extension (left) and with the eye guard removed (right)

1. OVERVIEW
Baader markets their Morpheus line as “high-end” 76° apparent field of view (AFOV) eyepieces
designed for visual / photo / video functions that can exploit the capabilities of the finest telescope
optics. The eyepieces have a optical design that utilizes 8 lenses in 3 groups and includes the useof 3 low dispersion ED elements and 1 Lanthanum element. With the introduction of the 17.5mm,
there are now six eyepieces in the line including 14mm, 12mm, 9mm, 6.5mm, and 4.5mm. All
eyepieces can be used in either 1.25” or 2” focusers without adapters. The Morpheus line touts arather long list of features and comes packaged with multiple accessories. Some of the major
marketed features of the line include:• A sharp flat 76° field of view with low distortion and sharp to edge
• Long eye relief (17.5mm to 23mm depending on focal length)• Phantom™ multi-coatings that are tuned/matched to the glass indexes of each element• Ray-trace optimized internal baffling• Immersive view design (large eye lens, long eye relief, AFOV to match human eye,
comfortable eye placement)• Binoviewer optimized (lighter weight at 12.7-16.1oz; slim with max diameter 55mm)• Photo-visual adaptation features• M43 threaded foldable rubber eye guard with included extension ring
• Slip-Protect Safety-Kerfs on barrels that do not hang like undercuts• Luminescent glow in the dark labeling• Belt carry pouch with tactile focal length indicator clip

The eyepiece come in a fitted box with a variety of accessories including two eye lens dust caps,
one field lens dust cap, screw-on foldable eye guard, optional screw-on winged eye guard, M43
eye guard extension ring, focal length indicator clip, carry belt pouch, and a 10 page manual
showing optional accessories. The manufacturer data sheet with detailed information on
specifications and accessories for the Baader Morpheus eyepiece line can be found online at:https://www.baaderplanetarium.com/en/downloads/dl/file/id/223/product/2851/morpheus_76_eyepiece_series_technical_data.pdf.
Some of the manufacturer specifications for the Morpheus eyepieces are provided in the tablebelow (figure 2). With the AFOV and eye relief (ER) specifications, I have also included direct
measures performed indoors on a test bench. What I look for from these measures is that they are“close” to the published specifications. Do not read more into these measures than that as while
they were done carefully, there is always room for error. Only when they deviate significantly
from the published specifications would there be cause for further investigation (into the measuring
process or with the vendor). As example, in my measures I found all the focal lengths within areasonable margin of error compared to the published specifications except for the 17.5mm
Morpheus which at the time of my testing had a published ER of 19mm. My reading of 24mm
was triple checked and remained the same, so I contacted a vendor regarding the discrepancy.
They contacted the manufacturer and discovered that the published material was incorrect and theeye relief specification has since been corrected.
Focal
Length
(mm)

AFOV
(°)
Listed

4.5

76

6.5

AFOV
(°)

Eye
Relief(mm)
Measure16.7

Elements/Groups

Weight(oz)

Coatings

Barrel(in)

Measure77

Eye
Relief(mm)
Listed
17.5

8/5

16.1

Index Tuned
Phantom™
Multicoatings

1¼ / 2

Field
Stop
Offset
(mm)
0

76

77

18.5

17.5

“

16.1

“

“

0

9

76

77

21.0

21.4

“

16.1

“

“

0

12.5

76

77

20.0

19.8

“

16.1

“

“

0

14

76

77

18.5

18.3

“

12.7

“

“

0

17.5

76

77

23.0

24.0

“

14.6

“

“

+2.5

Fig 2: Manufacturer supplied data and measured data (blue text) for AFOV and ER

NOTE - My previous review of the other focal lengths of the Morpheus line can be found here:
https://www.cloudynights.com/articles/cat/user-reviews/the-baader-planetarium-morpheusr3003.

2. PACKAGING, FEATURES, AND BUILD QUALITY

Fig 3: Items included in the box with the Baader Morpheus eyepieces.

The packaging for this eyepiece is both attractive and informative, including a manual showing
various adapter options for the eyepiece as well as a list of all its major features. I really liked theattention to detail with the contents: supplying two different eye guard options and multiple top
caps to fit the various configurations, and an extension ring to extend the eye guard even higher.
The inclusion of a carry pouch that be attached to a belt is novel and useful for those that may only
use a few eyepieces during an observing session. While the Morpheus line uses a glow-in-thedark graphics for reading of the focal length in the dark, a little indicator clip that has tactile
protrusions you set to indicate focal length is also included for the carry pouch. I thought this new
addition was quite innovative since I am forever forgetting what eyepiece is what focal length
when observing at dark locations. All-in-all the packaging includes many nice additions to theeyepiece, conveying more of a “system” approach to its use and function.
With this newest focal length to the Morpheus line Baader touts an improved the eye guard. The
rubber feels just a little thicker and more importantly, it now screws onto the eyepiece so it stays
in place when folding and unfolding. Additionally there is a supplied extension ring to extend theeye guard further if desired, making the new eye guard approach much more flexible andcompletely stable.
While many, if not most observers prefer the barrels on eyepieces to be smooth, the industry has
for some time provided the barrels with a form of safety feature to help prevent an accidental
slipping of the eyepiece out of the focuser should the observer not properly attach the eyepiece tothe telescope. One such type of safety feature is called the undercut, which has the distain of muchof the observing community. The undercut is generally a cut out indentation in the barrel where
the set screw or compression ring is meant to engage the barrel if they properly align. There have

been several attempts by manufacturers to improve the basic undercut feature, but most I have
tried either fail to resolve the issue of the undercut getting hung when extracting the eyepiece, orthey introduce other issues such as tilting the eyepiece away from a square seating when thecompression ring is tightened. The safety kerfs design that is unique to Baader, appears to
overcome the issues that the standard and modified undercut design introduced. Over the two plus
years that I have been using the Morpheus eyepieces, the design has not shown any propensity forgetting hung when trying to extract them from the focuser. In the field they perform very much
like a smooth barrel, inserting and extracting without issue.
All Morpheus eyepieces also use a housing design that incorporates a dual 2” and 1.25” barrel.
This allows the eyepiece to be used in either size focuser without the need for adapters, so one lessitem to fiddle with in the dark at the telescope. As with all dual barrel designs however, theobserver should always first test that when using the 2” barrel with a diagonal that the 1.25” barrel
does not extend so far into the diagonal as to impact the prism or mirror surface.

Fig 4: Eye lens view with eye guard removed for easy cleaning (left) and field lens view with light baffle (right).

Finally, the overall build quality of the eyepiece itself is very good. It feels good and solid in thehand with excellent fit, finish, and heft. The eyepiece is sealed to help protect the internal elementsfrom moisture and dust. As a consequence of the sealed construction, it is not readily apparent
how they would be disassembled (which is not recommended). Normal hand force will not
unscrew any part of the housing or barrel. The sealed nature is also evident when looking at theeye and field lenses as there are no retaining rings to be seen.
3. OBSERVATIONAL TESTINGLOCATION
Field testing took place over several weeks in a Yellow Zone in rural Virginia where the Sky
Quality Meter readings range between 20.5 to 21.2 mag/arcsec2 on Moonless nights. Outdoor
temperatures during field testing ranged from +13° to +60° F.

PROCESS
All outcomes are recorded at the time of occurrence at the telescope using a voice recorder. Each
performance test is generally replicated three or more times, and in multiple telescopes withmultiple accessories to ensure they are consistent and accurate. When results are compiled if there
are any discrepancies or conflicting test results, then those tests are redone until the root cause of
the initial discrepancy is discovered. Any test related to assessment of perceived contrast,
brightness, background FOV uniformity are only conducted on Moonless nights of darkest skies.
EQUIPMENT
Testing was accomplished in the Takahashi TSA-102 f/8 Super Apochromatic refractor,
Lunt/APM 152 f/8 ED-Apo, Orion XT10 254mm f/4.7 Dobsonian, and a Pentax 65 ED II f/6
spotting scope. Diagonals used were Baader Zeiss 2” Prism, Baader Zeiss 1.25” Prism, Baader
BBHS 2” Silver Mirror diagonal. A Tele Vue 2.5x Powermate was employed when moremagnification was needed and the following eyepieces of similar focal length were used to assesscomparisons in performance: 20mm Pentax XW, 18mm Takahashi LE, 17mm Sterling Plossl.

Fig 5: Size comparison of the Baader 17.5mm Morpheus compared to other eyepieces used in testing.

OBSERVED CELESTIAL OBJECTSA range of different celestial object types were observed to assess the general performance of the
17.5mm Morpheus across multiple object types. Objects observed included, among others:
The Moon
Star: Alnilam
Star: Iota & RX Lep
Star: Bellatrix

Star: Betelgeuse
Star: Sirius
Multiple Star: Alnitak
Multiple Star: HD 39758

Multiple Star: Iota Ori
Multiple Star: Meissa
Multiple Star: Mintaka
Multiple Star: Rigel
Multiple Star: Sigma Ori
Multiple Star: Theta Ori (Trapezium)
Nebula: M42 (Great Orion)
Nebula: M43
Nebula: M78
Nebula: NGC 1973/75/77 (Running Man)
Nebula: NGC 2024 (Flame)
Nebula: NGC 2244 (Rosetta)

Open Cluster: Collinder 70
Open Cluster: M38
Open Cluster: M41
Open Cluster: M45
Open Cluster: M46
Open Cluster: M47
Open Cluster: Melotte 25
Open Cluster: NGC 1981
Open Cluster: NGC 2360 (Caroline's)
Globular Cluster: M79

FIELD OBSERVATIONS

Fig 6: Pair of 17.5mm Morpheus with Baader Zeiss 1.25” prism diagonalin the Takahashi TSA-102 on a Vixen Porta-II Mount.

Typically I run eyepieces through my battery of tests, then when done spend time just observing
with them instead of evaluating. This time around, I decided to reverse the process and instead goout and just observe for a few sessions before I began and formalized testing. I like binoviewing,but mostly only for planetary and lunar observing. I rarely binoview deep sky objects (DSO)
because I do not like the extra hassle of setting up the binoviewer and also because I feel it is ahandicap since many DSO are dim and the binoviewer splits the light beam so only half the lightfrom the object is coming into each eye. Since the TSA is fairly binoviewer friendly, and I wasusing the very short light path of the Zeiss 1.25” prism diagonal, I had no need for the opticalcorrector accessory (OCA) on the binoviewer. Without the 1.6x magnification of the OCA meantI could enjoy the nice low magnification (47x) and full 1.6° true field of view (TFOV) the 17.5mm
Morpheus eyepieces would provide in my TSA.

Fig 7: Messier 42, the Great Orion Nebula with M43 adjacent.
Credits: NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA)
and the Hubble Space Telescope Orion Treasury Project TeamI started the binoviewing excursion with the great Orion Nebula M42 and my initial reaction was
to be completely blown away by the view! More than the entire Sword of Orion, with lots of roomto spare around the Sword, filled the field of view (FOV). Visual contrast came across as superb
and the star points were all perfect across the FOV. But the biggest impression was the contrast.
The nebula itself looked “neon sign” bright, and as bright as it was in all the dark spaces aroundand between the nebula the field remained richly black which added to that neon-like impression
coming from the nebula. The Fish Mouth was nicely defined as well as the dark lane through M43
that to me makes it look like a Pacman eating its way around. The mottled structure of M42 wasquite prominent showing portions of the nebula as a lattice-like structure of dark spaces aroundand through which coursed filaments of bright nebula. Then of course the four burning hot bluestars of the Trapezium glowed iridescently amidst it all, and below, nearer the field stop, little Iota
Orionis with its companion star remained nice and sharp and nicely spilt. Then I shifted my gaze
upward in the FOV to make a brief observation of the nebulosity around the Running Man Nebulaand 42 Orionis. Finally, I moved my gaze to the top of the FOV above the Sword to the open
cluster NGC 1981. I’ve always liked this little grouping of stars, but I never tend to linger there
long observing them. However, with such a comfortable binoview and a nice large patch of TFOV
I ended up staying on NGC 1981 for quite some time -- so much so that I ended up noticing somethings about it that I never did before. One of the new features I saw of this cluster was how justto one side of the main grouping of stars, there is a small gap then another clutch of a few stars.
This extra grouping of stars was quite obvious in this view I was having but I have never notedthat separated little grouping of stars before. It is always fun discovering something new, so I
loitered on this target and really enjoyed the cute little cluster for quite some time.
As I lingered longer and longer, mesmerized by the view, I began to realize just how long I wason the various targets yet was not encountering any eye fatigue. Unlike my typical monoviewing
with one eye squinted closed and the other usually pressed up against an eye guard, this binoview
was completely natural feeling. I was just like normal viewing since the eye relief of the 17.5mm
Morpheus was long enough that with the eye guards folded no part of my face or nose had to comeclose enough to touch any part of the eyepiece. Another interesting thing I noticed was that I was
finding I did not need to move my head positioning over the eyepieces as I scanned the FOV from
center to field stop as I am used to with most wide fields. So in addition to the nice stand off
distance I could use binoviewing with these eyepieces, I could also just shift my gaze to anyplacein the FOV without any blackouts or need to alter my head position, I just had to roll my eyeballs.
Overall, this was the first time that I have really enjoyed extensive binoviewing of DSO!
Next I drove the TSA with binoviewer on up to Orion’s Belt, enjoying the ring of stars that circle
Alnilam, then moving right to Mintaka to observe that wide double, then all the way left to Alnitak
where I was treated to the unexpected in seeing the Flame Nebula for the first time! I’ve never
had a lot of success trying to see this with my smaller aperture scopes but there it was, dim and notquite adverted vision only, but still an easy catch with the binoviewed 17.5mm Morpheus.

Fig 8: The Sigma Orionis multiple star system (STF 762). Graphic by the author.

From there I went up briefly to M78 (not a special object for me), then back down to visit Sigma
Orionis. Oh my! Sigma Orionis is just such a pretty multiple system. I can’t adequately express
just how enchanting this multiple star system appears for me, but it is and I had to stay on station
for quite a while observing and imagining what it must be like to be in the midst of this beautiful
star system. With the TV 2x Barlow three of the four stars of Sigma Orionis were easy to see, andthe dim fourth member was very difficult. Moving from the TV 2x to the TV 2.5x Powermate
made the observation much nicer through the 17.5mm Morpheus and even the dim fourth memberof Sigma Orionis was quite an easy catch in the TSA-102.

Fig 9: Composite color image of Betelgeuse showing its leading bow shock interaction
with the interstellar medium. Credit: ESA/Herschel/PACS/L. Decin et al.

When I was finally able to tear myself away from Sigma Orionis, I moved upward to thegargantuan beast of a star, the red supergiant Betelgeuse. If you have never studied the literatureon this star then I advise you do because some aspects of it are simply mind blowing! First off, it
is absolutely huge, with portions of its atmosphere extending out to almost the orbit of Jupiter if it
was placed in our solar system. Then its shape is not even round and its surface is not even uniformwith multiple hot spots. It is even moving so fast through space that it is travelling faster than thesolar matter it is spewing from its solar winds so that its own star material forms a bow shock wave
in front of it! All I can say is that we are lucky that this beast is not too close to our nice and quiet
little neighborhood of stars. But while thinking of all this observing Betelgeuse, in the same fieldof view you will also see the nice little double HD 39758 and HD 39759 just to the south (WDS05549+0702). This little pair of magnitude 8.7 and 8.9 spectral class A and K stars are dim andoffer quite a juxtaposition next to the giant likes of Betelgeuse. So while not an overly aesthetic
double, given the juxtaposition to Betelgeuse they are a fun observation. From there I went
upward more to NGC 2169 the “37” cluster, then over to Hyades to look at my favorite groupingof six stars of which Theta1 Tauri is a part. These six stars are arranged in three pairs of two, witheach pairing forming the apex of an equilateral triangle. I love the cool asterism these six stars
make and it reminds me of a portal or star gate in space just waiting for incoming or outgoingspacecraft.

Fig 10: Messier 45, the Pleiades Cluster.
Credit: Davide De Martin & the ESA/ESO/NASA Photoshop FITS Liberator.

Finally, to end this very first observing-only outing with the 17.5mm Morpheus in a binoviewer
configuration I slewed over to M45, the Pleiades cluster. These hot and young stars filled the FOV
like gleaming searchlights, shining in all their wondrous glory. This cluster is many times an acidtest for the off-axis of a wide field but for the Morpheus in the TSA-102 was a walk in the parkwith all these big and bright stars keeping their pinpoint nature across the FOV right up to the field
stop. The tight stars across the FOV with this cluster were also replicated in the Pentax f/6 spotting
scope, the 6” f/8 Apo, and the Orion XT10 f/4.7 Dob with Paracorr.
In successive outings of both binoviewing and monoviewing, I revisited all the already mentioned
objects, and observed a number of other quite beautiful stars, multiple stars, a globular cluster, andopen clusters in the adjacent constellations to the north, south, east, and west of Orion. Of these I
think that Caroline’s Cluster (NGC 2362) and M46 deserve special mention. Both of these wereenchantingly beautiful open clusters, especially through the 6” Apo. The memory of the viewcontinues to stay with me they impressed me so. All of these objects and more I observed not onlyin the TSA-102, but also in the Lunt/APM 152 f/8 ED-Apo, and through the Orion XT10 254mm
f/4.7 Dobsonian. As I said, many of these objects remain as pictures in my memory as they werestunningly portrayed though the Morpheus with a level of contrast and transparency that reminded
me of my cherished Pentax 30 XW eyepiece, which is my all-time favorite eyepiece. The views
were so enthralling for me that after each session I could not let it end. Once I stowed all theequipment back in the house, instead of going off to bed I instead immediately went to myInterstellarum Deep Sky Atlas to retrace the nights journeys, cross referencing my Burnham’sCelestial Handbook, the Night Sky Observer’s Guide, and the Atlas of the Messier Objects until
sleep got the better of me. The views got me so charged up each night that I just could not let theadventure end, and it has been too long since I’ve had observing sessions like that.

Fig 11: Orion’s Belt / Collinder 70. Observing the ring of fainter stars around the central Belt star Alnilam is a favorite.
Credit: Davide De Martin & the ESA/ESO/NASA Photoshop FITS Liberator.

Overall, through the course of the field assessment, several impressions stood out. First, the17.5mm Morpheus is exceedingly comfortable to use. The exit pupil is very stable and not once
did I encounter any blackout or kidney beaning. Eye relief was also both long and comfortable,
and flexibly adaptable. There are essentially six different configurations you can use with the eye
guard: 1) no eye guard, 2) standard eye guard unfolded, 3) standard eye guard with M43 extension
ring, 4) winged eye guard, 5) winged eye guard with M43 extension ring, 6) either standard or
winged eye guard folded down. My preference when binoviewing was with the standard eye
guards unfolded. In this configuration I found external light was effectively blocked but I could
still use the eyepieces without much of any contact between my face and the equipment, so
observing was with two eyes and felt very natural.
When monoviewing I preferred either the standard eye guard with the M43 extension ring, orwithout any eye guard. I also discovered that without any eye guard, the long eye relief and slim
housing made the Morpheus 17.5mm behave a lot like the Edmund 28mm RKE where the view
somewhat floats in space. It was a lot of fun to observe this way because unlike the 28 RKE, theexit pupil of the Morpheus is very stable, comfortable, and does not black out. Also unlike theRKE the housing of the Morpheus does not vanish so it is not as dramatic of an effect as with theRKE, but it is close enough and nicely controlled and comfortable. The final general impression
was the contrast and transparency of the view. It was markedly clean, crisp, and transparent, so
the eyepiece seemed to get out of the way when viewing more than most I have experienced –open star clusters and star fields really “popped” as a result and provided me with quite a numberof dramatic views.
OPERATIONAL ASSESSMENTS
I guess all good things must come to an end, so the time eventually came to stop the field
assessments where I just observe like a normally do and log impressions, and move onto the more
discrete testing looking for specific performance items. While I did do some comparisons between
the 17.5mm Morpheus and other eyepieces I had of similar focal length, most of these were notreally in the same league, and the one that was, the 20 XW, had a focal length that was too different
for effective comparison. So these comparisons were just casual in nature as neither the 17mm
Sterling Plossl nor the 18mm Takahashi LE could muster up anywhere near the perceived contrast,
brightness, and edge correction that the Morpheus was delivering. The major take away fromcomparison with the 20 XW was that the 20 XW was no where near as well behaved off-axis as
was the Morpheus showing significantly more field curvature than the Morpheus, and given its
longer focal length and therefore larger exit pupil, showed the less contrasted view since myobserving site does have some level of background sky light pollution given that it is a Yellow
Zone. Another interesting impression I had when comparing the views between the 17.5mm
Morpheus and the 20mm XW was just how much larger the AFOV in 76° vs. 70°. You would notthink the difference would be all that much but each time I moved from the Morpheus to the XW
I got the impression of the FOV being more constrained, even though the TFOVs between the two
eyepieces was fairly close.
FIELD CURVATURE (FC) –Field curvature is more a factor of focal length rather than focal ratio, but does not always
follow that directly if the optics are more complex and include flattening. This was evident
in my tests as while my shortest focal length scope, the Pentax 65ED-II (f/6) with its
390mm focal length showed no FC with the 17.5mm Morpheus, the TSA-102 (f/8) with its
816mm focal length did show a small amount of FC. At first look, give the much shorter
focal length of the Pentax spotter you would expect it to show more FC than the longer
TSA-102. The TSA-102 is a conventional triplet objective and nothing more, however thePentax spotter has additional elements in it which are no doubt are contributing to its flat
field performance (5 elements in 3 groups). The FC exhibited in the TSA-102 could becleaned up with just an either of a turn of the fine focus knob. This small amount of refocus
is consistent with what I have experienced with many other eyepieces in the telescope so
am fairly confident it is probably from the main objective. Moving to the 1200mm focal
length 6” f/8 Apo and Orion XT10 (f/4.7) without Paracorr, neither of these instruments
showed any FC between the center of the FOV and the field stop. With the addition of the
Paracorr to the XT10 however, at the setting where I was able to achieve a complete
elimination of the coma at the field stop, this position left a very minor amount of FC at
the field stop. However, the FC was so minimal that it did not affect double star splits so
Rigel for example, was still tight and nicely split even at the field stop.

LATERAL COLOR –This is one of the easiest aberration to detect, and present in all wide fields I have used. In
the Morpheus I characterize it as minimal. I could just begin to see it on a bright star like
Rigel at about 75% from center. It showed primarily as a small amount of blue fringe on
the side of the star facing towards the center of the FOV through my TSA-102 with Zeiss
1.25” prism diagonal and in the XT10 Dobsonian. When the star was at the field stop, thesmall color fringe about the same but still not objectionable by any means as Rigel stayeda nice split all the way to the field stop. When observing the Moon the limb of the Moon
when it was nearer the field stop would show either a thin blue line off the limb or a thinlime green line off the limb, depending which side of center it was. Again, I felt it was
minimal being neither very bright nor very wide, and at no time did the color extend into
the lunar surface. The lateral color did not seem to get any more pronounced as the focal
ratio of the telescopes became faster, so I estimate it was approximately the same in my
f/8, f/6, or f/4.7 telescopes.

Fig 12: On Dec. 13, 1972, scientist-astronaut Harrison H. Schmitt and the lunar rover of Apollo 17 are shown
amidst the starkly contrasted lunar surface at the Taurus-Littrow landing site. Credit: NASA JSC.

ASTIGMATISM –The 17.5mm Morpheus showed no astigmatism for me in any telescope. So racking abright star point in and out of focus only showed a nice round set of diffraction rings in my
f/8 Apos, my Pentax f/6 65EDII spotting scope, and my Orion XT10 254mm f/4.7 DOb
with or without Paracorr. But this was not the case when I began the testing. When I
started the astigmatism tests things went a little differently and what happened serves as areminder and lesson.

I started my testing with the TSA-102 and did my normal battery of tests, including testing
for astigmatism. At the initial end of testing in the TSA-102, my notes were that there wasa very slight amount of astigmatism in the far outer FOV. I could only detect it whenracking the star in and out of focus, and the diffraction rings would just be very slightly outof round, then altering direction depending if the star was out of focus from out travel orin travel of the focuser. It was not consequential to in-focus star points as they stayed niceand tight, but nonetheless it was there.
When I went on to testing in the XT10 with Paracorr, I was of course expecting to see theastigmatism again but it was not there. However, I did not think that was too odd because
the Paracorr really cleans up some eyepieces. But just to be sure I decided to then try theMorpheus in the XT10 without the Paracorr. I usually don't test without Paracorr because
no eyepiece eliminates the coma and Newtonian coma typically overwhelms all other offaxis aberrations. But my purpose here was to do the test and separate the coma from theastigmatism in the observation, and not to see how poorly the off-axis from a faster
Newtonian mirror always makes the view appear.
When I completed the astigmatism test without the Paracorr, I was very surprised as there
was no off-axis astigmatism to be seen. This was completely unexpected as I saw a minor
amount in the f/8 Apo and now none in a very much faster f/4.7 Dobsonian! I saw lots ofcoma, but zero astigmatism. Now that was of course odd and if anything, I would haveexpected more astigmatism given the Newtonian is so much faster than my Apos. I decided
to let the puzzle be for a while and went on to testing with my 6" f/8 Apo.
When I completed the astigmatism tests I was once more surprised as I was getting perfectstar points right to the field stop in the 152mm f/8 Apo, but I did not get this performancein the 102mm f.8 Apo. I then decided to flip the diagonals and took the diagonal that wason the TSA-102 and put it on the 6" Apo. After doing that, the 6” Apo was now also
showing mild off-axis astigmatism! So it was never the eyepiece generating theastigmatism but was the trusted diagonal I had on my TSA-102.
Taking the diagonal apart, which is a prism diagonal, I discovered there was some contactpressure on the apex of the prism. I relieved this pressure by not screwing the housingback together so tightly as it was originally and put the diagonal back into service as thisresolved the astigmatism. The morale of this story is to never assume something you areseeing is from the eyepiece when testing the eyepiece in a single optical chain, even whenusing trusted components. Before you can reasonably conclude the issue is with theeyepiece, you really do need to be diligent and switch out all components in the optical
chain, and repeating tests using your left and right eyes separately, and if warranted evenasking an observing buddy to repeat the tests as well.
PERCEIVED BRIGHTNESS & CONTRAST –In my opinion, it is not possible to separate brightness from contrast in visual field tests. If
a dim star is adverted vision in one eyepiece, but direct vision in another same focal length
eyepiece, that visual difference can be due to a multitude of factors operating in concert,like mean transfer function (actual instead of perceived contrast), transmission, coatings,
baffling, and perhaps others. So rather than attributing observations to a discrete root cause
criteria, I think it is more effective to just describe the differences of how the targets
appeared and draw no conclusion as to whether it was in fact a contrast difference, or atransmission difference, or some other factor.
In comparing the 17mm Sterling Plossl to the 17.5mm Morpheus, overall I felt the view
was just as bright in both. Faintest stars in clusters were just as visible in either eyepiece,
and the extent of nebula were also just as visible. Where the visual differences showed
was in the character of the background FOV and in the detail and structure of the nebula.
In the Sterling the background FOV was brighter than in the Morpheus. As a result, thedefinition of the edges of nebula was starker and more defined in the Morpheus.
Additionally, the internal mottled structure of M42 and the dust lanes of M43, the Running
Man Nebula and the Flame Nebula were all more discernable in the Morpheus whereas it
looked more milky in the Sterling, and in the Takahashi LE it was just much dimmer
overall.

Fig 13: NGC 2024/Sh2-277, the Flame Nebula, with a cluster of young 200,000 year old stars in the center.
Credit: X-ray: NASA/CXC/PSU/K.Getman, E.Feigelson, M.Kuhn & the MYStIX team; Infrared:NASA/JPL-Caltech

With the Flame Nebula, which was very faint in the 4” Apo scope, its outer boundaries
were exceedingly difficult to discern in the Sterling, and more defined and obvious in theMorpheus. In the 6” Apo, the Flame Nebula with the Morpheus was actually an easy target

and nicely defined both in external extent and internal dust lane. The Takahashi LE did
not compare well at all, comparatively showing a much dimmer view of nebula, less extent
to the nebula, and less defined or detailed.
On Lunar observing, the Morpheus showed features quite stunningly contrasted and also
very dimensional in nature. Adding the 2.5x Powermate to the Morpheus upped the gameand provided a wealth of closer up details that were all distinctly etched. The perceived
brightness and contrast from the views with the Morpheus were quite impressive overall.
Perhaps the best way to characterize this was that no matter whether I was observing andopen cluster, or a nebula, or the Moon, the bottom line impression was that the view was
exceedingly clean, bright, and transparent.
SCATTER –Compared to the 18mm Takahashi LE and the 17mm Sterling Plossl, the 17.5mm
Morpheus showed the least amount of scatter. I used a variety of stars to assess this fromvery bright Sirius, to others such as Bellatrix, Rigel, Iota, and the stars in the Belt of Orion.
Compared to the Sterling the Morpheus showed significantly less extent to the scatter andthe scatter was dimmer. The reduced scatter compared to the Takahashi LE had about thesame extent but was much dimmer overall and uniform whereas in the Takahashi LE thescatter was markedly brighter nearer the star then slowly fell off. My overall impression
was that scatter was as expected from premium-level eyepieces, and scatter wascomparatively very low making observation of dim secondary stars of doubles all theeasier.
FIELD STOP –The region of the FOV near the field stop showed no brightening or dimming. The fieldstop itself showed as distinct, but not as a completely etched line because it showed a slight
blue ring, which I only noticed when observing the Moon. When observing all othertargets, the field stop appeared tightly defined, but not razor blade sharp. As a note, while
my vision is normal, I do need to use reading glasses since I can no longer focus closely,
so this could be contributing to how I see the field stop.
EXIT PUPIL –Finding and maintaining the eye positioning to see the entire AFOV is easy andcomfortable with the 17.5mm Morpheus. At no time during the testing did I encounter any
difficulty, whether monoviewing or binoviewing. At no time did I experience any
blackouts or kidney beans (spherical aberration of the exit pupil) with any combination ofeye guard positionings, even with no eye guard. Overall, the exit pupil behavior was very
comfortable and the eyepiece provided a comfortable experience in field use.

FLARE & GHOSTING –Using very bright objects like Sirius and the Moon, I was unable to generate any unwanted
light artifacts in the 17.5mm Morpheus while the objects were positioned throughout the
FOV, or when they were positioned immediately outside of the FOV. I did not at any time
experience eyeball glint off the top of the eye lens, nor did I experience any reflections
from exterior lights around the observing location when the eye guards were in use.
Overall, the light control features of the 17.5mm Morpheus proved to be effective.
FIELD ERGONOMICS –I encountered no ergonomic issues when using the 17.5mm Morpheus in the field at night.
At no time did the eyepiece become hung on the compression ring in the focuser during
insertion and extraction. Adjusting the eye guard by folding or unfolding it was easy, andeven changing eye guards or adding/removing the M43 extension ring was effortless andintuitive in the dark with the threading/unthreading operating smoothly and effectively.
And when a speck of dust or debris found its way to the eye lens during the evening’s
observing, I found that being able to quickly unscrew the eye guard making it very easy tofield clean the lens with a quick swipe with a lens cloth or lens brush. With the eye guard
in place, as with any eyepiece with a raised eye guard, it can be a struggle getting the debris
off the eye lens then up and out over the eye guard unless you have compressed air handy– and note that one should never blow with their breath to remove any debris as doing so
you are also covering the lens with micro beads of moisture and sometimes larger dropletsthat will dry and leave a stain until properly cleaned.
At my test bench one day I decided to use my 20-50x inspection optic to examine an eyelens after conventional lens brush cleaning vs. using my breath to blow debris off thesurface. At close inspection I was amazed at the number of small droplets that were left
on the lens after blowing on it. Because of this I now never blow dust off my eyepieces in
the field. It is easier to just have a lens brush handy.
FIELD OF VIEW GESTALT –While assessments of individual tests for specific aberrations or performance criteria tell astory, they do not inform you how all the various aberrations and performance criteria work
together to bring you the final image. So this assessment is a general overview ofcharacteristics of the FOV in general. Like most wide field eyepieces I have tested, the17.5mm Morpheus does require accurate eye placement for best rendering of the entire
AFOV. If your eye is not placed accurately over the exit pupil, then far off-axis star points
can show some level of aberrations due to this misplacement of the eye. Therefore,
observing chairs and eye guards are always a wise recommendation for use with long eyerelief eyepieces, especially for novice observers.
Overall, in all my scopes, the general impression of the FOV was that it was accurate andtight. Star points stayed nicely tight, and double stars remained split and well renderedfrom center all the way to adjacent to the field stop. The Morpheus appears to be designed

for neutral FC from the objective as it showed the minor FC that all eyepieces show in my
TSA-102 with its 816mm focal length, and it showed no FC to my eye in my longer 1200
focal length telescopes.
I do have a shorter focal length optic, my Pentax 65ED-II spotting scope, but this spotter
has additional elements in it that are most likely, I would guess, flattening the FOV so theMorpheus 17.5mm showed no FC in that spotting scope. The only off-axis aberration ofnote was some lateral color that is common to most all wide field eyepieces. Aside fromits generally excellent off-axis performance in my f/4.7 through f/8 scopes, the major takeaway for me was the starkness of the FOV. The background FOV showed richly black,even adjacent to bright portions of nebula like M42. Its scatter control also contributed tovery dark backgrounds around stars in rich open clusters. In many respects, I think the best
characterization of the overall FOV the 17.5mm Morpheus rendered was one that was clean
and transparent to the point as to let the equipment get out of the way of the observation.
Focus snap was also very authoritative with the Morpheus, contributing to letting theeyepiece get out of the way from observing.
4. SUMMARY IMPRESSIONS

Fig 14: IRAS 05437+2502, a small, faint nebula in Taurus. Credit: NASA, ESA, Hubble, R. Sahai (JPL)

The latest Baader addition to the Morpheus eyepiece line up comes across to my eye like they
saved the best for last. Operationally there was nothing I could fault with its performance in myscopes, which was a bit of a surprise for me as I tend to have some level of problems with longer
focal length eyepieces. With this latest Morpheus addition, except for some expected minimallateral color it left me with nothing less than a string of highly memorable and often energizing
observations where once completed I felt compelled to continue the adventure indoors
investigating deeper into the objects I had just observed through my atlases and books. Its
strengths include a bright, crisp, transparent, wide, and starkly contrasted FOV, generous eye
relief, comfortable eye positioning, and hassle-free operation in the field. I so enjoyed thiseyepiece that it now completes my core favorite eyepieces to make a very effective minimalist
observing set – 30mm XW, 17.5mm Morpheus, 10mm XW, and 2.5x Tele Vue Powermate forpremium wide field viewing, and 6mm ZAO-II and 5mm XO for critical planetary observing.
Throughout the testing and observing, the 17.5mm Morpheus not only met but also fully exceeded
all my visual observing needs for and eyepiece in this focal length class. The base optics of the
17.5mm are clearly exceptional, offering some of the most transparent and contrasted views I haveseen, and should in my opinion provide a lasting wide field tool for observers for decades to come.
Highly recommended!
~*~

About the Author
William "Bill" Paolini has been actively involved in optics and amateur astronomy for more than 50 years, is authorof the desk reference on astronomical eyepieces: Choosing and Using Astronomical Eyepieces which is part of thePatrick Moore Practical Astronomy Series published by Springer of New York, has published numerous productreviews on major online amateur astronomy boards, and volunteers with public tours at a famous vintage Clark
refractor site.
Bill's professional background is as an officer in the U.S. Air Force and as a computer scientist, holding a Bachelor’s
degree in Computer Science and a Master of Science in Education. He has worked for the U.S. Department of
Defense, the U.S. Department of Commerce / Census Bureau, the Federal Trade Commission, the Federal Reserve,
the World Bank, and a variety of commercial corporations in the information technology, information technology
security, and telecommunications industries.
Bill has been observing as an amateur astronomer since the mid-1960's, grinding mirrors for homemade Newtonian
telescopes during the 1970's and eventually owning, using, and testing several hundreds of eyepieces in a wide
variety of telescopes from achromatic and apochromatic refractors to Newtonian, Maksutov-Cassegrain, andSchmidt-Cassegrain designs. Today he enjoys observing from his rural home southwest of Washington, D.C., where
his primary amateur astronomy pursuits are lunar, planetary, bright nebula, open cluster, globular cluster, and double
star observing.

***This article is placed into the Public Domain by William Paolini 2018; Images © William Paolini 2018.
For permission to use images separate from the full article, contact the author at wapaolini@hotmail.com.