My first real telescope (other than the toy store junk) was
a 4.1/2 inch 900 mm Japanese Newtonian with a solid equatorial mount on a
wooden tripod. I had with it 3 eyepieces, a 20 mm, 10 and 5 mm plossls. The
image at 180x with the 5 mm was decent but beginning to disintegrate. Never
the less I used that scope for 6 years almost every night even if it was for
a minute or two, from 12 years of age till I was 18 when I left for college.
For a small country like the United Arab Emirates, that was significant enough
that I was featured in the daily newspaper as the 13 year-old amateur astronomer.
Now, I am 33 years old and the point I am trying to make is that I am not
so experienced with telescopes, but I do have a decent observing experience.
Living in the US for a decade, I got to learn more about the
amateur astronomy movement and got to see the stars through a few other telescopes,
mainly 8-10 inch SCT’s a 6 inch dob a 6 inch ED apo, and a 12 inch observatory
class Newtonian in Waukesha Wisocnsin. Always wanting to buy a telescope for
myself, I never had the time to do it. Then in Year 2000 I went back home
to the UAE.
After working in US for a decade, I caught the American DIY
fever and I decided I want to build my own scope. I couldn’t sleep well
thinking of buying a commercial SCT with random optical quality. I was also
on the list for an astro-physics 130EDF but I lost hope of ever getting it
(now 4 years, and I am still waiting)
With the relocation came a budgetary strain not to mention horrific
shipping costs, all of which motivated me even more to build my own scope.
I decided that it will be an 8 inch dob (to start small and easy) and decided
that it will be collapsible like the Teleports. I got suggestions from Tom
Noe on how to mount the bogen struts, the spandex shroud and other things.
His comments were very helpful. Then I contacted Mr. Carl Zambuto asking him
to recommend me a good mirror maker (knowing well that he wasn’t into
the ATM scene), and he recommended: Robert Royce, Larry Hardin and Mike Spooner.
John Hall of Pegasus wasn’t making anything below 12 inches at the time
(now they do), so I decided to go with Mr. Royce simply because the amount
of information on his web site was excellent, and portrayed good customer
orientation and technical know how.
The mirror was shipped on schedule, but took a while due to
postal logistics between US and UAE. If I was in the US I would have received
it within a couple of weeks. Mr Royce was very kind to help me consolidate
a few items (buying online and shipping it to him) which saved a bundle in
shipping costs. Royce stated that all his mirrors have a strehl ratio above
0.96. Sounds good but I didn’t think I had the experience to judge on
I spent a month designing the scope then about 2 months building
it (in my one bedroom apartment, with a circular saw, router and drill, you
can imagine the mess I made). Everything went according to plans, except that
I was failing to build a light enough secondary cage like the ones on the
teleports, so I decided to go easy and simplify the design (make a bigger
more solid cage that doesn’t fully collapse into the scope) till I get
better equipment Also I got the Kine Optics 2-inch helical crayford focuser
which was not small but very light. The result is the R2D2 looking scope you
see in the picture. The ground board is small to smooth the motion but the
feet are extendable to provide stability.
Its compact enough to fit in the front passenger seat and solid
enough to hold collimation within good tolerances (about half the diameter
of the paper reinforcement ring marking the center of the mirror (thanks to
Tom Noe for his advice. He uses machined duralin inserts for the struts, but
I made mine from pc-7 filler cast in a plastic tube, then tapped). I mounted
the mirror as per RF Royce’s recommendation (with no clips), but added
a nylon thread attached to a small washer which in turn is silicon glued to
the back center of the mirror to prevent accidental falling of the mirror.
I also used Alan Adler’s cooling technique using a fan blowing air across
the face of the mirror (I use 2 fans) and also used AC filter pads to prevent
dust from settling inside the scope. Teflon on laminate was used for the azimuth
bearings and Teflon on Velcro (tip from Rick Singmaster) for the altitude.
The secondary was a straight 4-vain protostar. I also had the awesome skycommander
and an Orion red dot finder. The total weight of the my R2D2 was 25 lbs (with
12mm ply), which is a bit heavier than what I hoped for, but not bad.
After precise collimation with a Techtron set. it was time for
first light. My eyepiece set consists of: 2” 40 mm Koenig (not the MK/70),
25 mm televue plossl, 9 mm UO ortho, 7 mm Nagler type 6 a celstron Ultima
2x Barlow and klee barlow (2.8x). The Koenig was light and gave a nice 2 degree
view at 30x. The plossl was incredibly sharp and gave a one degree view at
48x, while the nagler gives half a degree at 171x. The Ultima Barlow pushes
it to 342X. With two and one degrees eyepieces and the orion red dot, I was
able to find anything I wanted under dark skies and rarly used the sky commander
except under light polluted skies.
The half moon was the first light the scope sees, beautiful
and bright, but the seeing wasn’t very good so I couldn’t push
the magnification higher. For a couple of months later I was testing and viewing
different objects but mainly was doing so early evening and was disturbed
by the seeing conditions. Mr. Royce reminded me that the best time was after
midnight, a fact which I have forgotten. So I started observing around midnight
to late morning hours and the experience was Zen like. There were some surprises
to me over the course of the last year, mainly:
The Nagler shows no visual artifacts and is very sharp all
the way. I know the hype about the naglers but didn’t think it was
true to that degree.
The 40 mm Koenig was sharp to about 80% of the field. It
was a good and light eyepiece, but got me confused at the edge. I didn’t
know if I was seeing comatic distortions (at f/6 ?) or eyepiece distortions.
The Teflon on Velcro was working beyond my expectations
(Many thanks to Rick Singmaster); I was hand tracking Saturn at 350x with
the Nagler/Ultima with such grace and ease, it really impressed me. With
the 7mm and klee (478x) tracking is not jerky, but does require that you
are seated comfortably and track carefully. The only reason I would want
a motorized platform is for astrphotos, or public viewing.
I spent years observing the moon with my older scope, but the
8 inch with a 7 mm Nagler left me stunned. With a half degree field, I was
hovering over the moon not looking at it. I spent hours upon hours observing
and pushing the magnification till the maximum my eye pieces were capable
of 940X (NaglerkleeUltima)and with no breakdown whatsoever (except for the
dust). Tracking by hand was messy and I was relying on the moon to drift across
the field (I wouldn’t do it with a planet).
Saturn was at its best with its maximum inclination toward the
earth. The Royce mirror was unbelievable.. The 350x view with the Nagler and
Ultima was the best. During excellent seeing, it was a razor sharp image with
superb contrast. The contrast was so good, I was counting numerous cloud bands,
and razor itched rings. During this year (August 2004) I observed Saturn when
it was low in the horizon (15 deg or so) around 4 am, and was startled to
see it in different coloration (due to atmospheric refraction) There was a
definite bluish tint to it and somehow I was able to see more colorful rings
that when it was high in the sky. The atmosphere was so steady, I had the
best view of Saturn in my life.
I have to improve my drawing skills or photograph it, cause
I can see immense details, Forget about the red spot or cloud belts, I was
seeing clearly turbulence in the cloud belts themselves and numerous white
and black spots. The darker belts swirling into the brighter ones. I think
this is due to a contrast phenomenon (like the Enke division on Saturn) I
never though such features can be viewed with an 8 inch scope. Its also the
first time I see the moons of Jupiter as sharp disks not as points. The Nagler/Ultima
combo was best.
At its closes encounter, and with the 7 mm Nagler, I was looking
at the red planet with detail I have never seen except in pictures. Polar
caps, features and shades upon shades of colors. I saw as much detail as any
hand drawing of mars or any armature taken ccd picture I have seen, though
with lesser contrast than the image processed photos. Somehow I liked the
view in the Nagler alone (171x) than with the Nagler/Ultima (342x)
I never get tired of this object. Now however I can see the
trapezium stars with the 25 mm plossl and filaments upon filaments and detail
like I have never seen. With the Nagler/Ultima, I had no trouble counting
6 stars in the trapezium. With the Konig in a 2 degree field and an O-III
filter, the nebula was scary, reminded me of the Shadow ships on Babylon 5.
The extreme contrast and subtle beauty of this nebulae stands in it own class,
and no printed image can portray the demonic and imposing beauty of this jewel
First time I see the nebulosity around the Pleiades. Under tar-black
skies of course.
M13 and M5:
M13 always appeared to me as a cotton blob in my old 4.5 inch.
Now I was seeing hundreds of separated stars with direct and averted vision.
Stephen James O’Meara mentions (in his “Messier Objects”
book) that a 4 inch apo under dark skies was equivalent to an 8 inch reflector
under suburban skies. With 8 inch first rate optics, ultra dark skies and
averted vision, well… M5 broke down almost entirely into diamond dust
Omega Centari: Yes, from latitude 24 of Dubai I can view it,
a bit low but still at a decent height. What a beast! Cannot count. However,
for some reason I like M5 better, its just more pleasing l than this old monstrosity.
M81: Ok, so I had to go to dark skies to see the arms of this
galaxy. I drove just 1/2 hour south of Dubai (not ultra dark, but the milky
way is clearly visible. we are still lucky here)
M51: The spinning structure is visible from moderately dark
skies, but under Oman skies much clearer and more distinct. Also the connecting
arm is clearly noticeable.
NGC 253: The galaxy in sculptor. A marvel. Very sharp and distinct
texture. But I was under some of the darkest skies on earth (mountains of
Oman 6 hours drive south, 6.5 magnitude I estimate).
M31: Excellent. So much detail but I had to go out of the city
again. Several dust bands can be seen under Oman skies.
M57: Very sharp hole, and a puff of smoke, as you can see the
smokey textured remains of the star.
The double double:
I was splitting this dual pair with my 4 inch newt, so I just
looked at it again. Of course a much cleaner split.
I did have to drive away to see this one, even with an OIII
filter. Once under dark skies, I spent 4 hours gazing into this marvel with
the filter on my 2” 40 mm Konig (2 degree field). The filter does work
with the 2 degree view even in dark skies as it eliminates sky glow. Never
seen anything like it. The detail on the filaments was visible and marvelous.
I never regretted the money on the OIII filter
Over two years I observed from dark skies and suburban skies.
Too numerous to list. I am surprised how many beautiful objects are not listed
in non NGC catalogs. I think it’s time for a new catalog of deep space
gems to be compiled.
I cannot overstate the importance of collimation even in an
f/6 instrument. While auto collimation makes a slight difference, accurate
Cheshire collimation makes a big difference on all objects, planets or seep
space. I also found out that under dark skies (which by the grace of God is
only a 1/2 hour drive away for me), a 2 degree field of view gave me far more
satisfaction than a 1 degree field. The mystical and profound beauty of a
wide field view of the night skies outweighed my desire for high magnification
and detail . I understand now why people like Al Nagler and Stephen James
O’Meara run around with small wide field Apo refractors. I think that
O’Meara’s great deep sky work was just an excuse to get immersed
in the profound beauty of the dark night skies. Why would anyone spend hours
over several nights on M103 except to get ones soul lost in the majesty of
the Cassiopeia star fields. Despite the beauty of the planets, and their ready
availability, they are no match in my humble opinion for the magic of those
ghostly deep space entities.
The Royce mirror is superb. I am glad I took Carl Zambuto’s
advice before deciding on a mirror. I never though an 8 inch can do this.
I saw more detail and contrast than the 12 inch Newtonian in a Wisconsin observatory.
The Robert Royce mirror also showed planetary detail I never though possible.
From dark skies this mirror will keep me busy for a life time I think. I also
have to recognize that no matter how good a mirror is, the execution of the
scope matters a lot. The Newtonian design, though simple is very tricky compared
to refractors. Proper collimation is important even in an f/6 like mine. I
would also rank thermal management as important as collimation. The views
drop down to moderate when I turn the cooling fan off, especially with the
temperature variations of the desert/sea climate in Dubai.
Another problem I faced was dew. It’s very humid in summer
here and dew forms quickly specially with the cooling fans. Using heating
elements alleviate the dew problem but introduce thermal currents that degrade
the image noticeably. But with the fans on, the image is sharp with no dew
forming. Basically, keep the mirror warm and keep blowing off the face boundary
layer. This was a tip from Bryan Greer of Protostar. The combination created
razor sharp images even in the heavy summer dew of the Persian Gulf.
Finally I wish to express my gratitude to the master opticians
and telescope makers who spared no effort in providing me guidance and technical
tips. Special thanks to RF Royce for his assistance, insights and first rate