Q. Who are you?
A. My name is Richard Shell, and I teach
business and computer courses at the University of Texas in the Lower
Rio Grande Valley. The weather, climate , and food here are wonderful,
but the night skies are generally depressing for amateur astronomers since
clouds roll in continuously from the Gulf of Mexico. Astronomy and astrophotography
have been hobbies of mine since I was 12 years old. This is a terrible
place to take pictures of stars, but
a great place to make focusers and talk to y'all. ( I just had to get that
in somewhere to preserve the Texan stereotype.)
Q. What type do I need for my camera?
A. Just click
here to read some guidelines on what model
you need to order for your own setup.
Q. How much does it cost?
Q. What about upgrades?
A. All of our products are capable of being
upgraded to the newest 'Stiletto' Series. I always hate getting stuck
with old technology, and I know you feel the same way too. The last
thing I want is for one of our products to wind up unused in your astro
accessory junk drawer. My own is full! So, an upgrade is always open
to you for a really reasonable cost - all you need to do is
email me and let me know what Series you have now. Y
Q. Is it worth it?
A. Well, if you're going to spend 60 minutes
bent over in the cold guiding your scope,
you will feel like a total idiot if the picture comes out fuzzy because
of lousy focusing. Your wife will later nag you to see the results of leaving
her alone all night, and your marriage
may be headed for the rocks. You sacrificed her for 'blur'. Most amateur
astronomers who give up the hobby are victims of FFDS - Fuzzy Focusing
Depression Syndrome. I have found that knife-edge focusing is the
ONLY guaranteed way of getting the focus right on. Hey, I have
a Nikon F2 with clear focusing screen and
8X Peake Loupe on it. The knife-edge beats it every time.
And I would be simply lost without using one with my
Canon EOS DSLR. You
can be near blind and still focus correctly!
And for CCD use, the Series IV is still miles ahead of focusing software
and using parfocal eyepieces. Take a look at how the Series IV comes
out against MaxIm software here.
Q. Is the Series IV a true knife-edge focuser?
A. It sure is, but.... most users find
that the new 300
line/inch ronchi screen will result in extremely sharp images and is easier
to use than a knife edge. After using a ronchi
screen, however, you may be curious to try our True-Knife Option which
employs a true knife-edge. Real knife-edge focusing really is not for
the uninitiated or faint of heart, but after practicing with
a regular ronchi grating,
you will know what to look for and become a whiz. Try one. You'll
like it. Click here
for a short tutorial on knife edge focusing using our True Knife Option.
Q. Do I really need the new 'Black Chrome'
300 line/inch screen?
A. The
difference between our standard 180 line/inch screen and the 300
line/inch 'Black Chrome' screen comes down to the amount of interpolation needed when
focusing. While focusing
with a Series IV, you are basically looking for that point where the
bars on the ronchi screen disappear altogether and
you see only a shimmering whitish/gray area where
focus is. There is usually a small play, however,
between where the left bar and the right bar reappear on each side of focus.
This is normally not much, so it is relatively easy to gauge the
exact center point of the whitish area even with
the 180 line/inch screen. The300 line/inch screen was developed for a
number of reasons, mainly when strong focal
reducers are used. The focal reducers tend to
stretch the image out and, necessarily, the bars
on the ronchi screen appear further apart making
it more difficult to interpolate. Down to about f/6,
users normally do not have any problems
using the standard screen, but below that
they may be wise to use the higher
resolution screen. This has been especially
successful with CCDs and f/3.3 reducers.
But for simple 35mm
photography, one does
not have this problem.
On the other hand, the Black Chrome screen does allow you to focus on dimmer
stars and makes interpolating a lot quicker and easier even with 35mm
cameras. So, if you simply want the best available regardless of what
telescope you may come to own, get a Series IV
with the Black Chrome screen. Read more about it
here.
Q. Can I fine-tune the 'Stiletto' assembly
myself and add different resolution screens?
A. Of course! We have made the Series
IV utterly flexible so you can tweak it to your own satisfaction or for
your own strange applications. (We even have Stanford Research Institute
sending one to the Sun to take pictures of the photosphere!) Click
here for instructions on how to easily tweak
the system for you own use.
Q. Will you tell me how to make one myself?
A. No! How else am I going to save
up for that new LX-200? Besides, you will end up spending more
on tools, finding suppliers, and messing it up in the end. Click above to
see how the Series IV is manufactured to see what you'd be getting into.
Q. Is this an original design?
A. If original means stealing ideas from
five other people and putting them together in a new
way, then,
yes, this is original. Credit has to be given to Jason Ware
for the main idea. Credit goes to me for developing it so it works properly
and looks nice. Thank Mr. Foucalt for
the physics behind it all.
Q. Are there other suckers?
A. Yes, thousands! Below is a photograph
from the very first victim of the Series I focuser, Dan up in Oklahoma, and what
he had to say years ago. The only complaint
he had was that the picture came out blue. Sorry,
I can only recommend buying Kodak if you like
blue, and Fuji if you like red, and saying a little
prayer. Experimenting with other film helps too though!
Since the introduction
way back then, the Series IV
has found it's way to all of the major continents -
even Antarctica!
" Well, here it is. This is actually
the second picture I've taken
with the camera setup. As advertised, the focuser
worked perfectly,
along with the camera. This is a good picture
for me, but I know
that it needs lots of work. I used Kodak
Max 400 film and everything
is blue! I dunno why. Maybe just the characteristics
of the film.
This is a 30 minute exposure. When compared
to the 15 min.
exposure I took, There is very little noticeable
difference other than the
nebula looks physically larger only because of the
extra nebulosity captured
on the outer fringes in the 30 min. exp."
(Editor's
Note: If you do not know what nebula this is, you do not need this
focuser.)
Q. Can I use the Series IV for eyepiece
projection photography?
A. While the Series IV was mainly designed
for deep sky work, it can effectively be used to focus on the planets and
Moon as well. In this case, the Series IV
Stiletto bayonet assembly is unscrewed from the Series IV body and used
separately. This is necessary since the diagonal and transfer lens
assembly attached to the Series IV body forms a small telescope specifically
designed to magnify the image on the ronchi grating. With eyepiece
projection, using the complete Series IV unit would be similar to putting
the end of one telescope up to the end of another. We all tried that
when we were kids and know what happens. Using the
Series IV modular mount assembly separately solves this
problem nicely. But if you are truly into
planetary photography, better check out our CVF 'Spotlight' Series of
focusers since they were designed for planetary use from the ground up.
Q. How dim a star can I focus on with
the Series IV?
A. The Series IV requires a pinpoint
source of light which is viewable in order to function properly. (doh!)
While it is possible to focus directly on magnitude 4 stars directly depending
on your dark sky conditions and your own eyesight, this really is unnecessary.
One essential to understand about focusing is exactly what you are trying
to accomplish: Since your telescope's own focuser has no set stop
at the infinity position like a regular camera lens, all you are trying
to do is to determine the infinity position for it. To your telescope,
any object over a few hundred feet away is considered at infinity.
Thus, to your telescope/camera combination, it makes no difference if a
star is 4 light years away or 4 trillion light years away. Both will use
the same setting. In practical terms, this means that you can use
a different star to set the focus and then retrain your scope on the exact
object you will be photographing. As long as you do not experience
significant mirror flop, or retraining your scope across vast areas of the
sky, the focal point will be virtually identical. In short, with the
Series IV you do not need to focus on the exact sky object you want to photograph.
The case is similar for photographing extremely bright objects such as the
major planets and the Moon. Just focus on a nearby star and retrain
your telescope on your subject.
Q. How well does the Series IV work
with newtonian reflectors?
A. It depends on the
telescope's optical design. Knife-edge focusing
is extremely effective for focusing SCTs with longer focal ratios, but falls
short in some respects for small newtonian reflectors
with low f / ratios. The problem usually boils down to
limitations in the telescope design itself.
All optical system designs are optimized for use over a
fairly narrow range of focusing. This distance is roughly the standard
length of a t-adapter (55mm) , plus an allowance for a typical
camera's film/plane distance (30mm-80mm). In the case of an SCT, this
design range usually extends about 20 centimeters behind the telescope and
there are no problems focusing. In a newtonian design, however, this
distance is intentionally made much shorter to minimize the effects of the
secondary mirror obstruction. The result is that there may simply not
be enough room to accommodate the additional length adapters and cameras
take up without moving outside of the optimal design range. This may
mean that you cannot properly focus a camera at all, or that the image you
achieve may be substantially degraded if you are able to do so. Having
said this, much depends on the design of your specific brand of newtonian
and what it's design parameters were. If it was designed with
astrophotography use in mind, the manufacturer has likely taken these facts
into consideration If it was primarily designed for visual use,
however, you may simply be out of luck using a camera effectively.
Overall, for low f/ratio telescopes of any kind, you
should seriously consider trying our Deluxe and Pro Edition models which
incorporate the new Black Chromium 300 line/inch screen. This
usually overcomes any problems.
Q. Why do I see a 'donut' when I'm focusing?
A. The donut you may see is a result of the
obstruction of the secondary mirror in your SCT. This is normal.
What you are more interested in is the lighted area surrounding the donut
where you will see dark bars when you are out of focus. To reduce
the donut problem, the Series IV transfer lens assembly
can be intentionally
set slightly off-center so that more of the lighted halo is shown than the
black hole of the donut. This is one reason why
the diagonal in the Series IV is collimateable. This also
gives a better depth of field
in the photo. Do not think that the
diagonal mirror needs to be exactly
centered. Doing so might center you on the central obstruction and
actually reduce your view!
Q. I dropped a Series IV
or CVF and smashed
it to bits. What do I do?
A. You simply send it back to get fixed.
I only charge fair shipping and the exact cost of repair parts for customers
who stumble across the dog in the dark by accident. So, you don't
need to trash the unit and order a whole new Series IV from us.
We're not that kind of company. Then again, we're not Zippo either.
Q. Can I use the Series IV for solar
photography?
A. Well... no.
Hey, I never claimed that the Series IV could do everything!
For solar photography, it is difficult to beat our CVF
'Spotlight' Series which was designed in the first place for solar
photography.
Q. I still have a question you haven't
answered. What now?
A. Just click
here
to leave some feedback.
