Sunday, May 10, 2015
The Old Fashioned Way
Another Free Comic Book Day
has come and gone. Avengers: Age of
Ultron is dominating Cineplex screens to no one’s surprise and will likely
continue to do so for some time. Flash
and Arrow and Gotham and Agents of Shield are winding down for the
season. But what’s going on around here?
If you read this blog regularly and closely, and especially if you are good at
reading between the lines, you are
aware I've been going through some changes with a capital “C” (I do not mean by that that I have cancer; I am physically in better shape now than I have been in years) the last several
months. I won’t bore you with the details. I will just say they are significant
and have affected many things including the way I practice astronomy.
Where have I been in (amateur) astronomy the last 5 – 7
years? I’ve been almost exclusively in the imaging camp. The closest I've come
to visual astronomy, usually, has been observing with a deep sky video camera,
with one of my Mallincams. Even out in my backyard, my normal setup has included
a telescope on a computerized goto mount, a camera, a laptop computer, often a
monitor and a digital video recorder, and assorted and numerous cables and
power supplies. Lotta stuff. But I was having fun, and my sensitive cameras
allowed me to get through The Herschel Project’s 2500 or so deep sky objects
more quickly than I’d dreamed I could.
I’ve done some crazy stuff with my Mallincams and DSLRs,
from observing quasars out on the edge of creation last
February down in Chiefland,
to getting the best comet photos (of Lovejoy) of my life. I was used to
setting up all the astro-stuff and observing with a monitor or computer instead
of my eyes, and didn't mind it a bit. Until
I did.
During the Chiefland trip, it became clear my observing
habits were, like other things in my life, going
to change. Like some other things, they needed
to change. In fact, they had to
change if I were to continue to observe. This might have happened anyway. I've
always swung back and forth between visual looking and more technologically
complicated modes of amateur astronomy, and I had been on a big-time imaging
jag at least since 2010. But there is no doubt the changes I was going through
accelerated my return to eyepieces.
So, I found myself ready—nay, anxious—to go back to a simpler sort of amateur astronomy. Which I
differentiate from my “casual” observing. Even at the height of my DSLR and CCD
and video observing, I've used grab and go scopes like the two we talked about
last week for quick peeps at the sky. When I've wanted to do serious work,
however, I've dragged out the C11 and a camera, even just for observing from
the back forty. It is that that will change.
I wanted to go simpler. No cameras. No computers (no
computerized goto mounts, at least). How would I get there? For me,
“simplicity” is spelled d-o-b-s-o-n-i-a-n. In its original and pure form, what you've
got with a Dob is a Newtonian reflector on a simple alt-azimuth mount. It’s point and shoot astronomy. Want to
look at something? You find it with a finder-scope, a zero-power reticle sight,
or setting circles (yes, on a Dobsonian). The scope moves up and down and right
and left in, if it has been built correctly, a buttery smooth fashion. There
are no motors or even locks for the altitude and azimuth axes. You push the
scope, it moves. You stop pushing, it stops. Yes, there are goto Dobsonians
today, but not for me.
I’d once embraced Dobs wholeheartedly, if for a relatively
short time, at the end of the 1980s and the beginning of the 1990s. Despite
having been away from the scopes for many a year, I still have a couple in my
inventory with a little more horsepower than the 4-inch StarBlast. The one with
the most of that is my 12.5-inch truss tube scope, Old Betsy. She’s always been
a stellar performer, and despite not always using her as much as I should, I've
never stopped loving the views she’s given me over two plus decades.
I will no doubt be using Bets a lot more now, but she didn't
seem to be the telescope for most of the backyard expeditions I had in mind, and
maybe not even for many trips to the club dark site. While she’s been modified recently
so that she’s a little lighter, she is still not a lightweight. Sure, I could
gin up a set of wheels or a wheely-bar system for her, but, even then, getting
her into the backyard sounded like work. More work that I want to devote to
telescope setup at this time.
That meant my other Dobsonian would be on deck—for a while,
anyway. This telescope really doesn't have a name. Or at least a name that
describes her in her present (elegant) form. I still call her Old Yeller. That’s because she was
originally a Konus f/5 GEM Newtonian (made by Synta) who came to me with a
hideous yellow-orange tube.
The Konus worked well despite that garish tube, and
certainly paid her way, since I did many of the observations for my book, The Urban Astronomer’s Guide with her. In the end, however, on her non-goto
CG5 mount she was just too inconvenient to set up regularly once the book was done.
That wasn't the end for the scope, however; my friend Pat needed a non-goto CG5
mount, so we worked out a deal. Pat rebuilt the scope into an elegant neo-Dob,
and I sent the CG5 to live with him.
Despite the Dob’s humble ancestry, her f/5 primary mirror is
quite good indeed, giving excellent views of the planets. The Konus delivered
some surprisingly good images of Mars when it was riding high in 2003, the year
of the great opposition. 2003 was about the time most of us had to at least
begin to admit the Chinese were beginning to produce some darn good optics.
Yeller in her current form is uber portable; I can easily carry her rockerbox in one hand and
tube in the other. She is at least as quick to set up as the C102 refractor,
and, naturally, an 8-inch brings a more to the table than the 4-inch. As I said
last time, small telescopes have their uses, but if you really want to see
lots of Stuff, deep sky or Solar System, from city or country skies, 8-inches
is where you begin. The difference between images in Old Yeller and in the
StarBlast or the C102 is simply “light years.”
Nothing is perfect, of course, and there is a fault with the
scope that needs correcting. Back when Pat and I were buying parts for the pair
of 8-inch Dobs (Pat did an identical twin for himself), focusers were not as
inexpensive and good as they are now. While we’d both used and liked JMI’s NGF
DX3, their lowest priced true Crayford at the time, we didn’t want to spend
that much for focusers for these scopes. Since the DX3 had been such a success,
we figured the company’s new bargain focuser, the RCF (“reverse Crayford
focuser”), would be good too.
I bow to no one in my respect for Jim’s Mobile Industries. I
own many of their products and just love ‘em. Except for that misbegotten RCF.
It is, I’m sorry to say, just this side of junk. While well built, more or
less, the focus mechanism just doesn't work right. It is always too loose at
one end of its travel and too tight at the other. You can adjust it so it is workable, but it will never be nearly as
good as the cheapest of today’s Chinese Crayfords. Now that I am back to the
Dobs, I hope to replace it with a Moonlite, but I can deal with it as is until
I can do that.
Alrighty then. With a clear and dry night just before the
First Quarter Moon upon me, it was time to get set up. In the interests of
keeping it SIMPLE, I left my big
observing table, the computer shelter, and all the other gimmicks I’ve used
over the last decade in my Shop. What went on the field in addition to the
telescope was a couple of wooden TV tray tables and my observing chair.
If you are going to use a low-slung Dobsonian like my f/5
comfortably, you have two choices. You can elevate it by putting the rocker
base on some kind of support like the one Orion sells (for way more money than they should if you ask me). That will work if
you want to stand while observing, but who wants to stand up to observe if you
don’t have to? There is no doubt you will see more if you are comfortable, and
the way to be comfortable while looking through a telescope is to sit.
A variety of observing chairs can work with low telescopes.
Heck you might be able to get a drummer’s throne low enough to serve. The best
solution, though, is one of the sliding seat chairs like my Buy Astro Stuff one. This chair, sold by various
merchants as a “utility” chair, will easily go low enough to make me
comfortable at the eyepiece of the 8-inch when I am scoping out objects low
down on the horizon. The seat has enough adjustment range, however, so I can also
use it with my 12-inch. I can access the finder while seated, and only have to
get up and rearrange the chair when I move to a distinctly different part of
the sky.
Ah, the finder. What sort of a finder would I be using for
my initial foray back into old-timey observing? I A Rigel Quick Finder, the
Telrad’s cousin. The QF features a Telrad-like bullseye that’s projected onto a
beam-splitter glass. That makes the red LED illuminated reticle seem to float
before the stars. There’s no magnification, nothing is inverted or reversed,
and finding objects is as simple as can be.
Why a Quick Finder instead of the Telrad? It is smaller and
is in a vertical rather than horizontal format. That makes it a better choice
for smaller scopes or for minimalist scopes like mine. It also offers something
the unmodified Telrad doesn’t: the ability to pulse the reticle on and off,
which can make it easier to position the reticle amid dim stars. If not always
that easy if your skies are light polluted.
The bottom line is that a Quick Finder or a Telrad or any
zero-power (“unit power”) finder can be difficult to use in suburbia. Oh, some
parts of the sky, areas of the sky where there are plenty of stars to lead you
to your targets, are easy enough. But spots like the region between the “arms”
of Virgo that are star poor can be difficult. You really want to have an
optical finder (which will deliver more stars than your naked eye can see) to
supplement your Quick Finder if your skies are not perfect. Unfortunately, there’s
no good way to mount one on my 8-inch, but, as you’ll soon hear, I have a
work-around.
What was on those TV tray tables? On one went my box of
eyepieces. Whether you are observing in the city or in the country, eyepiece
choice is an often complicated, potentially costly, and sometimes controversial
subject. It is one that deserves a blog of its own some Sunday soon. For now, I’ll just say I plunked my old Orion eyepiece case down
on one of those TV tables.
On the other table were my reference materials. My star
atlases. If I wanted to go completely Old Fashioned, that would be a print star atlas. I did place one on the
tray, a favorite, Sky and Telescope’s
Pocket Sky Atlas, but that wasn’t all. There was also my netbook computer.
It is a little thing, will go all night on its internal battery, and runs Deep Sky Planner and SkyTools 3 fairly well. I thought I
might eventually round up my hallowed copy of the Herald Bobroff Astro Atlas, but I didn’t believe I was quite ready
to give up those wonderful computer programs, and a little netbook seemed
humble enough to satisfy my desire for simplicity.
The Sun was soon setting and we were ready to roll, I
thought. First observation? How nice it was not to have to mess with batteries
or AC power supplies and cables. I do need a battery to power the secondary
heater on the 8-inch, but it felt like it would be dry enough that I wouldn’t
have to worry about that, which is pretty unusual down here in mid-spring, and
seemed to bode well.
Did Rod still have his mojo workin’? Could I still find
objects by looking at a chart and positioning the finder reticle among the
stars? I brought up the Messier list in SkyTools,
peered around the sky a bit, and decided M37, the great open star cluster in
Auriga, was a good place to start. It was beginning to sink in the west, but was
not yet too low. “Hokay. It’s just a couple of degrees outside a line drawn
between Beta and Theta Aurigae, and closer to Theta.” I positioned the scope
and took a look in the eyepiece, my 16mm 100-degree AFOV job, the Zhumell
“Happy Hand Grenade,” but no star nest did I see. Nudged around a little bit
and, “There she is. Little more subdued than I thought it would be.”
Despite its relatively low altitude, the cluster still looked
amazingly good. How could it not? It is one of the premier Messier objects. It
didn’t look anything like it does from Chiefland, Florida, where it often resembles
a globular rather than an open cluster, especially in a small piggybacked refractor, but it was still sweet. Even the reddish central star was obvious in the
skyglow/moonlight.
So it went with M36, M38, M35, M82, and a few others. I was
feeling good, friends. Pumped. I hadn’t lost it after all. Or I thought I hadn’t till I decided to take
a gander at M51. M51 is not exactly going to put your eye out in suburban
skies. But I’d seen it easily enough from a considerably worse location, the
backyard of a house half a mile from Bel Air Mall. It was just two smudges in
my 6-inch f/8 back then, in the early 1990s, but was visible. Surely it ought
to be more visible on this Pretty Good Night in an 8-inch from considerably
better skies.
Nope. What I saw was the dreaded Nuttin’ Honey. Took another
look at the chart. Nudged around. Tried higher power (helps to spread out
background sky glow). Nothing helped. The truth, I had to admit, was that M51
was in the worst of the light pollution, and its area is rather star poor
anyway. If I’d had an optical finder, even a 30mm like on my old 6-inch, it
would have been duck soup. But I didn’t have one. What I did have, though, were
setting circles. I decided I’d use ‘em on M51 on the next clear night.
Setting circles on an alt-azimuth mounted telescope? Yep.
People have been putting altitude and azimuth circles/scales on their
Dobsonians since the telescopes first became popular. There are some catches,
but fewer now than there used to be. Few enough that shortly after Pat and I
finished our 8-inchers, we put circles on ‘em.
You can read the whole story here,
but the gist is that I found a Cloudy Nights thread with links to .pdfs of degree circles. I had access to a large format
plotter (work) and printed a couple of circles for our scopes, and Pat did a
nice job installing them. He sandwiched the azimuth circles between the scopes’
rocker boxes and ground boards, gluing circles to ground boards, and cut windows in the rocker bottoms for
viewing the scale. In retrospect, it would have been more convenient if we’d
made the azimuth circle adjustable, for aligning it on zero, but it is
certainly workable.
The altitude indicator was a lot easier; we didn't make them,
we bought them. Larger hardware
stores (like Harbor Freight) sell angle indicators (inclinometers), large dials with pointers
to indicate the angle at which the base of the thing is tilted. They are
equipped with magnets on their bases, and it was easy to mount ferrous metal
plates to the “top” truss tubes of the scopes for attachment of the level. I
later went on to a supposedly more better gooder solution with an electronic
level indicator (also from Harbor Freight), but the thing used button cell
batteries at an alarming rate, and I went back back to the original, simple, plastic, unpowered dial
indicator.
What was the catch I mentioned above? Getting the alt-az coordinates
for objects. Obviously, as objects move across the sky their alt-azimuth
coordinates change—and surprisingly quickly. In the Stone Age of the early 1980s,
we used programmable HP calculators to get alts and azes. Input an object
name or an R.A. and declination and the calculator spat out altitude and
azimuth for the current time. That worked, but those calculators were not
exactly user friendly or inexpensive.
A little later, PC programs (for MS-DOS) appeared that would
give you altitude and azimuth coordinates of objects. Today, almost any planetarium
program for Windows or Mac will do the same. That’s not the perfect solution,
though; that came about 15 years ago. Beginning with PDAs (Palm Pilots) and
continuing on to smart phones, we now have hand held devices that will display
the current altitudes and azimuths of thousands of objects.
A couple of nights after my initial foray, I gave the
circles a go from the backyard. On this night, a big, fat Moon (sorry Diana) would
likely make finding objects via the Quick Finder difficult, so I set up the
scope with the circles in mind. That meant I leveled the telescope. If the scope
base is not close to level, objects will be farther and farther “off” as you
approach the zenith. When I am using the circles, the 8-inch sits on a little
plywood platform with screw in/out furniture sliders in the corners.
After you are level, step two is calibrating the azimuth
circle (altitude does not require any calibration). Point the scope at Polaris,
and with it in the center of the eyepiece field, set the azimuth circle to
zero. That’s where having a movable azimuth circle would be helpful. Instead, I
set the scope to zero azimuth and nudge the base till the star is centered in
the eyepiece without moving the azimuth pointer off zero. Not a big deal,
really.
Alrighty, then. First object was M3, spring’s primo globular
star cluster, which is located in a fairly star poor area. It’s always been
hard for me to find, and that was made worse on this night because the area to
the east-northeast is in the Airport Boulevard light dome. I dug my iPhone out
of my pocket, brought up Celestron’s SkyPortal
app (a free, basic version of SkySafari), hit search, entered “M3,” and requested “Info.” That got me the
current altitude and azimuth of the glob.
I exercised reasonable care in moving the scope till the
pointers were on the indicated coordinates. Be particularly scrupulous with
azimuth. With the circle on the base, beware of parallax effects if you are not
looking straight down at the pointer. The closer you get it to the indicated
azimuth, the better your results will be, natch.
I inserted the 16mm Zhumell, focused up and had a look. At
first there was no sign of M3, but a little staring brought it out. It was not
centered, but was in the eyepiece; out toward the edge of the field. In the fairly
bright sky background delivered by a 62x eyepiece, it was a little less than
obvious. While it had taken a minute or two to look the cluster up on my phone,
I was pretty sure it would have taken longer to find using the Quick Finder.
In the next half-hour or so, I did M36, M37, M38, M81, M82,
M35, M65, M66, and, eventually, even M51, which was somewhat out of the light dome
by the time I went after it. There was no doubt in my mind the analog circles
were a time saver under poor conditions. Was everything in the field of the
16mm when I stopped? No. Probably because I wasn't always careful enough with
positioning the scope. Still, whatever I wanted was always just
outside the eyepiece field and quickly swept up.
One thing that would have helped the circles would have been
a lower power, wider field finding eyepiece. But the catch is that in the sorts
of circumstances where I’d need to use setting circles—an overly bright
sky—lower power can make seeing objects difficult even if they are in the field.
Really, the only question concerning the Dob’s circles was “Do
I really want to use them?” Would that be true to my desire for “simpler”? I
decided they (or even the set of Sky Commander DSCs as on my 12-inch) would be.
At times. A big attraction of my new
observing mode is the relaxing experience of cruising the stars with a chart
and a finder. With a Moon in the sky and no optical finder on the scope, however,
that can be more frustrating than relaxing. I’ll use the circles when I need
them.
What next? One thing that may be next is a 10-inch Dobsonian. Chinese Dobs in
that aperture are surprisingly inexpensive today, and one would give me a
little extra oomph in my compromised backyard. And do that while not being
nearly as much of a pain to set up as my 12-inch. Stay tuned.
As for my visual observing agenda, I have a couple of
reasonably serious projects in mind that I can execute both from the back 40
with the 8-inch or the proposed 10-inch, and from the club dark site with the
12-inch (sometimes, anyway). I am still feeling my way with this y’all, but I
feel good, as if I have found a new lease on (observing) life.
Comments:
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Great Sunday morning reading as always.I work in a school here in nyc,and a couple of teachers are very interested in getting their husbands a "better telescope then their childhood department store scope that they use occasionally. Of course I am partial to my point and shoot 12" dob.I can literally roll it out from my garage and "look up" in 2 minutes.That is how I end many of my evenings after coming home from shopping with my wife or some other function,I tell her ,"honey I'll be in in just a few minutes,I want to look at something".
So my advice to these women who want to buy their husbands "a better scope is to keep it simple.I am leaning them toward a 6/8 inch dob which can be had for a few hundred dollars .They are asking me many question that I am glad to school them on.....thanks again.
So my advice to these women who want to buy their husbands "a better scope is to keep it simple.I am leaning them toward a 6/8 inch dob which can be had for a few hundred dollars .They are asking me many question that I am glad to school them on.....thanks again.
Good read Uncle Rod. I'm sitting here on my back deck this Monday morning watching the rain come down. I only work Tues Wed Thur nowadays. We've had the worse observing weather in 2015 in Texas that I can ever remember. Rain and clouds all the time. I think we're experiencing a rather song La Nina.
# posted by 
: 9:59 AM
: 9:59 AM
Suggest you try adding a 50 mm finderscope and print up your deep sky targets as they would appear in the 50mm finderscope view. I use 8-9 magnitude stars in the finderscope star maps. Use the Telrad and sky chart to roughly locate where you need to be, and then use the 50mm finderscope and finderscope chart to locate the faint object. This gives you many more reference stars for star hopping to the deep sky object.
# posted by : 1:48 PM
: 1:48 PM
Hi Lyle:
Unfortunately, a 50mm just isn't going to work on the 8-inch. I'll certainly have one on the proposed 10-inch. What work's well for me is not so much printing as using the onscreen display of Skytools, a three paned finder window that has naked eye, finder (your choice), and eyepiece. :-)
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Unfortunately, a 50mm just isn't going to work on the 8-inch. I'll certainly have one on the proposed 10-inch. What work's well for me is not so much printing as using the onscreen display of Skytools, a three paned finder window that has naked eye, finder (your choice), and eyepiece. :-)
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