A short detour, but then My 20"
F/3 and 14.5" F/2.55 hang out
two Paracorr Type 2s, and 599 other skywatchers under Florida stars
images and text Copyright Mike Lockwood, 2010
I think the picture to the right answers the question above!
definitely is winter, but I wouldn't call it a star party!
That is me, observing from my driveway on a moonlit, snow-covered night
in Illinois in
January. I am wearing a huge parka, snow pants, and layers
underneath. It was about 12° F with a light breeze,
it or not I was quite warm. So why am I showing this photo?
story before heading
observing report from
the night this photo was taken, Jan. 26, 2010. The report was
posted on my Yahoo
and on the Starmaster
Yahoo Group, but I wanted to
make sure it showed up
this web site.
after 13 days of
clouds, by some freak miracle of nature the skies cleared this Tuesday
scrambled to swap focusers
on my 20" F/3 Starmaster. Off came the standard Feathertouch,
on went the new one with built-in Paracorr Type 2.
Type 2 is an evolution of the
Paracorr that performs better for fast Newtonians. The lens
this is built into the base of a new Feathertouch focuser so that it
does not move, and the Paracorr-mirror spacing remains constant.
does this mean? By
keeping the Paracorr stationary, it is always the ideal distance from
the primary mirror, and all
one need do is focus the eyepiece and they get the optimal corrected
view. Of course with
the tunable top gone, there is
to fumble with locking screws, turn your flashlight on to check its
position, etc. This saves time. Also, the
assembly is more rigid and flexure is greatly
the Type 1, it has a
1.15X amplification factor, making my F/3 effectively operate at F/3.45.
are still a few unknowns, though. With the
Paracorr fixed, we don't know how binoviewers, Mallincams, etc will
work or if they will come to focus. I suspect they won't, but
the body of the unit (see
can be removed and the focuser mounted normally in this case.
Currently this option is ideal for visual observers
telescopes. I definitely fit in that category, having a 20"
and 14.5" F/2.55.
guessed at the tilt adjustment of the focuser, tightened
it down, and had dinner while it got dark. I called a friend
rolled the scope out of the ~40 F garage into the much colder night
air. Heading back inside, I pulled on my snow pants and
my parka. Gloves, waterproof boots and an headband to cover
ears completed the outfit.
brought the eyepiece case outside and popped in the 17mm
Ethos. It focused with no issues. Stars were moving
blobs. I used the light of the nearly full moon to take some
photos of me sitting by the scope in all of my winter gear. My
friend arrived and we went through all of the eyepieces in the case,
making sure they would come to focus. They all did with no
issues. What a treat to swap eyepieces and only deal with one
setscrew - there was no fumbling with the Paracorr to adjust it to its
optimal setting, or confusing it with the adapter or other setscrews
while I had my gloves on. Just pop in the eyepiece and
observe. Images improved as the scope cooled off. The
goal for the evening was to see if the focuser/Paracorr combo worked
properly, and it certainly did. Everything else after this
bonus. Boy did we get a bonus. After observing for
a bit we
went inside to sample a beer.
an illustrative break
from the report....
photo of the focuser-mounted Paracorr Type 2 (left in the photo) and
"drop-in" Paracorr Type 2 (right) is shown. The "drop-in"
version looks similar to the standard Paracorr, though the adjustment
positions are now designated with a letter rather than an unidentified
line. With the lines, I could never remember if all the way
was position 1 or position 5! Now, there is no
The adjustment is smooth and a single locking screw holds it firmly in
The focuser-mounted unit consists of a standard FeatherTouch focuser
sitting on top of the "body" of the unit. At the bottom of
body is an adjustable locking ring that allows the distance from the
Paracorr's removeable lens group (at bottom) to be adjusted so that it
sits the proper distance from the primary mirror. For this
prototype, I set the distance by focusing the moon or bright star on a
piece of scotch tape
placed across the 1.25" adapter. Simply screw the body in and
of the mounting plate (not shown here, it's still on the telescope)
until the image is sharp, and
then tighten the locking ring. Voila, you are done. Future
production models may adjust a little differently, but the method
should be similar. The body
height is adjustable between 1.88" and 2.25", so there is 3/8" of
adjustment range plus the range of your collimating screws. I
lowered the mirror in my 20" F/3 about 1/8" to 1/4" to lower the
focuser height slightly.
The lens group unscrews smoothly from the bottom for
I find this operation quite easy, and I do it with the telescope
pointed nearly horizontal.
The weight of the unit pictured at left (with mounting plate) and the
weight of the unit at right plus a standard FT focuser are nearly
identical, at about 2.25 - 2.3 lbs.
Here's a disclaimer - THE DESIGN FOR THE FOCUSER-MOUNTED PARACORR MAY
NOT BE FINAL. So, the weights and dimensions I have listed
may change. Already Starlight is working on making the
Paracorr unit mount on a standard FeatherTouch mounting plate/base
of a special threaded plate. This would mean the unit could
swapped out with the focuser only by loosening and tightening a few set
screws. So, the design may still evolve a little bit, but I
definitely going to use this on my 20" F/3 and on the 14.5" F/2.55 for
the forseeable future.
back to the frozen
half hour or so we came back out to find seeing
greatly improved. The six stars in the Trapezium were ROCK
SOLID. There was a lot of detail in the bright portions of
nearly-full moon.... and speaking of the moon....
almost-full moon looked
crater Gassendi was most notable, with fantastic detail visible within
and all around Mare Humorum. (I am not an experienced lunar
observer and I had to look those up.) Ejecta rays were
across most of the lunar surface. Even the fully lit portions
the moon showed fantastic detail. (The only comparable or
possibly better lunar view I
have had was through our uncoated 30" F/3.77 right after I had
an observing feat that I have never managed from
40° north latitude - the
companion of Sirius was easily seen
greater than 50% of the time I was looking in the eyepiece!
This is pretty much unheard of in the midwest in the winter.
really, we only had had half a beer each, and we were
not suffering from hypothermia! In fact, with my gear on I
having one of the most enjoyable cold-weather observing sessions that I
have ever experienced, just outside my garage. Mars was not
high in the sky, but it showed a very clear polar cap and some other
conclusion, the Paracorr Type
2 performs extremely
well at F/3, and the focuser-mounted version saves me a LOT of valuable
observing time by eliminating the step of tuning the Paracorr.
Also, again we see that, a
thin, fast mirror can provide
outstanding detail, resolution, and contrast.
20" F/3 is 1.25" thick Pyrex.) If this mirror had been
these views would not have come until much later in the evening, and
they might not have come at all if the seeing degraded during the night
(which it did by 11:30pm). Bottom
line, having the fastest-cooling mirror possible will maximize your
quality observing time and allow you to take the fullest advantage of
the observing opportunities that you are presented with.
by the way, the 20"
Super FX Starmaster
features a 1.3"-thick quartz primary and a quartz secondary.
is gonna be one fantastic telescope!
Custom Optics, Jan 26, 2010
in Latitude -
Southward to Florida
Pratte (of JPAstrocraft.com)
and I made
the two day trek to a friend's place near the Cape, we got up at 4:30am
on Sunday morning with hopes of seeing a shuttle launch.
clouds in the area caused it to be postponed until 4:15am on Monday
morning, the first day of the Winter Star Party. If all went
well, we'd see a shuttle launch and then see starry tropical skies
later the same evening!
As a Colts fan (they are about the only team around here that I can get
behind) the Super Bowl was not what I had hoped, but New Orleans has a
hell of a team and they certainly earned their victory. Oh
we got up at 4am and found out that the launch was on, and that made up
for it. We put on our coats and set up the cameras.
an HD video with my camera while trying to make sure that I watched the
launch with my eyes rather than just looking at it on the LCD screen on
the camera. The shuttle rose up in the southeast and headed
before disappearing in the northeast. The sound rattled the
on my friend's building after traveling for about two minutes to get to
my location. That was the first launch I have seen, and might
my last - there are only four more planned. It was the last
planned night launch. At right is a still photo that I shot
during the video.
After coffee and a quick stop for some breakfast, we were headed south
on I-95 by 6am. The trip was uneventful, thankfully, though I
to take very evasive action to miss a broken down car in the lane next
to the fast lane. It was over a rise, so not visible until
close. That would have been a bad day with four telescopes in
van, but thankfully my reflexes were good. Whew.
We arrived, said hello to Al Nagler, Scott Ewart, etc., and set
up. My tent and scope were on the berm, with some shelter
the palm trees and other tents.
My location was right next to some very kind folks from the Raleigh
welcomed me to move my 20" F/3 and 14.5" F/2.55 into their
We had a nice view of the southern horizon down to the water.
We listened to Tippy's opening address, and I snapped some
photos. Here a 20" Starmaster basks in the
tropical sun as Tippy
speaks. This is a moment that I look forward to every year,
because it signals the beginning of a week of fun on an island, far
away from my email and cold Illinois weather.
I collimated both of my telescopes in under ten minutes using my old
laser and a Catseye Infinity XLK Autocollimator (dual pupil).
Careful use of the laser nails the secondary collimation, and the
autocollimator fine-tunes the system.
As the sun was sinking low, we realized that we had not had
lunch! Maybe that was why we were really hungry!
Mickey's food stand was just what we needed, and then we watched clouds
come and go.
Al and I observed through some sucker holes in the clouds. On
this night and
later ones we marveled at the views provided by the 20" F/3.
clouds came, we could always test the performance of the 14.5" F/2.55
by aiming it at the red lights on the radio tower across US
did the same with his 127mm refractor. With the "drop-in"
Paracorr in the 14.5", images were sharp across the field to the edge
with the 13mm and 8mm Ethos. The 17mm and 21mm weren't quite
sharp at the edges of the field (probably mainly due to field curvature
on such a short focal length), but were still immensely fun to use
for wide-field view of star
fields when the skies cooperated.
I think F/2.75 to F/2.8 is about the fastest Newtonian that I would
recommend currently. That sort of splits the difference
the F/3 telescope, which the Paracorr had no problems with, and F/2.55,
where a few issues started to pop up.
I think a 30" F/2.8 would be fantastic, and should anyone want a 30"
F/2.8 mirror and a matching flat, I'd be happy to supply them with it.
I got up early in the morning on Tuesday and found one of the clearest,
skies that I had ever seen at WSP, with stars showing almost all the
down to the horizon in the south. I woke up John, and then
other people drifted by and we uncovered the 20" F/3 and observed many
of the best southern objects. Eta Carinae was getting low and
in a tree, so we moved on to Omega Centauri, Centaurus A, M104,
etc. M51 was very nice directly overhead, but then the clouds
returned, and I turned in.
The focuser-mounted Paracorr was
performing superbly, and it was a significant improvement over the Type
I. Overall coma correction is improved, but field curvature
also much less obvious. In other words, stars all across the
field were in focus, rather than those at the edge or those at the
center of the field. This can have as significant of an
observing as coma correction.
from the camp's road, here's a shot of Scorpius rising (Antares is to
the upper left of the taller palm tree) over the souther
southern cross is seen hugging the right side of the shorter palm tree,
so you can see where it is in relation to Scorpius and the summer Milky
dark on the sky,
indicating dark skies are to the south
of the WSP site. It is very dark overhead and to the
The telescopes and their covers were painted red by my flashlight.
To the right is a shot that really typifies the WSP experience early in
the evening - the winter Milky Way rising up out of the ocean and
towering overhead. This shot captures the reflection of
on the water all the way up to the belt of Orion at the top of the
frame. For us northerners, this is the only time we see this
The next few days kind of run together, but I generally observed early
and took a nap until about 2-3am when I got up to observe the southern
objects. We had significant wind on all but one night, but
is normal. The incredible seeing that occurs occasionally in
Keys did not materialize, though I did have Mars up to 500x in my 20"
on one night before conditions degraded. On two nights it was
definitely chilly, with temperatures in the 50s and sometimes stiff
breezes making us grab our winter coats! That's OK, the
rattle of the palm fronts reminded us that there would be no frozen
precipitation to ruin our fun at ~24° N latitude, and the light
southern stars like Canopus helped keep us warm.
Other objects enjoyed were:
complete list, but it lists some of the
highlights. I don't generally have time to keep a log book,
memory must serve, and I am writing this as it is a couple of weeks
after the star party.
nebula (NGC 2392) at
~500X+, showing lots of detail
(NGC 2359) looking
nearly photographic with an OIII
filter and 13mm and 17mm Ethos in the 20" F/3
complex in the
14.5" F/2.55 with the 21mm and 17mm Ethos
was quite easy to
see with an H-Beta filter in my 20" F/3 in the 17mm Ethos
- M46 with
planetary nebula (NGC 2438) showing detail on a black background sky
detail, and dark features than I have ever seen before
- M82 with
detail with the
8mm Ethos in the 20" F/3
distinct dark lane
resolved to the
core and filling a 13mm Ethos in the 20"
showing lots of
detail in its dark lane
- M51 near
showing lots of
nice detail when
the seeing cooperated. Some said it was as good in my 20" F/3
any other scope at the event!
high by 3-4am -
glimpses of the Cassini division were noted in steady moments, as well
as six moons. Superb view.
with my camera
Here's an image I have always wanted to capture - the southern sky from
WSP at about 2am early Wednesday morning. John Pratte is
on the beach in front of an old boat. It's low tide, and some
the limestone that the Keys sit on is visible above the
This night was not quite as transparent as the previous night, but we
weren't complaining at all. I used my red flashlight to
John, the boat, and the beach.
Recognize any constellations in that image? You might notice
Southern Cross, Eta Carinae, and Omega Centauri. Here's
image with these objects and some
others labeled. Later on, Alpha Centauri rises to the left of
Beta Centauri. Note the reflections of some of the brighter
in the fairly calm water.
this point the part of the Milky Way that we don't see from most of the
US lies flat on the southern horizon, forming a bridge between the
winter Milky Way setting on the western horizon to the summer Milky Way
rising in the southeast. Both exposures are about 20-30
unguided on a tripod.
Here some of the Raleigh club members enjoy views of Omega Centauri and
Centaurus A through my 20" F/3 Starmaster. Note the southern
cross right above the secondary cage of the telescope, and Alpha and
Beta Centauri above and left of the ship's light on the horizon.
On this night it
was clear enough to see the bottom star in the cross. On many
more humid nights it does not make an appearance.
By day, I relaxed, wandered around, and talked to people. I
around the TeleVue booth saying hello to people and talking to Al and
Scott. Here Al waves hello, and Scott is in the white
under the tent.
showing passers by the
constellation "Kermitus" by day
through one of his refractors. If you don't know where that
you will have to ask Al yourself!
already clicked on
the link for the Paracorr Type 2
literature, but if not, you can click at the end of this paragraph to
see a PDF version of the
page that Al was handing out at his booth. It provides some
about the new corrector: Paracorr Type 2 info
At WSP, when you're not talking about, looking at, considering
purchasing, or just generally thinking about telescopes, you can enjoy
other bits of tropical scenery, such as this scene, about 20 feet from
my tent. I could get used to this.
Below Al talks to the new owners of Starlight Instruments under the
food tent. I didn't get a photo of all of them together
at the camera, but I'll
try next time. If they give me a sweatshirt, I'll even make
it's a good photo!
Seriously, Starlight is now owned by the company that machines
the parts for the focuser, headed by John Joseph. They're
up with lots of new
product ideas, and with their skilled staff they can quickly build and
test prototypes. This is a well-equipped company with the
expertise to machine parts for military and medical
They care about quality, they make superb
products, and they are located here in the USA, in Indiana.
doesn't get much better than that. Their focusers are on all
my fast telescopes and are my choice for critical focusing.
Back to the skies - the light pollution at WSP is mainly in the
northwest and east.
Here's the view to the northwest, with Mars and the beehive (slightly
left of center) hovering over the palm trees. The light
appears brighter in the photo, and is from Big Pine Key.
To the east, the lights are from Marathon. In the photo
looking east, tents and telescopes are lit with red under the stars,
with scattered clouds between them. My 20" F/3 sits under its
shiny cover at bottom center.
A radio tower towers to the north, with a red strobe on top.
seemed dimmer than on previous years (I think it actually used to be
white), and I don't think it affects astrophotos. In
over 30 seconds
or so it is bright enough to "paint" stationary objects on the ground
with a red
glow. This tower marks your tropical destination as you drive
bridges to West Summerland Key.
Finally, I had to get a shot of the summer Milky Way blazing over the
souther ocean as it rose in the very early morning. This my
favorite image from the whole trip. I wish I could observe
Sagittarius from this latitude without it being obscured by haze in the
spring and summer. Maybe someday. The pilings from
dock and the rock wall are visible in the water. The green
at left near the horizon is a navigational beacon that blurs during
this ~4 minute shot on taken with my camera on my tracking platform
I made at polar
alignment was to roughly aim at
Polaris, including wedging part of a coconut under the front of the
to the frozen north
Here's one more palm tree photo, as I sit here in Illinois with the
wind howling outside it makes me feel just a little bit warmer.
Well, that mostly covers
it. To sum up, the Paracorr Type 2s both performed as
expected. It is an improvement on the Paracorr Type I,
at focal ratios under F/4. The focuser-mounted version
simplifies observing for me, and saves me valuable time under the
skies. It also ensures that I get the best possible images
every eyepiece without having to tune the Paracorr.
some observing in on every night, though for on a couple nights it was
mainly early morning observing. Conditions varied from very
winds to quite strong gusty winds. There was one brief rain
shower on Tuesday night, I believe, but that was it. Not bad.
Friday dawned warm, sunny, and
windy, and the forecast was for thunderstorms and high winds.
After not winning any door prizes, we broke
camp and left in the early afternoon, stopping for lunch at the Keys
Fisheries in Marathon, which
proved to be my favorite
restaurant in the area. (Try a lobster reuben, or enjoy a
fish sandwish for a fair price.)
After driving through storms in Miami,
we reached my uncle's place around 10pm. My WSP 2010 was
but the margaritas were only beginning!
Next year I hope to bring a new fast telescope, but I probably won't be
the envelope. With luck it will be something a bit unique and
little larger than my 20" F/3.
I hope to have time to observe objects in the winter Milky Way below
Canis Major. This year (and last year) I was basically
full-time to show people what the 20" F/3 could do. I also
to track down some more of the faint wisps of the Vela supernova
remnant that are best seen from this latitude, which I observed in 2008
(see my report here).
See you on the observing field at the Okie-Tex
this fall, or
maybe at a more local event before that. In the meantime,
getting my new shop running at full speed to get more quality, fast
mirrors out into telescopes around the world.
Lastly, here's another link to the Paracorr
Type 2 info.
to the WSP organizers, Al Nagler, Scott Ewart, John Joseph, Adam, and
the rest of the Starlight crew for making it an even more enjoyable
skies, warm weather, good friends, and good seeing.
Lockwood, Lockwood Custom Optics