Lockwood Custom Optics at the 2010 Winter Star Party

"Well, after 13 days of clouds, by some freak miracle of nature the skies cleared this Tuesday evening.  I scrambled to swap focusers on my 20" F/3 Starmaster.  Off came the standard Feathertouch, and on went the new one with built-in Paracorr Type 2.

The Paracorr Type 2 is an evolution of the Paracorr that performs better for fast Newtonians.  The lens assembly for this is built into the base of a new Feathertouch focuser so that it does not move, and the Paracorr-mirror spacing remains constant.

What 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 no need 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 reduced.  Like the Type 1, it has a 1.15X amplification factor, making my F/3 effectively operate at F/3.45.

There 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 diagram below) can be removed and the focuser mounted normally in this case.  Currently this option is ideal for visual observers with fast telescopes.  I definitely fit in that category, having a 20" F/3 and 14.5" F/2.55.

I guessed at the tilt adjustment of the focuser, tightened it down, and had dinner while it got dark.  I called a friend and 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 grabbed my parka.  Gloves, waterproof boots and an headband to cover my ears completed the outfit.

I 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 was a bonus.  Boy did we get a bonus.  After observing for a bit we went inside to sample a beer.

Now for an illustrative break from the report....

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A photo of the focuser-mounted Paracorr Type 2 (left in the photo) and the new "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 in was position 1 or position 5!  Now, there is no ambiguity.  The adjustment is smooth and a single locking screw holds it firmly in place.

The focuser-mounted unit consists of a standard FeatherTouch focuser sitting on top of the "body" of the unit.  At the bottom of the 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 out 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 collimation.  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 here may change.  Already Starlight is working on making the built-in Paracorr unit mount on a standard FeatherTouch mounting plate/base instead of a special threaded plate.  This would mean the unit could be 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 am definitely going to use this on my 20" F/3 and on the 14.5" F/2.55 for the forseeable future.

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And now back to the frozen observing......

After a half hour or so we came back out to find seeing conditions greatly improved.  The six stars in the Trapezium were ROCK SOLID.  There was a lot of detail in the bright portions of nebula despite the nearly-full moon.... and speaking of the moon....

The almost-full moon looked AMAZING.  The 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 visible across most of the lunar surface.  Even the fully lit portions of 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 refigured it.)

Now for an observing feat that I have never managed from 40° north latitude - the companion of Sirius was easily seen for greater than 50% of the time I was looking in the eyepiece!  This is pretty much unheard of in the midwest in the winter.

Yes, really, we only had had half a beer each, and we were not suffering from hypothermia!  In fact, with my gear on I was having one of the most enjoyable cold-weather observing sessions that I have ever experienced, just outside my garage.  Mars was not that high in the sky, but it showed a very clear polar cap and some other markings.

In 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 views with outstanding detail, resolution, and contrast.  (Remember, my 20" F/3 is 1.25" thick Pyrex.)  If this mirror had been thicker, 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.

Oh, and by the way, the 20" F/3.3 Super FX Starmaster features a 1.3"-thick quartz primary and a quartz secondary.  That is gonna be one fantastic telescope!

-Mike Lockwood, Lockwood Custom Optics, Jan 26, 2010

After John 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.  However, 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 well, 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.  I shot 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 north before disappearing in the northeast.  The sound rattled the metal 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 be 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 had 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 very close.  That would have been a bad day with four telescopes in the 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 from the palm trees and other tents.

My location was right next to some very kind folks from the Raleigh Astronomy Club, who welcomed me to move my 20" F/3 and 14.5" F/2.55 into their area.  We had a nice view of the southern horizon down to the water.  Excellent.

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 Kendrick 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!  Dinner at 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.  If 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 1.  Al 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 between 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, most transparent skies that I had ever seen at WSP, with stars showing almost all the way down to the horizon in the south.  I woke up John, and then some 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 was 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 is 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 effect on observing as coma correction.

• the Eskimo nebula (NGC 2392) at ~500X+, showing lots of detail
• Thor's Helmet (NGC 2359) looking nearly photographic with an OIII filter and 13mm and 17mm Ethos in the 20" F/3
• the entire M42 complex in the 14.5" F/2.55 with the 21mm and 17mm Ethos
• the Horsehead was quite easy to see with an H-Beta filter in my 20" F/3 in the 17mm Ethos
  
• M46 with ghostly imbedded planetary nebula (NGC 2438) showing detail on a black background sky
  
• M78 showing more subtle shading, detail, and dark features than I have ever seen before
• M82 with tons of detail with the 8mm Ethos in the 20" F/3
• M104 showing a distinct dark lane
  
• Omega Centauri resolved to the core and filling a 13mm Ethos in the 20" F/3
• Centaurus A showing lots of detail in its dark lane
• M51 near zenith showing lots of spiral structure
• Mars, showing nice detail when the seeing cooperated.  Some said it was as good in my 20" F/3 as any other scope at the event!
  
• Saturn, rising high by 3-4am - glimpses of the Cassini division were noted in steady moments, as well as six moons.  Superb view.
  

Here's an image I have always wanted to capture - the southern sky from WSP at about 2am early Wednesday morning.  John Pratte is standing on the beach in front of an old boat.  It's low tide, and some of the limestone that the Keys sit on is visible above the water.  This night was not quite as transparent as the previous night, but we weren't complaining at all.  I used my red flashlight to "paint" John, the boat, and the beach.



Recognize any constellations in that image?  You might notice the Southern Cross, Eta Carinae, and Omega Centauri.  Here's another 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 stars in the fairly calm water.

At 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 seconds 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 hung around the TeleVue booth saying hello to people and talking to Al and Scott.  Here Al waves hello, and Scott is in the white sweatshirt under the tent.

You may have 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 background 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 looking at the camera, but I'll try next time.  If they give me a sweatshirt, I'll even make sure 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 coming 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 applications.  They care about quality, they make superb products, and they are located here in the USA, in Indiana.  It doesn't get much better than that.  Their focusers are on all of 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 pollution appears brighter in the photo, and is from Big Pine Key.



To the east, the lights are from Marathon.  In the photo below, 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.  It seemed dimmer than on previous years (I think it actually used to be white), and I don't think it affects astrophotos.  In exposures 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 across the 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 the old dock and the rock wall are visible in the water.  The green streak 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 (from Equatorial Platforms).