Yankee Robotics Trifid Camera Review

By Gordon Lupien Jr.

Introduction:

Endless searches for inexpensive large format, cooled Astronomy Cameras… Sound familiar? Lucky for all of us, there is now a solution! While it still maintains a hefty price tag, the Yankee Robotics Trifid reduces the cost of a scientific camera by about 50% (compared to other camera manufacturers) while significantly enhancing the performance and reducing the weight. Yankee Robotics does, in fact, put an excellent, large format camera into the hands of amateurs for the first time.

Background:

I’ve been searching for an alternate to the SBIGs, FLIs and Apogees of the world for a while now. I’ve used the FLI MaxCam and a multitude of webcams and digicams. I almost leaped at the Starlight Express series of cameras (which seem excellent) until I stumbled on what I was looking for.

I saw the little ad for Yankee Robotics Trifid cameras in the back of Astronomy Magazine early this year. I was excited. Finally an alternate solution using Kodak KAF scientific sensors! I called up the company the next morning and had a chat with one of the Yankee Robotics gurus, Daniel Wisehart.

Everything fell into place. While they offered the full range of Kodak KAF series sensors for sale at Kodak’s price to them, Yankee Robotics was willing to install my own personal Kodak sensors into their new Trifid cameras! I placed an order for two Trifid cameras. One based on the KAF-6302LE and one experimental camera based on the KAF-6302CE.

KAF-6302 sensors? Aren’t they a previous generation? Yes, well, I had them available for installation and Yankee Robotics was willing to adjust their design to support them as alternates for the new KAF-6303E sensors they normally sell for this size class. Talk about support! The build up of my order began with a few hitches due to my personal sensors being in a slightly different mechanical packgage, and the finished cameras arrived in about a month.

The Trifid Kit:

The Trifid arrives in a relatively large box. Inside is a significant amount of equipment. I removed a genuine Pellican case and opened it. Inside was the Trifid camera, along with the required power connectors, Trifid software CD and a Yankee Robotics window sticker. Next I removed a Rubbermaid cooler, soft, flexible water tubing, an Attwood submersible pump with associated power cord, a Uline Cold Pack ice pack, and the hard cover book “The Handbook of Astronomical Image Processing”, which contains the full version of the AIP4WIN image processing software.

The Pelican case is a solid (you can dance on it) plastic case with a foam insert and a gasketed top lid. When the case is closed, it is airtight, allowing you to add some desiccant to keep your camera in a protective dry environment when not in use.

The power cords for both the camera and the pump are coiled 6 foot cords that terminate in cigarette lighter shaped plugs. The pump cord is attached to the pump and the camera cord is terminated in a plug that fits on the camera power input. Supplied with the camera kit are two wired cigarette lighter sockets for these cords so that you can connect to a 12 volt source either with the supplied adapters or with your existing 12 volt source.

The Rubbermaid cooler supplied in the kit has two holes cut into the top of it to supply access for the tubing. The pump just fits inside the cooler. I think this thermos solution is good for those of us on the go, however I would consider a more permanent reservoir for observatory use. More on this later.

The Camera Exterior:

The Trifid itself looks like a solid, black anodized aluminum, 4.5” in diameter, 3” deep cylinder. I ordered the SCT threaded version, so my “blocks of aluminum” have a threaded hole at the top. Turning the camera around, the back side has two round holes with connectors inside, one for the 12V power and one for USB. The sides of the Trifid feature two brass hose barbs for cooling water input and outflow.

The barbs come out through holes in the camera sides, or the sides of what is called the shell. The shell is available with the SCT threads, which I ordered, or with a 2” nosepiece. You can request either option at the time you place your order. The shell is a single piece design milled from aircraft aluminum to quarter inch thickness for light weight and durability. The shell is user replaceable, so you could order both the SCT threaded and nosepiece versions. Based on the fact that this shell is one piece that bolts to the quarter inch thick rear plate of the camera, there will be absolutely no flexture contributions from the Trifid camera.

Wow, it’s light! I weighed it and it weighs a mere 2.75 pounds with the brass water barbs installed. The brass barbs are removable, so you can replace them with nylon ones. The barbs that come with the camera are significant. You have the option to replace them with smaller diameter barbs in the future to reduce the size of the coolant tubes going to the camera.

Looking through the SCT threaded hole in the top of the camera shell, you can see the large shutter covering the optical window beneath. This is an electromechanical leaf shutter, controlled via a solenoid you can just make out if you angle the camera a bit. The shutter is large enough to handle the KAF-6303E sensor with a ton of room on all sides to spare.

The Camera Interior:

If the shell is removed from the camera (not recommended unless you have a good reason…) you can see the shutter system in plain view resting on stand-offs on top of the cold chamber. Below the shutter is the optical window on the top of the cold chamber. It is held in place by three screws and sealed against the cold chamber itself.

The cold chamber looks like it is actually milled into the water jacket. Inside this chamber is the sensor, mounted on top of its stack of two Peltier devices that provide two stage cooling. Now the threaded holes for the coolant are visible in the sides of the water jacket.

Underneath the water jacket lie the electronics on stand-offs. The heart of the camera consists of two boards. The top, mounted directly underneath the sensor, provides the isolated analog signaling required by the CCD while the bottom board handles the digital interfaces and controls for the shutter, Peltiers and temperature sensors. The rear of the camera is an aluminum plate that screws to the stand-offs holding the electronics. The rear plate is also the heat sink for a voltage regulator.

The electronics of the Trifid include 16 bit A/D conversion, isolated analog supplies and a USB2.0 burst mode interface that provides 480 Megabits per second image download capabilities. The sensor itself is clocked at over 4 megapixels per second. This is faster than any other scientific camera I have seen on the market. I am able to download my 6 megapixel sensor in a matter of less than two seconds.

Overall, the camera has one of the best form factors I’ve experienced. It is not delicate in any way, and looks like it could withstand some mistakes. There is nothing odd or fragile projecting from the camera and there are no odd angles. The 3” depth easily fits between the fork arms of all Meade LX200 GPS telescopes, with the focuser installed. Happily, there is no fan to worry about either.

Assembling the kit:

So, I have this new camera. I don’t know about you, but I’m in a rush to use it and, finally, a clear night shows up in Rochester, NY. I think I’ve had five clear nights since the start of the year, and it is now June. Wrong place for this hobby. They always say you have to go through the mandatory 30 days of cloudy skies when you purchase a piece of equiment.

My 12” LX200 GPS is mounted on a concrete pier in my very small domed observatory. The observatory is still under construction, and includes a home-made 6 foot dome with motorized retractable dome door. It’s still fully manual, so I have to stay out there and rotate the dome.

Oh, before any of you folks who have better equipment decide to stop reading now because I own a lowly LX200, keep in mind that I am using inferior equipment to achieve my images. This is exactly the kind of equipment that would NOT support a heavier camera. I am positive that your equipment would also benefit from the Trifid for the same reasons I am actually able to take decent images at all.

The LX200 is loaded with a piggy-back Tele Vue NP-101 (via the very secure Losmandy dovetail and rings) that I use for tracking and for wide-field astrophotography. It sits on a 1.25” thick adjustable aluminum plate. The plate is bolted to the pier, which has a permanent latitude angle cast to it. The plate is adjusted via top and bottom bolts on ¾” threaded rod coming out of the angled face of the pier. Very good alignment can be obtained (and held) with careful adjustment.

I guide the LX200 with an SBIG ST-4 via the NP-101 and a Tele Vue 5X Powermate. With this setup and the LX200 mirror locked, I can achieve 0.1 second intervals on the ST-4, which translates to a very tight guide. The inverse also works. I can guide with the LX200 (mirror locked) and use the fabulous NP-101 to capture wide-field images with excellent guiding.

The first camera I received was the color camera. Shortly thereafter I received the monochrome camera. I decided to try the monochrome camera first. Intellicast says clear and when I look up, by gosh, it is! I run out to the observatory with the Trifid equipment and my laptop in tow. I also carted out water and and the ice pack (now frozen for several weeks in anticipation of this moment of clarity)..

I set up the following image path: LX200 followed by the Meade microfocuser, followed by my Optec MaxiFilter, followed by my Van Slyke Versa-port Slider. We’re quite a distance away from normal prime focus on an F10 scope now, and this assembly does not slip through the forks of a 12” LX200 GPS too well.

I cut the supplied cooling hose in half and tied the halves to my concrete pier and then through the LX200 OTA handle to the camera. I connected one tube, through the Rubbermaid cover to the Attwood submersible pump and the other tube through the cover just dangling in the Rubbermaid cooler. I did not use any clamps, but you want to avoid kinking the tubing if you do this.. This might not be a good idea to avoid clamps in the long run, but it works fine for a start. I added the frozen ice pack to the cooler and then filled it with water and dropped the cover down without tightening it.

I connected the two cigarette lighter sockets to my 12 volt sealed cell and plugged in both the camera and the pump. cooling water went right up through the camera and began flowing smoothly through the tubes. I have had to lift the Rubbermaid cooler on occasion to start the flow as the pump only has so much head. Once the water starts flowing, everything is fine. The pump is quiet and there is no sound aside from the pump running. There are absolutely no vibrations from the water cooling system.

I then connected power to the camera and plugged in the USB cable. I turned on my notebook, placed the Trifid CD into the drive, let Windows XP finish booting and plugged in the Trifid USB cable. The software I initially loaded was version 1.4. As soon as the camera was plugged in, it was recognized, enumerated, and the software was automatically installed from the CD.

I opened the Trifid control panel and turned the camera on. Turning on the camera turns on the analog (and I assume some sleeping digital) circuitry. The software took a bias frame and set the auto bias with it. I then went into “Cooler” tab and cranked the cooling up to 80%. Yankee Robotics currently does not have temperature setpoints where the camera can stay at a fixed temperature. This will be added to the software in the future. I don’t think it’s a problem however, because the camera reaches equalibrium quickly and stays there.

I watched as the temperature went down to –28 degrees Celsius. I slewed the scope to Arcturus and I then started focusing by switching to “Main” and selecting “Focus” and setting the exposure to 0.1 seconds. When I was satisfied that I could not make the stars any smaller, I switched to “Object” under “Main” and started to look at the images after each focus maneuver. I ended up with Arcturus covering 8 pixels at 0.1 seconds of integration time. I’m sure I could have done better with a bit more patience…

I noticed then that the stars were taking on a washed out look. Odd… I removed the camera from the scope and took a look. Condensation on the outer window was evident, and Yankee Robotics had mentioned this. I was over cooling on a night of very high relative humidity. It had been raining all week, including earlier that day. I backed off the temperature and chose to image at 0 degrees Celsius. See my desiccant solution later in this review.

The condensation cleared up (with a little motivation from me) and I slewed to M51. I figured, why not take on something a bit tougher. I centered the image and turned off the bias. I then took a 5 minute integration to check things out. Amazingly, there it was. The main Trifid window does histogram stretching, so it can be a bit deceptive. The best thing to do is take a look at the output image with AIP4WIN. I then checked my temperature and took a 30 minute integration. After that, I had to hit the sack as a full day of the “real world” was coming up. Note that I did not take a dark frame.

The next day, I turned on the camera, brought the temperature down to zero again and took a dark frame. I then loaded these single frames into AIP4WIN, completed a dark frame subtraction followed by a histogram stretch and saved the image. Take a look at the result.

Before you get nervous, let me clear a few things up. First of all, I imaged M51 at F10, through a clear filter glass, on a 12” scope. M51, with a third generation Kodak ABG sensor (such as the KAF-6302LE) should take a minimum of 20 minutes to image at F6.3. Work that out and I should have been integrating for an hour or more at F10. Plus, add to the equation that I was at zero degrees C, and should have been cooler. Not exactly pushing the cooling system at all, I had been set at 40% of capacity. So it’s not really bad at all.

The next clear night (two weeks later) I took out the single-shot color camera, based on the Kodak KAF-6302CE, and hooked it up to the existing setup. I took a while focusing and then shot M57 for 20 minutes along with a corresponding dark frame. Again, these were taken at 0 degrees C. I did add a Meade F6.3 focal reducer to the image path. See the first-light image of the KAF-6302CE sensor in a Trifid camera. This image has had the dark frame subtracted and the histogram stretched a bit. I then ran it through my color generator software that takes the result of the Bayer pattern of color filters on the array and interpolates the missing colors for all pixels. The result is a full color image in one integration. I then tweaked the color balance a bit. Not bad at all!

Initial Conclusions:

Well, not that I’ve taken a ton of shots yet, but I can honestly say that I am surprised by the performance of the Trifid cameras. They are small, light, water cooled, and obtain excellent image quality, even with older generation sensors. I will be adding more in-depth analysis and more images as I am able.

Here is a summary of the Trifid Camera capabilities:

- 16 Bit Analog to Digital conversion

- Isolated analog circuitry and supplies

- 480 megabits/second download throughput

- > 4 Megapixel per second CCD pixel clock

- <1.8 seconds to download an unbinned 6 Megapixel sensor

- EEPROM upgradeable firmware

- Dual peltier cooling for up to a 40 degree differential

- Lightweight at only 2.75 pounds with the 2” nosepiece shell option

- Easily clears the fork arms of an LX200 GPS scope

- Comes with everything you need to get started for cooling down to –30C

- Can be ported for dry gas flow to prevent condensation at extreme temperatures (required for –30C operation)

- Excellent support from Yankee Robotics