Revolution Imager R2 Review and Tutorial

As my computerized mount slewed to Abell 2065, a galaxy cluster in the constellation of Corona Borealis, my eyes widened and a smile of satisfaction came to my face. This incredibly faint target had been on my observing list for many years, using my own 24” Dobsonian telescope, and I had never seen it with any level of certainty. Fast forward twenty years, and here I am using what I would have considered a tiny scope back in those days, a 6” f4 Newtonian, under far brighter skies, and that same target was seen with ease. On top of that, at the time of this observation, the galaxy cluster was only about 35 degrees above my western horizon, certainly not in the darkest part of my sky, far from it! The difference was that this time, instead of squinting through an eyepiece, I was using the incredible Revolution Imager!

The purpose of this tutorial

Several years ago High Point Scientific sent me an R2 kit and asked me to try it out for a few weeks so that I could become acquainted with it, in order to help our customers with any questions that they might have. As excited as I was in putting this accessory to the test, I must tell you that the first few nights I was quite baffled and frustrated. My initial complaints were “There are so many wires!”, “What do all these menu options do?”, and “The screen is way too bright!”. I have heard these same complaints echoed from many of our customers regarding this accessory. Thankfully, I pushed through the learning curve and quickly grew to love this product. So much so that I have recently purchased one for my own use under the stars! In fact, this product has honestly reignited my passion for EAA! The reason for this, I believe, is that when using the supplied 7” monitor, this system simply comes closer to true visual astronomy than anything else that I have used. To a large degree, you feel more in tune with the night sky with less technology poking through and getting in the way.

Among other things, I will be addressing the above three complaints within this tutorial and will show you how you too can push this accessory to its limits. As long as you have access to a telescope with a solid and accurate tracking mount, I guarantee that when used properly, you will be able to “see” many faint deep space objects in far more detail than ever before using traditional observing techniques! If you do not yet have a telescope or are upgrading to something better suited for EAA, I will give you some tips on what to look for in a telescope. My goal is to minimize your own learning curve so that you can get set up quickly and start viewing the wonders of our incredibly vast universe right away! You will learn how to navigate through the camera’s menu options with confidence, thereby tuning the camera’s gain, exposure, and contrast settings in order to properly match your own telescope’s focal ratio to your sky conditions.

Before I continue with this tutorial, let me first set the record straight. In my humble opinion, this camera package is not meant to replace a high-quality eyepiece when viewing the moon, planets, or double stars, nor will it compete with the high-resolution CMOS cameras that are capturing incredibly detailed images of the night sky when using much longer total exposures. I use these cameras all the time and they are truly amazing performers. One should therefore not view the R2 as a camera that takes pretty pictures to hang on your wall, but instead, more like an “eyepiece on steroids”, able to, very quickly, reveal details in small to medium sized deep-sky objects that no eyepiece can. If this product is viewed in that light then I believe that folks will more fully appreciate its purpose within their collection of gear.

Although you certainly can use a laptop with the R2, one glaring difference between this particular camera package and an astronomically dedicated CMOS camera is that with the latter, you absolutely need to use a computer to “see” what the camera sees. Although I do not have an issue with this personally, I have spoken to many folks who do not wish to lug their expensive laptops out in the cold. Also, when using these incredibly sophisticated stacking programs on your laptop, you simply can’t get away from the fact that there is a lot of technology between you and the universe. Call me a romantic or just old fashioned, but I like the simplicity of the R2, where if necessary, you can quickly and easily make changes to the number of stacks recorded, the contrast, color, or exposure time, and then simply exit out of the menu so that all you see on the screen is the beautiful night sky. I guess that the connection that I feel with the universe after looking through eyepieces for so many years has made this an important advantage.

Another thing to consider is that without a laptop, when the maximum exposure time tops out at 5.12 seconds and the maximum number of stacks that appreciably impact the image quality is 6 (although the program continues to stack, and you will continue to see small gains for a short time beyond that), you find yourself pushing your eyes, your scope, and the camera to their very limits to reveal the most deep sky detail. There is a challenge that you simply don’t feel when stacking on a laptop. This is because when using a laptop with programs such as Sharpcap, (should you have access to an accurately polar aligned equatorial mount or a fork mount on a wedge) you can simply keep stacking for as long as you wish. If you don’t see the details that you are looking for within a minute or so, you can simply sit staring at the screen for 20 minutes or longer and those details will usually come. With the stock Revolution Imager R2 package, I feel that every photon that strikes the sensor counts and you seem to appreciate the details that you can see a bit more because of the challenge, since there is now a time limit on how long you can keep stacking and building up details.

Keep in mind that the stacking procedure in itself does not make the target any brighter, it simply averages out the noisy background, allowing faint details originally lost in the noise to now be revealed. The CCD camera used with the R2 kit is extremely sensitive and seems to create an image that is less noisy than the CMOS cameras that I am used to using. It does not seem to require as many stacks to smooth out the background and therefore builds up those details within faint deep sky objects extremely fast.

Is there a “Perfect telescope” for the R2?

Another important consideration besides your telescope’s focal length is its focal ratio. Keep in mind that photographically at least, the brightness of extended targets like the moon, a galaxy, or a nebula, is dependent on the telescope’s focal ratio, not its aperture. Since the tiny field of view of this particular camera essentially magnifies small and faint objects to such a high degree, going with a larger, longer focal length telescope would only decrease its true field of view even more. With that said, there are most certainly increasing gains in the fine details seen within a small galaxy, globular cluster, or planetary nebula, by moving to a larger telescope with the same focal ratio, however, where you gain in one area, namely resolution, you lose in others.

Another problem with using a telescope that large and bulky is of course, portability. Using a 10” or 12” telescope of any type, as nice as that would be, would require a much heavier and therefore a more expensive and accurate mount. With that said, a fast focal ratio 4.5”, 6”, or 8” Newtonian, or a 5”, 6”, or 8” SCT coupled with a .5, .4, or .3.3 focal reducer, comes close, in my opinion, to the perfect telescope for this camera package, should one wish to view the smaller targets like most galaxies, globular clusters, and planetary nebula, while maintaining some level of portability! For achieving a wider field of view, for viewing larger nebula and star clusters, a fast 60 - 80mm refractor would be closer to ideal. To achieve an extremely large field of view, Revolution Imager even sells a 6-60 mm zoom lens that can be coupled to the R2, so you see there are plenty of options out there!

The focal ratio of this particular telescope would be f10, since the ratio between its 4” aperture and 40” focal length is 10. If the same 4” lens had a focal ratio of f5, the telescope’s focal length would be exactly half as long at 20”. Since both f10 and f5 telescopes are 4” in diameter, they are both gathering precisely the same amount of light. Now, as long as the exact same eyepiece or camera is used with each telescope, the shorter focal ratio f5 telescope would produce an image with exactly half the magnifying power, and exactly 4 times brighter vs. the f10 telescope. Why is this so? Since both telescopes are gathering the exact same amount of light? It is (and this is important!) because it takes 4 times the amount of light to maintain the same brightness at twice the power. This is just one of those pesky laws of physics and you don’t want to mess with the law!

How faint can you go with the stock R2 kit and no computer?

Let's Get Started: Unboxing the R2 kit!

Getting connected

“There are so many wires!”

This was my initial complaint when using the first R2 that High Point had sent me many years ago. The good thing though is that the kind folks over at Revolution Imager have all the wires connected properly from the get-go so that you won’t need to scratch your head to try to figure it all out. On top of that, they now have a “How do I…” section on their website that spells out a lot of the initial questions that folks new to EAA might ask. Click here to take a look!

What you may need to figure out though, is where on your own scope you need to hang all of this stuff. Of course, if you take the final approach that I did even this will not be an issue for you as you shall see. If you feel that you would like to attach everything to the scope you will certainly want to make good use of Bungee cords and Velcro. I personally went through three different “Revolution Evolutionary Phases” on my own setup before finding the best arrangement for me. The first phase was to attach the viewing screen to the scope itself. This was done by first bolting an optional “Vixen” style universal dovetail plate to the top of the telescope’s tube rings. If you have an SCT type telescope, these plates are available for the vast majority of them through ADM or Losmandy. High Point Scientific sells all of these so you won’t have to look far if you go this route. You will also need what is called an ADM-VPA or “Vixen Plate Adapter” which is a clamp that can be firmly mounted on such a plate. You will also want to purchase a ball head so that the orientation of the screen can be easily adjusted for the best views, as the scope slews to different parts of the sky. The screen then bolts to the ball head which in turn bolts to the VPA which in turn clamps to the dovetail plate that is firmly attached to your OTA. Another very popular and less expensive option for Celestron SCT and Edge HD users would be to purchase a Celestron “Piggyback mount” and attach a ball head to it in order to mount the screen.

“What do all these menu options do?”

Keep in mind the reason you have either purchased, or are contemplating purchasing, this product. The goal here is to enhance faint and distant deep-sky targets such as galaxies, nebula, and clusters, making those “impossible targets” that you have been longing to see such as spiral arms in galaxies, not only possible but in many cases, greatly detailed. This can be accomplished in three ways. Since our eyes, at best, can only “expose” for roughly 1/60th of a second, it is a wonder that we can see as much as we do. The Revolution Imager can expose for up to 5.12 seconds and on top of that, you have the ability to greatly enhance the sensitivity of the camera’s sensor. You can also stack up to 6 consecutive images and by doing so average out and cancel much of the noise that would be seen in a single image. My goal is to show you, the deep-sky enthusiast, how to use such a powerful system to reveal as much glorious deep sky detail as possible.

Although as mentioned earlier, this system can stack 6 consecutive images, should you choose to do so, the system will continue to stack exposures beyond this for as long as you care to look, and in my experience doing so continues to yield slightly better results even after the initial 6 images have been stacked. For this reason, don’t be too quick to move on to something else before you are certain that the camera is showing you as much as possible! At some point, however, the detail that you see will indeed level off. Should your mount not track accurately enough to handle this level of exposure time, you have plenty of exposure choices to choose from. The incredibly sensitive camera and viewing screen used in this system were developed for surveillance purposes and therefore have some quirks that need to be understood before one can feel comfortable using it. This may take some getting used to; however; it should all quickly become second nature to you as you push through the learning curve.

As mentioned earlier, you also have the ability to adjust the “gain” or sensitivity of the sensor using the “AGC” or “Automatic Gain Control” option. The higher the number you choose, the more sensitive the camera, but the noisier the image will be. This noise can of course be combated to a large degree with the internal stacking software, where more stacks, for example, 6, mean a smoother, more detailed image. These AGC numbers range from 6 AGC (least sensitive) to 44.8 AGC (most sensitive).

The trick here is to find out the best combination of exposure time and gain for the most detailed images without “blowing out” (overexposing) the background sky. Should you own a rock-solid mount with excellent tracking accuracy, my recommendation would be for you to choose the highest exposure times (5.12 seconds) along with the most stacks (6) and adjust your gain or ‘AGC’ and contrast settings to match the darkness of your skies. This will yield an image with the lowest noise levels while allowing you to maintain a natural-looking background that is not too bright. The flip side to this ideal situation would be lowering your exposure time and compensating for the dimmer image by choosing higher gain levels, something that you would need to do if your mount stability and tracking accuracy are less than stellar.

Adjusting the Monitor Settings

The aspect ratio can be set to stretch the image to fill the screen with sky (default 16:9 ratio) or to give you a more accurate view of the night sky leaving the edges of the screen dark (4:3 ratio). This is due to the fact that the camera’s sensor shape does not match the shape of the screen. Personally, I prefer the default 16:9 ratio setting when viewing deep-sky objects, however, since it does not affect the contrast of the image in any way I will leave that setting up to you. This particular setting can be quickly adjusted by pressing the “Mode Select” key on the bottom of the wireless remote without having to go through the menu setting to get there. The “Video Select” key at the top center of the wireless remote needs to be left at the AV1 setting otherwise you won’t see a signal from the camera. The red key at the very top right of the wireless LCD remote will turn the screen on or off should you need to step away from the action for a few minutes to get a snack. This will save on battery power until you are ready to resume viewing. You of course could simply flip the power switch on the battery off just as easily!

The next setting is the orientation of the image. If you desire to see the universe right side up and flipped left to right correct then you can make adjustments to the screen using this function to make it so regardless of how your particular telescope flips the image! Another tip is to make these adjustments, as well as altering the orientation of the camera within your focuser, visual back, or diagonal, so that when you press the “North” or “Up” key on the hand controller the image moves up on the viewing screen. When you press the “South” or “Down” key the image moves down, and so on. Doing so will save you lots of time later on. You will naturally know just which key to press on your HC when trying to center targets within your field of view! Once all of these adjustments are made you will not need to repeat them again as these changes are saved.

Adjusting the camera’s settings to your advantage

Since this system’s original purpose was for surveillance, as already mentioned, in my experience, many of the menu options are of little to no value for astronomy. This certainly makes things easier since we will need to only concentrate on a few of these settings. The first thing that you will notice is that the “Down” button is inoperable on the wired hand controller. I am really not sure why this is the case; however, you quickly grow to ignore it. The downside is that to access a certain option you may need to go the long way around the menu to get back to it. This only takes a few seconds though and in my mind is really a non-issue.

Another thing that you should know is that the menu options that have a down and left-pointing arrow to the right of the verbiage, can be more fully explored, should you wish to do so, by first adjusting the “Up” button on the wired hand controller until that particular option is highlighted and then by pressing the center “OK” key. Doing so will open up that menu’s internal options so that more adjustments can be made.

Should a particular menu option have the word “OFF” to its right, you can turn it “ON” by pressing the left or right arrow key on your wired hand controller. Furthermore, should the “ON” icon now reveal a down and left-pointing arrow you can then explore this menu option even more by pressing the center “OK” key once more. At the bottom of each and every internal option within the menu, you will find a “Return” option that can be chosen once any changes are made.

I have found that you will achieve better results with less noise when setting the “Shutter” to the maximum of 5.12 second setting (Shutter 256) and lowering the AGC, if needed, to keep the background from “blowing out”. This is much preferred over setting the AGC higher and then lowering the exposure time. This of course is provided that you have a solid and accurate tracking mount which allows you to take advantage of these longer exposure times. As already mentioned, another great feature built within this program is the ability to stack up to 6 consecutive images which will greatly reduce much of the ‘noise’ in the image. I highly recommend that you take full advantage of this feature for bringing out the best details. These stacking details are handled by the “DNR” setting in the “Advanced Menu”, which is accessed through the “Scene Select” icon.

With the Digital Noise Reduction menu opened you can now adjust the number of stacks using the right and left keys on your wired hand controller. My recommendation is to bring the number of stacks back to 0 once the mount is slewing from target to target. Once the object of your desire is located and centered within your telescope’s field of view you will at that point want to set this as high as possible depending on the tracking accuracy of your mount. I have found that a setting of between 3 and 6 usually renders a nice smooth background with the higher numbers doing slightly better. You can then exit this portion of the program by choosing the “Return” icon and pressing the “OK” key on your wired hand controller.

Once the “Fix” menu has been accessed you will be able to adjust the “Shutter” (Exposure), and “AGC” (Gain) icons that I have been discussing. In the screenshots below you will notice the camera’s minimum and maximum settings. You are blessed indeed if your skies are dark enough to employ the maximum settings below!