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| My best DSI IIc HαRGB image of IC 405 |
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| First light ASI1600MM-cool+EFW+AT8IN image |
I have used a Meade DSI IIc for a number of years and have long wanted a cooled monochrome camera with a larger imaging chip. I initially didn’t even consider the ASI1600MM-Cool because it uses a 12-bit CMOS chip which I thought inferior to the 16-bit CCDs. However, several things changed my mind. First and most importantly, I saw a lot of outstanding images on Astrobin that were produced with the ASI1600MM-Cool. The proof of the pudding is in the eating, and it is hard to argue with really nice results. Second, as I researched a bit more, I realized that the read noise of this camera is very low, compensating a great deal for the lower bit range. Third, the price for this camera is much lower than for a cooled CCD of comparable size. In addition, while ZWO’s prices are low, the kit looked like a good deal compared to buying the components separately. Finally, High Point Scientific had the kit for $100 less than I could find it anywhere else, so I finally convinced my wife and made the purchase. I ended up with a complete LRGB and narrowband imaging system for less than the price of a CCD camera alone. So even though this kit cost as much as all the rest of my gear put together, I still consider this "cheap," or at least economical, astrophotography.
I received the kit and installed the filters. I chose the 31 mm filters hoping to avoid any vignetting with my 800 mm F/4 AT8IN Imaging Newtonian with an Orion Thin Off-axis Guider (TOAG). The 31 mm unmounted filters are dropped into the filter wheel and held in place via 3 small screws with rubber washers. It took some careful work to install them. I was happy to find that the same wheel is threaded for 1.25” mounted filters, so I put a mounted 1.25” Baader UHC-S filter in the 8th slot. The kit comes with a nice set of adapters and I had no trouble screwing the camera directly onto the filter wheel with the TOAG on top of the filter wheel and some T-spacers to get the right distance from my coma corrector.
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| Best previous image of IC 410 |
The biggest snag in setting this system up came with getting the camera and filter wheel to talk with my software. I have a somewhat unusual setup: I use Sequence Generator Pro under Windows 10 on a MacBook Pro running the most recent version of VMWare under MacOS Sierra. After some fumbling, some support from the ZWO users forum, and some trial and error I discovered that VMWare has to be set to USB 2.0 to enable image downloads with my configuration. The system is also sensitive to how things are cabled. Using the USB 3.0 cable that came with the camera coupled with a 20-meter USB 2.0 repeater cable (so I can run the system from my warm living room!) did the trick. I connected the filter wheel through the USB 2.0 hub on the camera and that works fine, but I opted to connect my guide camera (a Meade DSI), mount, and focuser through a separate USB 2.0 powered hub and repeater cable. Since I got things cabled up correctly, everything has worked flawlessly.
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| ASI1600MM-Cool HαRGB IC 410 |
The performance of the camera/filter wheel combination has been everything I’d hoped for and more, except I do get some vignetting in the corners with my optical setup, especially with the narrowband filters. I love the much larger field of view and much higher resolution and sensitivity I get with this camera relative to the DSI IIc. The learning curve in switching to monochrome imaging has been steep but fun to climb. So far I have imaged 4 targets, and each image is far superior to the best I could get previously. I’ve used the H-alpha filter in each of these. The L, R, G, B, and H-alpha filters appear to be parfocal; in any event, I have have gotten away without refocusing when changing filters. I haven’t tried the SII or OIII filters yet. My images are posted at www.astrobin.com/users/dvdearden.
Some comparisons are shown here, although the size of the images posted here probably doesn't do them justice.
In conclusion, I’m very happy with this camera+filter wheel+filter set combination. I can finally get images with sufficient resolution and quality that I’d consider printing and displaying them. I expect to enjoy this setup for a long time.
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| Best previous HαRGB Jellyfish |
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| ASI1600MM-Cool HαRGB Jellyfish |
