Thanks guys! I'm glad this product is finally so close to release.
For those who haven't used an ADC yet, I think you may find them a bit awkward at first, but I think that the learning curve is very quick as you see how they work first hand. Scopes of 8" and up have enough resolution in good seeing to make the improvement obvious both visually and for imaging. I can't imagine imaging or observing now without one unless the target is over 60° high.
Steve, I agree with Piotr that one doesn't have to constantly adjust the device. 90% correction is difficult to distinguish vs. 100%, and in time you'll get a feeling on how often you want to adjust the prism levers. Within an hour or so of a target's culmination, time between adjustment can be over an hour or more without a problem. When a planet is on the rise or going down the period will be less. Larger apertures, and better seeing will mean atmospheric dispersion effects are easier to detect, so one may want to tweak the settings more often in those conditions. With deep red and near-IR imaging, since those longer wavelengths are distorted the least, you can go much longer between adjustments. The latest Firecapture 2.5 beta has an ADC tuning toolbar action for color cameras that appears to do a nice job in the limited time I've had using it--- time will tell how accurate it is, but it's a nice added feature to an already awesome program!
About the filter--- I'm using the Chroma L as it acts as an effective UV/IR-blocker, and has a somewhat deeper UV cut-off that any other L-type filter I know of. I'm thinking that the more B light in my 2016 Mars images with a OSC cam the better. But other fine UV/IR blocking filters include the Astronomik, Baader and certainly the ZWO versions. Since the ASI224MC (w/wo cooling) has such good near-IR performance the built-in filter in this model is a wider ranging clear filter without the typical UV/IR cutoff points.
As for the cooling--- With our current temperatures here in New England there is certainly no advantage over a regular ASI224MC for planetary imaging (It was 22°F/-5.5°C at the time of the Jupiter captures). There well may be in longer exposures for Uranus and Neptune during Summer or for heat build-up during prolonged, very high fps rates. I haven't tested truly high fps yet, but I have a new laptop on order that should allow me to find out! I also plan some deep sky imaging with it soon, which is the main reason I have interest in the cooled version.
Emil, according to Sam the prisms have high transmission down to about 340nm where the drop-off is fairly quick. While that would still cut off part of the shorter wavelength end of a typical Venus UV filter bandpass or the W47/BG39 combo, the CWL zone and all of the longer wavelength part of the bandpass will be essentially unhindered. I've tested both the BK7-equipped Aries and ASH ADCs before with the Astrodon UVenus filter, and while they were usable in the UV, they didn't come close to the performance of the ZWO ADC. The UV friendly Pierro-Astro with fused silica prisms is still the best in that regard though, but the ZWO is a surprisingly strong UV performer!
As far as how low in altitude it can correct, it should do as well as the ASH ADC I had tested earlier this year as they both are using 2° beam steering prisms. ADCs create more corrective dispersion with projection distance to the eyepiece or sensor, which of course would include the filter wheel light path, so if it appears to fall short in correction in a particular application you just need to add a T-thread extension. Without my filterwheel in place when I was using the cooled ASI224MC, I found I had to use my 25mm extension to easily get down to 20° when checking out Jupiter through the trees. It may have needed less extension that that, but I didn't really check that out. Fortunately there are plenty of sources for T-thread extensions of various lengths and other such adapters.
Edited by John Boudreau, 23 November 2015 - 08:43 AM.
). cheers, DJ
- the variable drag O-rings for example. 
