I’ve been really interested in theWilliam Optics RedCat 51since the original announcement. A few web bloggers got ahold of early versions of this scope, and took some really fantastic wide field images with it. Once the scope finally released early reports from purchasers showed lots of issues. Poor coma and off axis issues were prevalent. I waited for the initial manufacturing run to go out of stock, and ordered when they started the second run hoping any issues would be cleared up and I would get one without problems.
The day finally arrived. Agena Astro had them in stock, and I was quick to grab one. It arrived last week to cloudy skies, and I only had it out for a few minutes. Since then, i’ve been able to get it out for a full night of Hydrogen Alpha imaging on the Elephant Trunk nebula. I paired it up with an olderOrion StarShoot AutoGuiderthat I had laying around, aZWO Mini Guide Scope, and my existingZWO ASI1600MM-Promain camera,ZWO 8-slot filter wheeland Astrodon filters.
At first I couldn’t figure out how to focus. It turns out that the scope shipped with the lens hood flipped around covering the focus. I had to unscrew it and reattach the other direction. It makes the scope quite compact for traveling, and I intend to pair it with my Sky-Watcher Star Adventurer when I head out of town in the future. To set up for imaging, I had to reach the prescribed back focus distance, and I used one 16.5 adapter, the filter wheel and space to sensor to achieve 55mm of distance. William Optics also offers DSLR adapters that attach to the back of the scope where you can hook up your Canon or Nikon camera with no additional spacers.
Once set up to image, I placed it on myCelestron AVX mount, and loaded upEKOSto begin imaging for the evening. A quickPolar Alignment, and I was off imaging. I picked a target that would fully fit into this wide field of view, the entire Elephant Trunk nebula. Here’s the first night of imaging with around 6 hours of HA data. I calibrated and stacked the image withAstro Pixel Processor.
I ran the final image through PixInsight’s FWHM/Eccentricity and image analysis tools. The final image shows very little issues with the scope. There is an interesting aberration with the largest stars, it looks a bit liked pinched optics. I have an e-mail out to William Optics to confirm and see if I can fix it by adjusting the screws around the lenses. There is very little coma in the final image.
The above image shows the very slight coma in the extremes of the corners. It’s practically invisible zoomed out, so I can live with that. But one of the benefits of a Petzval scope like this is that it’s supposed to be corrected for these issues, and provide an extremely flat field. The field is definitely flat, but the coma still exists however minor it is.
Recent images taken with the RedCat 51
Image detailsFeb 14, 2022William Optics RedCat 51,ZWO ASI294MM-Pro,Rainbow Astro RST-135E
Image detailsSep 21, 2021William Optics RedCat 51,ZWO ASI294MM-Pro,Rainbow Astro RST-135E
Image detailsApr 12, 2021Rainbow Astro RST-135,William Optics RedCat 51,ZWO ASI2600MC-Pro
Image detailsDec 15, 2020ZWO ASI2600MC-Pro,William Optics RedCat 51,Rainbow Astro RST-135
Image detailsDec 15, 2020William Optics RedCat 51,ZWO ASI2600MC-Pro,Rainbow Astro RST-135
Image detailsDec 15, 2020ZWO ASI2600MC-Pro,William Optics RedCat 51,Rainbow Astro RST-135
Image detailsDec 15, 2020William Optics RedCat 51,ZWO ASI2600MC-Pro,Rainbow Astro RST-135
Image detailsDec 15, 2020ZWO ASI2600MC-Pro,Rainbow Astro RST-135,William Optics RedCat 51
Image detailsNov 3, 2020ZWO ASI2600MC-Pro,Rainbow Astro RST-135,William Optics RedCat 51
Image detailsJun 18, 2020ZWO ASI2600MC-Pro,ZWO ASI1600MM-Cool,10Micron GM1000 HPS,William Optics RedCat 51
Image detailsDec 4, 2019ZWO ASI1600MM-Cool,Celestron Advanced VX,William Optics RedCat 51
Image detailsDec 4, 2019ZWO ASI1600MM-Cool,William Optics RedCat 51,Celestron Advanced VX
Image detailsOct 28, 2019William Optics RedCat 51,ZWO ASI1600MM-Cool,Celestron Advanced VX
Image detailsOct 10, 2019Celestron CGX,William Optics RedCat 51,ZWO ASI1600MM-Cool
Image detailsSep 9, 2019Celestron CGX,ZWO ASI1600MM-Cool,William Optics RedCat 51
Image detailsJul 31, 2019William Optics RedCat 51,ZWO ASI1600MM-Cool,Celestron CGX
Image detailsJul 31, 2019William Optics RedCat 51,Celestron CGX,ZWO ASI1600MM-Cool
Image detailsJul 19, 2019William Optics RedCat 51,ZWO ASI1600MM-Cool,ZWO ASI071MC-Pro,Celestron CGX
Image detailsJul 18, 2019William Optics RedCat 51,ZWO ASI071MC-Pro,Celestron Advanced VX
Image detailsJul 7, 2019Celestron Advanced VX,William Optics RedCat 51,ZWO ASI1600MM-Cool