Experimenting with multi-star pulse auto-guiding using a Fedora Linux computer running an Indi server running a Celestron mount driver.

A William Optics ZenithStar 66 SD Apochromatic refractor with an  Atik 314L mono CCD camera at the focus, was mounted on a Celestron AVX mount, by the side of a 50mm guidescope fitted with a QHY 5L-II-M guide camera.

A Linux computer running PHD2 and an Indi server running a Celestron mount driver was used to do muti-star pulse guiding. This method of auto-guiding gives better control over the mount than ST4 guiding or pulse guiding with a single star. The effects of seeing are averaged out over the set of stars chosen by PHD2, allowing shorter guide-camera exposures to be used without ‘chasing the seeing’

Using AstroDMx Capture for macOS, 10 x 3 minute FITS exposures of M44, the Beehive cluster were made and stacked in Deep Sky Stacker with flat-fields and matching dark-frames.

Screenshot from the Fedora Linux computer doing multi-star pulse guiding.

M44, the Beehive Cluster

Multi-star auto-guiding was introduced into PHS2 in December 2020, and should improve the guiding process.

We have shown here that Multi-star auto-guiding using a Linux computer running an Indi server and imaging using AstroDMx Capture for macOS was a good working combination. However, any combination of Linux, macOS and Windows for PHD2 auto-guiding and AstroDMx Capture imaging can be used.

Autoguided data on the Christmas Tree cluster and nebula, and the Leo triplet of galaxies

A William Optics Zenithstar 66, apochromatic refractor was mounted on an aluminium plate at the side of a short guidescope with a QHY 5L-II M monochrome CMOS camera which was attached by the ST4 guideport to the Autoguiding port of the Celestron AVX mount on which everything was mounted. The PHD2 auto-guiding was done with a Fedora Linux Laptop.

A ZWO ASI178MC  14-bit CMOS colour camera was placed at the focus of the apochromatic refractor.

The AVX mount was slewed to Rigel so that a Bahtinov mask could be used to achieve optimum focus.

Screenshot of AstroDMx Capture for macOS showing the Bahtinov mask focusing of Rigel.

After focusing, the mount was slewed to the Christmas tree cluster for guiding and imaging.

There was only opportunity to capture 4 x 7min FITS exposures of the Christmas Tree Cluster before it moved into an unfavourable position .

The images were dark-frame corrected and Stacked in Affinity Photo, and post processed in Affinity Photo, The Gimp 2.10, FastStone and Neat Image.

The Christmas Tree cluster and nebula.

The scope was slewed to the Leo Triplet of galaxies and PHD2 auto-guiding commenced, using a Fedora Linux laptop.

12 x 5 minute auto-guided FITS exposures of the Leo Triplet were captured by Astrodmx Capture for macOS with matching dark-frames.

The images were tacked in Affinity Photo and post processed in Affinity Photo, the Gimp 2.10, Fitswork4 and Neat Image.

The Leo Triplet galaxies

ST4 PHD2 auto-guiding worked fine in Linux. Pulse guiding will soon be tested with a variety of guide cameras.

Meanwhile some features and SDK changes are being made to AstroDMx Capture on all platforms and will shortly be incorporated into another release of the software.

M37 plus uguided and guided data on IC 2177 and their combination

A William Optics ZenithStar 66 SD Apochromatic refractor wasmounted on a Celestron AVX mount. An Atik 314L mono CCD was mounted at the focus. FITS images with matching dark frames were captured using AstroDMx Capture for macOS of M37. 

35 x 20s exposures were stacked in Affinity Photo and post processed in Affinity Photo and the Gimp 2.10.

M37 in Auriga

The camera was fitted with a H-alpha narrowband filter and 5 minute, unguided FITS images were captured with matching dark frames. 9 x 5min unguided FITS exposures of the central part of the Seagull nebula were stacked in Affinity Photo with flat fields and post processed in Affinity Photo, the Gimp 2.10 and Neat Image.

Unguided Seagull nebula, IC 2177, 45 minutes total exposure time

The next night, the Atik 314L CCD camera fitted with a H-alpha narrowband filter was mounted alongside a 50mm guidescope fitted with a QHY 5L-II mono CMOS guide camera.

The scope was autoguided using PHD2 running on a Fedora Linux computer.

The guiding rig

Screenshot of PHD2 autoguiding.

8 x 10 minute FITS exposures were captured of the central part of the Seagull nebula using AstroDMx Capture for macOS on a Mackbook Air computer.

The equipment capturing images of the Seagull nebula

Screenshot of AstroDMx Capture for macOS capturing 10 minute, guided images of the Seagull nebula, IC 2177.

The FITS images were stacked, dark frame and flat field corrected in Affinity Photo. The final image was post processed in Affinity Photo, the Gimp and Neat Image.

The Seagull nebula, 1 hour, 20 minutes total exposure time

The two images of the Seagull nebula covered slightly different areas of the nebula so they were stitched into a mosaic using Affinity Photo.

Mosaic of the Seagull nebula

Autoguiding allows for longer exposures  and these experiments have shown that PHD2 can be used with Linux, whilst the capturing was done by AstroDMx Capture for macOS.

Testing AstroDMx Capture and an SV305 camera with MX Linux

With a virtually full Moon in the sky, a William Optics ZenithStar 66 SD Apochromatic refractor was mounted on a Celestron AVX mount and an SVBONY SV305 camera was placed at the focus.

AstroDMx Capture for Linux running in MX Linux was used to capture two overlapping 2000-frame SER files

Click on an image to get a closer view

Screenshot of AstroDMx Capture capturing a 2000 Frame SER file in MX Linux

The best 50% of the frames in the SER files were stacked in Autostakkert!, wavelet processed in Registax 6 and post processed in The Gimp and Affinity Photo, and the images stitched in Microsoft ICE.

The Final image

Final image with enhanced colour saturation to reveal more of the mineralogical variation in the Moon's surface

The SV305 once again proves it's worth in combination with a short-tube apochromatic refractor and yet another distribution of Linux; MX Linux.

The Horsehead region with AstroDMx Capture and PHD autoguiding.

A William Optics Zenithstar 66, apochromatic refractor was mounted on an aluminium plate at the side of a short guidescope with a QHY 5L-II M monochrome CMOS camera which was attached by the ST4 guideport to the Autoguiding port of the Celestron AVX mount on which everything was mounted.

An Atik 314L mono CCD camera fitted with a narrowband H-alpha filter was placed at the focus of the apochromatic refractor.

The capture and guidescope mounting on the Celestron AVX mount

The Atik CCD camera was attached to a Macbook Air running AstroDMx Capture for macOS and the QHY CMOS guide camera was attached to a Lenovo ThinkPad X230 laptop running Fedora Linux with PHD2 running as the autoguiding software

The capturing and autoguiding equipment

Screenshot of the PHD2 autoguiding of the scope

The MacBook Air capturing 16-bit FITs data on the Horsehead/Flame nebula regionT

The 16-bit display controls in AstroDMx Capture allowed a good preview of the objects being captured

Screenshot of AstroDMx Capture capturing a 24 minute exposure

10 x 6 minute exposures, 1 x 12 minute exposure and 2 x 24 minute exposures were captured with matching dark frames. The Autoguiding performed extremely well and there was zero movement of the image as each image was captured and displayed.

The FITs files were stacked and calibrated with the dark frames and previously captured flat fields in Affinity Photo on the MacBook. The resulting stacked image, which comprised a total exposure time of 2 hours was post processed in Affinity Photo, The Gimp 2.10 and Neat Image Pro, all on the MacBook.

The Horsehead and Flame nebulae in H-alpha light

Closer view

The Celestron AVX mount performed extremely well in conjunction with the PHD2 autoguiding. The new 16-bit brightness controls enabled the display to be set, non destructively to a pleasing view of the objects being captured without the captured data being affected.

These results demonstrate that macOS is a perfectly good imaging platform using AstroDMx Capture for macOS and all native image processing software.