Nebula imaging while testing advanced functionality in AstroDMx Capture.
Although it is, of course, possible to use a finder scope and an illuminated reticle eyepiece to do a scope/mount alignment, it is not required if the mount can be placed in the same position each time so that the previous alignment can be used. In our case, marks on the concrete slab on which the mount is placed are sufficient for us to be able to place the mount in essentially the same position for each imaging session.
The imaging scope, an Altair Starwave ASCENT 60ED doublet refractor with flattener, was mounted on a Celestron AVX GOTO mount. An SVBONY SV165 guide-scope fitted with a QHY-5II-M guide camera was mounted on the imaging scope. A Raspberry Pi computer running an INDI server was connected to the hand controller and communicated with the indoor computer running AstroDMx Capture via WiFi. The guide camera was connected by USB to the indoors computer running PHD2 auto-guiding software. An Altair 2” magnetic filter holder version 2 containing an LeNhance narrowband filter was placed in the optical train.
Nicola has implemented an INDI Configurator in AstroDMx Capture which is capable of configuring up an INDI server on another computer running the Linux operating system, in this case, a Raspberry Pi running Raspberry Pi OS. It can configure the INDI server for whatever tasks it is to perform. This can be done even if AstroDMx Capture is running on a Windows computer or a macOS computer.
The AVX mount was placed on the alignment marks on the concrete base. The mount was powered on and AstroDMx Capture passed the time, altitude and location coordinates to the hand controller via the INDI server. The hand controller which now contained all of the correct information was set to its previous alignment and was unparked by AstroDMx Capture.
AstroDMx Capture connected the SV605CC OSC camera natively by USB, set the camera temperature to -10 degrees C and sent the scope/mount to Aldebaran. AstroDMX Capture plate solved the field and centred Aldebaran in the field of view. A Bahtinov mask was placed on the imaging scope and Aldebaran was brought to sharp focus.
AstroDMx Capture was then used to send the scope/mount by means of the INDI server to the California nebula, plate solve and centre the nebula in the field of view. The mount nudge function was then used to compose the image as required.
AstroDMx Capture captured 20 x 3 min FITS exposures of the California nebula
The images were stacked and partly processed in Deep Sky Stacker and post processed in The Gimp 2.10 and Neat Image
The California nebula
AstroDMx Capture was then used to send the scope/mount to the star Alnitak in Orion’s belt, plate solve and centre in the field of view. Then AstroDMx Capture’s mount nudge function was used to compose the image so that the Horsehead nebula and the Flame nebula were optimally positioned in the field of view.
Twelve 5 min FITS exposures were captured of the Horsehead and Flame nebulae region.
The imaging computer indoors
Screenshot of AstroDMx Capture saving 5 min FITS exposures of the Horsehead/Flame nebula region
The hour’s worth of data were stacked and partly processed in Deep Sky Stacker and post-processed in the Gimp 2.10 and Neat Image.
The Horsehead and Flame Nebulae
The scope/mount was then sent by AstroDMx Capture to the Monkeyhead nebula, plate solve and centre the nebula in the field of view.
AstroDMx Capture was used to capture 12 x 5 min FITS exposures of the nebula
The data were stacked and partly processed in Deep Sky Stacker and post processed in the Gimp 2.10 and Neat Image.
The Monkeyhead nebula
Finally, AstroDMx Capture was used to send the scope/mount to the Jellyfish nebula, plate solve and centre the nebula in the field of view.
Only 5 x 5 min FITS exposures were captured before clouds moved in and stopped imaging. In fact the last two images were captured through very thin clouds.
All five images were stacked, partly processed in Deep Sky Stacker and post processed in the Gimp 2.10 and Neat Image.
The Jellyfish nebula
No dark frames were captured for any of these images. The SV605CC OSC camera produces no significant amp glow and the images produced were satisfactory. In a poor and changeable weather system such as we frequently have in the UK, such an amp-glow free camera allows for more time to be spent on image capture. Of course, dark frame calibration is desirable, but with this camera it is not essential.
The paradigm shift mentioned here is that with a mount that is not permanently installed and which requires placing on the ground for each separate imaging session, it is possible to acquire the desired objects and to image them without first having to align the mount. In fact, the mount only needs to be aligned once and at least for several sessions can be set to previous alignment before proceeding, as long as it is placed carefully on marks on the concrete upon which the tripod rests.
Nicola’s newly implemented INDI Configurator in AstroDMx Capture allows the configuring of an INDI server on any Linux computer, such as the Raspberry Pi that we use. It allows for the INDI server to be configured for any of the tasks for which it may be required without having to manually login to the remote computer via SSH (Secure Shell).
Again, these features bring AstroDMx Capture that much closer to a major incremental release. We shall report here when that happens.
