Backyard of the Week | May 3, 2021
The AstroBackyard Backyard of the Week highlights astrophotography setups from around the world. We break down each piece of the system so you can understand exactly what goes into a successful imaging kit.
This week’s backyard astrophotography equipment profile comes to us from Kai Westhöfer, in Germany.
Kai uses a 6″ Sky-Watcher Newtonian reflector to capture images of deep-space objects at a focal length of 750mm. A well-collimated reflector will reward you with impressive light-gathering ability, and record beautiful star diffraction spikes that make even the biggest refractor telescope fans jealous.
This telescope rides on a Sky-Watcher HEQ5 GoTo equatorial telescope mount, with camera control via the ZWO ASIair. This compact wifi device controls the imaging sequence and handles the autoguiding.
This setup also features an astro-modified Canon EOS 6D full-frame DSLR camera to photograph nebulae and galaxies in the night sky. You’ll also notice a small guide scope and camera system mounted in the finder scope position of this setup.
This image not only highlights the contrasting warm and cool stars surrounding the cluster, but reveals faint galaxies NGC 6207 and 4617.
The M13 Globular Cluster by Kai Westhöfer using the setup featured below.
What does Kai love most about this deep-space imaging rig? The Sky-Watcher HEQ-5 GoTo Equatorial Mount, which is able to accurately track the apparent motion of the night sky with over 9 kg’s of weight riding on top.
I can personally attest to the ridiculously reliable performance of the Sky-Watcher HEQ5 mount. After nearly 7 years, my HEQ5 continues to reward me with amazing astrophotography images night after night.
I find it useful to see this particular mount being used so well with a Newtonian reflector on top. My Sky-Watcher HEQ5 has been used almost exclusively with compact apochromatic refractors at short focal lengths.
Kai mentioned the superb autoguiding performance achieved using the ZWO ASIair and ASI120 MC on this setup.
Kai’s Astrophotography Equipment:
|Primary Imaging Camera||Canon EOS 6D (modified)|
|Telescope||Skywatcher 150PDS Newtonian Reflector|
|Telescope Mount||Sky-Watcher HEQ-5 (hypertuned)|
|Guide Scope||Sky-Watcher 50mm Finder/Guide Scope|
|Guide Camera||ZWO ASI 120MC|
|Dew Control||USB Dew Heater Band|
|Camera Control Software||ZWO ASIair|
The following photo of the Eastern Veil Nebula highlights the superb results Kai was able to achieve using the Optolong L-eXtreme filter and his modified DSLR camera. If you’ve ever tried to photograph this nebula using a broadband filter, you’ll know how the stars in the field can easily take over the image.
With a dual-bandpass narrowband filter in the imaging train, this supernova remnant is can be fully appreciated. The focus and framing of this image are also top-notch.
Eastern Veil Nebula by Kai Westhöfer.
Kai uses a Sky-Watcher 150PDS Newtonian Reflector. This telescope uses a 6-inch diameter parabolic primary mirror and has a focal length of 750mm at F/5.
The 150PDS includes a solid 2-inch dual-speed Crayford-style focuser, which comes in handy when attaching a DSLR camera or dedicated astronomy camera.
A telescope like this is an affordable option for astrophotography, offering the largest aperture for your buck. Most people (myself included) enjoy the star diffraction spike patterns created as a result of the Newtonian design.
The following image of the Horsehead Nebula region displays this characteristic perfectly.
Horsehead Nebula by Kai Westhöfer
The challenge of owning a reflector telescope is the regular collimation process (to maintain optimal performance), and the overall weight and size of the OTA. Kai did not mention using a coma corrector for this telescope, but it is something to consider if you are looking into purchasing a Newtonian reflector telescope.
Sky-Watcher 150PDS Specs
- Type: Newtonian Reflector
- Diameter: 150mm (6-inches)
- Focal Length: 750mm
- Focal Ratio: F/5
- Focuser: 1.25″/2″ 10-1 Dual Speed Crayford
- Weight: 9 kg (20 lbs)
The Telescope Mount:
The Sky-Watcher HEQ-5 is a computerized GoTo equatorial telescope mount with autoguiding capabilities. I have personally owned and enjoyed this telescope mount for many years.
An imaging setup like Kai’s is approaching the maximum payload capacity limit for this mount (for astrophotography). An 8-inch Newtonian Astrograph is possible, but achieving balance with each piece of photography gear attached is essential.
The Sky-Watcher HEQ-5 Telescope Mount
I highly recommend this mount to anyone looking for a stable astrophotography platform. If you are handling a slightly heavier load the Sky-Watcher EQ6-R Pro is another stellar option.
Kai uses an astro-modified Canon EOS 6D DSLR camera to photograph objects in space. The 6D is an incredibly popular camera for astrophotography, and you may see one pop-up in the astronomy classified sites from time to time.
It is a 20.2 MP full-frame DSLR camera with an ISO range of 100-25600. This camera is well-supported in the astronomy software realm and can be controlled with ZWO ASIair.
Canon EOS 6D (modified)
Kai uses the Optolong L-eXtreme filter to help isolate deep-sky objects from a light-polluted in the sky. The narrow bandpass qualities of this Ha + OIII filter record smaller stars, and allow important wavelengths of light to pass through.
This filter is especially useful on supernova remnants such as the Veil Nebula and the Crab Nebula.
Although it is less useful on broadband targets such as galaxies, the Optolong L-eXtreme filter will get plenty of use on a massive catalog of nebulae targets.
The ZWO ASI120MC (Super Speed) is a 1280 x 960-pixel resolution guide camera that can also be used for planetary imaging. It houses an uncooled 1.2 MP color CMOS sensor, in a compact package (0.22 lbs).
The high frame rate (60-254 fps depending on resolution) is perfect for lucky imaging and planet photography using software like FireCapture or SharpCap.
This is an affordable guide camera that works perfectly with the ZWO ASIair camera control device. The specs of this camera lend themselves well (frame rate, pixel size, to planetary astrophotography, making it a dual-purpose camera.
Camera Control Software:
The original ZWO ASIair (version 1) automates the image capture sequence, as well as autoguiding. A dedicated mobile app is used to control key functions such as exposure length and dithering.
The ASIair (and ASIair Pro) are incredibly popular in the amateur astrophotography community. They remove the need for a laptop computer in the field and allow wireless control of your telescope mount, camera, and autoguide functions.
The ZWO ASIAir (version 1) Wireless Imaging Controller.
This is a great way for beginners to see a deep-sky imaging setup that is being used to successfully photograph the night sky.
- Building a Deep-Sky Astrophotography Kit
- Optolong L-eXtreme Filter Review
- ZWO ASIAir Wireless Imaging Controller Review