Tele Vue-76: Imaging the skies from South Africa!
Our dear friend Vineet Bewtra in London, UK, has transported his trusty Tele Vue-76 APO refractor to Kagga Kamma Remote Observatory (KKRO) at the southern tip of South Africa, 180 km (110 miles) northeast of Cape Town. Located in a wilderness area known as the Cederberg, at 1200 meters (4000 ft) above sea level, the arid skies offer Bortle-1 seeing for astro imagers and views of wind-carved sandstone formations during the day. The shift from imaging at latitudes 52° North to 32° South has dramatically changed his astrophotography experience. This blog covers his journey through 84 degrees of latitude and provides a learning experience for others wishing to install a remote telescope.
“I am so glad I set up a remote scope, and also it’s been so eye-opening what even a 3-inch scope can allow in dark skies.” Vineet continues: “I’ve found it a revelation and have absolutely no regrets about doing it, other than perhaps I should have done it earlier!” But don’t rush your favorite scope to a remote site right away: “I’m glad I started with imaging from my back garden, because that’s how you learn the skills and quirks and also get to the realisation that you can actually remote image with normal equipment” without buying a monster scope.
Remote Imaging Revelations
Image sub-frame scheduling requires consideration of sunset and sunrise times as well as moonrise and moonset times. Like many astrophotographers, Vineet employs Luminance, Red, Green, and Blue (LRGB) as well as narrowband Hydrogen-alpha, Oxygen II, and Sulfur II (Hubble Palette) filter sets on nebulae. The choice of when subframes are taken with each set depends on the presence of the Moon in the sky. Imaging through Hubble Palette filters encounters no interference from moonlight and can be employed while the Moon is up. LRGB imaging, where the filters pass moonlight to the camera sensor, can only be done during moonless hours.
Vineet notes the “sheer volume of data that can come in when it’s night after night of clear skies” is a “wonderful problem to have.” For example, “In the UK, it can take me a year to get the data on something that I can get in 3 days” from the remote scope. This amount of data requires a higher level of organization than when the scope was in the garden. “It definitely helps to be methodical, and keeping an electronic tally is incredibly useful — otherwise I’d forget what was where.” Advanced planning “is also a great way of learning about a large new sky.” During the day, after each imaging run, he inspects the light frames and checks if new flats are needed. The final image “processing begins when enough hours of data has accumulated.”
If you peruse Vineet’s images on AstroBin, you’ll immediately notice there are several versions of each object, representing processing with a different blend of narrow and wideband filters.
Hardware and Software
As a longtime Mac user, Vineet stayed in the Apple universe for the hardware and software choices. All the hardware on the telescope is connected to a Mac mini computer. “The Mac mini M4 processor is very fast (even ignoring the M4 Pro version),” but he needed more storage for this project. He decided on 2TB to hold all the subframes at the remote location. Luckily, the “Mac mini M4 model allows users to very easily swap the hard drive to 2TB from a generic manufacturer without any hitches — which is what I did.” Vineet recommends this website for others seeking to do the same: https://expandmacmini.com.
The Mac mini setup is “headless,” as it lacks a keyboard, mouse, or monitor. In the event of a power outage, the system is configured to restart and reconnect to the Internet. All control and image storage is on the remote machine. Therefore, Internet failure will not interrupt the automated imaging at the remote location.
Vineet uses the free version of Tailscale to set up a stable private connection between a home computer in London and the remote Mac mini in South Africa. Initially he used RustDesk, remote desktop software, to log in to the Mac and control the imaging session.” Recently he’s run into issues with Rustdesk (“maybe because I was using the free version”) and switched to the macOS built-in Screen Sharing application (Mac-to-Mac only). “So far it seems much better.”
Vineet uses KStars desktop planetarium program with the built-in EKOS module that schedules and manages the imaging session using the INDI protocol to control the hardware. “I’ve grown quite fond of it, although it’s not without its idiosyncrasies (especially when new versions come out — there’s always a few little wrinkles, so I’ve learned to not get rid of older versions until the new versions are bedded in fully).”
Telescope Imaging Hardware and Software List
This is a list of the remote hardware and the remote or locally run software used to capture and process images.
Hardware
- Tele Vue-76 APO refractor
- Player One Poseidon-M Pro camera
- Sky-Watcher HEQ5 PRO mount (upgrading to AZ-EQ6GT in late Feb)
- DeepSkyDad Autofocuser 3 (AF3)
- DeepSkyDad Flap Panel (FP2) (custom designed for TV-76 dew shield)
- Rouz Astro dewshield retaining ring (prevent sagging due to DSK Flap Panel)
- Pegasus Astro Ultimate Powerbox 2 ·
- TS-Optics Photoline 2″ 0.79x ED Reducer/Corrector (TSRed279)
- Astronomik 36mm filters:
- CLS-CCD
- Deep-Sky Blue
- Deep-Sky Green
- Deep-Sky Red
- H-alpha CCD 12nm
- OIII CCD 12nm
- SII CCD 12nm
Software
- Aries Productions Astro Pixel Processor (APP) (run at remote computer to stack)·
- Bill Blanshan Screen Stars (add and/or remove stars from image) ·
- Cranfield/Payne Generalized Hyperbolic Stretching (GHS) Module/Script ·
- KDEdu KStars (planning, scheduling, execution)
- Pleiades Astrophoto PixInsight
- Russell Croman Astrophotography:
- BlurXTerminator
- NoiseXTerminator
- StarXTerminator
Imaging Insights
Having a powerful machine at the remote site greatly diminishes the amount of data transferred to the main processing computer. “I find it better to do the calibration and stacking on the remote machine in Astro Pixel Processor and then file transfer the stacked masters for each filter back to my home machine for the post-processing in PixInsight.”
Due to the better horizon, Vineet notes that “classic” northern hemisphere targets, like the Horsehead Nebula (B33), are easier to image from South Africa than from his London home. “I could probably image B33 a couple of hours a night max if the skies are clear during the window that the Horsehead is visible, given buildings and trees.”
While processing NGC 4945 galaxy in Centaurus, “I realised that the little scope had actually caught the dust in the Milky Way that you have to look through in that direction. I’m now practising continuum subtraction to be able to add some more twists to the images.”
Meet the Tele Vue-76
The Tele Vue-76 is a compact, travel-ready apochromatic refractor with a 76 mm aperture, 480 mm focal length, and f/6.3 focal ratio. Its doublet objective minimizes chromatic aberration, making it well-suited for both serious astrophotography and visual observation with 2-inch eyepieces. The maximum field-of-view is a binocular-like 5.5° with our 41-mm Panoptic (11.7x) or 55-mm Plössl (8.7x). The 5.0° field-of-view of the 31 mm Nagler (15.5x) is another option for wide-field/self-finder use. The power range and field afforded by this scope allow you to explore astronomical, spotting, and birding targets with the same instrument.
Features include a 2″, 10:1 dual-speed, rack-and-pinion focuser with dual tension adjustment screws on the drawtube and dual lock screws on the end-ring. The OTA includes a sliding metal dew shield and screw-on metal lens cap. Available tube colors are ivory or evergreen using a tough, durable powder coat instead of paint. A custom-fitted padded case with room for accessories is included.
For imaging, the Model TRF-2008 0.8x Reducer/Flattener was specifically designed for use with the Tele Vue-76 and Tele Vue-85 refractors. It converts the Tele Vue-76 into a 380mm f/5 and the Tele Vue-85 into a 480mm f/5.6 telephoto lens — this allows you to capture expansive nebulae while correcting for edge abberations.
Just slip its 2″ chrome barrel into the drawtube and attach your camera to the T-thread on top. You’ll fit a 6.5° image on the diagonal of a full-frame camera on the Tele Vue-76. TRF-2008 can also be used with any 400—600 mm doublet refractor with a 2″ focuser. There is more information on our website (mobile site).
Vineet tells us his latest project is to photograph under-imaged targets. We wish him continued imaging success from the Cederberg of South Africa.
Did you observe, sketch, or image with Tele Vue gear? We’ll like your social media post on that if you tag it #televue and the gear used. Example:
#televue #tv76 #velaSNR
Do you want your Tele Vue images reposted on Tele Vue Optics’ social media accounts? Use this hashtag for consideration:
#RPTVO
More Info
- Tele Vue-76 website (mobile site)
- Kagga Kamma Remote Observatory (KKRO) website
- Vineet’s website: leela.astro.imaging
- Vineet’s AstroBin page.
- Vineet’s Instagram page.
- Vineet on CloudyNights.com
