More individuals now reside in flats with out gardens, and even city-dwellers with gardens can discover themselves enveloped by mild air pollution. So over latest years there was rising curiosity in star trackers, that are moveable, compact mounts usually monitoring in RA solely that may be simply carried to associates’ gardens and even on abroad journeys.
Sky-Watcher’s vary of star trackers, known as Star Adventurer, have been common. The unique Star Adventurer was launched in 2014, operating off an exterior 5V provide or 4 AA batteries, motorised and guiding in RA solely. I purchased one then and it nonetheless works effectively at the moment. The 2i model adopted in 2020, including WiFi management in order that the mount may very well be operated utilizing a free Sky-Watcher app operating in your telephone or pill.
Whereas variations 1 and 2i tracked effectively as soon as they have been aiming at a goal, some customers struggled to seek out their targets within the first place – they wished GoTo performance in a Star Adventurer and that’s precisely what the brand new Star Adventurer GTi now gives. The product was introduced in April 2022, motorised and guiding in each RA and Dec axes. Samples have been provided to a number of YouTube influencers who reported their expertise with the mount in glowing phrases. I used to be eager to check a pattern on the earliest alternative but it surely was not till July 2022 that mounts truly began to be shipped. On the time of writing they continue to be in very quick provide and I’m grateful to Optical Imaginative and prescient for supplying me with a pattern unit to assessment.
The mount is obtainable in two configurations: the mount head solely, or the mount head plus tripod and tripod extension. I already personal a tripod with a 3/8-inch central bolt on prime, so I requested to assessment the mount head solely.
The mount is delivered in a single compact field. Packed safely inside are the mount head, counterweight shaft and counterweight, USB cable and a printed person handbook. I screwed the top onto my tripod and was impressed by how secure the whole lot appeared, a lot better than my unique Star Adventurer on its separate wedge. The provided single counterweight, weighing 2.26 kilograms, feels very heavy. Even proper on the prime of the shaft, it’s too heavy to steadiness a light-weight system equivalent to a DSLR and a modest lens. I might have most well-liked to see two separate counterweights, maybe one among a kilogram and the opposite 1.5 kilogram. That may provide higher flexibility.
The mount usefully gives a selection of two holes into which the counterweight shaft might be screwed. For increased latitudes, say between 30 and 70 levels that features the UK, the shaft can go within the decrease gap. At decrease latitudes of, say, 0 to 30 levels, there’s a danger that the counterweight would possibly collide with the mount, so in such areas the higher gap must be used.
To energy the mount, 12V of DC energy is required. This may be provided both by putting in eight AA batteries contained in the mount, or by an exterior 12V battery or 12V mains adaptor that may be plugged into the management panel. I don’t approve of single-use batteries and have had poor expertise with low cost AA rechargeable batteries, so I used my 12V Tracer lithium polymer battery all through my testing, which labored fantastic. Another excuse to keep away from utilizing inner batteries is the poorly-designed thumbscrew that holds the quilt for the battery compartment in place. When unscrewed, this thumbscrew detaches from the quilt, which is an accident ready to occur. I can see this screw being dropped and misplaced in the dead of night – it could be higher to make the screw captive to the quilt with an appropriate washer.
Photo voltaic imaging with the Star Adventurer GTi
It was daytime however I used to be eager to make use of the mount right away so I arrange the tripod and mount head in my again backyard to strive some photo voltaic imaging. The bottom of the mount head has a helpful bubble indicator to substantiate that the tripod is stage. I needed to polar align the mount first, which was difficult provided that it was the afternoon and so there was no likelihood of seeing Polaris via the polar-scope. I reside in London at a latitude of about 51 levels north, so I wanted to level the mount in the direction of true north (which I may do utilizing a compass app on my telephone) after which elevate up the altitude of the mount to 51 levels (which I may do by reference to the altitude scale on the mount).
I put in my Lunt 60 solarscope and Imaging Supply mono digital camera within the Vixen clamp on the prime of the mount and balanced the whole lot in RA and Dec. This solarscope and digital camera weigh 3.4 kilograms collectively, so they’re in the direction of the highest finish of the five-kilogram said most.
There’s a selection of how by which the mount might be managed: WiFi through good gadget, WiFi through pocket book pc, by USB cable to pocket book pc, or through the use of a hand controller. It’s a matter of private selection which you employ. The WiFi strategies use the SynScan Professional app, obtainable free of charge on Android, iOS or Home windows. For this assessment I attempted all of the strategies: utilizing the app on an Android telephone, utilizing the app on an Ipad, utilizing the app on a Home windows 10 pocket book, by USB cable to this pocket book, and through the use of a SynScan hand controller that I already owned. Word that no hand controller is provided with the Star Adventurer GTi – if you would like one, they’re obtainable for buy individually. All the management strategies labored efficiently, so the flexibleness of this mount is spectacular.
I chosen a solar-tracking price and slewed the solarscope to level on the Solar. After capturing 1,000 frames, the Solar had hardly moved on my display, so the daytime polar alignment and photo voltaic monitoring had labored fantastic. I stacked my frames in AutoStakkert, utilized wavelets in Registax and colored my picture orange in Photoshop. I used to be happy that the ultimate picture clearly confirmed the extra lively interval that the Solar has now entered.
Night time-time imaging with the Star Adventurer GTi
After my photo voltaic imaging, I waited for dusk to do some conventional astro-imaging. I changed my Lunt 60 solarscope with a William Optics Star 71 telescope (a small refractor with a focal size of 350mm), matched with a handbook filter-wheel and an Atik 460EX mono digital camera. Additionally connected have been a 120mm focal-length guidescope and an Orion information digital camera. The entire ensemble weighed 3.3 kilograms, just like what had labored efficiently with my photo voltaic imaging.
This time my polar alignment needed to be correct. The Star Adventurer GTi advantages from an illuminated polar-scope constructed into the mount. The brightness of the illumination might be adjusted in SynScan Professional or with a SynScan hand controller. Kneeling low down, I used to be capable of match the place of Polaris within the polar-scope to the place the SynScan Professional app informed me it must be. I additionally personal a PoleMaster digital camera system to realize polar alignment, and having polar aligned with the polar-scope I then ran the PoleMaster routine that pleasingly suggested me that my polar alignment was nearly bang on.
With a view to use the GoTo operate, I first needed to perform a star alignment in order that SynScan Professional knew which path it was pointing in. I might usually select a one-star alignment utilizing a brilliant star near my final goal, however for this assessment I selected a three-star alignment and aligned efficiently to Arcturus, Vega and Altair. My imaging goal for the night time was going to be the Crescent Nebula in Cygnus, so I entered NGC 6888 into SynScan Professional and the mount slewed there. Beginning up my imaging program with a hydrogenalpha filter, I used to be happy to see the nebula within the centre of my display – the GoTo had labored properly. Having confirmed the main focus in my imaging program, it was now time to arrange the guiding. The mount has a standard ST-4 port for a cable from the information digital camera, so I adopted this route. Customers who need to management the mount through a standalone pc equivalent to the favored ASIAIR will use the guiding functionality of the ASIAIR reasonably than the ST-4 port, however there’s nothing flawed guiding with a cable to the ST-4 port and operating a separate program equivalent to PHD2 in your pocket book.
I began up PHD2 and let it calibrate itself within the normal approach earlier than it began guiding. The standard of the guiding efficiency of my assessment unit was solely reasonable, with complete RMS error of three or 4 arcseconds. In some intervals the whole lot appeared fantastic with solely small changes made to RA and Dec, however there have been different intervals the place massive errors arose and this system took a while to get issues again underneath management. I’m all the time prepared to confess to the potential for person error, however there are additionally YouTube movies that report modest guiding efficiency for this mount, in addition to others that report good efficiency with a complete RMS error of lower than one arcsecond. It might be potential to open up the unit and attempt to modify the backlash within the gears to enhance the guiding, however this could most likely void your guarantee.
I persevered with my imaging and captured 10 six-minute subs every of H-alpha and O-III, binned 1 × 1 at zero levels Celsius. It was a balmy 24 levels Celsius at night time in London, so I couldn’t push the digital camera’s cooler a lot decrease, which was uncommon.
The following morning I studied my captures. Two of my H-alpha subs and two of my O-III subs had vital trailing and needed to be discarded. I mixed the remaining eight subs of every filter to supply my last picture of the Crescent Nebula area.
Conclusions
The star-tracker idea has matured, with the Star Adventurer GTi introducing GoTo performance into a light-weight and compact system. The built-in wedge implies that the mount is secure and the illuminated polar-scope permits correct polar alignment.
There was criticism that the five-kilogram most payload is not more than the Star Adventurers 1 and 2i, however I don’t agree with this criticism. 5 kilograms is loads for a small telescope with an astro-camera or a DSLR/ mirrorless physique with a heavy lens, and that’s the type of payload that the GTi is meant for.
It’s essential to have real looking expectations of the guiding efficiency out of the field. I discovered the guiding corresponding to operating an AZ-GTi mount in equatorial mode (described within the October 2018 challenge of Astronomy Now). If you’d like a lot better guiding efficiency then both you can purchase a dearer mount or you ought to be ready to tune the backlash out of the system.
General, the Star Adventurer GTi operated a lot in keeping with my expectations. It fills a spot in Sky-Watcher’s product vary for a compact equatorial mount and I feel it is going to be common when the product is freely obtainable.
At a look
Weight of mount head: 2.6kg
Equipment provided: one 2.26kg counterweight
Payload capability: 5kg
Monitoring: twin axis; lunar, photo voltaic or sidereal
Energy: DC 12V, 8 AA batteries or exterior provide
Particulars: opticalvision.co.uk
Value: mount head solely, £515; mount and tripod equipment, £599
