I have done my first mount upgrade this year, from a Skywatcher Star Adventurer (SA) to an AZ-GTI running in equatorial mode, and I expect this will be a path taken by many people just moving on from astrophotography beginner status, and who want to retain a lightweight and fairly cheap setup but with GOTO and dual axis guiding capabilities. The AZ-GTI is much cheaper new than the Star Adventurer GTI and there are also examples for sale on the used market (mine was £150 used). The following applies to my particular upgrade journey, but even if not all of it applies to you, I hope that at least some of my experience will prove useful.
- I’m continuing to use a (modded) DSLR and long camera lens (Canon 300m F4 prime).
- I use external rechargeable power packs.
- I continue to use the same tripod I used with my Star Adventurer
- I’m guiding. This was the source of most of the issues I had to overcome. I will cover those in a second post.
Many on this forum have provided me with useful tips on the various problems I encountered on the way (thanks to all), so I’ll try to summarise my whole upgrade experience in a couple of posts. In this first one, I will focus on the basics – getting your AZ-GTI up and running in Equatorial mode.
First up, physical fit. If you are retaining your SA, you only need to do a couple of things. First, get a thread adapter, so that your SA counterweight bar will fit the AZ-GTI’s M12 fitting. Second, you’ll either need to replace the clamp tightening knob on the SA wedge with a hex bolt, in order to avoid it fouling the body of the AZ-GTI as it rotates on the RA axis, or get a raised dovetail. I sold my SA, so I did the following.
- I bought an M12 threaded bar, two nuts and some repair washers for my counterweight system. I glued the nuts to the two outer washers with epoxy and now I just have to rotate the whole thing round to move it up and down. I can easily change the weight too, by adding or removing washers. This was about a quarter of the cost of buying a new SA counterweight system. The first attached photo shows my setup.
- I needed a new wedge and bought a used Ioptron one. I think these are better that the SA wedges because they have a lower profile and seem generally less wobbly. As can be seen in the second photo, it came with the tightening knob already replaced by a bolt.
- I bought a small dovetail bar to fit the mount to the wedge. Try to get one with hand-tightened bolts, with one bolt that can be used to fit into the small dimple in the AZ-GTI base. You can of course get an original SA one, but I thought that was quite expensive for what it is. See third photo.
One other thing you may find is that, unlike the SA, the RA axis is quite stiff with the clutch loosened – far too stiff to be used for equipment balancing on the wedge. There are a couple of solutions this, both of which need everything to be fixed to the mount, equipment and counterweight. First, you can balance it on a table using a pencil under the pivot point. That certainly works, but is a bit fiddly. My tripod has a ¼” thread on the underside of the pillar. I attach a ball head to that, upside down and then hang the AZ-GTI from that, using its normal mounting thread. See photo 4.
Second – Firmware. You need to go to the support section of the Skywatcher website and then ‘Software and firmware’>’Motor controllers’. Download ‘AZGTi Mount, Right Arm, AZ/EQ Dual Mode’ and ‘MCFirmwareLoader_WiFi.exe’. Connect your PC to the mount to with its own Wifi and run the firmware loader to upload the controller. I actually use Ubuntu Linux on my laptop, and the Windows firmware loader executable ran perfectly under the Wine program loader.
Third – power. I used to run my SA from a USB power bank, which worked fine. However, the AZ-GTI needs 9-12V, so that won’t cut it. I sourced a rechargeable 8000mAh battery on Amazon, and that gives me a whole night’s usage. (see fifth photo).
Fourth – Basic operation. The place to start is, obviously perhaps, the Synscan App. It is beautifully intuitive to use so I’m not going to say much about it, apart from two things:
- It might be the place to start, but if you are guiding, it’s not the place to end up! (see next post)
- The AZ-GTI has no polar scope, so you’ll need to find some other methods of polar alignment. My only comment at this point is that Synscan polar alignment is a joy. You just need to do a 2- or 3-star alignment and then follow the instructions in Utilities>Advanced>’Polar Alignment’. I use the live view on the back of the camera, but it’s also really helpful to have a finder, to get the alignment stars into the camera FOV. As can be seen in the first photo, I actually use both a red dot and optical finder, as well as the live view, but the optical one is arguably finessing. I fit them to my camera’s hot shoe mount using a homemade bracket, but you can cheaply buy a hot shoe to finder bracket mount.
That’s it for this post. The next one covers autoguiding, which is not only a game changer to the quality of your astro photos but also a game changer in how you use the AZ-GTI. For me anyway, that journey was quite a testing one.
