We’ve all been there. It was a lovely spring evening, and you shrugged off the gloom of winter and went for an evening stroll through the alleys and byways of the internet. Suddenly something catches your eye; you’re only distracted for a moment, but when you look back you’ve suddenly bought thousands of dollars worth of astronomy gear.
Like I said, we’ve all been there. And in that moment, you find yourself asking 3 crucial questions:
- What did I just buy?
- What do I do with it?
- What am I going to tell my partner?
In this post, I’m going to try to answer the first two questions. For the third, I’m afraid you’re on your own, though I have an extensive list of explanations and excuses that didn’t work.
1. The OTA
The OTA is the Optical Tube Assembly, or as most normal people would call it, the telescope. The significance of it being an OTA is that it does not come with a tripod or mount – the telescope is what you get, and you need to already have something to put it on, or you need to buy a mount separately.
Be aware, that telescopes are both heavy and fragile, so take care with it. Larger telescopes like this Celestron SCT have a handle on them for easier / safer carrying, take a look for one before you attempt to pick it up.
The rear of this telescope has (from left to right) a handle, a mirror lock, a visual back, and another mirror lock. Different telescope designs have different features – not all will have (or need) a mirror lock, for example.
Hiding further down on the back of the scope is the focus knob. Normally it is a nice rubbery grip knob, but this telescope is being sold complete with a ZWO Auto focuser, which can be bolted on with 4 screws and the job is done.
2. Focus Pocus
The ZWO focuser is also in the box, complete with the mounting bracket and focus knob adapter specifically for the celestron SCT telescope. Simply slide the cylindrical adapter onto the focus knob shaft, attach the L bracket to the matching bracket on the scope through the end slot (furthest to the right in the shot above), and then tighten the two grub screws in the knob adapter so that it gets a good grip, and you’re good to go. Almost.
EAF units are normally used with an astrophotography setup, and typically have a controller like a computer or an Asiair Pro to control the focusing. If you want to start off using the telescope for visual observation but have an EAF unit, then one of these hand controllers is your best friend. Plug the end of this cable into the focus unit, give the focuser power, and you’re all set to go.
3. We have visual
Next for visual observation, you need a diagonal – literally this is just a mirror in an assembly that does two jobs: first, it lets you put an eyepiece in at a comfortable angle (rather than needing to squat down behind the telescope to look straight through), and secondly it adds some necessary distance so you can find focus.
Into your diagonal, you put eye pieces, well, only one at a time. But eye pieces are magnification devices, so you probably want an assortment if you’re doing a lot of visual work. With eyepieces, the larger the number the wider the field of view, so generally pick the largest numbered one you have and use that until whatever you’re trying to look at is directly centred in the field of view, then you can work your way down through the eyepieces to get a progressively more magnified view.
4. Finding your target
Actually getting your telescope pointed at something you want to look at isn’t as easy as you might think, even with something as big as the moon. To help with that, telescopes can be equipped with a finder scope.
This finderscope comes with a bracket that needs to be attached to the telescope. If you’re doing a lot of astrophotography then typically your control unit is responsible for pointing the telescope at the target, so it is common to see astrophotography telescopes without a finder scope attached.
Seldom talked about, but almost all telescopes come with a bag or two of bits that you don’t know what to do with. I don’t know what to do with these either to be honest, but I do know that there are screws in this bag that will be needed to attach the finder bracket to the scope, so that’s something!
5. Random bits and bobs
Lastly there are always some odds and ends that get thrown in when you’re buying something second hand. In this instance there is a solar filter, a dew shield, and the original parts that were taken off when some accessories were fitted to the OTA – the original ring that has been replaced by a dew heater ring, and the original collimation screws that were replaced with Bob’s Knobs.
Stay tuned for part 2, when I’ll go through all the bits and pieces that make up a pretty schmick imaging train for deep space astrophotography…
