Plate solving is a revelation!
It feels like everyone else has been doing this for years and I’ve only just discovered it. It ranks up there with the greatest time-saving devices for astronomers. Why did no one tell me about this earlier?
If you don’t know what plate solving is, let me explain. Using a camera attached to your scope and linked to some type of computer, you take an image (plate) of the sky. The computer software, having been told what the focal length of the scope is, quickly calculates the field of view, analyses the stars it can see and tells you precisely what you are looking at using its in-built sky catalogue. Once you know exactly where you are, you can then quickly slew to the object your are seeking and continually refine the accuracy of your mount’s alignment.
Compared this to the last 10 years: performing a one star align on hands and knees peering through a guidescope or red dot finder, following up with a three star alignment (more crawling, more peering), maybe having to start again because you made a mess of it, finally completing your alignment and slewing to your object only to find its not in the eyepiece, back on your knees, straining your neck, grinding your teeth…have we done any astronomy yet? No, and it’s already 10.30pm and you’ve got work tomorrow.
I recently purchased an ASIair (see Astrobackyard’s excellent video review) and used this initially for guiding and now for imaging too. The ASIair is a Raspberry Pi computer linked to both camera and mount and uses an interface on your phone or tablet. I love it; its simple and it works. For years I struggled with standalone guiding using the LVI SmartGuider2 and I now realise I was never doing it properly because it was just.…so…. hard. I encourage anyone to check out the ASIair or similar products out there that do not require a laptop.
The night of Feb 26th went something like this: switched on mount linked to a ZWO ASIair and ZWO camera. Performed a one star align on Aldebaran, using the live view on my phone from the ASIair to help centre the star. I linked my mount to SkySafari App, which now showed me the direction of the scope and a field of view indicator box. Next I selected an object using the interface on the ASIair - M35. It began to slew then stopped. I took a 2 sec exposure - no star cluster was visible, but no worries. I performed a plate solve and within maybe 2 seconds it realised where it was pointing (slightly off) and gave me the option to ‘sync and slew to M35’. Yes please I said, and it moved a fraction, placing M35 centred in the screen of my phone. All this within maybe 3 minutes - WITH ME SAT IN A CHAIR.
After running 15 or so 60sec subs (all saved to the ASIair’s 32GB memory card) I picked M36, performed a plate solve and found my next cluster almost instantly. The only manual part of the operation was having to rotate my observatory roof. It was this speed of finding objects that allowed me, in the space of about 3 hours, to image: M35, M36, M37, M38, NGC2244, M108 & M97. All these are in the gallery. It helped that the first 5 of these were is a similar patch of sky, but still this was by any stretch of the imagination the most successful night’s astronomy I have ever done, made possible by plate solving and the ASIair.
My knees are grateful, my neck is grateful, my teeth are grateful - I am a convert.
March 2019