2nd Observation Night

So this one was always going to be hit and miss…turned out to be more miss than hit…thanks UK weather!

The forecast for the last observation night was for mainly cloud. It ended up being clear for the entire observation period. The forecast for tonight was similar, so I decided to take a chance and drag my main rig out. The main rig being the ST102, mounted on the SW SA and not the best set of legs in the world. To try and compensate for that instability I lowered the centre of gravity and stripped off everything I wasn’t going to need, leaving attached the focus controller and Nikon D5300, along with an erecting prism diagonal and finderscope. The latter needed alignment-checking anyway so I figured tonight was as good a night as any.

It looked as though I was going to be in luck. The evening thus far had remained predominantly clear, with some fast moving patchy cloud. Within 5 minutes of gaining polar alignment of the mount, that changed to fast moving lots of cloud…typical. For about an hour it stayed like that, threatening to clear one minute before clouding completely the next. Eventually though I was rewarded with a big beautiful clear patch that lasted about 10/15 minutes.

I’d already struggled to get focus with the Nikon in place, so during the cloudy period I’d switched to the 25mm EP and obtained focus with that through some of the small breaks.

As I knew I’d be time limited, I immediately honed in on my old favourite, M42, despite really wanting to go comet hunting for 46P. As soon as I got on target I immediately switched to the 10mm EP. I have to say that M42 looked pretty spectacular through a 500mm lens. That nebulosity was very apparent, even though “seeing” wasn’t that great due to the amount of moisture in the air and increasing wind speeds. At the same time, I re-aligned the finderscope, for once actually getting it spot on the crosshair.

I was mentally kicking myself at this point for leaving the x2 Barlow sat on my desk at home. I think seeing M42 at the equivalent of 1000mm would’ve truly been something else.

The ST102 performed about as well as I expected and hoped for, in that it’s a doublet refractor with quite a pronounced curvature on the objective end. If I can locate one, then a flattener is definitely going to be needed. It’s also definitely too much for the SA on the legs that I currently have. Even in a slight breeze it acted very much like a sail and movement was quite apparent through the EP. For visual observation, it’ll be more than okay at this moment in time. For imaging, it’s going to prove quite challenging to say the least.

For future reference

Upgrade the legs. At least 2″ steel would be good.

Source a flattener

Also source a Bhatinov Mask.

Sort out critical focus with DSLR attached. Not sure what was going on but I was clearly way out on the markings I had. Try again with a focus extender during daylight.

Retighten 2″ to 1.25″ focus adapter. This came loose.

Have a look at the focus tube. With a DSLR attached there seems to be a fair bit of vertical “slop.” Chances are it just needs re-tensioning.


Not the best night in the world but it did pinpoint some areas that need attention with that scope, so it wasn’t entirely wasted. Plus I got “eyes on” with M42. That’s never going to be a wasted evening 😉

I have to say as well, that having used both an RDF (red dot finder) on my old newt, and a finderscope, on both the ST80 and ST102, I definitely prefer using a finderscope. Just seems to be so much easier. Plus you don’t need to worry about another battery running flat!

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