Time under the stars has been very little of late for us in Sydney. And when the clouds do clear, seeing has been poor. But you take what you get and look to make the most of it.
So during last week's rare clear night I tried a few things with my ED80.
I've been wanting to experiment with these modest 1.25" 0.5X focal reducers in something other than with DSO's. These focal reducers because of their simple design introduce significant field curvature (FC) to the field as the lens arrangement is not corrected. Well it can't as correcting for field curvature in a reducer needs to be scope and f/ratio specific.
The little reducers do serve a purpose, particularly in video astronomy with some FC is easy to tolerate with DSO's. But I hadn't tried one with the Moon.
The ED80's focal length and the small chip size of the 224 camera see's the Moon just a little too big (first pic is of the Moon neat though the ED80). So a fit the 1.25" reducer to the camera and had another go at getting some AVI footage, and for good measure add some shocking seeing conditions to the mix!
To my great surprise, the processed image with the reducer came up really well! The whole of the Moon fit in the FOV, and remained sharp across it entire span.
I then tried using a 3X barlow for the hell of it, namely to see how the poor seeing conditions would challenge the processing. Seeing by now had degraded even more too. And yes, there are a lot of processing artifacts that can be seen in the third pic. Conditions were certainly not good enough to go for any high magnification.
All images were processed using Registax 6 & AutoStakkert, and touched up a little with Photo Gallery (yep, from Microsoft...). Part of the exercise was also to push software that is already on many computers and see what can be done with them. With seeing being so blooming poor, I only used 5% of the captured frames for each image (roughly 420 frames in each).
I am very pleasantly surprised what this modest little reducer did with the Moon for me!
It certainly allowed for a better image to be obtained than what neat through the scope could do on the night, and a hell of a lot better than high magnification could offer.
Alex.
