MAK 127 Contrast....

[eddy]

Hey guys, hope everyone enjoyed SGL5, shame i couldnt make it and i am still to find some good 'dark skies' although my garden is adequate at the moment and keeping me keen.

Now then, Contrast whilst observing, is there any quick and easy fix for inducing more contrast on images at higher Mags? I find myself always reaching for more detail on certain things, specifically Saturn, its great until i hit the 150x - 200x Mag levels then it becomes quite dim, and lacks sharpness, now i know there is a lot to take into consideration, ie. Atmospheric conditions etc etc but is there anything i can do to try and improve on this?

Any help, tips or advice will be greatly used and appreciated

All the best

Eddy

[MikeOram]

I know exactly what you mean, and have the same issue (Skymax 127). As I'm new to star-gazing, please take what I say with a pinch of salt - but isn't it always going to be the case that as the magnification increases, the image will get dimmer? As you up the magnification, the field of view decreases so the area that you are looking at - and hence getting light from - decreases. So if you go from X50 to X100 you'll get 1/4 of the light, going from X50 to X200 will give you 1/16 of the light. The dimness will reduce the effective contrast - so everything starts to look less well defined. So in this sense, I don't think there's much that can be done.

Someone with more experience than me will know about using filters - these might help, but they will be at the cost of reducing the light levels further so any increase in contrast might be negated by the reduction in light levels [my guess is that filters work better with light buckets because with so much light entering they can cope with a slight reduction in the light]

Let's hope that I'm talking rubbish and someone knows a way around this ...

[Jove]

I think Mike is right in saying that as you increase the magnification you inevitably reduce the brightness - you're spreading the same amount of light out over a greater area.

I have found that making sure that the eyepiece is not illuminated by any nearby terrestrial lights cuts down stray reflections and can help give the impression of a darker background. Good dark adaptation probably helps too.

I do have a filter set, bought in a fit of enthusiasm when I first bought some eyepieces. I don't use them that much yet... the effect of them is a bit odd to me. The contrast enhancement they provide is quite subtle, features haven't leapt out at me when using them, making the most of them I am sure will require some patient observing. I've mainly used Yellow on Saturn, which does a little to accentuate the banding. With the 127, though, many of the features filters are supposed to enhance are on the borders of visibility anyway, and no filter can change that (indeed, the cut out light) - perhaps filters are a more useful accessory on bigger scopes.