Balls of bright white light - please help

[stargazerlily]

The one thing that is putting a big downer on astronomy for me is the problem I have with my eyes. Shine a bright light into my eyes and they go all hazy and watery in double quick time.

When I'm observing Jupiter, I see a ball of bright white light (and some bands) but after a short while, my eyes go hazy and watery. And that is then that for the observing session.

I have two filters ... a moon filter and an Neodymium filter.

Please could some one suggest other filters that I could try, to cut down on the glare and also to bring out some colours or to see some features on Jupiter (and Saturn) rather then just seeing a bright white ball.

Many thanks

Pete

[umadog]

Generally, filters aren't all that useful on planets and most people don't bother with them. You don't need them to see detail. Jupiter shouldn't be bright enough in your scope to cause you viewing trouble. However, your eyes may have a reflex tearing response induced by bright objects. Do you get this problem when not observing planets? If not, my bet is that you have such a reflex. You could try the neutral density filter (moon filter) to knock down the brightness of Jupiter. Another thing you could try is to remain light-adapted when viewing Jupiter (keep a light with you and look at it often). This may work because Jupiter isn't actually very bright in absolute terms, it just seems bright because everything else is so dim. So remaining light adapted should mean you don't need a filter. Remember that a telescope can't make an object brighter than it already is. It can only make it bigger.

However, first thing to do is to pop over to the optician and describe what's happening. Ask them if they think it's light-induced tearing response. If it is, it'll probably happen during their testing procedures.

[stargazerlily]

Wow ... I reckon you've hit the nail right on the head!!!

I think I do have a light-induced tear response. I remember at my very first eye test (when I was a wee nipper) having a bright light shone in my eyes and the eyes going all watery. I've had that ever since. Amazing ... wow ... I thought it was just me being odd.

When you talk about having a light with me when observing, do you mean having a small torch by the eye piece or scope?

Cheers

Pete

[jimmyjamjoejoe]

I think he just means having the general area around you lit moderately, so that you don't get your dark adapted vision...

Think how much brighter things seem when you've been sat in the dark for 20minutes and then BAM someone turns a light on. Thats the effect you want to avoid, so keep the lights on

Keeping one of those torches with the strip lights on them around you might help (something like this, or at least a similar design). It'l give some nice diffuse light that won't blind you, but won't let your eyes adapt to the dark either.

Definitely go see the optician though, they might be able to help you cure the problem, or at least give you some advice on how to avoid it.

edit: also, about the filters, there's a post in the help section about different coloured filters for use with planets. They might help reduce glare, but will likely make the image appear in false colour.

[umadog]

What I'm getting at with the light is that it's not going to be the absolute brightness of the object which induces tearing. Probably you can walk out in daylight and your eyes don't tear, yet daylight is thousands of times brighter than Jupiter or moonlight (telescope or no telescope). The reason those two appear bright is because you're looking at them in darkness. It's the contrast between light and dark that matters since it is this which your brain interprets as brightness.

Any ambient light that decreases your dark adaptation will help to keep Jupiter from appearing too bright and so should reduce the tearing response (if this is indeed what is going on). The ambient light will simply keep Jupiter from appearing too bright. You may need to combine this with a neutral density filter as there is considerable contrast between Jupiter and the sky background. Have a play and see what light level works for you. It may also help to put white card around the focuser.