light-sensitive eyes?

[Ags]

I wear glasses and they are slightly tinted because I am light-sensitive. Does that mean I can see fainter stars than most people? For example, I can see lots of stars in M13 with a 100mm scope, while others say they only see a few stars with a 5 inch or six inch scope.

PS: I take off my tinted glasses when looking through the telescope lol.

[Capricorn]

Suspect not, it is the ability of the eye to resolve 2 close objects that enables a person to detect individual stars and that is a property of the lens, as in how sharp an image it produces on the retina.

Slightly tinted seems of minimal use as the iris will be compensating for the incident light to a far greater extent then a slight tint will cover.

Think the iris can range from 7-3mm that is a percentage change of over 500%. If your iris cannot shrink enough then you will get a greater degree of spherical abberation then someone's iris that can.

I assume the glasses are prescription so with them off the errors that the eyes have will then be present when you observe.

[abumuhannadh]

...I assume the glasses are prescription so with them off the errors that the eyes have will then be present when you observe.

i wear glasses too, but haven't found it any more difficult without it when i observe through binoculars or the scope, the focus mechanism compensates for myopia, i guess

[James]

I have very light sensitive eyes but my most sensitive one is astigmatic and shortsighted so basically I can see faint light very well but can't necessarily resolve it into more stars.

It's great for detecting faint galaxies though

James

[Ags]

Slightly tinted seems of minimal use as the iris will be compensating for the incident light to a far greater extent then a slight tint will cover.

Capricorn, the glasses are prescription, and the optician did seem to think the tinting would have a beneficial effect for me, so it must do something...

I was thinking that there might be a range in the sensitivity of the human retina - that different eyes might have slightly different ISO ratings.

[Ogri]

"Does that mean I can see fainter stars than most people?"

I wouldn't be at all surprised.

My pupils are welded wide open, and I get 'star swamped'.

The Skywatcher LPF and the Castell UHC, are a great help in pushing excessive star numbers into the background dark contrast, so I can see what I am trying to look at.

PS best tints for optimum contrast are green for daytime bright conditions (mine are heavy green), and amber for poor visibility/night use (my amber tint is heavier than most would need at 66%, whereas driving glasses tend to be around 30% for normal people, for example). I also have anti UV, anti reflection, anti glare, mirroring, etc., on all pairs (costs a bomb but without them I can't go out unless it's heavily overcast, and night time with car headlights is like being hit with a laser).

[Macavity]

To add interest, my eyes dark-adapt at quite different rates. I do keep an eye (sic!) on this sort of thing tho' - Two past generations of my family fell eventual prey to macular degeneration...

[nicnac]

mine are photosensitive too, my vision in low light conditions is great.

one draw back though, when viewing the moon for the first time it felt like pins jabbing my eyeballs, i had to get a variable moon filter (a fantastic purchase)

[Ags]

And I've been complaining Jupiter is too bright! I guess I need to get a moon filter.

[nicnac]

good prices at first light optics

http://firstlightoptics.com/proddetail.php?prod=vari_pola_filter

[Odd Thomas]

good prices at first light optics

Moon & Neutral Density Filters - Variable Polarizing Moon Filter

Can these be adjusted while you are observing or do you have to remove the eyepiece and then adjust it?

[nicnac]

take out to adjust but its not something that you have to do often.

PS - if you are using a telescope that uses a diagonal (refractor/mak), put the filter on the diagonal not the EP

[Ogri]

You can use separate ones too, stick one on the diagonal, and the other on the eyepiece, then just rotate the eyepiece to vary the light throughput.

I have a pair of the separates, but have found with the Skywatcher LPF 2" in the nose of the diagonal, just one of the polarising filters used with it seems to be pretty good.

[ronin]

and the optician did seem to think the tinting would have a beneficial effect for me, so it must do something...

Something it will be doing is increasing the opticians profit.

Sounds as if the optician couldn't give a specific reason for it. As was said earlier a slight tint simply means that your iris's will open a little more when behind the lens. The difference will be that the whole scene will a have it's colour balance changed.

Unless you have been told that you need prescription sunglasses I also would be dubious of a slight tint. I had prescription sunglass when in Australia, the light in Alice Spriings is intense. Doesn't make me sensitive and I use them here, still do not count myself as sensitive. Nor I guess do the people that appear each summer wearing sunglasses. Slightly more comfort under bright conditions, but they are about a 70-80% block, not slight.

Like the term photo sensitive eye's. Thought they were all photo sensitive? Isn't that how they work?

Could count the problem of too great a degree of sensitivity is one of noise as in a DSLR, the "signal" from one cell floods into nearby ones and so the final image is poor. Your sharp one pixel image is now spread over 3 or 4.

Remember to differentiate between image quality and observing comfort. If eyes are sensitive then in low light conditions, as at night, the comfort level is better. As in "I can see comfortably now, that is a lot better".

How do you tell if your eyes are better then mine? I have no idea the actual image detail you see and you have no idea of the image detail I see.

[nicnac]

i suppose i could have wrote "overly photo sensitive" but i chose not to, i rarely do.

as far as my eyesight goes, being overly photo sensitive, i do have the ability to resolve fainter objects when in comparison to others within my group.

one thing i wont say is "my eyesight is better than others" it just makes my hobbie all the more worthwhile to me, nothing more

[Ags]

I seem to be seeing fainter thangs than average. The tint was prescribed by an optician/optometrist (can never remember the right term - the one that has to go to med school) who did not sell specs, so I'm inclined to trust the prescription.

[Ogri]

Ronin the tints and coatings I have on my glasses, cost a fortune (about the value of a new HEQ5 every year, or more often if people steal my glasses thinking they are sunglasses - which has happened to me the last two years).

They are worth every penny, as they mean I can go outside the front door, and I can pick up a piece of paper and read what is on it (as long as I don't overdo it, and I still can't handle flourescents and a few other things though).

After my operation went wrong, this might sound crazy, but I spent the next six months plus sat in a dark room, with heavy curtains closed, wearing sunglasses, and if I picked up a blank sheet of A4 paper, the glare from it (no light on, and wearing dark glasses) was excruciatingly painful, and you would not believe how many high strength painkillers (codeine and nurofen) I got through.

The arc eye I suffered if the sun came out, or if a car zapped me with those amazingly high brightness headlights, or just opened the curtains without checking what the light was like, has put me in bed chewing painkillers, for over a week at a time.

I'll take normal eyes anytime. Seriously.

It took me years of experimenting with things like eyepatches, different lens coatings, different tints, etc., to find the things that worked. eta: As I have mentioned on here before, when setting up dads 'scope, and with a Meade moon filter fitted, I got arc eye off the moon in a few minutes viewing, which gives some perspective.

Luckily I have had the advantage of an outstanding optician who has helped me tremendously along the way. She has far better gear than my eye specialist in the hospital, and she can use it too.

She won't sell rubbish either, which means even her £10 frames are better than those some people sell for over £200.

She's one absolutely awesome lady.

Unfortunatley not all are in her league.