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Eyepiece glare vs seeing


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I am new to astronomy and was wondering if there is a relationship between eyepiece(telescope?) glare and seeing conditions?I noticed that at times the glare seen was very bright and "washed" out detail on the planets.I attributed this at first on the eyepieces used(Celestron Luminos),but as I have aquired different ones...TV Delos,3-6 Nagler zoom they all at times have a significant amount of glare.Does moisture in the air cause more glare?I noticed this effect when it was very cold out,-25C,but still happens now that it is warmer.By the way,the 10mm Luminos@63x is my goto eyepiece,very sharp,excellent clarity,etc.In moments of good seeing all my eyepieces offer incredible views,just wondering if anyone else noticed glare vs atmospheric conditions?

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I'm not sure what you mean by "glare". It's possible it's an illusion caused by bad seeing. It's also possible it's related to humidity: the glare may originate in condensation on the outer surface of the eyepiece.

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By glare I mean bright area(big) surrounding the planet,most notably Jupiter,in darkness.I have started viewing Jupiter at sundown with greater success,seems a little bit of light in the sky helps?In the cold weather I leave my scope(and eyepieces) outside for about 45min to cool off.There is no frost or condensation on any lenses-unless I mess up and breath on the eyepiece!Also the effect isn't always there or bad,but when its bad its BAD.Maybe atmospheric dust does something to-not sure

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Sounds like haze/thin high cloud in the atmosphere to me. This is a visual/emotional nuisance but normally means the 'seeing' (stability of the air) is better so you get better detail on planets.

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What RikM said.

There can often be very thin haze in the air, invisible to the naked eye, which creates a fuzzy halo around bright stars or planets. The slightest amount of dewing on optics can create the same effect. If the haze is in the atmosphere then it can often be a sign of stable air and hence good seeing, which is good for planetary views. Either can potentially be a bit of a nuisance for DSO viewing, but as long as the haze is minimal I find it makes little difference.

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Hmm... Strange. As Acey says, haze in the atmosphere is often correlated with stable air and good seeing. So the opposite of what the OP is describing. Furthermore, such haze doesn't wash out planetary views--it just dims them. I've had quite good views of Jupiter through thin high clouds in good seeing conditions. The glare description the OP provides sounds more like phenomenon related to the telescope (or even his eye) than one related to the atmosphere. Sounds like scattering near the eyepiece or eye.

What telescope do you have? Can another observer corroborate what you're seeing? When it happens, does it occur with all eyepieces?

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Good point Umadog - if the image looks washed out then I agree it might be light-scattering in the telescope/eyepiece (as opposed to light-scattering by atmospheric haze). On the other hand it seems to be a transient phenomenon, so maybe there's a bit of both going on. The suggested tests would be a good way of narrowing down the possibilities.

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The telescope I'm using is a Stellarvue 90mm refractor,carbon fiber tube,a 2" diagonal from them and the eyepieces I have are: 23mm Luminos,10mm Luminos,6mm TV Delos and a 3-6 TV zoom.Light scattering may be a better term for this,can the telescope cause light scatter as well as the eyepieces?I have "fogged" up my eyepieces and it creates a similar effect,but much worse.Maybe light dew or frost...?

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I wiil try to narrow it down,it does happen with all eyepieces to a varying degree,but as I'm new I don't know whats normal or not.There are few if any astronomers around here that I'm aware of to give an experieced look,my family members who viewed just thought it was awewsome to see these things.I just joined the Royal Astronomical Society of Canada,Thunder Bay-350km away though.They have regular observing nites so I will go on a road trip sometime to compare scope to scope.

So far I have viewed the: moon-stunning views,sharp and clear

Saturn-can see Cassini division at times,some light banding on planet,yellowish colour,saw 5 moons one night

Jupiter-2 bands always visible,3 sometimes,looks like top of planet lighter shade at times.One night viewed a back dot appear on surface...Starry night program said asteroid impact?

can see moon transits.

M31-never realized how big this is,saw m110 as small fuzzy next to it

M42-stunning from dark site,looks green in my scope-looked like an Eagles spread wings.I can split the double double at minimum of 105x.

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For a 90mm scope the performance you are getting seems top notch to me :smiley:

Most eyepieces produce some light scatter around bright objects - the better quality ones seem to produce less as do the simpler designs such as a well executed abbe orthoscopic. As has been noted, some viewing conditions can enhance this effect as can cold eyepieces in cold conditions - they tend to fog slightly from the warmth of the eyeball. I know the TV 3-6mm zoom can be a little prone to this as the eye lens is not recessed at all.

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Just to clarify - seeing is instability in the atmosphere causing targets to move in and out of focus and shimmer - not related to this problem

Transparency - the clarity of the sky, which may be the issue.

I sometimes get a halo and it is nearly always due to some condensation in the optical path, usually the EP. Often I can't see it but a hair dryer cures it!

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You guys sure have a wealth of information to share,nothing beats experience.I noticed that the 3-6 TV zoom will lightly fog from my eye(close eye relief?) sometimes in the cold...can this happen in warmer weather but not as noticeable?Can a telescope get moisture INSIDE the tube?I have not noticed this just wondering.I keep my lenses very clean,but outside dust does seem to acumulate during a viewing session.Transparency,I'm trying to get a handle on that....ClearDarkSkies gives a viewing forecast,seems accurate,still amazes me when it looks great for viewing,but....and then other nights it doesn't look as good but is much better.The other night for about 20 minutes Saturn became so clear I couln't believe it,very sharp at 105X to about 160X,first time my zoom really showed its stuff on the planets.And then it was over.Jupiter now is terrible to view for me-too low in the sky I think.You know a halow is a very good description of what I see sometimes,I think I need to figure out a way to keep my optics as "dry" as possibe,gonna look for my wifes hairdryer!lol!I just can't wait to try my scope in excellent conditions,right now my most usefull magnification-works all the time- is 63x anything higher is gravy.

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If I step away from the eyepiece for any length of time, it tend to put the top lens cap back on. The large eyelenses of modern wide-angles seem quite prone to misting up, at least in my garden they do :(

I generally keep the remaining eyepieces in my case with the lid closed and that seems to protect them quite well. If it is very dewy, I will pop an eyepiece in my pocket to keep warm (with the dustcaps firmly on!) before dropping it into the focuser.

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You can tell if it's moisture on the outside of the eyepiece by doing two things: firstly, shine a flashlight at the lens. If it looks dull there is moisture. If it's shiny, there isn't. Secondly, you can use a camera dust buster (the bulb blowers, not the compressed air) on the lens. The air will blow away condensation. To me, it sounds like condensation. But it's hard tell over the internet!

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We just got back from fishing in the rain-BUT-I saw clear blue sky to the North!Looks like it may clear up this weekend,so after work I'll be checking things out again,great idea about shining light on lens to see any moisture.Thanks umadog.And also I will find a bulb type air puffer & try it out on dust and any moisture that may be there.I sure have a lot to learn here,but I`m really having fun.My wife just laughs when I`m out moving the scope around the yard to see between the trees and such!I will report back on what is found to help from all the info that been given to me.I got confirmation back from RASC with a schedule of events,it will be great to check out other scopes,etc. and get some opions on my setup.When I bought the scope I really had no idea of cool down,seeing, transparency,observing Jupiter just as it appears in a semi bright sky.All this help is awesome.

Thanks again

Gerry from Fort Frances,Ontario

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Well just to report....I said I kept my optics very clean...I took a flashlight to shine the lenses for the first time and they were not so clean.OK they were very dirty.But I couldn't see much without the use of the light.Thanks umadog.A whole pile of fine dust(pollen,tissue dust?) was on the obective,eyepieces and the diagonal mirror.That mirror seems hard to get spotless-maybe I'm seeing relections of dust too.I need to learn how to clean my optics,I bought a puffer ear syringe at the pharmacy until I can get the proper lens puffer.The dust that was on everthing was "stuck" ,couldn't blow much off.I'm wondering if the condensation on the optics from bringing everything back inside in the winter caused the dust to stick.I had been breathing on the lenses first,then tissue wipe followed by pure isopropyl alcohol wipe.I heard not to clean everything too often,but I think I have to.Any cleaning suggestions?I am going to continue tracking down my problems,one by one.Thanks

BTW-after cleaning, the Cassini division became a nice sharp thin line with both the Delos & zoom at 105x

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As you have discovered, shining a flashlight at a lens or mirror surface is a great way of showing up all the garbage that may be stuck to it. For that reason I was suggesting you use the approach at night when you're wondering if condensation has accumulated on the outer lens of the eyepiece. However, I would suggest a little caution in diagnosing the dirtiness of your optics using this approach. For instance, a flashlight shows up dust and coating marks on most of my eyepieces, but I know they perform well in practice. So you need to be careful to distinguish between dirt levels that are problematic and unavoidable dirt levels that just accumulate through normal use. If you're finding the views become clearer following cleaning, then maybe the eyepieces really are too dirty.

Your mirror will never be spotless, but even a fairly dirty mirror will perform well. You can remove it and wash it. I simply use distilled water and let it air dry.

I think you're right that condensation from winter tends to cause dust to stick. I've noticed this happening too. My solution is to cap eyepieces outside when they're cold, put them in the box, and just leave that way until they warm up. If you don't remove the caps the condensation can't form. If you're really paranoid, you can even bag them in ziplock bags. Another alternative is storing them in an area that's cooler than the rest of the house (e.g. the basement). Since you're in Canada and have really cold winters, you could even keep your eyepieces in the fridge (!). If you take steps such as these then you will need to clean the eyepieces far less often (possibly only every couple of years or so).

This seems like a reasonable cleaning guide: http://www.cloudynig...php?item_id=510 As does this: http://www.televue.c...page.asp?id=103

Edited by umadog
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Eyepiece the the fridge-I love it!!Great idea,gonna try that next winter until I build a storage locker outside.The other night I took my flashight outside & scanned around just looking in the air-the tree pollen floating was crazy.Got to keep my caps on for sure and hopefully get a system going to help keep my optics clean.I noticed a big difference after cleaning,until the seeing changed.I will check out those links after work in the morning.I think I notice that the sky conditions contribute to the issues seen in my telescope-odd thing is the Luminos maybe scatters light more but for instance on Saturns moons the other night,I saw as many in the Luminos as in the TV's,all by a near full moon about 12 degrees away.I saw 3 moons in all three.The Delos is awesome but that big lens is more prone to picking up stray light I'm sure,just have to be careful.I really like the scope and am having fun laerning how to use it.Great ideas and advice umadog

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I am sure the Baader optics cleaning fluid is the answer to the problem,I just checked it out on web & am gonna order some.Thanks.You know after cleaning all the Rubbish off of everthing I split the double double with the 6mm Delos VERY easily-the best yet.The 10mm Luminos at 63x almost split them,looked elongated.This was with not too bad conditions.I can't wait to try again when seeing is REALLY GOOD,if this ever happens here.I havn't seen a star in days & more rain coming!

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  • 4 weeks later...

Sounds like haze/thin high cloud in the atmosphere to me. This is a visual/emotional nuisance but normally means the 'seeing' (stability of the air) is better so you get better detail on planets.

As an update,now that I keep my optics clean,the glare issue seems to be atmospheric related as the situation comes and goes.Possilbly dust,high cloud as RikM suggested, in the summer, and atmospheric ice cystals/cloud in the winter.At times the seeing is better with "haze"-I had a great view of Saturn a while back with a little in the air.Summer viewing on Saturn seems better than in the late winter and Jupiter seems "fussy" when its cold but crystal clear out.Thinking back now the light scatter/glare was worse in the winter on the planets,but I think the DSO's in the winter are gonna be great here.I compared the same few objects I know between seasons and I have high expectations for this fall & winter.Planning some already when they are high in the sky.Also I'm gonna try an Astro Hutech Ortho 7mm on Jupiter this winter at 90x in the frac,hopefully my eye doesn't fog it up,but I have a feeling this is gonna work well....

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