Green / Hazy Eyepiece

[SimonGodfreyUK]

Hi all - my first post!

I inherited a telescope from my dad and it's as per my signature (save you time: Skywatcher EVOSTAR-90 (EQ2) 90mm f/900 Refractor Telescope). I've only tried it once or twice as I normally use my camera for imaging. However, when I tried it earlier this week I noticed there was a sort of green haze when viewing the moon. I was getting some condensation on the eyepiece which I just couldn't get rid of and I'm wondering if it's time for a new eyepiece or if there's something I'm doing wrong (e.g. in the cleaning / maintenance of it).

 

Thank you

[Peter Drew]

Moon filter still attached to eyepiece?  Has been known!     Welcome to SGL.    😀

[johninderby]

A Baader neodymium filter can remove the green tint and make the moon look a nice neutral grey. 

[Alan White]

Firstly, welcome  to SGL as a poster, no one bites, all are happy t help, just ask away.

As to the condensation on the eyepiece, I doubt you need a new one.
You will no doubt be breathing onto it in the cold and causing the problem and not realise you are doing it.
It's a hard learnt art keeping your breath from the eyepiece in the damp laden air.
 

[SimonGodfreyUK]

23 minutes ago, johninderby said:

A Baader neodymium filter can remove the green tint and make the moon look a nice neutral grey. 

Interesting, so this suggests that a green tint is something that is common?

[SimonGodfreyUK]

31 minutes ago, Alan White said:

Firstly, welcome  to SGL as a poster, no one bites, all are happy t help, just ask away.

As to the condensation on the eyepiece, I doubt you need a new one.
You will no doubt be breathing onto it in the cold and causing the problem and not realise you are doing it.
It's a hard learnt art keeping your breath from the eyepiece in the damp laden air.
 

Thanks! It certainly seems a very nice place to post based on the threads I've read through thus far.

I think breathing through my nose certainly played a part! I'll have to practice.

[banjaxed]

9 minutes ago, SimonGodfreyUK said:

Thanks! It certainly seems a very nice place to post based on the threads I've read through thus far.

I think breathing through my nose certainly played a part! I'll have to practice.

If learning not to breathe on your eyepieces is all you have to learn you are way ahead of most of us here 😀  Welcome to SGL.

[RT65CB-SWL]

Hi @SimonGodfreyUK and welcome to SGL. 

In answer to your question, how old is the ‘scope? - I once owned a refractor that included a Moon filter that had a green tinge... it also used 0.965” e/p’s and accessories... now days 1.25” is the standard.

When I view the Moon I use this type of variable filter --->

BTW - the Baader Neodymium is one of my most used, and I often refer it as my 'Swiss Army Knife' filter.

Edited December 13, 2019 by Philip R

[joe aguiar]

just so you know that's scope is an acro NOT the apo version.

here in North America too all the scopes were called black diamond as the colour is black with small white dots (hense the name) BUT not all of them were the apo designs.

The only ones that have always been apo 51 glass when skywatcher first came out with that light blue version like 12 years to 15 years ago then after all were 53 doublets noe in the gold/  black diamond/evostar lines.

Again the apo 53 glass models are Only the

80mmf/7.5

100mmf/9

120mmf7.5

150mmf/8 models

the other scope may be called also black diamond or now its evostar but they are acros not apos so there will be colour around the bright stuff

joejaguar

Edited December 12, 2019 by joe aguiar

[John]

I don't think anyone is suggesting that the scope in question is one of the ED doublets

Condensation on the eyepiece is not conducive to good viewing. The conditions lately in the UK means that you might have had some condensation on the objective lens as well, which again, is not going to help the clarity of the view at all.

It is worth checking the end of the eyepiece and diagonal barrels to see if a moon filter has been left screwed on - many types of these give a greenish tint to the image.

The scope is an achromatic refractor and it will show a thin fringe of violet / green around the limb of the moon and this tint may also show on the dark shadowed areas of the lunar suface such as craters and mountains near the terminator. Across the illuminated face of the moon you should not be seeing a noticable colour tint with this scope though.

I would check to see if any filters are in place, remove them if they are then try the scope on the moon again enusring that the eyepiece and the objective lenses are not fogged / or misted before observing. Keeping the eyepiece a bit warmer than the outside temperature helps stopping misting from breath / body warmth.

 

[joe aguiar]

ok was just saying cause he said was an evostar maybe he thought was a apo and should have zero colour, cause this also confused someone else who thought they got a ed scope instaed of the acro cause of the same name. so in case he sees fringing

joejaguar

[Louis D]

I would check the scope/eyepiece combination in the daytime on a neutral surface like an off-white wall (even if out of focus) to see if the color cast persists.  I would also hold the eyepiece above a white sheet of paper and see if the view through it imparts a color cast or darkens the view significantly.  If the two views differ, then the scope is involved as well as possibly the eyepiece.  If they're similar, its the eyepiece.  I'd also check the field lens side of the eyepiece for an attached filter as others have suggested.  A third check would be to look through the scope at the wall without an eyepiece and looking strictly for color cast and dimming.

Edited December 12, 2019 by Louis D

[Ruud]

Here's another vote for removing any filters, and clean the eye lens with a few cotton buds lightly moistened with alcohol.

[SimonGodfreyUK]

Thanks so much for the input. I have no idea what some of the acronyms mean but I have enough to go on to try and figure out what's going on. Hopefully I won't have to wait long for another clear night 🙂

[Geoff Lister]

1 hour ago, SimonGodfreyUK said:

I have no idea what some of the acronyms mean

Yes, some are confusing, but this may help:-

Apo = apochromatic lens https://en.m.wikipedia.org/wiki/Apochromat

Acro = Achro = Achromatic https://en.wikipedia.org/wiki/Achromatic_telescope

Geoff