Yellow Halo Around The Edge Of The Moon

[Matt2011]

Not sure if its normal but I am using my Helios 15x70mm Apollos Binoculars on the moon right now and the moon is quite low down and in focus, But around the edge is a bright yellowish halo around the edge of the moon. Is this normal or would there be something which is causung it. Thanks

[Zakalwe]

Moisture in the atmosphere? This hot and humid weather means that the air is very smoggy.

[Matt2011]

Many Thanks, Could be just that and the yelllow halo is in the right half of the moon and on the left side its not visible. Lovely view of the moon though. cheers

[Damo636]

Sounds like Chromatic Aberration (false colour) to me Matt. The Apollo is basically two fast achromatic refractor's strapped together and as such will show some minor CA on bright objects such as the moon. I find that accurate focus and precise eye positioning in the eyepiece's help reduce the affect.

[MooMoo]

Maybe it's really made of cheese.

[rowan46]

I am pretty sure that it's ca. My pentax xf's used to show a violet purple on the ede odge of bright objects, My ts 80x20 show yellow on the edge of the moon. as has been said eye placement and focus helps a bit but its best to learn to ignore it

[Luke]

I noticed a lot of colour fringing on the edges of the moon in my Equinox 120mm last night just before 10pm when pushing the moon to the edge of the field of view. Yellow on one side and blue (or Sarah thought green or turquoise) on the other.

I'm no expert on fringing, but I'm guessing it was partly the conditions last night and the moon being relatively low, I've not seen so much fringing before in the Equinox.

I did notice that there had been a huge amount of colour in the clouds that evening, right the way across to the east.

[Zakalwe]

From my location I could see a yellow fringe with the naked eye. The humid air is full of dust, smoke particles and pollen. We need a good thunderstorm to wash all the muck out of the air.

[Stu]

I noticed it as well in an 80ED, more than normal CA. The moon was also a very orange colour the other night, all indication of something in the atmosphere making it worse I guess

[Matt2011]

I think it's just that abd it's CA and pollution maybe thrown in for good order. Going to check the moon out tonight with the Helios 15x70s Apollo's. Thanks

[Matt2011]

I am out tonight observing the moon and I am seeing the yellow tinge around the moon. I thought at first when I first saw it yesterday that I had problems with my Helios Apollo 15x70s but it's probably CA but would like to know if any other Helios Apollo 15x70 Binocular owner is seeing this yellow halo on there's. Thanks

[BinocularSky]

If it's yellow, it's "difficult" to see how it could be caused by CA in an achromatic objective. You'd expect "apple and plum" (green and/or purple) fringing, not yellow.

[MooMoo]

If it's yellow, it's "difficult" to see how it could be caused by CA in an achromatic objective. You'd expect "apple and plum" (green and/or purple) fringing, not yellow.

mmm Apple and Plums...

Thanks for making me hungry again.

[Alma]

I get a thin yellow halo around the Moon under certain conditions with my Fujinon 16x70's - I've heard it's a form of "lateral" CA as opposed to longitudinal and is normal in most binoculars, even relatively high quality ones - it's just a function of short focal length and achromatic lenses. I wouldn't worry about it - my Fujis are ultra sharp for stargazing and the inherrent CA doesn't detract from the views in any way; If I want to look at the Moon or planets I use a telescope.

[BinocularSky]

I get a thin yellow halo around the Moon under certain conditions with my Fujinon 16x70's - I've heard it's a form of "lateral" CA

I'd be delighted to be corrected (for false colour? ), but I don't think that is right. There's some good stuff on CA:

http://www.kenrockwell.com/tech/lenstech.htm#ca

http://www.image-engineering.de/index.php?option=com_content&view=article&id=510

and, if you really want to get into it, as it were:

http://www.handprint.com/ASTRO/ae4.html is superb

[SteveNickolls]

Some colour photo's I took of the Moon on the 17th July were decidedly of a yellow hue- put it down to atmospheric contaminants. Cheers, Steve

[rowan46]

If it's yellow, it's "difficult" to see how it could be caused by CA in an achromatic objective. You'd expect "apple and plum" (green and/or purple) fringing, not yellow.

In that case I would love to know what causes the yellow fringe on my ts 20x80 triplets I only notice it on the moon

[BinocularSky]

If it's yellow, it's "difficult" to see how it could be caused by CA in an achromatic objective. You'd expect "apple and plum" (green and/or purple) fringing, not yellow.

In that case I would love to know what causes the yellow fringe on my ts 20x80 triplets I only notice it on the moon

If it's a triplet, by definition it is not an achromat.

However, as I said, I'd be delighted to be corrected. There are quite a few reports of yellow, or yellow and purple, fringing on the Moon with achromats, and I wonder if it is the green fringe being perceived as yellow by some people due to the moonlight glare or ...? (I've only ever seen purple and green, but I may well not be typical...)

[rowan46]

If it's a triplet, by definition it is not an achromat.

However, as I said, I'd be delighted to be corrected. There are quite a few reports of yellow, or yellow and purple, fringing on the Moon with achromats, and I wonder if it is the green fringe being perceived as yellow by some people due to the moonlight glare or ...? (I've only ever seen purple and green, but I may well not be typical...)

I think you have probably hit the nail on the head with it being a perception thing much as some people can detect colour cast with some eyepieces and some can't

[Matt2011]

Going to see if I experience the yellow fringe around the moon when it is higher up in the sky as it might be due to the moon being low down and atmospheric conditions. How do Helios Apollo15x70 binocular owners find these binoculars for terrestrial viewing. Cheers

[avtaram]

I noticed a yellow fringe around the moon the other day through my skywatcher evostar 120ed ds-pro.

I was using the baader hyperion zoom. I had not noticed this before.

Avtar

[BinocularSky]

Hmm. The more I nag away at this, I wonder if I have been completely wrong (in which case, apologies!). This thread on CN:

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5306471/Main/5305007

also mentions yellow fringing on the Moon. Thing is, I've never seen it (only green & purple) and it's now bugging me that I don't understand it. If it's clear tonight, I'll see if I can replicate it somehow...

[rowan46]

Got my 20x80's out on the moon last night and the fringe was there again greenish yellow describes it fairly well. So I guess some would describe it as a yellowish green

[philhas]

very slight Greenish yellow for me as well on Helios Q4's

[chops]

If it helps the discussion (I appreciate this is older topic, but the issue is timeless), I get heavy yellow fringing on my, fairly new, Helios Apollo 15x70, but none on a Mak 'scope viewing at the same time.

Doing a bit of searching, I've come across the term "intra focus yellow fringing" but I don't know if it's an accepted phenomena, or just a specific type of Chromatic Aberration.