Sun is so small!!!

[Guest]

Hi,

This might be a stupid comment and question, but I bought a white light solar filter to use with my 80mm scope, it came on Saturday and I took outside today and looked through it at the sun, and could not believe how small it looked, I was a bit surprised, I assume this is normal or is it something to do with the filter acting like a focal reducer??

Like I say stupid but have to ask

MM

[oldpink]

you are used to seeing the glow in the sky, the sun is only a small part in the middle of the glow
and a lot smaller than you imagine

[Moonshane]

it's the same size as the moon (in the sky at least hence eclipses)

[nightfisher]

It does not act as a focal reducer, if you were imaging say with an ED 80 and dslr it would appear larger on the camera

[RikM]

To get an impression just how small in the sky the moon (and the sun) is, you can cover it with the rubber on the end of a pencil held at arm's length.

[Tiny Small]

It' a hundred million miles away... would be surprised if it wasn't small. At 100x mag it would appear to be the same size as if it were only a million miles away which is still a very long way.

[ronin]

The eye/brain combination makes or translates something bright into something apparently big(ger).

If you can get to somewhere really dark you can see Andromeda it will look small, it is actually 6 times bigger then the moon. Did you look at the Orion Nebula in the last couple of months. That is about 1 degree across, twice the size of the moon, the Pleiades is also about 2 degree across so again twice as big as the moon.

Just about everyone would say the moon is the bigger however.

[Guest]

it's the same size as the moon (in the sky at least hence eclipses)

Well I would say it is not anywhere near as big as the moon, it's the glow of the sun that makes it look as big,

Like oldpink says it is a small disc in the middle of the huge glow that makes it look as big as the moon.

MM

[Moonshane]

it certainly is. moon =  29.3′ – 34.1′ minues of arc   sun = 31.6′ – 32.7′ minutes of arc so it depends on position etc but they are both about half a degree across.

[Stu]

Well I would say it is not anywhere near as big as the moon, it's the glow of the sun that makes it look as big,

Like oldpink says it is a small disc in the middle of the huge glow that makes it look as big as the moon.

MM

Not true, they are both roughly half a degree across, so as Moonshane says, that's how solar eclipses happen because the moon just covers the sun allowing the corona to be seen around it.

Sometimes, due to orbital variations causing differences in the distances, the moon doesn't quite cover the sun, causing an annular eclipse.

The next eclipse looks to be 23rd Oct this year, haven't checked where, but if you look at the following screen shots it shows that the sun is actually showing a slightly larger disk than the moon at that time, 32.1 arc minutes vs 30.2 arc minutes.

Cheers,

Stu

EDIT must type faster! :-)

Sent from my iPhone using Tapatalk

[Guest]

Not true, they are both roughly half a degree across, so as Moonshane says, that's how solar eclipses happen because the moon just covers the sun allowing the corona to be seen around it.

Sometimes, due to orbital variations causing differences in the distances, the moon doesn't quite cover the sun, causing an annular eclipse.

The next eclipse looks to be 23rd Oct this year, haven't checked where, but if you look at the following screen shots it shows that the sun is actually showing a slightly larger disk than the moon at that time, 32.1 arc minutes vs 30.2 arc minutes.

Cheers,

Stu

EDIT must type faster! :-)

Sent from my iPhone using Tapatalk

Yes that is the suns complete solar disc, including the glow around the sun that is how it looks I agree, but the actual sun without any glow is a lot smaller, because of the distance away, if you look with the naked eye through a solar filter, it is quite small a lot smaller than the moon which has no real glow around it, but with the glow they are about the same size.

MM

[RikM]

Yes that is the suns complete solar disc, including the glow around the sun that is how it looks I agree, but the actual sun without any glow is a lot smaller, because of the distance away, if you look with the naked eye through a solar filter, it is quite small a lot smaller than the moon which has no real glow around it, but with the glow they are about the same size.

MM

No. That's the size of the actual disc. The moon is a lot smaller than you think. The actual discs of both sun and moon are almost exactly the same size in the sky.

[Moonshane]

sorry Magnaman but without meaning to be rude you are just plain wrong. do some reading (or actually look at them at the same magnification) and you'll eventually agree with us. the moon is a little smaller than the sun but also a little closer. as it happens about 400x smaller and also 400x closer than the sun.

[ardbeg74]

I remember back in 99, i was out building a conservatory at my parents house and i remembered it was around time for the total eclipse. I looked up with the cardboard solar glasses that my brother had brought with him,  and there it was... the sun with a bite out of it. I was too far north to see more than just a chunk out of the corner and it didn't feel darker or colder, quietness and all that. But it left a lasting impression on me. More so i think because of the smallness of this object (the sun) i knew to be so big in reality.

I remember thinking about the angular size of the sun and moon then. Not sure where i picked up the fact but the moon is 400x smaller than the sun but by amazing coincidence the sun is 400x further away.

When you think of it really, there is no reason for that ratio other than pure serendipity. There are infinitely more ratios that it could have been, but we are blessed with the one that is beautiful.

Not sure where im going with this other than  the universe full of beautiful things, mostly small, but beautiful none the less.

Mark

[Stu]

Yes that is the suns complete solar disc, including the glow around the sun that is how it looks I agree, but the actual sun without any glow is a lot smaller, because of the distance away, if you look with the naked eye through a solar filter, it is quite small a lot smaller than the moon which has no real glow around it, but with the glow they are about the same size.

MM

Sorry, but that's not true. The figures shown are for the size of the disk, not including the outer corona.

Stu

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[Guest]

Sorry, but that's not true. The figures shown are for the size of the disk, not including the outer corona.

Stu

Sent from my iPhone using Tapatalk

Well do me a favour and go outside tomorrow with your solar filter and look, then tell me if it looks the same as the moon, either that or my filter is acting as a focal reducer.

[Moonshane]

I do that every time I use it as it's sensible to check it before putting on the scope. it's always the same size. approximately moon-sized.   :grin:  let's keep this thread well natured as we all want to help but you are honestly mistaken. the moon is not really visible currently so what's your reference recently? just check next time and I bet you'll agree. if not, I surrender.  

[Guest]

sorry Magnaman but without meaning to be rude you are just plain wrong. do some reading (or actually look at them at the same magnification) and you'll eventually agree with us. the moon is a little smaller than the sun but also a little closer. as it happens about 400x smaller and also 400x closer than the sun.

Well whatever science says is fine

But I am telling you that through my solar filter it is very small compared to the moon, maybe my filter is faulty or demagnifying it I don't know, but through it it looks a hell of a lot smaller, maybe something to do with the amount of light it is filtering out...I don't know....

[Moonshane]

best bet is to look with an eyepiece that covers 0.5 degrees of field. this will mean the sun's and the moon's disk will fill the field. I hope you will then agree. for a plossl, this would be one that gives 100x magnification.

[RikM]

Well whatever science says is fine

But I am telling you that through my solar filter it is very small compared to the moon, maybe my filter is faulty or demagnifying it I don't know, but through it it looks a hell of a lot smaller, maybe something to do with the amount of light it is filtering out...I don't know....

Your filter is fine. It's an optical illusion I am afraid; they are the same size. I know the moon seems to look bigger but it really isn't. Try the pencil test I mentioned earlier and you will see for yourself.

Edit: better yet, Shane's test using the same magnification.

[oldpink]

A solar filter isn't a lens so it won't effect anything apart from the amount of light it allows through
so it won't have any effect on the size you see the sun, you perceive the moon as bigger as its normally bright in a dark sky
where the sun is always in a bright sky so totally different contrast
look at both through your telescope and you will see they are the same size

[Guest]

I don't think anybody is actually listening to what I am asking, or maybe I am not wording it correctly and now you are all getting a little annoyed.

I agree with you all

But why does it look so small through my white light solar filter, a lot smaller that the moon, it is obviously something to do with the filter, because without that they look the same size......so what is the filter doing to the view

[Moonshane]

I think we are listening but it's simply an optical illusion which I think someone mentioned above. if you look objectively as suggested in my last post you'll see they are the same size.

[Guest]

Ok

It's an optical illusion, that's as good reason than any.

Let's end the thread there and all go,to bed

MM

[Moonshane]

aaaaand breathe