M33 naked eye object?

[jinstan]

Hi,

Some books says M33 is an naked eye object with visual brighteness 5.7 mag. The light pollution where I am living is about average in UK, I suppose. But I have never seen it with 15X70 bino, not even a 6 inch newtonian (focal length:750mm) with the supplied 25mm eyepiece which gives the magnification of 30X. This really surprises me as the newtonian shows the bands of Jupiter and ring nebula which I thought are difficult than M33.

Maybe I need to buy small focal lenth eyepiece like 10mm or some filters?

Br,

Jinsong

[Andrew]

Hi,

Jupiter and the ring nebula are both very bright compared with M33. It has a high surface brightness but that light is spread over a very big area so it is hard to see. If your light pollution is not too bad you might see the core in the 6 inch Newtonian, but I would stick to low magnification. I've no idea if you can see it in 15x70 bins from a light polluted site. I doubt it is visible naked eye unless you have very dark skies.

cheers

Andrew

[Doc]

It's surface brightness is only mag 14.2 so will be really hard to see visually with the naked eye.

[brianb]

M33 is a very diffuse object - it's hard to see with any size scope except at the lowest power available, not more than x5 per inch. It's actually quite easy with 10x50 binoculars given a halfway decent sky and I can believe that it would be a naked eye object in exceptional (unpolluted high altitude desert) skies.

[John]

The smallest instrument that I have seen (detected !) M33 with is a pair of 8x40 binoculars amnd that was knowing just where to look for it.

Even in my 12" scope it really only looks like a faint, largish, patch of misty light from my back garden.

I really think galaxies are some of the most challenging astro objects to see - they don't seem to respond to filters so dark skies are really the only way to go !.

John

[Merlin66]

One of the benefits of living north of the Great Divide, about 100Km north of Melbourne, Victoria was seeing M33 naked eye.

Naked eye Limiting magnitude was just under +6

So good infact, that the Astronomical Society of Victoria purchased 40 Acres close by, as their Dark Sky Observing Site.

A fantastic place.. hope to get back there in the near future.

[jinstan]

Thanks a lot for all the replies which are very informative and helpful. I will give some tries with the binos.

Br,

Jinsong

[narrowbandpaul]

visible from kielder!!!

[RobH]

It was visible from Salisbury naked eye (just)

I've seen it with 10x50's and also with my 120mm F5 startravel refractor at very low power from the back garden.

Your eyes are tuned to pick up movement, so the trick with very low surface brightness objects is to point the scope at where it should be, then tap the OTA to make it move slightly.

This will allow you to register faint stuff that would otherwise be invisible.

Cheers

Rob

[iamjulian]

Oo, that is cunning Rob. Thanks for that tip!

[skye at night]

The skies where I live (when cloudless) are about as dark as it gets....

M31 is very clear to the naked eye but M33 I have only seen a few times and a lot of me thinks it is partly 'suggestion' because i know where to find it...

It wouldn't need much LP to make it impossible....

So on the whole I would not classify M33 as naked eye object.

Steve

[jgs001]

I've seen it a couple of times, but it's a tricky devil. It was using Bino's... although I think... on one very clear night last year (M31 was very visible naked eye)... I did spot it... but that might be imagination on my part...

[jinstan]

I can't even see M31 with naked eye (actually not naked eye, I am wearing glass), so it must be the light pollution.

Thanks rob for the trick, it applies also to other dim objects I suppose.

Jinsong

[TheThing]

Yep, light pollution from London robs me of M31 as a naked eye object as well. In fact, tracking it down in a scope can be near on impossible as well!