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M81 & M82 Not impressed yet !

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Hi All,

Last night I eventually found M81 and M82 and I was very pleased to have found them using the setting circles and a bit of intuition (basically just getting close then scanning for them)

However I was sadly dissapointed with the image I got of both of these, I was using a 9mm GSO super plossl with a GSO 2x Barlow on my skywatcher 150p which has a focal length of 750mm so I should have had a mag of 750/9 x 2 = 166x But the image of these were so small I couldnt make out any detail at all, I have looked at 12D string field of view calculator and using a skywatcher 10mm without a barlow the image is totally different, So why am I not getting the image as shown ?

Has anyone got any pics of M82 which were taken with a 150p so I can compare.


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Here is a sketch of M81 and M82 as it looks though a 6" scope under really dark skies. My 6" scope was showing a little less detail but was not too far off this view at the SGL6 star party. I found the best view was at 69x with my 13mm Ethos eyepiece:


Were you getting views of this sort or not so good ? - there was a lot of moonlight around last night.

The impressive thing about objects like this is that we can see them at all at the immense distance they are located.

Edited by John
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Hi Kev

166x!! ;) You might wanna ease up a bit on the old power there buddy.

Take 100x off and it should get you a better view.

If you over magnify a DSO the light becomes too spread out and you start to lose it into the sky background this is made worse by any LP or moonlight.

Think of ya Galaxies image as a bright red balloon when it's smaller the colour is much fuller, but as you inflate it, it starts to become more and more opaque.

The telescopes image is like this, your mirror can only collect a set amount of light so the more you magnify the dimmer things get.

The first things your gonna lose are low surface brightness Galaxy spiral arms like M81's.

Regards Steve

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Agree with post #3 about the too high mag. And the pic in post #2 is about what

I can see visually with my 10" from my light polluted back yard. They may only be

a couple of fuzzy patches, but these galaxies are the combined light of billions of

stars that form those objects. We observe with our minds as well as our eyes.

Best regards, Ed.

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Thats a great sketch Jahmanson, and yes when I open up your pic that is roughly the size I was getting but you say this is with a 32mm eyepiece and I was using a 9mm with barlow, but I'm now doubting myself as to waht eyepiece it was, but I'm sure it was the 9mm,

Swamp Thing, Thats probably the best way that it has been put on how mag + quality dont always meet together happily.

I suppose I can still console myself with some cracking images of The ringed giant.


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