Help with M51

[johnkirkpatrick]

I tried to locate m51 for the 2nd or 3rd time, I know where it should be but just cant seem to find it. What should I be looking out for using my 200p dob? I found something very small almost like a double star using my 20mm cranked up the mag all the way to 200x still nothing, I know it not a double by checking stellarium. any help would be great as ive always wanted to see it.

Oh yeh, I found the great Hercules cluster and failed to resolve any stars, could be the moon being so bright but also prob not having a big enough scope, fantastic all the same though lol

[pvaz]

The moon will make it very hard.

M51 is dim and needs darkness to be seen. You ware probably seeing the 2 cores with all other detail washed away by the moonlight. It's easily found with a 8" at around 40x. I could see 2 spiral arms and the bridge (connection between the cores of the 2 galaxies) with excellent seeing conditions at around 80x. At higher mags it got too dim and detail was lost.

M13 also benefits from darker skies and you should make individual stars outside the core at around 120x.

PS-> I take a peek at M51 nearly every time I go out and only been able to see that much detail 2 or 3 times. If seeing is average I usually can't make the spiral arms.

[Chris H]

I've seen M51 during spring when it's high in the sky and with my 10" I could make out the spiral structure. Try from a real dark location and without a moon and with your 8" you should have more luck.

As for M13 I would check collimation, at x150 I can see chains of stars flowing out from the centre of the glob.

[Talitha]

Moonlight bleaches out the galaxies, but i've seen the cores during a Full Moon with the 8"SCT and am betting that's the double star you saw. The best time of year to view M51 is mid-summer, but you can get a good view after 3am when it's rising out of the airmass in the east.

[brianb]

The best time of year to view M51 is mid-summer

Not in the UK, it never gets dark enough in mid-summer. Early morning in late winter or around midnight in spring are best for M51 & other objects in this general area.

[Talitha]

Not in the UK, it never gets dark enough in mid-summer.

So get out of there.

[ollypenrice]

So get out of there.

Seconded! Come to southern France!

Seriously, I agree with Carol that your double was probably the pair of cores. Moon time and low elevation are killers for galaxies. You want high elevation, dark sky and good transpareny. When I have all these in our 20 inch the spiral structure is easy. But even with 20 inches it is soon bleached out.

Olly

[johnkirkpatrick]

Maybe so, But the "double thingy" was ever so small and if I remember right one was slightly more red than the other. Does this mean its a very small object to view? I will defo try again once the moon is out the way.

[ollypenrice]

Maybe so, But the "double thingy" was ever so small and if I remember right one was slightly more red than the other. Does this mean its a very small object to view? I will defo try again once the moon is out the way.

Like many galaxies it gets to look bigger with more aperture. Small scopes only reveal the cores which look small and slightly stellar as a result. Lots of aperture and a good night bring the huge faint spiral structure into view. The cores still look intensely bright by comparison, though.

Olly

[brianb]

Small scopes only reveal the cores which look small and slightly stellar as a result.

Hmmm ... the issue with this sort of object is that they need a very low power, certainly not more than 5x per inch of aperture. I see M51 quite regularly with 10x50 bins - it's "on the path to" some of the variables I monitor and it stands out well enough to be an obvious "stepping stone" on a reasonable night. Small of course but with a trace of spiral structure and the companion galaxy. Increasing aperture does make the thing bigger at the same relative power but in my experience makes it harder to see the fainter parts of the structure because the contrast is spread out. Like M33, easy in binoculars, practically impossible to see anything but the core in a medium sized scope.

But I'm sure it looks great in your 20" Dob with a power of about x80 high in a good dark sky!

[ollypenrice]

Hmmm ... the issue with this sort of object is that they need a very low power, certainly not more than 5x per inch of aperture. I see M51 quite regularly with 10x50 bins - it's "on the path to" some of the variables I monitor and it stands out well enough to be an obvious "stepping stone" on a reasonable night. Small of course but with a trace of spiral structure and the companion galaxy. Increasing aperture does make the thing bigger at the same relative power but in my experience makes it harder to see the fainter parts of the structure because the contrast is spread out. Like M33, easy in binoculars, practically impossible to see anything but the core in a medium sized scope.

But I'm sure it looks great in your 20" Dob with a power of about x80 high in a good dark sky!

That's exactly the 'default' power but it has sometimes held up at a whopping 200. 100x is often great.

Olly

[johnkirkpatrick]

Still no luck with M51 but I did find M81 & M82, One vertical and the other horizontal again no detail but had them in the same fov which was cool. Will look tonight if clear and try for some hint of arm's. will also try M33 AGAIN lol still not found this one.