Getting the most from M31

[Size9Hex]

I'm interested in how much detail other folks have been able to see within M31 please (and how you did it), beyond the obvious "It's a long smudge, with a bright smudge in the middle". Is it realistic to hope to see dark lanes, or brighter regions (other than the core) for example? What's the best you've managed, and what was the key to you seeing it? Aperture, darkness, transparency, the right magnification, or simply persistence and experience?

Thanks as always everyone!

[Mike73]

Basically the darker it is the larger it appears in the EP, seeing the dust lane from dark skies is easy but you need excellent transparency when its close to zenith to be able to spot the second fainter dust lane.

[SteveNickolls]

Hi Paul,

As an object I've always been underwhelmed at M31 but then using binoculars in quite a light polluted place that is expected. In the last week I have made a step using a refractor an alt-az mount and my canon DSLR and 20 mins of exposures has revealed some detail. I have also seen M110 for the first time. Ad astra.

Cheers,

Steve

[Astro Imp]

I observe from my edge of village garden and find transparency is key to viewing this and other DSOs. At it's best I've seen the obvious bright core together with an extended outer region, M110 reminds me of a thumb smear on the optics. When the sky is not playing ball M31 fades to an insignificant smudge and M110 disappears.

[glowjet]

It really depends on aperture and more essentially the seeing conditions from a very dark site. I expect that those with a very large mirror truss Dobsonian, using the scope in excellent transparency, will resolve more detail in M31 due to the scopes light gathering capabilities, than a scope of more moderate dimensions. The sketch image from Mike in the preceding thread is a prime example.  

You have a decent size Dob in the 250mm, the more times you observe with conditions of good transparency, with practice, the more you will tweak out detail, but there will be a limit to what your eyes can reveal, only photographic images with long exposure, can reveal more of the detail. Even the larger aperture instruments have their limits with observing.

You might like to consider placing a thread on this issue in Observing- Discussions, I don`t doubt that there could be some interesting comments from those with big aperture scopes

[Coastliner]

This was a thread of mine, just an experiment. 12*30 secs with a DSLR and 300 mm lens, wide open.

http://stargazerslounge.com/topic/254442-im-astonished/

[John]

On the best nights I have approached the level of detail that Mike73 indicates in his excellent sketch with my 12" F/5.3 dobsonian and an ultrawide eyepiece. On many nights it offers somewhat less than this though because transparency is key to teasing out the details with extended deep sky objects.

In some ways I prefer the views of M31 with my 4" F/6.5 refractor though. With the same ultrawide eyepiece this scope can show around 3.8 degrees of sky which shows more of this very extensive object at once and squeezes it's neighbours M32 and M110 in as well. I've managed to detect the main dust lane with this scope as well, on a very good night so large aperture is not always a mandatory factor.

[Size9Hex]

Basically the darker it is the larger it appears in the EP, seeing the dust lane from dark skies is easy but you need excellent transparency when its close to zenith to be able to spot the second fainter dust lane.

Mike, great sketch and advice. This really helps. From your sketch, I can orient myself nicely with the two companions, and I recall seeing the diagonal swipe of mag 11 stars that march across the front of M31 on the M32 side (that you've captured nicely). It shows me exactly where to look (in an averted sort of way!) for a dust lane. Thanks!

[Size9Hex]

As an object I've always been underwhelmed at M31...

I think I know what you mean. Although it was the object that really grabbed me and got me into this hobby, it's also I think it's the only one that I've not yet managed to improve much upon with repeat viewings. I'm determined there must be more to it!

[Size9Hex]

Thank you generally everyone. Lots of good comments and it seems there is a nice consistent message on both darkness and transparency. Hopefully I'll have a session this winter that will do a bit more justice to our impressive next door neighbour in the universe. :-)

[Charic]

........for me, I head off to a darker site to get an eyeful of M31 in my 70°afov 32mm PanaView, giving 37.5x power!

From home, its  a small grey wisp of a smudge?

[John]

Are filters generally helpful with M31, the Andromeda Galaxy?   I have several but have not tried them yet.   They are listed in my signature.

Hi Ed,

The LP one might make a slight difference if you suffer from some man-made light pollution. I have the DGM NBP and a Lumicon O-III but, excellent filters though they are, I've not found they help with galaxies.

Someone once quipped on the Cloudynights forum that the best accessory that you can buy to improve the views of galaxies is a tankfull of gas (petrol in the UK) to take you and the scope to a dark sky. Thats probably sound advice