Little help please if someone has a minute.

[mikey32shaw]

Set up my new skywatcher 150p this evening and a had a great time scanning the skies. I have a small query as I think I'm doing some thing wrong. Scope was great looking at the moon although very bright and I can find my way around the skies without a goto BUT...............After finding andromeda with a wide angle eye relief lens I couldn't get it any bigger with other lenses I am aware not to expect views like I'm looking out of the tardis but why can I get it in my other lenses????Am I doing something wrong or was conditions not the best with a full moon?

Thanks in advance

Mik

[Qualia]

Hiya, Mikey and please accept my welcome to SGL. Okay, from my perspective the good news is you're doing nothing wrong. The same idea cropped up in another thread a day or so again, so I'll basically repeat what I said there: if you increase magnitude, the object you're looking at will cover a larger area of the EP's image - so with something like Jupiter, say, the affect of magnification does make Jupiter appear to get bigger and so you can go further into more detailed study but what is also happening when you increase magnification is that the light is getting more spread out over a larger area, so it gets thinner and in consequence the brightness drops.

Now upping the magnification on Jupiter to a certain degree is one thing, but it's only about 0.0000621 light years away. If you take into account that M 31 is a lot further away, some 2,500,000 light years away, you begin to appreciate that if you start whacking up the magnification what you're really doing is spreading that light over a greater area, so you're decreasing its surface brightness.

For purely visual practice, with M 31 in dark skies, for example, I'm using about 40x (my lowest focal length EP) and with an f/10 it still doesn't fit into my image. It's a monster of a galaxy, because in relative terms it is still so close to us.

[RikM]

The bright moon spells disaster for viewing extended deep sky objects. Especially for galaxies, a dark sky makes all the difference.

[mikey32shaw]

Thanks for the response, can't believe how helpful people are on this forum. Hope I don't bore you over the coming weeks. Already looking forward to getting back out with it on the next clear night.

[umadog]

Check out the ring nebula. Even with a full moon you will see what the gains are by using more power.

[Stu]

Hi

As Qualia said, there is another thread which has some useful discussion on M31, here is the link to it.

http://stargazerslounge.com/index.php?/topic/163319-Andromeda!#entry1650475

As said, it needs low magnification, widest field possible plus dark skies to see it at its best. Upping the magnification just shows you the central core.

When the moon is out, best to stick to brighter dso's or star clusters

Cheers

Stu

[starman1969]

I use the lowest power eyepiece on mine, for M31. Its a great sight, but I wouldn't bother trying to look if a pretty full moon was nearby. The glare would pretty much erase M31 from the sky.

[8472]

Difficult to see much last night, as mentioned, the moon was very bright.

[Capricorn]

One other consideration is that the scope has a 1200mm focal length, if you had a 25mm eyepiece then that is 48x.

With a plossl that means a 1 degree view, with a 60 degree eyepiece that is a 1.2 degree view.

Either would mean that you didn't have all of Andromeda in view, Andromeda is about 3 degrees across.

I would expect that you were basically looking at just the central bulge, which hasn't any real structure, the other lens again were probably just selecting this bulge, not the arms.

As has been said with the moon recently you will find it difficult to see Andromeda, and the arms will be the first bits to vanish.

Wait around a couple of billion years and it will be a really magnificent sight is a scope.