Beginner Questions

[crystal_stars]

Hi all,

I have some questions that I hope you can clear up for me. I love my new Lightbridge that I have now had for 11 days, and it has already seen several viewing sessions. My questions are as follows:

1) A book I have says I should be able to see to about mag 14 with a 12" scope, so can you see to this level with any magnification or only when you go to high mag?

2) I plan to use some observing lists to plan my sessions (messier, bennett, and the ones here on IIS) but given that I do my observing from my backyard in suburban melbourne with some light pollution, can I still see galaxies and nebulas (such as in the 100 brightest articles here on IIS)? because I don't have any nebula filters as yet.


Thanks,

C

[janoskiss]

Hi C.

1) You see deeper as you up the magnification, up to about 1.5-2mm exit pupil, beyond which more magnification will not let you see any more stars. (Exit pupil = aperture / magnification = eyepiece focal length / telescope f-number).

2) You can see some of the brighter galaxies, but they are rather unimpressive compared with what you see from a dark site. NGC 253 is one of the easiest right now. Brighter nebulae you can see easily with quite a bit of detail in the brightest ones. But go for a drive to darker skies whenever you can. The difference between the suburbs and somewhere 100+km from Melbourne is like going from a 4-5" scope to a 12". Or in your case like going from a 12" to a 30". ;)

[crystal_stars]

Thanks.

I was out obseriving last night and trying to improve my star hopping skills, and stopped on what I thought was a globular cluster, but even with increasing magnification I couldn't get it much bigger. So I figured ether it was a very small globular or not a globular at all. But I did locate some nice open clusters (M6 and M7) :thumbsup:

But this got me wondering what sort of maginification do people use to observe DSO's. So can people give me some suggestions as to what magnifications you prefer to use when observing DSO's.

Thanks.

C.

[janoskiss]

As a "general" rule, for the 12" Dob, about 120-200x works best depending on object/conditions. But for big DSOs like M6 and M7 you mention, you need to go as low as you can go, to fit as much in the FOV as possible. Or better yet big binos.

[rmcpb]

My little bit would be to concentrate on globular and open clusters, planets, moon and double stars when in surburbia and take the odd trip to a dark site to have a serious go at the nebulae and galaxies.

After saying that, try for them in your yard and keep a good log with a description and sketch then compare with what you see at a dark site.

If you are looking for a good dark site your local astro society would have a site they meet at near the new moon so try getting in touch with them.

Keep looking up

[OneOfOne]

The asv website is down at the moment, but our next general meeting is Monday 11th at the Herbarium, near the shrine, at 8pm. Drop in!

[janoskiss]

Geez, you could not find a much more light polluted spot if you tried. What can you see from there?

[OneOfOne]

The General meeting is at the Herbarium, the dark site is in Heathcote. I haven't been there, but apparently naked eye to 6 or 6.5 they say! You can see lots though from the Herbarium, just nothing in the sky:lol:

[crystal_stars]

I am a member of the ASV. I haven't been up to Heathcote yet, but was planning on attending my first general meeting next week, I've been told they are really interesting.

[astro_nutt]

HI C..
I"ve been the Leon Mow Dark Sky Site at Heathcote several times and when conditions allow...mag 6 is about right...the next field trip with no Moon will be on the 21st of October..and weather permitting I'll be there!!!
Cheers!