What eye pieces should I be using and when?

[HeavenlyHiLites (Dave and Chris)]

Hi, could somebody pls advice me as to what EP I should use to view a cluster, a nebulae and a galaxy? and when would it be best to use a barlow?
regards
Christine

[BlackWidow (Mardy)]

Hi Christine... Thier are no rules to this, it's all about conditions really.. I start with a 24 -25mm eyepeice to look at objects and you will get a nice clear image. Then keep trying more and more power. IE try a 15 - 17mm and see if the image stays clear. The barlow will in most cases double the power of your eyepiece. IE a 25mm would now be a 12.5mm.. You will know when you have used too much power as the image becomes unclear or fuzzy.. This will change from night to night dependent on the conditions. On a still cool winters night you wil be able to use more power...

As for nebulae and a galaxy I have found that often less power is better. You often need a wider view (less close up) to see all the Nebulosity. I oftem use a 32mm eyepiece for this purpose...

It's all a bit of trial and error to see what suits you situation best. You will get the hang of it in time.. It's all part of the fun..


Hope I have been some help, and I am sure others will give you some good advice also..

Regards
Mardy

[HeavenlyHiLites (Dave and Chris)]

Thank you.... I appreciate your advice. There is SO much to learn... but as you say, its all part of the fun!

regards
Christine

[dj gravelrash (Dino)]

Gr8 question christine, been meaning to ask this myself lol.

[mental4astro (Alexander)]

Hi Chris,

As Mardy suggest, there are no 'strict' rules to how to use eyepieces with what ever object, but it helps to understand what different focal lengths can do.

Mardy also hinted at the quality of the atmosphere to viewing. The greater the amount of thermal activity, the poorer the viewing quality. The thing is that the typical maximum magnification the atmosphere allows is around 120X. Double that (250X) is rare with a steady image that shimmers very, very little. Greater than that is a very rare bird. AND it doesn't matter how large your scope is or its quality - the atmosphere is a great equaliser, .

Now, focal lengths. Long focal lengths not only give the widest, steadiest views, but the background sky glow is also the brightest. This may make spotting really faint objects a challenge from the background. A trick here is to give the scope a little 'tap' to cause a vibration in the scope. This shake helps our eyes to spot the faint variations in light intensity.

Medium focal lengths, around 15mm, darken the background a little, and the faint stuff can be easier to see, but still gives a wide enough field to be able to see extended objects, such as a nebula. The slightly darkened background will also allow non-luminous components to become visible, such as the dark pillars, in bright nebulae such as in Eta Carina.

Short focal lengths, around 6mm, can be a real help with galaxies at a dark site. These EPs really darken the background an help bring out faint details. This requires a good quality EP, and a lot of patiences.

Quality EPs don't need to cost a bomb as a bit of research will show you which are the real gems at a modest price.

The above are just a description of what the various EP focal lengths can do. It is then upto you to see what various EP/scope combos best suit you and the observing site you are at, etc.

Also, have a look in the Observational and Visual forum sticky on Improving and Honing Observation Skills. There is a lot of good info there on this, and a good place to pose more questions.

Mental.

[sasup (Stacey)]

I think it depends on a few factors such as your own eye sight, budget and feel. I have high end ethos eye pieces that I love and some cheapish one to ,so just get out there and try heaps till you find some that work. A great place to start is a star party where there are many to look through. I would not get to caught up in the whole whats best game till you look through a few.
As for the Barlow I have never had much luck with them and so not sure of there value to the beginner. My 2 cents

[HeavenlyHiLites (Dave and Chris)]

Thanks heaps everyone for your tips. Alex, some great hints there as to what each EP achieves. I now understand a little bit more...