Beginner viewing questions

[Geeman]

Hi there,

Just got a new telescope for a christmas present ( go girlfreind )

Managed to set it all up and align my view finder etc.

Its a 700 mm focal length tube. Newtonian reflector.

Ive got 3 eye peice with it.

20 mm

12.5mm

4mm

and a 2 x barlow lens.

So from the reading ive done am i right in thinking my magnification setups can be... ?

20mm 35x with barlow 70x

12.5mm 56x with barlow 112x

4mm 175x with barlow 350x

If so what my best x configuration to view a planetary object like saturn? And will i be able to view any nebulas etc with a another x setup? ( sorry if my all my lingo is incorrect im a complete novice

Hoping ill embrace and run with this a new hobby. Im quite obbsesinal and have an addictive personality if i find something i like doing

Thanks for taking time to read and i appreciate any advice forthcoming!

Dave

[ItIsOnlyMe]

Hi Dave, welcome to a great hobby!!

I too got into thie hobby with a christmas pressy from my girlfriend, so girlfriend rock :-)

You don't mention the aperture in your post and this has a big impact in what eyepiece will give good results. Though you may get 350* with the 4mm+barlow unless you have a fairly large aperture and perfect sky you aren't likely to get a great view.

Generally a less magnified but sharp view will be more rewarding than a greater magnified, therefore bigger image of something fuzzy and indistinct.

Rough rule of thumb is that the max you can use is twice the aperture in millimetres, so a 100mm apperture gives a rough 200* max usable subject to sky conditions.

Your 20mm without barlow will be your best best for deep sky, nebula, clusters e.t.c.

Regards

Phil

[Geeman]

Cheers for the reply Phil.,

Girlfriends are indeed good when there not complaining

Just looked and the aperture size is 76mm. so with that in mind what would be the best setup for planets with the above eye peices?

so by that rule of thumb the max maginification i can go for is 152* mag?

Dave

[Mr Q]

Dave - The max power for any planet observing depends on the "seeing" conditions of the sky. When upper atmosphere turbulants are pronounced, the views will be "watery" or seem to move around, making details very hard to see. The rule of thumb is - if stars are "twinkling" nearly overhead, the conditions are bad. This holds true for objects near the horizon also. So when you observe the planets, start with a low power EP and work your way up in power to the best view.

[BinocularSky]

If so what my best x configuration to view a planetary object like saturn?

A general "rule of thumb" for planetary observing is that the most detail will be seen when the magnification is approximately equal to the aperture in mm (sky conditions permitting).

[scoobee]

have a play around with this site

http://www.12dstring.me.uk/fov.htm

If your scope is not listed, you can input the data yourself

[Geeman]

Cheers chaps. Appreciiate the replys. Cleared a few things up for me.

[maryc]

As a newbie myself - telescope from my sons I found the comments very helpfull especially

http://www.12dstring.me.uk/fov.htm

This has given me good insight as to what to buy.

Thanks

[CSM]

I'm guessing that it may be the Celestron LCM 76 which has a focal length of 700mm though not the 3 eyepieces that you mention. What you will be able to see will depend very much on how steady the atmosphere is and the amount of water vapour and dust - and light pollution. This will vary considerably from night to night. Always start off with the lowest 20mm and then increase if the viewing is good. With a 76mm you should get good views of the Moon, Jupiter and the brighter objects.

[perrin6]

I guess the 12.5mm with the barlow giving 112X would be about right for a 76mm reflector but if the planet is a bit too pale and washed-out try the 70X option.

[Michaelo]

The rule of thumb is - if stars are "twinkling" nearly overhead, the conditions are bad.

Another nice bit of info I didn't know... thanks!

[meteoriot]

Some great hints here (noted)