help on lenses

[djlloydb]

hi all

i hve just got my first telescope and lovin every minute of it

i bought this second hand an it came with a few filters which i am not sure what they are for could anybody point me in the right direction

i have an lx90 meade

with 3 filters

antares variable polarzer is this just for the camara ??

uv-ir rejection filter ?? looks clear

alp filter ?? looks green when i look through it

6.4 mm this seams very blured then i look at anything

12.4 mm

26 mm good but image small

and a x2 bit tele xtender

[brantuk]

Hi Dj - sounds like you have the beginnings of an astrophotography set up there. Someone with more experience will tell you about the filters (I'm a photography beginner really - so just learning myself).

The 6.4 sounds like a planetary eyepiece which will look blurry if the seeing is not so good. Use it on saturn or jupiter on a crystal clear night and it may be better - it's your highest power.

Images in the 26 will give small planets, but it may have a wide field in which case you'll get nice views of nebulas and clusters. Experiment with the filters on nebs and clusters - you may get better results. The 12.4 is approx half way between giving a reasonable spread of magnifications.

The make/spec of the ep's will tell you more about their capabilities. The x2 tele xtender is for camera work far as I know.

[djlloydb]

thanks for that

the guy who i bought it from said one of the was like a moon filter but i cant remember witch one of the filters he said now

will just have to have a play around could you sugest the best lenses to view saturn with

i am gonna sort a laser pen out for spotting the planets up this looks a lot easy

but wondered if i need to get some new lenses

[Hypernova]

Looking at the names of the items, I think that the variable polarizing filter is the moon filter he was talking about.

See here:

Moon & Neutral Density Filters - Variable Polarizing Moon Filter

As for lens and scope magnification, look at this site developed by a member on this forum. Just choose your scope and eyepiece and it will give you the information regarding magnification and FOV etc.

http://scopecalc.grid-itc.com/

[John]

...6.4 mm this seams very blured then i look at anything

The 6.4mm gives 312x magnfication which needs very good atmospheric conditions to be effective.

Also you will need to allow your scope time to cool down to the outside temperature - this can take 40-60 minutes - before it will give good views at higher magnifications.

The variable polariser can act as a moon filter - you can adjust how much light it filters out.