Which eye piece!!!!

[hev]

i've had my telescope (Skywatcher Heritage 130) for almost 5 weeks now and it looks like tonight may be my first chance of seeing stars!!! I've looked on stellarium and it's showing that Saturn, Mars and Venus are all going to be visible (as long as the cloud stays away) my scope came with two lenses a 10mm and 25mm super i'm not sure which lense i should use for what purpose!!! Any advice or common sense would be greatly appreciated!!! Many thanks

[TopHouse]

I think you're either very lucky or have stellarium set wrong to have a chance of viewing any of those three planets tonight. I'm betting you haven't set up your position and time correctly in Stelarium. Those 3 planets are practically below the horizon about now.

[hev]

i'm on a hill, does that make a difference? Can definitely see venus as i'm typing this?

[hev]

Seriously! I can see something very bright and shiny where venus should be!

Even if i'm wrong, which eyepiece is best for planet viewing?

[runoffshed]

Saturn has the greatest altitude of the three at present...but as already stated, it's very , very low - about 4 degrees from my location near Oxford ( 10.20pm ) For me Mars and Venus have already set. Being on a hill might make a difference of a few minutes but at that low altitude you won't see much due to the atmosphere. Perhaps you'll have better luck tomorrow. Venus can be easily picked up in twilight - you can see it during the day with binos.

With regards to the eyepieces, start with the longer focal length and if the image is good, try the shorter one. If you can't see as much detail - even if the image is larger - go back to the longer focal length.

Good luck

[hev]

Thanks for the advice, i'm going to be a total dunce now.... which i longer length and which is shorter length, i'm almost embarrassed to ask, but if i don't how will i ever learn!!!

[hev]

I'm going out for a look now, will let you know if i see anything resembling planets or is it just my imagination!!!

[TopHouse]

25mm is long, 10mm is short, the 25mm gives least magnification and the 10 gives more.

[runoffshed]

Apologies, I should have mentioned that! The 25mm is the longer one.

I don't know what focal length your scope is but if you divide that by the eypiece in use you get the magnification ie if the scope had a focal legth of 1000mm. then using a 25 mm eyepiece would give a magnification of 40 x's. The 10mm on the other hand would give a mag of 100 x's ...and if the design of the eyepieces was similar, a smaller field of view.

[pbyrne]

Use the 25mm as a finder eyepiece, it gives a wider field of view due to lower magnification. When you have the object you are seeking in the centre of the field of view then pop in the 10mm to get a magnified view.

One thing about an increased magnification is that it moves quickly through the field of view and you have to readjust the scope more often. The 25mm moves the object through more slowly because of the greater distance it has to travel across the field of view.

Hope this makes sense.

Good luck with the scope and I hope it gives you years of pleasure.

[hev]

Saw lots of nice stars but no planets!!!!

[hev]

Just read your replies, thanks so much, it makes a lot of sense and will be of so much use in the future. Seriously, I was that confused!!! Looking forward to seeing some really good things x

[LukeSkywatcher]

The 10mm EP is fine for observing planets when they are visible. I have the same scope and i have used the 10mm to look at planets. Not great views but that was more to do with the conditions then the EP.

[Mouse on the Moon]

Try this for a good starter on Eyepieces in general.

http://stargazerslounge.com/primers-tutorials/63184-primer-understanding-choosing-eyepieces.html

Clear Skies!