Eyepieces: 10mm and 20mm

Onesimus

I've just gotten my astromaster 70 EQ today. Basically the eyepieces that came with it are 10 and 20 mm. What am I expected to see with these pieces quality wise?

Also what pieces would you recommend I purchase along with filters? Along with a moon filter should I purchase the eyepiece set? or should I buy these seperate? which would be more appropriate to do?

Thanks for all your help,

Onesimus

Plug

A 10mm eye piece is good for the planets and moon etc. But the 20mm eye piece is good for viewing wide field. So think of the 10mm as zoomed in more and the 20mm not as far zoomed in but it has a wider field of view so you will see more stars etc around the object you are viewing.

Onesimus

Plug wrote: »

A 10mm eye piece is good for the planets and moon etc. But the 20mm eye piece is good for viewing wide field. So think of the 10mm as zoomed in more and the 20mm not as far zoomed in but it has a wider field of view so you will see more stars etc around the object you are viewing.

Would you reccommend I buy a moon filter? I hear some say they are usually made with cheap glass and not worth the buy I was also thinking: would I be too impulsive to go for 4- 5mm peice? or should I hang around and wait till I get using the scope first?

Thanks for all your help so far.

captin

i have a scope like yours and to be honest the 4mm is not much good its too zoomed in, i went and bought a 26mm and 12.5 plossl's and a meade diagonal secdond hand and they are great i was looking at saturn with the 12.5 and it was savage, these scopes wont show you everything but if you have good eyepieces you can always use them on a better scope if you upgrade in the future

ComeraghBlue

As captain said your best staying away from the 4mm with a scope of that aperture as it will be mostly blurry as it would be too zoomed in. Best to invest in a 12mm and 20mm plossl eyepieces for better quality viewing

Onesimus

Cheers lads. I already have a 20mm that came with the scope. Is that the same 20mm your talking about?

How much would a 12.5 set me back. Loving the idea that you've seen Saturn with it. Possibly everyones favourite planet to view.

captin

Ya the 20mm you have will probably do the trick as
For the price of the 12mm I don't really know how
Much they are new I picked mine up second hand for
A bargain so I'd say your best bet is contact a dealer
Or look out for used ones on eBay or something!

Hope this helps you

Onesimus

captin wrote: »

Ya the 20mm you have will probably do the trick as
For the price of the 12mm I don't really know how
Much they are new I picked mine up second hand for
A bargain so I'd say your best bet is contact a dealer
Or look out for used ones on eBay or something!

Hope this helps you

Whats the diff between the 12mm and 10mm? clearer image? I would of thought that the less the mm the closer you get?

peterako

General Rule of thumb.....

The maginifaction you get from your 'scope is:

Focal Length / Lens Focal Length

So, say your 'scope has a focal length of 750mm.

And you use a 10mm Lens....

You'll get 75x magnification.

If you use a 12mm it'll be 62.5x....etc.

The more magnification (smaller lens) you use the more 'light/detail' you are trying to squeeze out of the scope.

Your 'scope apperture and quality will dictate the amount of magnification you can reasonably hope to get. The manual you got with teh scope will tell you.

As to clarity.

Much of a muchness on the 10mm vs 12mm.

12mm may give you a 'sharper' image but it will be smaller.

Generally as magnification inceases the area of the sky you see will reduce.

So, for example, to look at large nebulae and galaxies low magnifcation is usually better.

For planets....higher magnification....

NOW to muddy the water......most Plossl eyepieces have a field of view of about 50 degrees....but some go up to 82 degrees....

Onesimus

thanks a lot guys. Peter is there any point in spending money on a moon filter? or lets say even the celestron eyepiece set which retails at 199euros?

Onesimus

peterako

That's a tough question, and will be down to personal choice.

I have a Moon filter, which is very good when the Moon is 'bright'.

BUT....I got it WITH my 26mm Meade 4000 on eBay.....£22

When I started (not so long ago) I did look at sets, but in the end bought eyepieces etc. one at a time.

If you look at the €199 you could probably buy some higher quality eyepieces as they come up, for example on eBay or the IFAS site etc.

But that's just my preference.....I buy/bought my HiFi the same way

On filters in general. I don't use them much....some do though!

For astro photography I DO use a UV/IR filter, but for visual observation I have found my filters more of a hinderance thus far (with the exception of the Moon filter).

Clear skies,
Peter