Difference Between 9.7mm and 6mm

[Anubis]

Hi,

I'm looking for some guidance for planetary viewing. I have an ETX80 with the supplied Super Plössl 9.7mm and 26mm eye pieces. I have viewed Saturn (my main astronomical target) with the 9.7mm and barlow lens in place. It looked like a yellow star with a thin yellow line through it.

What could I realistically expect to see with a 6mm eyepiece? Is there a better eyepiece for planetary viewing?

Any advice much appreciated!

[John]

Hi,

I'm looking for some guidance for planetary viewing. I have an ETX80 with the supplied Super Plössl 9.7mm and 26mm eye pieces. I have viewed Saturn (my main astronomical target) with the 9.7mm and barlow lens in place. It looked like a yellow star with a thin yellow line through it.

What could I realistically expect to see with a 6mm eyepiece? Is there a better eyepiece for planetary viewing?

Any advice much appreciated!

I believe the ETX80 has a focal length of 400mm so your 9.7mm eyepiece is giving you a magnification of just 41x which is on the low side for planetary viewing. To see a little more detail you will need a magnification of 100x or more - this would need a 4mm or shorter focal length eyepiece to achieve. One option would be to get a 6mm (66x) eyepiece and a 2x barlow lens. As the barlow lens effectively doubles the magnification of the eyepieces you use it with you would have a good range of magnifications up to 133x which is probably as much as your scope will usefully take.

John

[Andrew*]

Check with Steve if these excellent planetary EPs are still available

The 3.2 would give you a decent 125x, and the 2.5mm is possibly bordering on the scopes capabilities (2x aperture in mm), but would give you a higher 160x mag.

Andrew

[Anubis]

Thanks for the replies, this is the kind of info I was looking for

Another question, are all eyepieces a standard diameter? That is to say I do not need to buy brand specific eyepieces.

[John]

Thanks for the replies, this is the kind of info I was looking for

Another question, are all eyepieces a standard diameter? That is to say I do not need to buy brand specific eyepieces.

As long as you buy 1.25 inch fitting eyepieces you will be OK - most eyepieces are in this size.

John

[jgs001]

I found on <a href=http://www.telescopehouse.com/acatalog/End_Of_Line_Products.html>here</a>, a couple of ortho ep's (at the bottom of the page). They have a 5 and an 18 mm listed at £29.99. I don't know if they are any good.

[John]

I found on <http://www.telescopehouse.com/acatalog/End_Of_Line_Products.html>here</a>, a couple of ortho ep's (at the bottom of the page). They have a 5 and an 18 mm listed at £29.99. I don't know if they are any good.

These are very good - the 5mm is an excellent planetary eyepiece

John

[Anubis]

Thanks for the link, I just bought the Meade 4mm Plossl Eyepiece ETX70/80 from them! :D

[Anubis]

£24.99 inc delivery!

[jgs001]

Glad the link was helpful.

[Anubis]

It definitely was

[Anubis]

Eyepiece was delivered this morning :shock: :shock: :shock: :shock:

Fantastic service and a great price... I'm impressed!

[dezmaas]

Let us know how you get on with Saturn!

[Anubis]

Will do!