EP'S for 12" Dob ??

[frogman (Anthony Lord)]

Righty o boys what EP's are a "must have" when your packing 12"..... Dob of course..... (rude buggers) and WHY is it a must ? ??



4mm
6.5mm
10mm
12.5mm
15mm
20mm
25mm
30mm
40mm

[ving (David)]

i got a 25, 15, 9 and 6.5 with my dob. gives a good range.

add to this at a later date a 30mm GSO SW and you are set... till you want to upgrade the quality

[mch62 (Mark)]

What's ya budget and what type of viewing are you looking for the EP to do?
Is your dob an f5?
Are those the Ep's you have now and are they all 11/4"
Are you after 2"EP's?
Do you have a barlow, if so what?

You will want to try the wide field of 2"Ep's , so you can go the cheaper way with the Andrews30mm 80deg or a 30mm GSO SV's.
40mm will be too large an exit pupil for F5 you want to stick to somthing <35mm.
Both of these EP's are resonable good for the money , but they do have limitations and it will depend on how fussy you are with certain aberations.
If you want to invest in the best for wide field and your budget allows , then Naglers .
Mark

[frogman (Anthony Lord)]

Ok i have
4
12.5
15
and 30

They came with my 12" from Andrews ummm Plossl's
My budget is not a cent till i pay the boss back for the scope
yes 1 1/4


What's ya budget and what type of viewing are you looking for the EP to do?

Nothing, no idea yet im a :noob: still havent seen through my new toy been too .

Is your dob an f5?

Whats that ?

Are those the Ep's you have now and are they all 11/4"

see above

Are you after 2"EP's?

Worth the expense ???? Why ????

Do you have a barlow, if so what?

Not yet but ill get one eventually from Andrews !



OK CHANGE THE QUESTION...........

" Righty o boys what EP's are a "must have" when your packing 12".....FOR A BEGINER/NOOB and WHY is it a must ? ??

[Striker (Tony)]

That question is impossible to answer...everything regarding what eyepieces you must have is speculative...their is no right or wrong answer...it depends on what you want to see....just by having the eyepieces you have already is sufficent for all observing.....

Some may say a 9mm would be handy but thats it...once you start looking at widefield and see the price you may start to think the eyepieces you already have is all you will ever need.....hehehe

[Starkler (Geoff)]

[QUOTE]Originally posted by frogtwat
Ok i have
4
12.5
15
and 30


Thats a good useful range ( with the exception of the 4mm which you will find pretty much useless).

See if you can trade the 4mm for a 20mm, and get a good 2x barlow. I suggest an Orion shorty-PLUS (approx $150), which will be superior to any that Andrews carry and you will keep it forever.

A barlow in conjunction with the 12.5 and 15mm eyepieces will give you a good range of high magnification options for planetary viewing.

[frogman (Anthony Lord)]

just by having the eyepieces you have already is sufficent for all observing....


Thank you Striker

yes i saw a few ep's around the $300 USD mark *shakes his head with a scowl*.....


Hey what do you guys use to carry your ep's ?????

[Striker (Tony)]

A case.......lol

[ving (David)]

a converted leather brief case with foam insert.

you EPs will do you for now.

get a wide field later tho. wide field EPs give you that walking in space feeling. dont go above 35mm tho

[ballaratdragons (Ken)]

Mark,

to answer your question, he owns an f5.

[Striker (Tony)]

yes i saw a few ep's around the $300 USD mark *shakes his head with a scowl*.....

$300 USD is about average....keep looking down to the ones around $600USD......lol...you must have to be some kind off an idiot to spend $1000AUD on 1 eyepiece.....woops.

[frogman (Anthony Lord)]

so whats the f/5 thing about ive seen verrrry expensine ???scopes???? (i think you could call them that) with f/10 and f/15 whats that all about ?

[Striker (Tony)]

Its the ratio of your Focal length devided by your aperture....eg

My Lx200 has a focal length of 2500mm and its a 10" meaning 250mm width = 10...mine is a F10......

So I would imagine your 12" scope has a focal length of 1500mm with aperture of 300mm meaning F5.......

[frogman (Anthony Lord)]

Tah dude

[mch62 (Mark)]

The faster the focal ratio as in an f5 is faster than an f10 the harder the scope is on lower cost eyepieces designs.
The light cone becomes steeper at f5 and 4 or 5 element eyepieces have difficulty in keeping stars in the outer field corrected if they are quoted as wide field design..

Meaning that for example the $150 Andrews 5 element 30mm 2" barrel 80deg (wide field) works well in an f10 and reasonable well in an f6 - f7.5 but has only about 60-70deg field out of the 80 degs with very sharp stars at f5.
Meaning stars towards the outer edge become elongated.

So for the price you just accept that it is only a 60-70deg eyepiece.
Some people can accept this considering the cheap price , but others who want perfection will go for the mega bucks Naglers (several hundred $) with there better corrected outer fields.

This is just one example and there are many others to consider when buying Eyepieces.

Do you where glasses for viewing?
If so you also have to consider a thing called eye relief.
This is the distance you have to have your eye from an eyepiece to see the full field of view.
It varies greatly form focal length of the eyepieces to designs .
You will have noted this with your set you have now the difference from the largest down to the smallest focal length.

As you are only new to astronomy and telescopes I would not rush out to buy eyepieces now as you have a good starting range. Get a 2x barlow and leave it at that for a while and see if you are still interested 12months down the track.
In the mean time try to find some one in you local area with different eyepieces that you can try in your scope.Go along to a club if need be.
Hands on is always better than word of mouth when it comes to eyepieces .
Word of mouth just helps to narrow the large variety in EP's down.


Mark

[gaa_ian (Ian)]

Thanks Mark
That is a very good description explaining why there is such a difference in performance of the widefields between scopes.
When we used my widefield's on our club LX-90 the results were quite astounding.
Also I have replaced my GS 2" 40mm widefield with a UO 40mm Konig. The difference in performance is much more noticeable on my F5 10" Dob than on the F10 LX-90.
Mike ... I think Marks "Mini review" needs to go in the EP review section of the home page

[frogman (Anthony Lord)]

mhodson brilliant thank you for your description... I dont know if i am going to wear my glasses or not when im using my big girl. Still havent looked through her yet *Grrrr* bl#$(y clouds are giving me the ****s.

Once again Thank you

Anthony

[frogman (Anthony Lord)]

Woo Hoo yeah yeah yeah yeah clouds lifted for around 2 hours then closed in again BUT

Located:
Sirius
M41 left of Sirius
M42 very cool
Saturn and its 4 moons
Beetle thingy
And the most incredible Moon see the pics below (if i can get them small enough.

[frogman (Anthony Lord)]

same one with a moon filter..

[ballaratdragons (Ken)]

That is a fantastic photo of the Moon Anthony! WOW!!

Is it taken Afocally or with a camera attachment?