Should I Get a 3 or 4.5mm Eyepiece?

[markleton]

Hello All -

I have an Apertura AD8 8" dob (1200 mm focal length) and am using the 12mm Explore Scientific 92 series and the 8.5mm Explore Scientific 82 series eyepieces. I'm very happy with both eyepieces and am considering a high magnification 3 or 4.5mm eyepiece in the 52 series from ES.

My question is, should I even consider a 3 or 4.5mm eyepiece? My 8.5mm paired with my 2.5x barlow will get me solid magnification, but is there a situation where a 3 or 4.5mm on their own would do a much better job? I know I can't barlow them because my theoretical max magnification is 400x. Should I round out my collection, or is it not necessary?

Thanks again!

[Guest]

12 minutes ago, markleton said:

Hello All -

I have an Apertura AD8 8" dob (1200 mm focal length) and am using the 12mm Explore Scientific 92 series and the 8.5mm Explore Scientific 82 series eyepieces. I'm very happy with both eyepieces and am considering a high magnification 3 or 4.5mm eyepiece in the 52 series from ES.

My question is, should I even consider a 3 or 4.5mm eyepiece? My 8.5mm paired with my 2.5x barlow will get me solid magnification, but is there a situation where a 3 or 4.5mm on their own would do a much better job? I know I can't barlow them because my theoretical max magnification is 400x. Should I round out my collection, or is it not necessary?

Thanks again!

Have you thought about the BST StarGuider 3.2mm ED eyepiece?

https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-32mm-ed-eyepiece.html

[John]

If I had your scope and your current eyepieces, I would be looking for a 6mm to give 200x. Very useful and usable high power.

Do you have anything with lower power than the ES 12mm ? - if not I think you have a niche or two there that might need filling.

Eyepieces that give more than 250x will not get a lot of use whereas the ones I mention above will

[markleton]

25 minutes ago, merlin100 said:

Have you thought about the BST StarGuider 3.2mm ED eyepiece?

https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-32mm-ed-eyepiece.html

Nope, but I'm open to all suggestions. I was intending to stick with ES since I was so happy with my two other eyepieces. Should this be at the top of my list? Thanks

[markleton]

19 minutes ago, John said:

If I had your scope and your current eyepieces, I would be looking for a 6mm to give 200x. Very useful and usable high power.

Do you have anything with lower power than the ES 12mm ? - if not I think you have a niche or two there that might need filling.

Eyepieces that give more than 250x will not get a lot of use whereas the ones I mention above will

Thanks. Any suggestions? I have a 30mm SuperView with a 68 degree FOV that came with the scope. I hardly ever use it anymore.  

[John]

 

10 minutes ago, markleton said:

Thanks. Any suggestions? I have a 30mm SuperView with a 68 degree FOV that came with the scope. I hardly ever use it anymore.  

 

What sort of budget do you have in mind ?

 

[markleton]

7 minutes ago, John said:

 

 

What sort of budget do you have in mind ?

 

I'd go up to $150ish... Seems like some of the midrange stuff I'm seeing (along with the StarGuider suggested above) are well below $100.

[Ruud]

Agena has the starguiders for $60

https://agenaastro.com/catalogsearch/result/?q=starguider

[bingevader]

10 hours ago, markleton said:

Hello All -

I have an Apertura AD8 8" dob (1200 mm focal length) and am using the 12mm Explore Scientific 92 series and the 8.5mm Explore Scientific 82 series eyepieces. I'm very happy with both eyepieces and am considering a high magnification 3 or 4.5mm eyepiece in the 52 series from ES.

My question is, should I even consider a 3 or 4.5mm eyepiece? My 8.5mm paired with my 2.5x barlow will get me solid magnification, but is there a situation where a 3 or 4.5mm on their own would do a much better job? I know I can't barlow them because my theoretical max magnification is 400x. Should I round out my collection, or is it not necessary?

Thanks again!

Hi,

I have the same spec' 'scope as you, and you can see the range of eyepieces I have in my sig'.

I barlow (2x) to get the highest magnifications possible, but this is only ever on the moon.

As John has said, in the UK, the 6mm is about as good as it gets on the planets.

I've rarely used the 5mm on the planets and often drop back to the 7mm or 8mm when conditions are less favourable (like now!).

My 6mm WO SPL is smashing and I've no complaints what so ever, in my 'scope, of the OVL Nirvana 82° eyepieces.

[JOC]

I have an 8" 1200mm FL Dob and I have never got any joy out of anything more magnifying than a 4mm and most times a 5mm.   I have once tried a 3mm in it and it was hopeless - in my opinion I think it you stick at half of what is theoretically possible you won't go far wrong.  I would 100% buy the 4.5mm if you have to get one of them, but I reckon you'd be better off stopping at 5mm IMO.

[markleton]

42 minutes ago, JOC said:

I have an 8" 1200mm FL Dob and I have never got any joy out of anything more magnifying than a 4mm and most times a 5mm.   I have once tried a 3mm in it and it was hopeless - in my opinion I think it you stick at half of what is theoretically possible you won't go far wrong.  I would 100% buy the 4.5mm if you have to get one of them, but I reckon you'd be better off stopping at 5mm IMO.

Got it. Thanks. The 4.5mm option specifically brings up what I'm trying to understand conceptually... My 12mm paired with my 2.5x barlow gets me to 250x. A 4.5mm on its own gets me to 266x. Other than the small magnification increase, Is there any advantage to using a standalone eyepiece without a barlow? Does the barlow impact image quality in any way?

[John]

Well, the image is as good as the weakest link in the optical chain. As long as the barlow lens is of good optical quality it's impact on optical quality should be negligible.

The only snags that I can see are:

- The 12mm ES 92 (which I believe you said you have) is a very large 2 inch eyepiece. Adding a 2.5x barlow to that will make a heavy and tall "stack" to hang out of your focuser.

- The 12 ES 92 already has quite long eye relief and the barlow lens will extend that further. You might find that eye positioning becomes tricky ?

 

[markleton]

13 minutes ago, John said:

Well, the image is as good as the weakest link in the optical chain. As long as the barlow lens is of good optical quality it's impact on optical quality should be negligible.

The only snags that I can see are:

- The 12mm ES 92 (which I believe you said you have) is a very large 2 inch eyepiece. Adding a 2.5x barlow to that will make a heavy and tall "stack" to hang out of your focuser.

- The 12 ES 92 already has quite long eye relief and the barlow lens will extend that further. You might find that eye positioning becomes tricky ?

 

My barlow is the Celestron 93436 Luminous 2-Inch 2.5x. It's definitely not high end, but seems to be of good quality and has really given me some impressive views with the 12mm ES. I have no complaints with it. 

It's definitely a tall and heavy stack, but my focuser seems to handle it quite well. I haven't noticed any difference in terms of eye positioning, but I'm still kind of getting used to proper eye positioning in general (still a rookie!)

[Louis D]

21 hours ago, markleton said:

I'm very happy with both eyepieces and am considering a high magnification 3 or 4.5mm eyepiece in the 52 series from ES.

Unless your Dob is on an equatorial platform, you are going to want at least a 65 degree AFOV for any eyepiece yielding powers above 200x for manual tracking purposes.  I have a Pentax XW 3.5mm for this purpose that works really well.

Try out your existing 2.5x Barlow with your eyepieces to see if you like the combinations.  Going to a 52 degree eyepiece at high power after using that 92 degree eyepiece will feel almost suffocating.

The Morpheus 4.5mm might be another option.  It has a bit of EOFB from what I've read, but is otherwise very nice.

[John]

3 hours ago, markleton said:

My barlow is the Celestron 93436 Luminous 2-Inch 2.5x. It's definitely not high end, but seems to be of good quality and has really given me some impressive views with the 12mm ES. I have no complaints with it. 

It's definitely a tall and heavy stack, but my focuser seems to handle it quite well. I haven't noticed any difference in terms of eye positioning, but I'm still kind of getting used to proper eye positioning in general (still a rookie!)

If you wear glasses while observing I can see that the ES 12mm 92 would be good. I don't wear glasses though and found that I needed to "hover" my eye some way off the eye cup of the eyepiece which is not how I like to observe - I prefer to nestle my eye socket gently into a soft eye cup so that the eye cup keeps stray light off the top of the eyepiece and acts as a eye positioning guide.  Because I could not do this with the 12mm 92 I let that one go to a new home. I still have the 17mm 92 though which suits me better although that has taken some getting used to as well.

They are excellent eyepieces optically though, quite probably the best that ES have produced to date.