DSO Eyepiece for 8" dobsonian

[Gervas39]

Hey guys! I own an orion xt8 (8" dob f5.9) and a 25 mm plossl. I am going to order a 7mm skywatcher nirvana 82° for planetary viewing (178x) and i am looking for a new eyepiece for deep sky objects. What range of focal lenghts, and eyepieces, do you reccomend? Thanks in advance.

[johninderby]

The 28mm Nirvanna is pretty good for low power viewing. 

https://www.microglobe.co.uk/ovl-nirvana-28mm-uwa-82-high-performance-eyepiece-p-9272.html

The 16mm Nirvana would also come in handy for something in between.

[Louis D]

We need to know your budget if we're going to spend your money for you. 😉

For most DSOs, something between 12mm and 17mm  will work well in your scope.  The 12mm and 15mm BST Starguiders (AT Paradigm) would work well, though only 60 degrees AFOV.  If you've got deep pockets and can balance heavy eyepieces, it's hard to beat the 12mm and 17mm Explore Scientific 92 degree eyepieces.

Below are some images taken of and through eyepieces in this range in an f/6 AT72ED fractor.

[cletrac1922]

First of all, welcome from Land Down Under

I am out a couple of times per month with my club doing presentations in primary schools, space badge, Cubs/Joeys, scout movement

With my 10" flex Dob, I mainly use 15mm or 17mm wideangle eyepieces, and has perfect eye relief for 7 - 9yos

For the moon, find the 25mm eyepiece ideal. With 15 or 17, does fit entire moon in viewer

Lot of people talk about 5mm and 7mm, and I have never had any success using them with my Dob, ideal for my ED80 on EQ5pro mount

Happy viewing

 

John

[pregulla]

I have found 11-12mm range most useful for DSO. I usually use 35mm Aero ED as a low power/finder and then switch to ES82 11mm for most objects. Some objects benefit from 16mm or 24mm, but 11mm does the bulk of the work :).

BTW for planetary I prefer zoom eyepiece + barlow. Best magnification varies with seeing from night to night and zoom allows to get most of it. I quite often push above 200x on the Moon and Jupiter. On the other hand I found that wide filed eyepieces (ES82 11mm, ES68 16mm) show lateral color in the outer field so the useful field is pretty close to that of a zoom eyepiece.

[JOC]

DSO's always seem a bit problematical for me in terms of EP.  The issue I find is the sheer range of sizes that they are and the range of visibility in the sky.  I often think that there is probably not a one size fits all DSO EP out there!  I have a full range of EP's still struggle to find many of them!

Edited November 12, 2019 by JOC

[Louis D]

5 hours ago, pregulla said:

On the other hand I found that wide filed eyepieces (ES82 11mm, ES68 16mm) show lateral color in the outer field so the useful field is pretty close to that of a zoom eyepiece.

The ES-92, Pentax XL, and some Pentax XWs and Morpheus don't show lateral color near the edge.  The 30mm ES-82 is horrible with lateral color at the edge.  So much so that earlier this year, Mars was showing as a widely separated red disk and blue disk at best focus near the edge.  I was trying to figure out why there wasn't a green or yellow disk in the middle.  You really do need to keep planets on axis for best results in just about all eyepieces regardless of correction level.

[John]

4 hours ago, JOC said:

DSO's always seem a bit problematical for me in terms of EP.  The issue I find is the sheer range of sizes that they are and the range of visibility in the sky.  I often think that there is probably not a one size fits all DSO EP out there!  I have a full range of EP's still struggle to find many of them!

I agree. Practially all my eyepieces have proved useful for observing DSO's of one type or another. Tiny planetery nebulae need a lot of magnification to differentiate them from stars. The Veil Nebula needs a field of view 6-7x as large as the moons disk to fit the whole thing in.

 

[Gervas39]

Thank you all for your advice.

I am thinking about going for:

Explore Scientific 82° 11mm ~150$

Or Baader Morpheus 76° 12.5mm ~225$

Is the baader worth the extra 75$? Which one do you reccomend?

[jetstream]

On 10/11/2019 at 09:46, Gervas39 said:

What range of focal lenghts, and eyepieces, do you reccomend? Thanks in advance.

Depends on the targets- the mentioned 28mm would be vg for emission nebula with a filter and your 11mm-12mm good for galaxies and planetary nebs , the latter with and without a filter (OIII,UHC).

[GlenM]

The Morpheus line are excellent eyepieces. I have the 17.5mm and it's a beauty in all respects, well worth the money. The 76 degrees seems just about right for me.

 

Glen.