Eyepiece for deep sky objects

[earth titan]

Got a bit of cash to spare. Looking for a new eyepiece and would value some advice.

Currently have a 25mm as the biggest but wonder about going bigger to get better contract on some of the DSOs (whirlpoole ? M3 / M13 etc. I have in mind a 30mm ish which would give me a magnification of 25 (if I've done the calcs right).

Any thoughts?

I have seen this one (just an example) which I think would suit the purpose.

GSO GSO 32mm Super Plossl eyepiece

[pvaz]

For M3/M13 you need some magnification so bigger is not the answer.

For the whirlpool less mag will show a bigger star field around it and provide a nice view but won't help on detail, unless your current EP is really low quality. Then an upgrade would help a little bit.

Only 3 things can help you with detail on faint DSOs:

1) Very dark skies

2) Larger aperture

3) both at the same time

For example to easily spot the spiral structure on a small group of galaxies, you need a big aperture, such as 14" or 16". Or so I read. Unfortunately I only own an 8".

On my 8" dob the best I could see was 2 spiral arms, 2 dust lanes and the bridge on M51, under excellent seeing conditions and very dark skies. M31 showed a dust lane, while every other galaxy is a "faint and fuzzy light cloud".

[twotter]

I have seen this one (just an example) which I think would suit the purpose.

GSO GSO 32mm Super Plossl eyepiece

I've got one of those and it's my favourite EP. It gives me a nice widefield view of the stars and it's great for DSO hunting. Once I've found my target though I start to 'zoom in' using my other EPs/barlow, depending on the seeing etc...

[pvaz]

I mean it's a good thing to have a wide field EP. It's always the one I use the most (currently a 31mm and before that I had a cheaper 32mm).

My previous post intension was just to point out it won't help much regarding the amount of detail you see with it. Aperture and dark skies are the main limiting parameters for that.

[michael.h.f.wilkinson]

The key question is what your focuser will accept. If 2" EPs fit, I would check out the Paragon 40 or 30mm (both 69deg AFOV). I have the 40mm and love it. It is really great for extended objects such as the Pleiades or the double star cluster of Perseus. It is also the single most comfortable EP to use: good eye relief, no kidney beaning. It completely blew away my Plossl 36mm. The 30 is supposed to be every bit as good.

I also have the Nagler 22mm T4, which is great. More magnification, and great field of view.

Cheers

Michael

[John]

If your scope is limited to the 1.25" format then a 32mm plossl is a good choice as it will show you as much sky as you can see within th 1.25" size. If your scope can handle 2" eyepieces then consider a similar focal length but in the larger size - you will get a larger field of view which is helpful for extended objects such as M31.

If you can use your scope under dark skies you will get a much larger performance boost on galaxies and other faint DSO's than any eyepiece can give. When someone asked on another forum "what is the best thing I can buy for around $100 to give me better views of galaxies ?" the response from one poster was "a tankfull of fuel to get you and your scope to dark skies". He was not wrong .....

[Merlin66]

Some very good advice so far.

Low power eyepieces give nice views of general DSO's, but if you want to observe in detail you need a bit more magnification.

I did Super Nova searching for many years in the 1980's using a 12" f5 newtonian. I was regularly observing stars in and around galaxies visually down to 15.5mag.

When I started I was using UO ortho's and the 12.5mm (x120) was the favourite; I bought my first TV plossl about this time and ended up with the 10.4mm ( x 154) to do the searches. Gave a very good tight contrasty FOV and allowed me to check and verify hundreds of Gregg Thomson's initial/ draft Super Nova Search Charts.

This work was recognised in the final book. Well worth trying to find a copy ( out of print at the moment) (BTW I scanned all the charts and linked them to AstroPlanner - so they come up when you select a galaxy included in the search)

Ken

[michael.h.f.wilkinson]

I agree with Ken, I often use my 14mm (140x on my 8" F/10 SCT) for deep sky, especially for planetary nebulae, but really any fairly compact source (because it is a UWA, I get good views even of M42). However, for really extended sources, such as large open clusters or nearby galaxies such as M31 and M33, or groups such as M81/M82/NGC3077, the Paragon and Nagler I have rule.

I am aiming to get a 24 mm super wide angle (like the Hyperion) for my little spare 4.5" F/4.4 Newt, which only accepts 1.25" EPs. It gives the same true FOV, but higher magnification (and smaller exit pupil) than a 32mm would. If you are my age (NOT DEAD YET, but >40) a good rule of thumb is not to use an EP with a focal length larger than 5 x the F-ratio of the scope in mm. This ensures the exit pupil is no bigger than about 5mm.

[crazyjedi]

The Skywatcher 150 has adaptors for both 1.25 and 2" eyepeices (i have one) i think it depends more on where you live. I live right on the outskirts of birmingham, frustratingly close to the M5 and it's wonderful orange road lights . and galaxies are very elusive even with an LP filter. I spend lots of time at our caravan in wales where things improve dramatically as far as light pollution goes but still the 150's lack of light grasp makes galaxies very hard to see. Nebula's look good with a UHC filter tho

TTFN

[michael.h.f.wilkinson]

I had a 6" Newton years back (my first real scope) and spotted plenty of galaxies (from a fairly dark spot) including the Sombrero galaxy with its dust lane. An 8" SCT in the city cannot beat that (still spotted detail in M51 though).

Given that you can use 2" EPs I would go for one.