Best magnification for galaxies?

[DaveGarland]

Hello all. I want to buy a new eyepiece for galaxy viewing. What would you all recommend as the ideal magnification for viewing galaxies in general? Obviously the more they are magified the fainter they become and the less the smaller they become. Also they are all different sizes and magnitudes anyway so I realise there is no one perfect mag. But what do you all find is best in general?

Dave.

[Daniel-K]

your aero should be pretty good, i found i loved my old 24mm panoptic for fuzzy's nice eyerelief with a nice FOV from a dark site you cant beat them

[NGC 1502]

Hi Dave. What I've found is that to find the galaxy, low power, wide field. With my 10" Dob, I generally use a 27mm EP, 44x, 1.5 degree field.

Often I will switch to a 14mm EP for 86x. The sky background will be darker, increasing contrast between galaxy and sky.

My best view of M33 was with just that EP. From Kelling star party, the 'backwards S' of the main spiral arms were apparent.

Same with M31, main dust lane seen, from Fieldview astronomy B&B, north Norfolk.

My best view of M51 was at 120x. From my clubs dark site, faint spiral arms could be seen, confirmed by fellow clubmates.

It's very rare for me to go to a higher mag on galaxies. Some find it worthwhile to go high, especially with a large Dob, 20" +.

So for me, low power to find, medium for viewing.

Regards, Ed.

[rwilkey]

Hi Dave, I do hope you are well! I use my 32mm PanaView most of the time (28x), but if I go higher in my view there is no better ep than the Vixen LVW 13mm that I have, giving 69x, not high mag I know but after this fuzzies start to get a little bit feint. Well that's my preferred options.

[swamp thing]

For me it depends on the scope, and the intended target.

There are just too many variables on these objects.

The larger the scope the more power that can be used.

[Mr Spock]

For me it's x106 (22mm in a C925), though x94 is just as good (25mm). I find anything less leads to lighter backgrounds and anything more makes the objects too faint (low surface brightness).

[ronin]

For your scope I would guess a 12mm.

A lot will depend on the skies, but 12mm should be a fair balance.

[michael.h.f.wilkinson]

I use a 22mm and 17mm most in my F/10 scope on galaxy hunts (like Mr. Spock I like a dark background). That translates to 11 and 8.5 on an F/5 scope. I also like the 31T5 for slightly wider field views (like for Markarian's Chain).

[John]

I find the 13mm Ethos a fabulous galaxy eyepiece for all but the larger ones - huge field of view but a decent amount of magnification to darken the backgound sky and allow the contrast features in the galaxies surface to show.

[ampleamp]

you could always use David Campbell's FOV calculator to give you a good idea of view sizes etc - obviously use the visual view. http://www.12dstring.me.uk/fov.htm

I agree with john in that my 13mm Ethos is by far the best and most used eyepiece

[michael.h.f.wilkinson]

Actually, I find that in most cases FOV is not really the issue; exit pupil is. That tells you how dark the background appears, and how well it will contrast the galaxy. This depends very much on sky conditions. I can use lower magnification (exit pupils 3-5mm) in dark locations more often. Even then, an exit pupil of between 2.5 and 1.5mm is probably better for a large number of fuzzies (in my 8" scope at least, in bigger scopes things might be different)

[Laurie61]

Have a go with this, just put in your scope and eyepiece and select a target.

http://www.skyatnightmagazine.com/field-view-calculator

[Laurie61]

Ampleamp beat me to it

[RikM]

I use my 14mm most often for galaxies in my 250PX

[DaveGarland]

Hmmm thanks guys. Plenty of input there. I'm off on my holidays Saturday so that gives me plenty to think about. Decisions decisions eh?

Dave.

[Moonshane]

sky conditions affect things more than anything. in my 16" dob from home most galaxies look best in the 26mm so 71x. occasionally on the best nights the 13mm can be used (142x) but not often. I am going to be experimenting with TV plossls when I get a chance to see if my 25mm, 20mm or 15mm would be better. I suspect they will as they have a narrower field and you can in theory omit brighter stars from the field more readily.

from dark sites you often benefit from better seeing too (less effect from houses/roofs etc) and then you can use more power with more contrast.

as Steve says though, different types of galaxy and different brightness and size of galaxy will all have a different effect on their visibility even from jet black sites.

[Bart]

I like hunting galaxies at x50 (or sometimes x90 if I have a good idea where to find them). Usually observe them at the x90 and sometimes go to 130 or 160 if the seeing is good and the galaxy is offering some detail. I should say this is with a 16" in decent dark skies. With the 10", probably wouldn't often go above x130

Barry

[jetstream]

Actually, I find that in most cases FOV is not really the issue; exit pupil is. That tells you how dark the background appears, and how well it will contrast the galaxy. This depends very much on sky conditions. I can use lower magnification (exit pupils 3-5mm) in dark locations more often. Even then, an exit pupil of between 2.5 and 1.5mm is probably better for a large number of fuzzies (in my 8" scope at least, in bigger scopes things might be different)

This is what I've found also,in light sky conditions low magnification(larger exit pupil) tends to wash out the image,but in a darker sky there is more flexibilty for eyepiece choices.Also picking a scope with appropriate focal ratio for galaxy use will help...thankfully manufacturers have taken a lot of the guess work out of it for us.So a 10" f 4.7(1200mm F.L.) @ 120x with a 2.13mm exit pupil seems like a reasonable place to start for my sky conditions,& probably will use lower mag eyepieces more often than not.But you know keeping " brighter stars" out of the field of view sounds very interesting.....

[Stargazer_00]

Exactly what I was about to post. Fuzzies are more about exit pupil than magnification. You need to right exit pupil for the scope rather than magnification. It's for this reason that a larger aperture scope is good for fuzzies as you can increase the magnification to get an exit pupil of 2-3mm compared to a smaller scope where the magification would have to be much lower to get this exit pupil.

[DaveGarland]

Ive only just looked up what an exit pupil is. Would I be right in calculating that with my scope (200 aperture x 1000 fl) a 14mm eyepiece would give me an exit pupil of 2.8mm and a magnification of 71x? Would this perhaps suit me?

[Stargazer_00]

exactly right and yes if imagine that'd look rather nice you could push the magnification to a 10mm giving 100x for a perfect 2mm exit pupil. anything between 10-14mm would work for you on fuzzies. obviously you could go lower mag and that would work for larger objects too but the exit pupil would not be as good. The larger exit pupil the brighter the background sky. 2-3mm shiws good target brightness with dark background so increased contrast between them.

[michael.h.f.wilkinson]

Ive only just looked up what an exit pupil is. Would I be right in calculating that with my scope (200 aperture x 1000 fl) a 14mm eyepiece would give me an exit pupil of 2.8mm and a magnification of 71x? Would this perhaps suit me?

Correct. The easiest way is to divide the focal length of the EP with the focal ratio of the scope, and 14mm / 5 = 2.8mm

[Moonshane]

this is exactly why the 13mm for many people is the workhorse eyepiece.

[DaveGarland]

Ok, so a 14mm Delos is £295 and a 13mm Nagler is £265. Which one do I plump for fellas? Is the extra FOV of the nagler worth the slight loss of magnification???

[John]

Both great eyepieces but I reckon the Delos will go just a little "deeper" than the Nagler will and, as galaxy eyepieces are the subject of the thread, that should make the Delos a slightly better eyepiece for that purpose. The extra 8mm of eye relief of the Delos should not be ignored either.

You should be able to get the Delos for £250 - there is a 15% discount on them at the moment.