Even lower power EPs - better at 2" ?

[JulianFR]

My lowest power eyepiece is the very nice 24mm Maxvision, but as I like (trying to find) DSOs I'm wondering if an even lower power EP would be helpful, say 32mm. I would welcome any thoughts on that: maybe that kind of low power would barely magnify anything (I'm thinking for my 300 Dob, but maybe the 127 Maksutov would also benefit from a lower power).

And if you do think the lower power eyepiece is a sensible option, is there benefit in looking at a 2" as opposed to 1.25"

Thanks in advance.

[nightfisher]

On uk astro buy sell there was a celestron silvertop plossl, 36mm 1.25 that would work well

[Schorhr]

Up to 25mm or so you can make wide angle eyepieces at 1.25". Over 32mm apparent field of view gets narrow, a 40mm Plössl has about 40degree only, and too large exit pupil on most fast scopes under light polluted skies. :-)

So a 2" 30mm 82 degree will show more field then a 32mm Plössl or a 40mm Plössl, and the exit pupil is smaller, too.

[crashtestdummy]

When I had a 300p dob my most used eyepiece by a country mile was an explore scientific 82° 30mm eyepiece and I would massively recomend one to you too.I used mine for 95% of my viewing

[bingevader]

I have a relatively cheap 2" 32mm EP with a 68° FOV, the difference between that an a 32mm plossl is quite significant. Try it out in Stellarium, by adding the 2 EPs in the Oculars plug in. The difference between the plossl and an 82° 2" 30mm EP will be phenomenal.   

[-Aldebaran-]

I.have been wondering that myself, been pondering on getting the ES maxvision 24mm and wondering if a lower power 30mm would be better even if it meant a slightly less fov, the comments here have helped sway my decision.

[JulianFR]

Thanks for the advice everyone. Dumb question this... but is a (say) 32mm at 2" the same apparent focal length as a 32mm at 1.25"?

Thinking about balancing budget and quality the Sky Watcher PanaView 32mm 2" seems like good value for money, if it's any good that is.

[John]

Thanks for the advice everyone. Dumb question this... but is a (say) 32mm at 2" the same apparent focal length as a 32mm at 1.25"?

Thinking about balancing budget and quality the Sky Watcher PanaView 32mm 2" seems like good value for money, if it's any good that is.

A 32mm focal length eyepiece is the same focal length regardless of whether it is a 2" or 1.25" one. It is the apparent field of view that can be larger in the 2" eyepiece.

The Panaview eyepieces show some distortion in the outer part of the field of view when used in a fast scope such as an F/5 but are popular wide angle eyepieces for a relatively low cost despite this. 

[Schorhr]

http://www.12dstring.me.uk/foveyepiece.php

and for example a meade 4000 plössl 32 and then a wide angle eyepiece.

Choose some large object, m31, m45, :-)

[avtaram]

I have the 38mm Panaview which gives me TFOV of 2.95 degrees in my ED120 and 1.75 degrees in my 12" Dob.

In the Dob it does show a slight softening towards the edges but to be honest I hardly ever notice it as I concentrate more on the centre of the field. For me its a keeper and its the first eyepiece I use at the start of my observing.

Through experience I have found the right positioning for my eye that gives a really immersive out there in space view.

Avtar

[JulianFR]

I'm going to sound like a Philistine asking this ... I don't mean to as I'm genuinely curious... But is a 32/38mm always 'just' a finder eyepiece, so you can immediately swap to a higher power on locating (say) an M-object? Or do people actually spend creative time observing with these low power EPs ?

I must admit I tend to locate something with my 24mm and then 'zoom' in with higher power. But I sense that is the impatience of the relative beginner, like a child who can't wait to open the next present, without enjoying the one just opened first. Also, with the poor weather I tend to jump from low to high quickly to make the most of the available time.

I would though like to think there is value to be had just cruising with a low power, that there is a lot to see without just using it as a spotter.

[triton1]

I find the max vision 28mm 2inch a very usable eyepiece,great on fuzzies and news and at 95 euros won,t break the bank

[triton1]

Damm predictive text I mean,t nebs

[John]

I'm going to sound like a Philistine asking this ... I don't mean to as I'm genuinely curious... But is a 32/38mm always 'just' a finder eyepiece, so you can immediately swap to a higher power on locating (say) an M-object? Or do people actually spend creative time observing with these low power EPs ?...

I do a bit of both with my low power / wide field eyepieces. Sometimes it's nice to see a small deep sky object in the context of it's starry backdrop though. Some of the larger deep sky objects need low power and a wide field of view to fit them in. The Veil and Orion Nebulae and M31, the Andromeda Galaxy are examples of this. Seeing more than one DSO in the field of view at the same time is also rewarding and the low power / wide angle eyepieces make this possible.

[JulianFR]

I haven't seen a 28mm Maxvision EP. I had better check the Explore Scientific site again.

[AlexB67]

The 28mm MV is a very nice eyepieces, it is my main low power.   The 28mm  gives about 1.6 degrees in the 10 inch. In your 12 inch it would be a bit less.

Seeing you were thinking about the Panaview.  Skywatcher also produces  the 82 degree Nirvanas. I spotted there is a Nirvana 28mm in the ads here at what seems a very reasonable price. Never used one but from what I read the Nirvanas are very decent quality and superior to the panaviews. The 28mm is close to 1 kg though, so you may need counterweights for smooth movement at low angles.

[avtaram]

I'm going to sound like a Philistine asking this ... I don't mean to as I'm genuinely curious... But is a 32/38mm always 'just' a finder eyepiece, so you can immediately swap to a higher power on locating (say) an M-object? Or do people actually spend creative time observing with these low power EPs ?

I must admit I tend to locate something with my 24mm and then 'zoom' in with higher power. But I sense that is the impatience of the relative beginner, like a child who can't wait to open the next present, without enjoying the one just opened first. Also, with the poor weather I tend to jump from low to high quickly to make the most of the available time.

I would though like to think there is value to be had just cruising with a low power, that there is a lot to see without just using it as a spotter.

Apart from using my 38mm Panaview as a finder eyepiece I also use it to view star clusters which in my opinion are best studied with a wide field eyepiece. For example the Double Cluster, the Alpha Persei Cluster, the Pleiades Etc.

I also like using Binoculars for studying the wide views but was even more hooked on the wide views when I managed to get some 7x35 Binoculars with a 11 degree FOV.

This opened up a completely new experience of viewing the night sky. I came across asterisms that would be too dim to view with the naked eye and too large with my 10x42 Binoculars with a FOV of 6 degrees.

One such asterism looks like a big question mark near to Polaris.

Another thing I have noticed in these 11 degree views is that in some places the stars do not look as if they just randomly placed in the sky but there seems to be a definite relationship between them, its as if they are all streaming out from a single point.

I find it all very fascinating.

Avtar

[crashtestdummy]

For larger objects like the pleides or the markarian chain these large fov eyepieces really come into their own.I've always preceded looking at objects through a wide ep rather than zoomed in

[JulianFR]

Thanks for all your thoughts here... I'm really tempted by more low power observing from what I've read and will look for a suitable 2" EP in the 30-38mm range. It will have to be at the cheaper end of the scale and possibly 2nd hand (Alex I looked for the Nirvana in the ads but couldn't see it).

[avtaram]

If you put in 'nirvana' in the search on ABS 2 28mm Nirvanas come up at £160.

Avtar

[John]

If you put in 'nirvana' in the search on ABS 2 28mm Nirvanas come up at £160.

Avtar

There was one listed at £130 a couple of weeks back. Fantastic bargain if you are in the market for a big, wide, low power eyepiece that delivers 95% of the performance of a Nagler 

[JulianFR]

Oh, ABS. Thanks. I was looking in the SGL ads.

[crashtestdummy]

For your 300p I would avoid the 38mm panaview as the exit pupil is way too high

[JulianFR]

Thanks for the warning! Would the 32mm be better?

So much to consider with EPs isn't there!

:-O

[John]

Thanks for the warning! Would the 32mm be better?

So much to consider with EPs isn't there!

:-O

Yes - you want a maximum exit pupil that more or less matches the size of your fully dilated pupil otherwise not all the light gathered by the primary will make it into your eye. 

With your F/4.9 scope the 38mm would give an exit pupil of around 7.75 mm whereas the 32mm delivers a more reasonable 6.53mm. As I'm probably older than you my max pupil dilation will be smaller so I tend to stick to a max exit pupil of 5.8mm.

This is also where ultra and hyper wide eyepieces come into their own - showing a really wide field of view while maintaining a usable exit pupil even in relatively fast scopes. The budget also starts to expand with those though !