Widefield options for a 200P dob

[KevUU]

I'm debating my options for a widefield ep for Jeffrey. I really miss the widefield aspect of my ST80 and would like an option for, eg, the Andromeda troika (M31/32/110) or Pleiades framed in one fov.

At the moment my widest ep is a Vixen NPL 30mm, giving 1.25 degrees tfov. This is the same as a BST 25mm.

I did try a 36mm hyperion (in 1.25" mode) at Sixpenny Handley star party, but it won't come to focus in Jeffrey - I ran out of in-focus.

So my thinking is to go for a 2" ep. I'm hoping if I leave the 2" adaptor on the 2" ep (I intend it to be my only one) there shouldn't be much extra hassle when swapping.

Unfortunately no-one at the star party had one I could try, and I don't want to wait until SGL9...

Does anyone have any advice here?

My initial thought is something like a 38mm panaview - rather cheaper than the Aero EDs - giving a nice 2.2 degree field ... but I basically have no idea... Help!

[Lee M]

http://www.explorescientific.de/maxvision-68deg-okular-34mm-p-25564.html

x35 and 1.9 deg fov if my spreadsheet's correct.

I don't have this one (yet)

[KevUU]

http://www.explorescientific.de/maxvision-68deg-okular-34mm-p-25564.html

x35 and 1.9 deg fov if my spreadsheet's correct.

I don't have this one (yet)

Thanks Lee. I've not heard much about the MaxVisions, would you say they're a better bet than the Panaview then?

[Lee M]

There's several threads in this area of the forum. Have a search. You'll find other people's views on them compared to other EPs.

In short though they're 'rebadged' Meade 5000 UWAs being sold off for a song.

Optically they're very good. The eyecup is a bit of an acquired taste though.

[John]

You can get a bit over 2 degrees true field with your scope if you go for the widest apparent field of view that you can get in the 2" format eyepieces. Eyepieces such as the 41mm Panoptic, 31mm Nagler, 30mm ES 82, 42mm Vixen LVW will get you there but at some cost. At the other end of the budgetary scale the 38mm Panaview will also do the job if you are OK with stars not being pin sharp across the whole field of view. I guess it depends what you want to spend.

In 2" mode the Hyperion 36mm would probably have come to focus. Using it's 1.25" barrel option both reduces the apparent field it's showing as well as moving the focal plane of the eyepiece. 

[Mr Spock]

Whatever eyepiece you choose, you need to be aware a Newt will suffer from a lot of coma at those wide angles. So unless you go for an expensive widefield eyepiece plus coma corrector you won't have the outer edges sharp. With that in mind something like a Panaview would be ok and give you a reasonable view.

[KevUU]

There's several threads in this area of the forum. Have a search. You'll find other people's views on them compared to other EPs.

Have done now, thanks. TwoPi stuck up a similar thread a couple of months ago (sorry for the repitition). My problem with the MaxVision is the >£100 price tag, my most expensive eps to date are BSTs! So the question is, would I be sorry if I got a Panaview 38mm...

You can get a bit over 2 degrees true field with your scope if you go for the widest apparent field of view that you can get in the 2" format eyepieces. Eyepieces such as the 41mm Panoptic, 31mm Nagler, 30mm ES 82, 42mm Vixen LVW will get you there but at some cost. At the other end of the budgetary scale the 38mm Panaview will also do the job if you are OK with stars not being pin sharp across the whole field of view. I guess it depends what you want to spend.

In 2" mode the Hyperion 36mm would probably have come to focus. Using it's 1.25" barrel option both reduces the apparent field it's showing as well as moving the focal plane of the eyepiece.

Hmmm, expensive glass is tempting but not while I'm trying to buy a house! Since I'm planning to use this for sweeping and widefield gawping, I don't expect the edge-distortion to be a huge problem to me, but I have no way of knowing until I try I suppose.

(The Hyperion-donor didn't have the 2" paraphernalia with him, unfortunately )

Whatever eyepiece you choose, you need to be aware a Newt will suffer from a lot of coma at those wide angles. So unless you go for an expensive widefield eyepiece plus coma corrector you won't have the outer edges sharp. With that in mind something like a Panaview would be ok and give you a reasonable view.

You seem to be on the same page as John here, I feel a consensus forming

Thanks guys for your useful advice. I'll have to do some thinking, and no doubt some more 'research' aka procrastination...

[Space Beagle]

I have used an Aero 30mm in my 200P (1000mm f5) which gave just over 2 degrees true fov and very good images if a little coma evident at the edges. It has become a little redundant now, however, due to a Nagler 26mm T5 somehow appearing in my ep case

Umm, maybe if you have a peek at the classifieds there might be a nice 2" ep there for you to think about!

Good luck in your procastination

Doc

[KevUU]

I have used an Aero 30mm in my 200P (1000mm f5) which gave just over 2 degrees true fov and very good images if a little coma evident at the edges. It has become a little redundant now, however, due to a Nagler 26mm T5 somehow appearing in my ep case

Umm, maybe if you have a peek at the classifieds there might be a nice 2" ep there for you to think about!

Good luck in your procastination

Doc

Thanks doc. Unfortunately in the f/6 200p dob I'd get about 1.7 degrees tfov, which is drifting a bit lower than I want

[John]

They do a 35mm and a 40mm in the Aero ED series as well, both with a 68 degree apparent field of view. They are nice eyepieces and a touch better corrected than the Panaviews. A touch more expensive new too of course but not so far apart on the used market. Another good thing about the Aero ED's is that they are a bit lighter than most 2" eyepieces of that focal length which might help maintain the balance of your scope.

[KevUU]

They do a 35mm and a 40mm in the Aero ED series as well, both with a 68 degree apparent field of view. They are nice eyepieces and a touch better corrected than the Panaviews. A touch more expensive new too of course but not so far apart on the used market. Another good thing about the Aero ED's is that they are a bit lighter than most 2" eyepieces of that focal length which might help maintain the balance of your scope.

Cheers John. It's justifying the extra £40-£50 (to myself) is the problem...

£89 for the 38mm Panaview giving 2.2 degrees

£130 for the 35mm Aero giving a better 2 degrees (actually at this point I'd probably go the extra fiver for 40mm, 2.3 degrees)

Hohum. I can find the cash, it's just how often would I use this ep? It's a hole I do feel I need to fill but it needs a dark site to really be worth it, which means star parties (twice a year) or a local dark field (a few times a year at best)...

Having a conscience is overrated!

[John]

I think "how often will I use this ?" is a very sensible question to ask 

I don't use my Nagler 31mm at home that often really. My 20mm ES / 100 shows a darker background sky because of it's extra magnification so it's often worth loosing that ultimate FoV for a more contrasty view of a faint deep sky object.

[swamp thing]

John makes excellent points here.

I too find I use wide field eyepieces around 20mm far more in my mid sized scope (10" f/4.5 Dob )

[KevUU]

I think "how often will I use this ?" is a very sensible question to ask 

I'm good at 'sensible', it's the engineer in my head. The problem is my soul couldn't care two hoots what the engineer thinks, it knows I *need* it! And this game, the universe in its awesomeness, cries out to my soul first and foremost...

I don't use my Nagler 31mm at home that often really. My 20mm ES / 100 shows a darker background sky because of it's extra magnification so it's often worth loosing that ultimate FoV for a more contrasty view of a faint deep sky object.

Yes, there is that concern too. But I know this ep would be serving a different purpose. It wouldn't be there to find the new objects or to observe faint fuzzies, its raison d'etre would be explicitly to give me a widefield hit.

Argh!

[bingevader]

Maxvision 68^o Okular 40mm? 

[KevUU]

Neuargh! Stop it stop it stop it

It's so tempting, but it's more than I really want to pay for an occasional-use ep. Both that and the Aero ED are about the same price point of £135 ish (accounting for postage), vs £90 for a panaview.

The weights are interesting:

38mm Panaview ... 450g

35mm Aero ED ... 650g

Maxvision 40mm ... 1.25 kg!

No sign of any 2nd hand at the moment... Will keep my eyes peeled while I procrastinate about a new one

[Stargazer_00]

Personally I think something like a 24mm 68 degree (1.25") would be good for you. Maxvision do this eyepiece (not sure the price but its less than £100).

It wont give you maximum field of view in your 200p but it'd be a very good view at 50x 1.36 degrees.  This EP will frame pretty much any DSO worth looking at and supply it in a 4mm exit pupil, which will be nice.

And then if you want really wide field (where aperture really doesn't matter in my opinion) you can put the same eyepiece into your ST80 and get 16x 4 degrees.  Can't ask for much wider than that in my opinion.  The most that can be gotten out of that scope (with it's 1.25" only focuser).

[bingevader]

About £68 plus postage. You'd lose nearly a degree, but gain in magnification.

But why would it need to be an occasional EP? If you got the 24mm It would spend a lot more time in the 'scope!

And with that in mind.  Maxvision 82^o Okular 24mm! Now losing about 2/3 of a degree but still at x50.

Cheers

[Stargazer_00]

I was considering promoting the 24mm 82 degree but it wouldnt fit into the ST80. 

I guess the basis of my suggestion was dont use the 200p for ultra widefield because you have an ST80 for that.  Use the 200P for anything up to 1.5 degrees ish.

I find anything beyond 5mm exit pupil is a washout anyway (which mosty of the options above would be)

[YKSE]

Neuargh! Stop it stop it stop it

It's so tempting, but it's more than I really want to pay for an occasional-use ep. Both that and the Aero ED are about the same price point of £135 ish (accounting for postage), vs £90 for a panaview.

The weights are interesting:

38mm Panaview ... 450g

35mm Aero ED ... 650g

Maxvision 40mm ... 1.25 kg!

No sign of any 2nd hand at the moment... Will keep my eyes peeled while I procrastinate about a new one

Just a coment on the weight, I think 35mm Aero weighs about 370g, and 40mm Aero about 520g.

[KevUU]

Unfortunately I'm energy limited so having both scopes out at once doesn't appeal... Hence the current debate!

If there was a sensible way to piggy-back my ST80 onto the dob as a super-finder / widefield combo I'd do it, but it's not straightforward and anyway the liitle frac weighs 1.5kg even before any paraphernalia needed to attach it...

Exit pupil, hmmm, hadn't thought about that.

Why can't it be easy?!

[KevUU]

Just a coment on the weight, I think 35mm Aero weighs about 370g, and 40mm Aero about 520g.

Thank you! I struggled to find consistent figures on line...

[Stargazer_00]

Why can't it be easy?!

I think it is easy, decide before you go out what mood you are in and take the appropriate scope   I rarely get both my scopes out at the same time even when they take less than a few minutes to set up each.  I'll decide before I set up what I fancy looking at. 

I must admit though that on occasion I'll get my grab and go out and realise the sky is good quality so put it away and get my main scope out.

I'm really waiting for the clock change before I start using my main scope in anger though.    I'm saving my first view of M42 through the main scope until it's well positioned in the sky.

The reason I think it's wise to get the 24mm 68 degree is as I've stated, it works well for both scopes.  Buying a 40mm (massive 6.66mm exit pupil) for the 200p to get the widest field out of it is a real possibility but that 40mm eyepiece wouldn't work in your ST80 making the ST80 used less.  I always try to buy eyepieces that will work well in all my scopes.  I don't have anything too long to get the wide field out of my main scope as I realise that at a certain point I'll get my 6" out and use that for its wide field properties instead.  Over 2 degrees I dont think aperture does much anyway if im honest.  You really only looking at star points for anything this size anyway and very dim star points are much easier to resolve than DSOs.  I can resolve 11th magnitude stars in a 6" scope and I doubt I can see many 11th magnitude DSOs even in my 14".

[TwoPi]

Hi Kev,

You've already mentioned the similar thread where I was asking this kind of question, so you know what I went for. I came to the conclusion that slightly higher mag (24mm) and wider aFOV (82deg) was the way to go for me as I felt I wanted to avoid the weight and possible sky background lightness & exit pupil issues with longer focal length eyepieces. As a result I use my MaxVision in pretty much every observing session.

FWIW, I much prefer the view in my MaxVision 24mm EP compared with my old Hyperion 24mm (that I've now got rid of).

Good luck in your choices!

[Reeny]

I was thinking about getting a 2" Revelation (GSO) 42mm, 65 Degree field, 5 Element - for £36 inc postage.

Obviously this eyepiece might have problems with Coma, otherwise we wouldn't be talking about spending up to £150.

I did look at the Maxvision range as well - but the prices are high for the low magnification sizes (28mm = 95euro / 34mm = 119euro / 40mm = 149euro) 

On that basis - I guess the advice is to avoid the budget 2" eyepieces for the moment.

This hobby is a minefield.