Longest/Widest Eyepiece

[Moonhawk]

Hi

I have a 10" LX90 - which at F/10 provides quite high magnification views.

I have an F6.3 reducer which helps things - but i'd also like an eyepiece that gives me as wide and low magnification views as possible. I already have the 2" Moonfish 30mm 80 degree eyepiece which fits this bill quite well - but was wondering if there were any alternatives that would give even a lower magnification/wider views. The Meade series 4000 56mm 52 degree eyepiece does give lower magnification - but its narrower field means it doesn't really show that much more sky than the moonfish.

Can anyone offer any suggestions.

Cheers

[Mr Spock]

The F6.3 has a small field stop which causes vignetting with wide field eyepieces, so isn't really of much benefit. The best you can do in a 2" fitting is the Vixen LVW 42mm at 72°.

[Mr Bond]

Have you thought about a Denkmeier "Star sweeper" ? Kind of a rich field lens that has a M48 thread and will screw into your diagonal/2" EP?

it's a focal reducer of sorts (f6.6 from memory on a SCT) but very high quality.

[Rickstar]

Panoptic 41.

[Moonshane]

it's often cheaper to buy a shorter focal length scope than a max field eyepiece.

e.g. you could buy an 8" f6 dob for maybe £200-250 used. this would give a field of 2 degrees with your 30mm eyepieces at 40x. pretty good for most objects really.

[John]

it's often cheaper to buy a shorter focal length scope than a max field eyepiece.

e.g. you could buy an 8" f6 dob for maybe £200-250 used. this would give a field of 2 degrees with your 30mm eyepieces at 40x. pretty good for most objects really.

This is true. I see so many threads on how to get wide angle, low power views with SCT's which they are really just not designed to deliver.

By the time you have invested in a reducer and / or a 2" diagonal and a 2" eyepiece you may well have spent as much as an 8" F/5 optical tube or dobsonian would cost.

[Laurie61]

If you removed the focal reducer you could use the 56mm. I have one and used it with a 12" lx 200 and it was OK. The 56mm 2" Ep gives you the lowest mag with the widest field you can get. The wide angle Ep's can show the same piece of sky at a higher mag.

[alan potts]

The widest field you can get is with the reducer and a 24mm UWA or 26mm Nagler. Somewhat cheaper you can use the same with 28mm SWA from either Meade, Maxvision or ExSc. Higher than this as already pointed out will cause vignetting, you could try your 30mm and see what you get without cost.

Removing the reducer then only leaves you eyepieces that have already been mentioned, I once had the 55mm Televue Plossl, this gives good results, the 56mm Meade is also very good I am lead to believe.

I now use a 41mm Panoptic for my lowest magnification on my 12 inch LX and don't bother with the reducer at all.

Alan.

[Stargazer_00]

As others say, you'd be better off getting another scope for that price and give yourself more option.

If an 8" dob is too big consider a s/h ED80 or something. I use an explorer 150p on an AZ4 as my wide field, my 14" is quite narrow by comparison but still shows very wide views compared to large aperture SCTs.

You can pick up a second hand explorer 150p OTA for £100 or less I'd expect.

[michael.h.f.wilkinson]

Contrary to popular belief, SCTs are fine for DSOs visually, as visually, aperture is what counts. Only for a handful of very wide-field objects, like the Veil, NGC7000, M31 and M33 does the field of view become an issue. My DSO count is approaching 800, including 392 galaxies, which shows what an 8" F/10 SCT can do visually on DSOs.

In my 8" SCT I do not use the focal reducer for visual any more (since I got a 2" visual back for it), and get 1.25 deg FOV (more than enough for most DSOs) using a 31mm T5 Nagler (a.k.a. the "Panzerfaust"). The double cluster fits into that FOV. I used to have a 40mm TMB Paragon which gave 1.33 deg, which is nearly the maximum (the 42mm LVW pips it by 0.02 deg). However, I found that after the purchase of the Nagler 31mm, I did not use the Paragon at all, so I sold it. This suggests your moonfish 30mm, without focal reducer should be near optimal for your scope. You could consider a 40-ish mm super-wide angle EP, but the nice thing about a 30-ish mm ultra-wide is that the 3mm exit pupil means that the background is darker too, compared to the 4mm when using a 40mm TMB Paragon (really great EP; clones now sold as SW Aero). For truly wide-field objects, a 10" dob will also struggle, and for these binoculars, or short refractors like my 80mm F/6 are ideal. The view of NGC 7000 and the Pelican through that scope, with the 31T5 at 15.5x with a true FOV of 5.3 degrees is breathtaking.

[AlexB67]

it's often cheaper to buy a shorter focal length scope than a max field eyepiece.

e.g. you could buy an 8" f6 dob for maybe £200-250 used. this would give a field of 2 degrees with your 30mm eyepieces at 40x. pretty good for most objects really.

Go no further than the Heritage 130P , For that reason alone I can imagine once I have a bigger scope I'll get it out for the 2 degree plus views and an eyepiece that will go beyond that. Somewhere in between a set of bins and a higher power scope. You see, I've got all the arguments ready when the missus says "You got too many scopes" and I can say "no I don't"

[Macavity]

Contrary to popular belief, SCTs are fine for DSOs visually, as visually, aperture is what counts. Only for a handful of very wide-field objects, like the Veil, NGC7000, M31 and M33 does the field of view become an issue.

And that is a very important point.

So often are (were!) SCTs (MAKs) described, in stentorian tones, as "planetary" (only) scopes.

Had I my time over, I might consider an 8" SCT. Given (rather excessive) "educational" spending,

maybe even a (sweet spot) Celestron C11. A small APO to do the wide-field, portative stuff...

I sense I would avoid the loss-making "eyepiece tango". More into VIDEO Astronomy these days?

The Vixen LVW 42mm. But saving for a Delos or two (the natural Hyperion upgrade?) now...

[swamp thing]

Contrary to popular belief, SCTs are fine for DSOs visually, as visually, aperture is what counts. Only for a handful of very wide-field objects, like the Veil, NGC7000, M31 and M33 does the field of view become an issue. My DSO count is approaching 800, including 392 galaxies, which shows what an 8" F/10 SCT can do visually on DSOs.

In my 8" SCT I do not use the focal reducer for visual any more (since I got a 2" visual back for it), and get 1.25 deg FOV (more than enough for most DSOs) using a 31mm T5 Nagler (a.k.a. the "Panzerfaust").

I've never quite understood this labelling of SCT as planetary scopes either. They make excellent deep sky tools, they offer great contrast, with lovely dark sky backgrounds.

I would get a 10" one myself, but they make such lousy Dobs

[Mr Spock]

It's because people confuse 'deep sky' with 'wide field'. A SCT is no good at wide field, a short focal length refractor is better, but a SCT is good at deep sky.

My C925 will get down to X56 with the eyepieces I have. However, for deep sky, I usually use X107 or X138 - more if it's a globular or faint planetary.