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Least mag for nebulas with a Televue


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What is the minimum magnification needed to get a good view of nebulas and clusters? I have a 10" f5 dob and want to get the best Televue for the job as I can't afford more than one at a time. I have a UWA Ascension 15mm (terrible) and 10 and 25mm meade plossls at present with a 2" Ascension Barlow.

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While Tele Vue eyepieces are excellent they won't show you things that other eyepieces (eg: your Meade plossls) don't. Nebulae, clusters and galaxies vary a lot in apparent size so a range of magnification is useful. Low power (say a 32mm eyepiece) is good for finding the objects and enough for the larger ones such as M31 (which is actually 8x the size of the moon !) and M42. For planetary nebulae and globular clusters I find a medium power eyepiece such as a 13mm or even a 9mm is good.

Wide and ultra-wide angle eyepieces such as Tele Vue Naglers and William Optics UWAN's are great for deep sky objects but do cost a lot of money.

You might want to invest in a humble 32mm plossl to use with your current Meade pair. Eyepieces with a focal length much longer than 32mm (and offering lower magnification) can cause issues when used with fast (eg: F/5) scopes as the exit pupil gets rather large. You can also start to see the shadow of the secondary mirror in some circumstances.

Edited by John
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The skywatcher nirvanas seams the most cost effective way to get some nice wide field eps with great quality.

The 28mm and the 16mm should do for 90%+ of all DSOs. If you go for televue then the 31mm (or 26mm) Nagler and the 13mm (or the 12mm) will do it.

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I have a 2" 35mm Panoptic which I use in my 12" Dob I went for this rather than the 41mm as I was worries the 41mm would have too large an exit pupil for my reflector.

The 35mm Panoptic is quite simply a stunning eyepiece.

It gives just a little less sky than the 31mm Nagler (Pan about 1.5 and Nag about 1.6 degrees in my dob) and costs about half as much used - I got mine for £200. It's also quite a bit lighter which matters in a dob (Pan 1.6 pounds Nag 2.2 pounds) for balancing purposes.

As others have said though there are eyepieces not much worse (or almost as good to put it another way) than TV for a lot less money. Personally, I am sticking with TV as if not I'd always be wondering if I'd done the right thing. There's really not much to choose as far as I can tell from lots of reading, between the top brands - it's just different 'versions' of excellence.

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Thanks everyone, most helpful indeed. Now has anyone tried the Televue 8-24mm zoom? It seems like a good convenient option but I wonder about degradation of quality...

As a photographer I have found that zoom lenses are now almost as good if not the same as fixed lens quality but you have to buy top quality. I also note that you all use mostly Naglers or TV eyepieces which tells a story :eek:

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I had the 8-24mm zoom and sold it within a day of buying it. the quality of the image was not too bad - actually quite good, but the narrow field at 24mm was really quite constricting as at this focal length you really want a wider field of view.

I think the eyepiece is the only one in the TV range that is not a 'true' Televue eyepiece and it's basically the same eyepiece as a number of others (like the Meade version). The Hyperion zoom seems to get the better reviews in this range.

I have the 3-6mm zoom at the other end of the scale which most say is excellent - unfortunately, and typically, it's been cloudy since I bought it!

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The Televue 8-24 is the only eyepiece sold by Televue that isn't actually made by Televue. It's the same as the Meade 8-24. It's an "OK" zoom, good but there are newer designs available now.

The Baader Hyperion 8-24 would be a better choice. The new Mk.III version is just out but not sure how much of an improvement it will be over the Mk.II. I changed my Hyperion zoom for a Pentax XF zoom, a very nice and compact zoom, and not that much more expensive than the Hyperion.

The Televue Nagler 2-4 and the 3-6 zooms are fantastic eyepieces, every bit as good as the Naglers in optical quality, although only a 50 degree FOV.

John

Edited by johninderby
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Back a moment to the 35 Panoptic, in my view it is lighter and cheaper than the 31 Nagler but, more importantly, it is also better! It comes more easily to the eye and is more relaxing. Also it has no blackout or kidney bean. When I was in the UK my clubmates all preferred my 35 Pan to the club's 31 Nagler. It is the default EP in our 20 inch Dob (F4.1) and really cleans up the edge of field in a way that cheaper EPs simply don't.

Zooms? Personally I wouldn't. I would prefer a premium view compromised a little on magnification - but that's just me.

Olly

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No one single magnification will work for all nebulas and star clusters. I use a 17mm Ethos, a Nagler 12T4 and an Ethos 8mm. The 17mm is excellent for the Orion Nebula and larger clusters. The 12mm really brings clusters such as those in Auriga to life and the 8mm is superb it gives stunning views of small tight clusters and globular clusters and will also, on a good night, show me the E and F stars in the trapezium of M42. So in answer to your question if you want to get a Televue you could do a lot worse than the Nagler 12T4 or 17T4 if you have a lot of cash to spend the Ethos 13mm would be an excellent buy.

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Thanks again, everyone, you have confirmed my darkest suspicion about the televue zoom, at that price I thought there must be something wrong and the narrow FOV was offputting so thanks for your experience. I think I'm going for the 35mm Panoptic and 13mm ethos. I have an ascension 2" Barlow with "1.25 adaptor. Will this be good enough quality to use with the TVs or will it compromise them?

Also is there a good UK website to buy quality used eyepieces as well as selling off less than wonderful ones?

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While my initial post pointed out that there are other decent options that cost less than Tele Vue, like Moonshane, I've invested in Tele Vue and don't regret it one bit. My most used deep sky eyepieces (I've a scope with a similar spec to yours) are:

Nagler 31mm

Nagler 20mm (though to be honest I often find I skip straight to the 13mm Ethos)

Ethos 13mm

Nagler 9mm

OK it's a large investment but these are lifetime eyepieces and will work very well with just about any scope I may own in the future.

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I agree with your sentiments Jahmanson, My photographic lenses are all top quality and give me great joy every time I use them, and they hold their value very well too. I think many people don't realise that a camera and a telescope are similar in that they are the collection device only and it's all about the lens/eyepiece quality. I can see why you skip to the Ethos with that FOV :eek: better to have fewer top quality eyepieces methinks...

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I have William Optic UWAN's and for the money they are not that far behind Naglers.

Very comfortable fov at 82° and very good eye relief.

But if you can afford Televue then thats the correct choice in my mind it's just they are pretty expensive.

Edited by Doc
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Well I fell on my feet! Ace Cameras had an 8mm TV Ethos going for £300 and a 24 mm TV Panoptic for £175 - "ex demo" i.e. one show that they did with them so absolutely mint. They arrived today, look the business and I can't wait but typically it's cloudy today and all night. I figure as they both "Barlow well" with my 2x I should have 12mm and 4mm covered too. I'll let you know. I passed on the TV 35mm as it would only give me 30x mag and I can find my way about easily enough with the 24mm. The DGM Optics NPB filter made M57 jump out of the sky the other night with a cheap 10mm plossl so I look forward to using that too with the new kit.

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Nebs and clusters are best observed with low power EPs

Very true but there are many DSO's that will look great through an 8mm Ethos in a 10" dob, X150 and a 0.66 TFOV and 15mm eye relief all make a very nice ep indeed.

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I have just made the stupid mistake of looking through an 8mm Ethos at the double cluster. just awesome.

BUT I also really love the view through my 24mm Panoptic and my 18mm Radian. The latter eyepieces are superbly sharp - dare I say it, sharper than the others mentioned here to my eyes anyway, across the whole field (although there's a lot more field of course to the others).

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Nebs and clusters are best observed with low power EPs

depends on the focal length of the scope eg a 35 mm in my 10" Dob will only give 34x mag where as the ethos will give me 150x with a wide field of vision and plenty of detail

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well I see just how good the barlow is although I'm sure it will be a slight compromise and if so I'll be looking for good second hand TV deals eventually :mad:

For the 24mm I would recomend a 2x powermate instead of a barlow. I get too much eyerelief when I barlow my 31mm, a powermate solves this.

The 10mm Ethos barlows very well.

Take into acount the weight of this combination. The bigbarlow + ethos 10mm is about 1kg, with the 31mm even more. tightening the alt tension knobs on my dob solved it so check if your telescope can coupe with all the extra weight.

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For the 24mm I would recomend a 2x powermate instead of a barlow. I get too much eyerelief when I barlow my 31mm, a powermate solves this.

The 10mm Ethos barlows very well.

Take into acount the weight of this combination. The bigbarlow + ethos 10mm is about 1kg, with the 31mm even more. tightening the alt tension knobs on my dob solved it so check if your telescope can coupe with all the extra weight.

Yep i hear ya about the weight issue, my dob is auto tracking so I look forward to seeing if it will handle the weight tonight with clear sky forecast. How do you know when you have too much eye relief?

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.... How do you know when you have too much eye relief?

i) You get black outs or kidney beaning and it's difficult to find the correct position for your eye.

ii) You may see the shadow of the secondary mirror when viewing brighter objects.

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With my 250mm f4.8 I use:

22mm Nagler for larger objects, clusters etc - the widest view, x55 and 1.5 deg

13mm Vixen LVW for galaxies - the most comfortable viewing, x92

7mm Nagler for globulars and planetaries - wide field + high power, x171

This combination works really well for me and I have no intentions of changing a thing!

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