5mm eyepiece for planatary views

[michael.h.f.wilkinson]

5mm SLV anyone? VERY nice EP, close to my XWs in performance for a much more modest price (but only 50 deg FOV).

[John]

5mm SLV anyone? VERY nice EP, close to my XWs in performance for a much more modest price (but only 50 deg FOV).

I agree. If you are OK with a 50 degree field I think the SLV's are as good as anything out there, including eyepieces that cost 2x or 3x as much.

[Stuart1974]

Hi. May I please ask several idiot questions as a new observer? I recently bought a SW Skyliner 250px (f/4.7) having previously owned a SW Explorer 150p for a year. I'm now looking at buying a couple of EPs to upgrade the 10mm and 25mm ones the scope came with.

I'm looking for one high power EP for planetary viewing and one low power for DSOs, perhaps with a decent Barlow to double up. What is the difference between a 'planetary' EP and one of the same focal length but not identified as planetary? I assume there is a difference, but is it significant? Looking at spending up to say £90 per EP and thinking broadly of a c28mm and one c8mm, which turns into 14 & 4 with a Barlow.

Also aware that f/4.7 is fairly 'fast' so how would this impact my decision making?

Brands I'm considering for the two EPs having viewed the FLO site are:

- Celestraon xcel

- Skywatcher SWA

- Skywatcher Panaview

- Skywatcher UWA Planetary

There's a reasonable price difference on these but is it simply a case of more expensive is better for these four ranges?

Any thoughts or recommendations greatly appreciated!

Thanks

Stuart

[michael.h.f.wilkinson]

There is a second-hand SLV 5 (not mine, that's not going anywhere) on ABS-UK here: http://www.astrobuysell.com/uk/propview.php?view=95343

[SpaceWalker]

I have at the moment the skywatcher f6 dob ive been using a 5mm hyperion eyepiece and noticed that it softens the image a lot which eyepiece would you suggest for this telescope ??

Nick suggested you a very nice option -- 5.5 Meade 5K UWA. This eyepiece has collected tons of positive reviews as a planetary EP for fully manual Dobs. It has relatively short eye relief so it's not for eyeglass wearers, otherwise it's good, I'm planning on getting it.

As for now I successfully use for planetary in my f/6 Dob the 6.5mm Meade HD-60. I did several shootouts and found that it works on par with good Orthos e.g. 6mm BCO in sharpness and scatter control. And in f/6 Dob it gives magnification of 185x that is quite comfortable for the average and below average seeing conditions

I'm looking for one high power EP for planetary viewing and one low power for DSOs, perhaps with a decent Barlow to double up. What is the difference between a 'planetary' EP and one of the same focal length but not identified as planetary? I assume there is a difference, but is it significant? Looking at spending up to say £90 per EP and thinking broadly of a c28mm and one c8mm, which turns into 14 & 4 with a Barlow.

Also aware that f/4.7 is fairly 'fast' so how would this impact my decision making?

Brands I'm considering for the two EPs having viewed the FLO site are:

- Celestraon xcel

- Skywatcher SWA

- Skywatcher Panaview

- Skywatcher UWA Planetary

There's a reasonable price difference on these but is it simply a case of more expensive is better for these four ranges?

Any thoughts or recommendations greatly appreciated!

Thanks

Stuart

Your scope is fast and that means you need eyepieces well-corrected off-axis (and more expensive). From all what you've preselected I can recommend only Celestron X-Cel LXs. All others will show you significant amount of blur in outer part of FOV, just not worth your money, IMO.

As a candidate for the 28mm I'd suggest this Explore Scientific Maxvision 2", 68° . It looks like it's within your price range. With a 2x Barlow It'll give you an exit pupil of ~3mm, good for many DSOs and appropriate for using dense nebula filters. Of course, keep in mind it's a 2" eyepiece and will require  2" Barlow, e.g. 2x ED that I saw at FLO.

I wouldn't worry about the 4mm since under most seeing conditions it will be pushing your scope too hard. Your 10mm Plossl combined with the 2x Barlow will give you 240x what is good enough for Jupiter and Saturn. In addition, most telenegative 2x Barlows work actually like 2.2x, so you may get the 4.5mm anyway.

Instead of the 8mm I'd suggest this 8.8mm Meade 5K UWA, excellent EP, best in the Meade UWA and ES82 lines, I have it. With the 2x Barlow it'll give you 4.4mm and whooping 82*AFOV what provides additional comfort in manually driven Dob for high power observations. But if you think it's out of your budget, than get the 9mm Celestron X-Cel LX, it's also very good EP.

Of course, those 8.8mm and 9mm would be too close in FL to your 10mm stock Plossl but you've said you wanted an upgrade, right? If you still want to incorporate this focal length into your current collection with a better FL spread, than look into this TS NED 8mm, it's actually a rebrand of AT Paradigm/BST Explorer etc., excellent eyepiece with 60*AFOV.

Good luck.

[Stuart1974]

Many thanks for your prompt and very helpful response, SpaceWalker.  Plenty for me to think about there.

You and many others seem impressed by the ES eyepiece you recommended above so I think I'll go for that.  The eyepiece in the link below seems to be the same, but cheaper.  I'd be really grateful if you'd cast your eye over it and confirm that it is indeed the same and I'm not missing something!

http://www.explorescientific.co.uk/en/Eyepieces/Explore-Scientific-Maxvision-68-Okular-28mm.html?cur=1

I was thinking about buying a 2x Barlow to create 14mm but I'm wondering whether my Skyliner 250px would be too weighed down by this EP (@ 534 grams) + a 2" Barlow.  Again, grateful for your opinion, but if too heavy then I'll need to consider something in the 14-18mm range. What might you recommend (again, up to perhaps £90 max, but I'm not desperate to spend every last penny of that!)

Re the other eyepiece I think I'll go for your recommendation of the x-cel 9mm, also with the matching Celestron x-cel Barlow.

May I please thank you again for your thoughts and recommendations; you have helped me avoid some costly errors!

Regards,

Stuart

[Alkaid]

I too can recommend the XCel range.  I find both the 5mm and 9mm to be very good.  Only issue is that the dust caps are very tight indeed.  After not much prolonged use, when you remove the dust cap, the rubber eyeguard unsticks too.  I haven't bothered to glue it back on, though others might.  I just pop it back onto the eyepiece once I have removed the dust cap and it stays on quite happily.  This issue aside, the view is excellent for the price.  Sharp to the edge on my F8 Newtonian and my F10 refractor.  They should be ok down to F5, so your F6 Newt should like them too.

One other point which hasn't been mentioned regarding softness of views at high power.....how is the collimation of the scope?  Don't mean to pry or ask obvious questions, but are you collimating it before use and is the collimation good?  With a Newtonian, for visual on DSOs this is not of worry....but for high power planetary viewing it is absolutely critical. 

[Roy Challen]

There is a second-hand SLV 5 (not mine, that's not going anywhere) on ABS-UK here: http://www.astrobuysell.com/uk/propview.php?view=95343

Yep, I recieved this very eyepiece today - it looks very nice indeed much better than the NLVs they superceded. It might be a little too much for my Tal on all but the best nights, but thats what I got it for, and it was at a very good price!

 Hope it stays clear later tonight.

[John]

Yep, I recieved this very eyepiece today - it looks very nice indeed much better than the NLVs they superceded. It might be a little too much for my Tal on all but the best nights, but thats what I got it for, and it was at a very good price!

 Hope it stays clear later tonight.

The SLV's are really nice eyepieces. Orthoscopic type views but with great eye relief and a nice large eye lens to gaze into

[Roy Challen]

Just had a quick go with the Vixen SLV. On the Moon. Wowzers! Now I need a Moon atlas. Jupiter appeared a little dim and lacked contrast but I guess that was kinda expected. Very good eyepiece, well happy

[Reeny]

Just had a quick go with the Vixen SLV. On the Moon. Wowzers! Now I need a Moon atlas. Jupiter appeared a little dim and lacked contrast but I guess that was kinda expected. Very good eyepiece, well happy

My 6mm Delos in the 200p dob is too much for Jupiter tonight.

You will need to use 160-180x magnification for a clear, crisp view of the storm bands.

Or wait until the daytime heat dissipates, and catch Jupiter when it is highest in the sky.

The first night I used the 11mm ES82 barlowed - it showed me a moon transit

[SpaceWalker]

Many thanks for your prompt and very helpful response, SpaceWalker.  Plenty for me to think about there.

You and many others seem impressed by the ES eyepiece you recommended above so I think I'll go for that.  The eyepiece in the link below seems to be the same, but cheaper.  I'd be really grateful if you'd cast your eye over it and confirm that it is indeed the same and I'm not missing something!

http://www.explorescientific.co.uk/en/Eyepieces/Explore-Scientific-Maxvision-68-Okular-28mm.html?cur=1

No problem, Stuart.

I'm sure you'll like the ES/Meade 5K UWA (Maxvision) eyepieces if you get any of them. They are a really excellent option for a budget observer especially if you buy used.

And the eyepiece you've linked to is exactly what I meant. The X-Cel LX/Meade HD-60/BST Explorer are also very good but just a step behind.

I was thinking about buying a 2x Barlow to create 14mm but I'm wondering whether my Skyliner 250px would be too weighed down by this EP (@ 534 grams) + a 2" Barlow.  Again, grateful for your opinion, but if too heavy then I'll need to consider something in the 14-18mm range. What might you recommend (again, up to perhaps £90 max, but I'm not desperate to spend every last penny of that!)

Yes, most of 2" gear is really heavy as you might notice. If I may recommend, I'd suggest avoiding the 2" barlow. So, you're right it's better to invest into a 1.25" Barlow and quality midpower eyepieces.  I have the 2" 2x ED Barlow I refered to in my previous post and over 2 years I used it just several times. It's too bulky and heavy. But I always use my 1.25" Meade TeleXtender.

Being a budget observer myself I understand well your desire to save some extra money on a hobby. Just don't forget that we are not so rich to buy cheap things   .  I'd recommend you to get the best what you can afford for the most important exit pupils of 2mm and 3mm.

IMO, the best candidate for the 18mm eyepiece would be the 18mm ES82, the best of the 2" ES82 line, but the new one it's out of your budget. I just bought it second-hand, it has very short eye relief (12mm) but that's OK for me. In this focal range you can look into the 20mm ES Maxvision instead, it's quite cheap. I can't recommend the 18mm Celestron X-Cel LX/Meade HD-60 since according to some reports I trust they show significant FC (Field Curvature).

As for the 14mm, there is the 14 ES82/Meade 5K UWA. I have the 14mm Meade 5K UWA, excellent 82*AFOV eyepiece, but shows some significant FC in the last ~20% of FOV. I'm OK with that but not everybody likes it. What's interesting more expensive *premium* eyepieces like the 14mm Pentax XW also have this problem.

The closest option I can think of would be the 16mm ES68 , the best in the 68*AFOV line. The thing to remember it has very short eye relief, so it's not for eyeglass wearers. I don't see the similar Maxvision rebrand, it's probably sold out, so the price is a little bit off for the ES68 (£95)  but it's up to you.  The cheaper option is the 60*AFOV 15mm BST Explorer.

Re the other eyepiece I think I'll go for your recommendation of the x-cel 9mm, also with the matching Celestron x-cel Barlow.

Any decent Barlow should work good. If you can afford, e.g. on the used market, get a telecentric Barlow like the ES Focal Extender or other Meade rebrands like  Bresser SA-Barlow or Omegon.

IMO, at f/4.7 you may want to think about the Coma Corrector. For example, read  this thread on CN.

Hope, that helps.

Clear skies to you.

[russ.will]

I agree completely with the above having got, or previously owned many of the EPs from those ranges. The possible exception is the ES82 18mm, which I actively disliked. We are not all the same, but I wouldn't argue with anybody who does like it!

IMHO, the killer combo from the lineup is the 24mm 68deg and the 16mm 68deg (which ever cloak and badge they are shrouded in) for several reasons.

For one, they are both 1.25". In the case of the 24mm, it is a lot lighter than the 28mm and will not pose balance issues, even in a Barlow. Of course, because they are both 1.25", you can simply buy one good Barlow and be done with it.

Because they are both 68deg SWAs, rather than 82deg UWAs, the slightly more restricted field of view is less prone to showing the coma of the scope and at F4.7, you do have a fast scope. At shorter focal lengths, like 11mm and down, this is less of an issue and the extra apparent FOV can be useful in the nudge, nudge world of Dobs.

Much as I liked the UWAs, the SWAs are one of the sharpest EPs I've ever looked through and even the three Delos I had, didn't embarrass the SWAs.

The SWAs are very colour neutral, whilst the UWAs are slightly warm in tone. Not something you tend to notice unless swapping back and forth, but the SWAs were better at showing the subtle tonal shadings of the moon, which the UWAs seem to flatten.

If you get the 24 & 16mm SWA, plus one of the 2x 4 element SA/Telextender/Focal Extender as uggested above, you will end up with 24, 16, 12 and 8mm focal lengths and magnifications of 50, 75, 100 & 150x at exit pupils of 5, 3.4, 2.5 & 1.7mm. That's a range of very useful magnifications with well suited exit pupils and more to the point, it's an [effective] range of EPs that will work work in any scope - from an 80mm F6 frac, to a 300mm F10 SCT, all of those [effective] EPs will be usable.

I know the 2x multipliers linked to are as much as an EP, but in my opinion, they are a different class of tool to a Barlow. When you slip one of these in the focuser, it just simply disappears and it is just like using a double power version of the EP, because eye relief is unaffected.

I realise this leaves you slightly short of that tempting 5-6mm planetary EP, but that will get a fraction of the use of the suggestion above. Get the core EPs right and then the 'specialist' use stuff can follow.

Russell

[Stuart1974]

After a prolonged period of indecisiveness i think I've settled on the ES 24/68 maxvision, ES 16/68 and a decent focal extender thanks to you help! Idiot question perhaps, but is a focal extender the same as a Barlow?!

I'm also looking to buy a nebula filter. From what I've read I think an O-III is better for me than a UHC but would really welcome your views.

Many thanks

[John]

A focal extender does a similar job to a barlow in that it multiplies the effective focal length and therefore the magnfication. Focal extenders

(also Powermates and Telextenders) keep the eye relief and focal position of the eyepiece largely untouched wheras barlow lenses tend to alter both and

can vignette the field of view in some eyepieces. Focal extenders need more glass in them than barlows to achieve this and tend to cost more.

The focal extenders I've owned / used do seem to be of high optical quality and seem to just "get out of the way" in use just adding the magnification

boost with no side effects.

For a long while I used just an O-III filter but now I have a UHC type and the more specilized H-Beta as well. The O-III is still my filter of choice I think.

[russ.will]

Yes and no.

Yes it does give a 2x magnification, just like a Barlow. No, because a Barlow is a negative doublet (Smyth lens) that causes the exiting light rays to diverge and hence the image amplification. If you move the EP further from the Barlow the magnification increases, whilst taking the Barlow nose-piece off and screwing it onto the EP will [generally] give 1.6x magnification.

In the FE/Powermate/TE/SA Barlow (the latter isn't a Barlow, which is a confusion) the negative doublet is followed by a positive doublet that turns the exiting rays back to parallel - ie, telecentric. Because the rays are parallel, the distance between the EP and the amplifier elements is [broadly] irrelevant as the image amplification was done inbetween the lens elements.

In practice, this still means that the effective focal ratio of the scope is doubled - It's a common misconception that the EP focal length is halved - but unlike a Barlow, the eye relief of the EP in use is unaffected. in other words, you insert an ES FE in the scope and the EP behaves exactly as it did before and the scope has effectively doubled in focal length.

The down side is that double the number of lens elements costs more, but whereas a Barlow (which has other uses because of what it does) tends to feel like a second-best-to-an-additional EP, the ES FE simply feels like you have and extra EP.

<EDIT> No real idea on the filters, but John seems to have covered that whilst I was typing! I must start looking at filters....

Russell

[Stuart1974]

Thank you both for your valuable insight. One final question, for this evening at least!.... What attributes does a 'planetary' EP have that differs to an EP without planetary in its name?

[John]

.... One final question, for this evening at least!.... What attributes does a 'planetary' EP have that differs to an EP without planetary in its name?

Good question and one that created a fairly heated 18 page thread on another forum a couple of years back !

This web page seems to have some useful stuff on the topic:

http://scopeviews.co.uk/Eyepieces%20for%20Planets.htm

[gooseholla]

A planetary eyepiece is usually sold with more lenses in. But then again certain Kellners and orthoscopics are good at planets with less lenses. Basically, a planetary eyepiece should give good contrast and sharp views. I sometimes think the only real thing that makes it different is the price

John

[John]

I think the inclusion of the word "Planetary" on the eyepiece barrel is a piece of marketing blarney rather than anything else.  

[russ.will]

Quite.

All of the supposed qualities for optimal planetary viewing are applicable to any other subject available in the night sky. Perhaps the the word 'Planetary' is used to obfuscate the fact these qualities are only available on-axis and/or with a restricted field of view?

Russell

[alan potts]

I think the inclusion of the word "Planetary" on the eyepiece barrel is a piece of marketing blarney rather than anything else.  

Agreed John but for me a Planetary should be as flat field as possible, you know them well and as good as they are I would never call Naglers Planetary, but I have used them as such only last Saturday with the T6 9mm offering the best ever view I have seen of Jupiter, looked funny near the edge though.

Alan

[SpaceWalker]

... but is a focal extender the same as a Barlow?!

I'm also looking to buy a nebula filter. From what I've read I think an O-III is better for me than a UHC but would really welcome your views.

Many thanks

Russell provided you a very good explanation on focal extender. If you will want more details read posts #8 and #11 by David Knisely in this thread and look at the chart attached to post #16  illustrating how a telenegative Barlow works vs a telecentric (focal extender). 

As for nebula filters, both UHC and OIII are useful, but if you can have only one than I'd suggest a UHC. I have both.  You may want to read more about the filters in this article, Filter Performance Comparisons For Some Common Nebulae.

[Stuart1974]

Many thanks for your replies; this has all been very helpful stuff. I'm now a little less in the dark than I was a few days ago!

Stu

[scarp15]

I use 6mm, 8mm, 10mm and 13mm eyepieces with my 8" F6 dobsonian. On Jupiter, the 8mm (150x) and 10mm (120x) receive the most use.

A second hand 8mm delos might be a worth while consideration.