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jaydee3839

Eyepiece advise please, thinking 17mm-22mm + barlow

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Posted (edited)

I have 1200mm FL (F/8) Dob/Newtonian that I am just getting started with.  It came with a 25mm Plossl (Orion Sirius), and I recently purchased the Vixen NPL 30mm (correction, not GSO).  I am looking to add to the collection and would like some input.  I probably won't use the 25mm Orion Sirius much as it's pretty low-end and what ever I get will likely be overlap.  Ordering from/shipping to the USA (AgenaAstro or BHPhoto or Adorama preferred vendors, but there are others).

I'd like to get two pieces sometime this year for under ~$200 total.  Then adding a final piece sometime in the future.  I would like good eye relief, as I do not personally need glasses for viewing, but I'd like to share the experience with family members, some of whom have astigamatism.  My scope is not computer controlled, so a wide angle is better to keep things in view for longer periods of time.  I don't think size/weight is a huge concern with a Dob/Newtonian, but correct me if I'm wrong.  Still lighter is better if I end up getting a new scope sometime down the line, or try one of these pieces on another scope during an event.

My current thought for this year is, a 17-22mm 68-70 deg piece + barlow, then a higher mag planentary peice for later.  After some research on this site, it appears the Baader Classic Q 2.25x is about as good of a barlow for it's price as there is.  Additionally, I read that it easily converts to 1.3x barlow also, which gives more options in a small eyepiece collection.  Here are a couple scenarios I'm considering:

Baader Hyperion 68° 17mm  ($119) + Baader Classic Q 2.25x ($59)

Mag FL Arrangement
40 30 Vixen 30mm
52 23.1 Vixen 30mm / 1.3x barlow
71 17 Hyperion 17mm
90 13.3 Vixen 30mm / 2.25x barlow
92 13.1 Hyperion 17mm /1.3x barlow
158 7.6 Hyperion 17mm /2.25x barlow

 

Explore Scientific 68° 20mm ($149) + Baader Classic Q 2.25x ($59)

Mag FL Arrangement
40 30 Vixen 30mm
52 23.1 Vixen 30mm / 1.3x barlow
60 20 ES 20mm
78 15.4 ES 20mm / 1.3x barlow
90 13.3 Vixen 30mm / 2.25x barlow
135 8.9 ES 20mm / 1.3x barlow

 

Baader Hyperion 68° 21mm  ($119) + Baader Classic Q 2.25x ($59)

Mag FL Arrangement
40 30 Vixen 30mm
52 23.1 Vixen 30mm / 1.3x barlow
57 21 Hyperion 21mm
74 16.2 Hyperion 21mm / 1.3x barlow
90 13.3 Vixen 30mm / 2.25x barlow
129 9.3 Hyperion 21mm / 1.3x barlow

 

Olivon 22mm 70° ($129) + Baader Classic Q 2.25x ($59)

Mag FL Arrangement
40 30 Vixen 30mm
52 23.1 Vixen 30mm / 1.3x barlow
55 22 Olivon 22mm
71 16.9 Olivon 22mm / 1.3 barlow
90 13.3 Vixen 30mm / 2.25x barlow
122 9.8 Olivon 22mm / 2.25x barlow

 

 

They all give a good spread of different magnifications, with good FoV, while leaving some room for a high-mag planetary piece down the road, but they all have concerns as well.  The Olivon 70° 22mm weight is a whopping 18.6oz/526g, which may be a problem and availability is questionable.  The ES 68° 20mm is lowest weight (250g) and seems to have very good reviews, but has the smallest eye relief of 15.3mm, which I'm not sure is enough and cost more than I'd rather spend.   The Hyperions are bit heft at 388-394g and I've read some lackluster reviews regarding it's quality.  

Does anyone have any thoughts about these pieces, or if there are other 17-22mm pieces I should consider instead?  I've thought about a single 7-21mm or 8-24mm zoom piece (such as Vixen for $169), but the only ones I've found in my price-range, have much smaller FoV than I'd like.  
 

Edited by jaydee3839
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Just a quick point about the Baader 2.25x barlow. When you unscrew the lens element from it and screw that into the barrel of a 1.25 inch eyepiece the barlow does indeed give a 1.3x (approx) amplification. To do this you need eyepieces that do not have any optical elements or other obstructions within the 1.25 inch barrel because the optical elements of the barlow need about 15mm clearance up inside the barrel. A number of the eyepieces you have listed have optical elements within their barrels which will prevent the Baader Q-Turret 2.25x being used in that way.

On the magnification spread you have, it seems crowded to me in the sub-100x area and lacking in the medium to higher ranges (eg: 100x - 250x).

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Posted (edited)

Thanks John.  Do you know if the clearance will allow the Baader 1.3x barlow on the Vixen NPL 30mm eyepiece that I already have?  (correction, not GSO)

As far as spread of magnification, do you have a better idea of what I could do for < $200 USD?  

Also, if it helps to know, where I live, according to the light pollution charts, I have about SQM of 19.6 mag./arc sec2.  I would probably bring it down to friends/family houses a couple times a year further from the city at SQM of 20.8 and 21.25. 

Edited by jaydee3839

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You'd also need a 2" to 1.25" filter thread adapter to use that 1.25" barlow with 2" eyepieces (30mm GSO and 22mm Olivon).  You'd probably get vignetting.  I'd get the 2" GSO 2x ED Barlow instead.  Keep in mind, there will be vignetting with any non-telecentric magnifier (Barlow) when used with eyepieces having about a 27mm or larger field stop.  I use the long discontinued Tele Vue Panoptic Barlow Interface with my GSO ED Barlow to good effect.  It makes for a poor man's Powermate.

I rarely use my 22mm eyepieces in my 8" Dob, and Barlowing is a pain.  I would just get a 9mm Meade 5000 HD-60 which is eminently usable with eyeglasses at 17mm of usable eye relief and actually has a 63 degree AFOV.  It is very sharp across the field as seen in my 9mm/10mm comparison photo below.  I'd also get something in the 12mm to 14mm range.  The 12mm Meade HD-60 is decent, but not as exceptional as the 9mm, but still quite good with the same eye relief and AFOV as the 9mm.  I've included the 12mm comparison photo I made as well below.  A 1.25" 2x Barlow might be a good choice with those two to get to 4.5mm and 6mm.

473084620_9mm-10mm.thumb.JPG.3d8f66abd0891380524009082edde233.JPG1349518648_9mm-10mmAFOV.thumb.jpg.bf8afac3fffc6c3a9109186a471c885f.jpg

899871120_12mm-12_5mm.thumb.JPG.97bbd987cd5612a2fe6659f365551197.JPG1920390915_12mm-12.5mmAFOV.thumb.jpg.245b384c069b3e9baab028193a468c7d.jpg

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Sorry about that... I did not get the GSO 30mm (I did look at it), I got the Vixen 30mm Plossl (which is 1.25", so there is no adapter required).  I will fix my above posts.

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Hi Jaydee. Another option would be to get just one really good eyepiece and a barlow this year rather than two mediocre ones. If you were to buy a 17.5mm Baader Morpheus you'd have a spectacular eyepiece for deep sky. At 17.5mm it would give you a power of ~ 69X, and if you were to use a 2X barlow you'd get 137X. Not at all bad for great lunar views! 

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Unsing a barlow lens with a long focal length eyepiece does not always give satisfactory results. This is mainly because the eye relief (distance that the eye needs to be from the top lens of the eyepiece) is already long with such an eyepiece and a barlow lens increases that futher. So you get the image amplification but the eye relief increase may well mean that you need to "hover" your eye someway off the top of the eyepiece which is neither relaxing or comfortable.

@mikeDnight makes an interesting alternative proposal above.

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Thanks guys.  I do like the idea of the 17.5mm Baader Morpheus + barlow, but at $240 USD, the Morpheus alone is well over budget.  Is there anything 16mm-19mm eyepiece comparable in the $100-150 USD (75-115 GBP) range?

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12 minutes ago, John said:

Unsing a barlow lens with a long focal length eyepiece does not always give satisfactory results. This is mainly because the eye relief (distance that the eye needs to be from the top lens of the eyepiece) is already long with such an eyepiece and a barlow lens increases that futher. So you get the image amplification but the eye relief increase may well mean that you need to "hover" your eye someway off the top of the eyepiece which is neither relaxing or comfortable.

@mikeDnight makes an interesting alternative proposal above.

John, how do I figure exactly (or approximately) how much eye relief any given barlow (such as Baader Classic Q 2.25x), adds to an eyepiece?

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9 minutes ago, jaydee3839 said:

John, how do I figure exactly (or approximately) how much eye relief any given barlow (such as Baader Classic Q 2.25x), adds to an eyepiece?

Its difficult because it depends on the focal length of the barlow lens optics (they do have a focal length like eyepieces do) and this spec is not widely available.

Short format barlow lenses increase the eye relief more than the longer ones. I believe it can be as much as a 50% increase.

 

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It’s easy to measure the focal length of a Barlow lens.

measure the front lens aperture, draw a circle on a card twice this diameter, point the Barlow towards the Sun, when the image fills the circle, the spacing between the Barlow lens and the card is the focal length.

works for all Barlow and negative lenses.

 

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On 03/01/2020 at 17:54, John said:

Its difficult because it depends on the focal length of the barlow lens optics (they do have a focal length like eyepieces do) and this spec is not widely available.

Short format barlow lenses increase the eye relief more than the longer ones. I believe it can be as much as a 50% increase.

Thanks John.  Since you have the Baader Classic Q 2.25x, can you comment on how much (or little) this specific barlow adds to the eye-relief to your estimation?


And you also said a number of the eyepieces I mentioned have optical elements within the barrel preventing the use of the 1.3x magnification option on the Baader Classic Q.  Which ones?  Hyperions or ES 68?  How would I find this out for sure?

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I don't know exactly what the figure is but the Baader Q-Turret 2.25x barlow increases the eye relief by around 30% I believe.

All the 1.25 inch Hyperions except for the 24mm have optical elements within their 1.25 inch barrel sections as I recall. I'm not sure about the Explore Scientific 68 degree range. If you ask a specific question on this in the eyepiece forum I guess those who own them will give you the information you need.

 

 

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On 03/01/2020 at 22:14, mikeDnight said:

Hi Jaydee. Another option would be to get just one really good eyepiece and a barlow this year rather than two mediocre ones. If you were to buy a 17.5mm Baader Morpheus you'd have a spectacular eyepiece for deep sky. At 17.5mm it would give you a power of ~ 69X, and if you were to use a 2X barlow you'd get 137X. Not at all bad for great lunar views! 

I think Mike's logic is sound here, especially if you buy used pieces..over 90% of the eyepieces I've ever bought were used  (a lot of eyepieces!), and the vast majority performed like new ones. The Morpheus are a big step up from the Hyperions.

You might also consider a used Vixen LVW 22mm - a wonderful, now discontinued 65 degree widefield which I believe is superior to the Pentax 20mm XW. It also barlows very well.

Good luck with your choice 👍😊

Dave

 

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Thanks for the input all.  Doesn't sound like anyone wants to endorse the 17-22mm eyepiece in the $100-$150 (USD) range, that the $240 Morpheus is much better (yet out of my price range).  Other threads suggest the Vixen NPL 20mm and Baader Classic Ortho 18mm are excellent in the $50-$65 (USD) range (albeit much narrower FoV).  Barlows seem to have mixed reception (except for higher end) here, so maybe I should pass on this for now also.

 

Based on the above (and reading lots of other threads), I'll skip my original plan of "low-medium" 17-22mm + barlow, and instead get a "high-medium" ES 82 deg 11mm for $150 USD right now.  It seems universally praised as a great piece and give me some diversity as I already have a "low" mag 30mm piece. 

 

Eventually I'll fill out a "low-medium" 17-22mm and a "high" ~7mm, but for now, I'll enjoy the Vixen NPL 30mm plossl and 11mm ES 82 deg.  

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20 hours ago, jaydee3839 said:

Thanks for the input all.  Doesn't sound like anyone wants to endorse the 17-22mm eyepiece in the $100-$150 (USD) range, that the $240 Morpheus is much better (yet out of my price range).  Other threads suggest the Vixen NPL 20mm and Baader Classic Ortho 18mm are excellent in the $50-$65 (USD) range (albeit much narrower FoV).  Barlows seem to have mixed reception (except for higher end) here, so maybe I should pass on this for now also.

 

Based on the above (and reading lots of other threads), I'll skip my original plan of "low-medium" 17-22mm + barlow, and instead get a "high-medium" ES 82 deg 11mm for $150 USD right now.  It seems universally praised as a great piece and give me some diversity as I already have a "low" mag 30mm piece. 

 

Eventually I'll fill out a "low-medium" 17-22mm and a "high" ~7mm, but for now, I'll enjoy the Vixen NPL 30mm plossl and 11mm ES 82 deg.  

If you ever get a ~2000mm focal length scope, then a 17mm to 22mm eyepiece would make a lot of sense.

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