Which is better for DSOs? C9.25 or Altair Starwave 152mm F5.9 Refractor?

[Commanderfish]

I currently have an Explore Scientific 127mm ED Apo Refractor which gives lovely sharp views, and a C9.25 which I pretty much use as a light bucket as I'm not going to be buying a big dob (due to storage space, viewing preferences,  aesthetics and being blindingly obvious to the wife as a new purchase rather a long white tube which appears confusingly similar to the existing ones  )

The C9.25 with it's bigger aperture does pick up more light ; most notably on the double cluster where it shows more stars than the 127 Apo.  However, for DSOs I'm not certain that it gives a better view. For instance, when viewing galaxies M81, M82, M65 and M66, the views I get from the 127mm Apo actually seem to have more contrast, although the image presnted to the eye is not as large.  Likewise on M42 Orion Neb, the image is bigger in the 9.25 but not more contrasty.  Part of the problem is light pollution, which is not a problem for the 127mm Apo but definitely shows up in the 9.25, robbing contrast.  The central obstruciton reduces contrast too.

Some will point out that really the C9.25 is a planetary scope, and this is true.  It delivers a bigger image of Jupiter, though it's not overly easy to get a sharper image than in the 127mm Apo.  This turns into a balancing act of magnification against seeing conditions, and with the eyepieces I have, in great seeing conditions the C9.25 at x181, wins but in typical UK seeing conditions it's a toss up between the two scopes (and sometimes the Apo wins at x75 when seeing is really bad).  The C9.25 does deliver a larger image though.  Both are great at Lunar; the c9.25 can deploy more magnification; but I don't spend that much time viewing the moon.

Now I've read that the 152 Altair F5.9 achro refractor (also available as a Lyra Optics scope and some others I think) is a stunning DSO scope.  As it's a 6" refractor I am pretty certain it won't suffer from Light Pollution as badly as the 9.25.  The 152 is supposed to deliver as much light as an 8" Newtonian, but with more contrast due to having no central obstruction and no mirrors or spider vanes.  So I wonder whether it would beat the C9.25 as a DSO scope?  Clearly the field of view will be better.  It will lose at planetary to the C9.25, but that is not much of a concern as I already have the ED127 (and if people feel that selling the c9.25 is likely to be a big mistake for planetary I guess I could keep it, sell other gear and save longer for the Altair 152).

Does anyone have any opinions/experience regarding the C9.25 vs the 152 F5.9 for DSOs?

[John]

At the end of the day it's aperture that creates light grasp so a 152mm scope will not gather as much light as a 205mm one even if the latter does have an obstruction. The contrast of an unobstructed scope tends to be higher though so that goes some way to bridging the aperture gap and the faster refractor will be able to show a wider expanse of sky than the SCT which is great for extended deep sky objects and groupings of objects.

The smaller aperture refractor can "cut through" mediocre seeing better than larger aperture scopes but I'm not sure that it will handle light polluted skies any better.

Looking at your current scopes I think the 152mm F/5.9 refractor would complement them well, rather than replace one of them.

[mikeDnight]

The 9.25" SCT will give great views of galaxies and globular clusters but the 6" apo will give you stunning wide field views of nebulae, star fields, comets etc. The 6" will also give great views of galaxies and glob's! As many spectacular dso's are large, I'd personally prefere the refractor. It's star images will be far more pleasing to the eye and the sharper images offered by the refractor will aid with definition. 

Mike

[Commanderfish]

Yes, star images are definitely sharper in my 127 Apo than my c9.25, so I suspect you're right that the 152 Achro would be sharper than the C9.25 on stars too.  I'd forgotten about globs, the C9.25 is great at those, better than the ED127 as the larger image seems to help. If the 152 is as good at globs as the C9.25 than that would be a big bonus.  

[John]

 

Yes, star images are definitely sharper in my 127 Apo than my c9.25, so I suspect you're right that the 152 Achro would be sharper than the C9.25 on stars too.  I'd forgotten about globs, the C9.25 is great at those, better than the ED127 as the larger image seems to help. If the 152 is as good at globs as the C9.25 than that would be a big bonus.  

On globs, I've always found that more aperture delivers better views of them - more resolution and resolution deeper into the core. The 6" refractor will show them nicely but, for example, an 8" newt would resolve more stars and a 9.25" SCT more so.

I'm not arguing against the 6" refractor but just reflecting the views I've had of globulars with the various scopes I've owned over the years. I really enjoy viewing those objects as well

 

[Commanderfish]

Hmm I wonder if the 152 would overlap with the 127 Apo too much? The Apo is sharp as anything and colour free, but the 152 would have more light grasp.

[Commanderfish]

The 152 achro has 43% more light grasp than 127 Apo, but less than half as much as the sct.  The achro has the widest field though, 2.7 degrees with a nagler 31 or ES 82 30mm.

[t0nedude]

IMHO, the 152 achro f5.9 does not overlap much with the 127 Apo, the achro is a RFT and the APO is a good all rounder, and especially good on solar system objects. There is a bigger overlap between that 127 APO and the C9.25. The C9.25 has a bigger light grasp that is true but doesn't do RF well at all due to its long FL. You have to decide which type of object is more important to you; wide field, lower power razor sharp contrasty refractor views vs higher power, narrower fields deeper views (although the unobstructed, contrasty refractor views will mitigate that somewhat).

My choice would be the achro, also due to other issues like; cool down times, easier to maintain, and not a dew magnet. (and the fact I'm a refractor nut )

My $0.02.

Tony.

[Commanderfish]

3 hours ago, t0nedude said:

IMHO, the 152 achro f5.9 does not overlap much with the 127 Apo, the achro is a RFT and the APO is a good all rounder, and especially good on solar system objects. There is a bigger overlap between that 127 APO and the C9.25. The C9.25 has a bigger light grasp that is true but doesn't do RF well at all due to its long FL. You have to decide which type of object is more important to you; wide field, lower power razor sharp contrasty refractor views vs higher power, narrower fields deeper views (although the unobstructed, contrasty refractor views will mitigate that somewhat).

My choice would be the achro, also due to other issues like; cool down times, easier to maintain, and not a dew magnet. (and the fact I'm a refractor nut )

My $0.02.

Tony.

I feel I am becoming increasingly certifiable as a refractor nut too Tony.  I love the ED80Apo  and ED127Apo.  The absolute sharpness they deliver somehow distracts me from the enjoyment of the SCT, which is in of itself a very good scope and very sharp for a Cat or Newt type scope.  My personal experience is that you just can't beat the sharpness of the Frac (obviously I'm spolit by Apo views in this respect).

I do really like Richfield and DSOs, I spend more time on these than planetary.  Can't resist Jupiter or Saturn when they are up though.  Yes you are right, there is an overlap between the ED127Apo and SCT for planetary.  The SCT gives a bigger image but I find I have to battle the seeing conditions in it due to it's high mags; the ED127Apo fares better in this respect.  At the moment however, I'm not using the ED127 above x75 mag, because my next highest mag eyepieces  (8mm - x120 and  6mm - x 160) have a longer focus than is permitted by my 35mm tube extension.  I've just ordered a 50mm extension.  I had ordered one from Altair Astro a month ago but I've just logged in to their website and found that they cancelled the order due to lack of stock (could have done with an email notification from them really). I have a second 35mm tube extension taking me up to 70mm total extension, but I don't use it then I can't bring my low field pieces into focus!

Once I have the 50mm extension for the 127Apo I will give it a run against the SCT on Jupiter and Mars and see how they fare.  If the SCT isn't showing a clear advantage then maybe it's time to change it for the 152 achro.

A secondary function of the SCT for me is as a light bucket for galaxies; obviously the field is smaller so it can't be used on big objects like Andromeda.  The odd thing is that on small objects like M81/M82 I'm finding the ED127 preferable.  The Skyglow doesn't seem to affect the Apo as much as the SCT, and the contrast is a little better in the Apo, though the image is smaller.

[t0nedude]

3 hours ago, Commanderfish said:

I feel I am becoming increasingly certifiable as a refractor nut too Tony.  I love the ED80Apo  and ED127Apo.  The absolute sharpness they deliver somehow distracts me from the enjoyment of the SCT, which is in of itself a very good scope and very sharp for a Cat or Newt type scope.  My personal experience is that you just can't beat the sharpness of the Frac (obviously I'm spolit by Apo views in this respect).

I do really like Richfield and DSOs, I spend more time on these than planetary.  Can't resist Jupiter or Saturn when they are up though.  Yes you are right, there is an overlap between the ED127Apo and SCT for planetary.  The SCT gives a bigger image but I find I have to battle the seeing conditions in it due to it's high mags; the ED127Apo fares better in this respect.  At the moment however, I'm not using the ED127 above x75 mag, because my next highest mag eyepieces  (8mm - x120 and  6mm - x 160) have a longer focus than is permitted by my 35mm tube extension.  I've just ordered a 50mm extension.  I had ordered one from Altair Astro a month ago but I've just logged in to their website and found that they cancelled the order due to lack of stock (could have done with an email notification from them really). I have a second 35mm tube extension taking me up to 70mm total extension, but I don't use it then I can't bring my low field pieces into focus!

Once I have the 50mm extension for the 127Apo I will give it a run against the SCT on Jupiter and Mars and see how they fare.  If the SCT isn't showing a clear advantage then maybe it's time to change it for the 152 achro.

A secondary function of the SCT for me is as a light bucket for galaxies; obviously the field is smaller so it can't be used on big objects like Andromeda.  The odd thing is that on small objects like M81/M82 I'm finding the ED127 preferable.  The Skyglow doesn't seem to affect the Apo as much as the SCT, and the contrast is a little better in the Apo, though the image is smaller.

Having looked through APO's myself, I too have been seduced by the views.  You will probably find on most nights when the seeing is average the APO will win on the planets but when the seeing is super still the SCT might edge ahead for detail, over a period of time and on average you will probably get more quality viewing with the APO refractor.  Having said that, if I were forced into the purchase of a SCT the C9.25 would be the one I choose, why? Because I do hear good things about them compared to the more common (C6/8/11 etc) models, which seem to be more variable in their quality. Have you thought of acquiring a good barlow (if you haven't already) to effective double the amount of EP's you have? (for the APO of course - the SCT doesn't need it).

I can sense your dilemma, maybe there is a local society nearby that you can use to look through a 152 F6 achro to get a taste of what to expect?

Tony.

[Commanderfish]

Hi Tony,  I'm in the local Astro Society, Walton Astro, I'm familiar with most of the scopes the group members have, and I think the most similar scope would be Stu's Vixen 152 which has now been sold!

I had one cheaper barlow back when  I used 1.25" eyepieces and didn't really get on with it.  Plus, most of my eyepieces are 100 degree/82 degree so are already very tall, I wouldn't really want to add a barlow to the height/weight!

[t0nedude]

33 minutes ago, Commanderfish said:

Hi Tony,  I'm in the local Astro Society, Walton Astro, I'm familiar with most of the scopes the group members have, and I think the most similar scope would be Stu's Vixen 152 which has now been sold!

I had one cheaper barlow back when  I used 1.25" eyepieces and didn't really get on with it.  Plus, most of my eyepieces are 100 degree/82 degree so are already very tall, I wouldn't really want to add a barlow to the height/weight!

No. Stu's Vixen 150ED is a different animal entirely! It's a 150 ED Apo F/9 - so a bigger version of your 127 APO, it will eat 152 F6 achros for breakfast... But I thought he didn't have it any more? (EDIT: Yes just noticed, you mentioned he sold it).

Well worth a shot, but I do know that used 152 F/6 achros go for a very good price on ABS (there is a F/8 one going for £235 with a diagonal and 3 plossl EP's) so what of the possibility of buying one and doing a comparo and then making a decision that way? Also be warned 152 achros are not light, they need some significant mounting, F6 would be easier but still fairly heavy..

Tony.

 

[acey]

On 09/05/2016 at 12:58, Commanderfish said:

I currently have an Explore Scientific 127mm ED Apo Refractor which gives lovely sharp views, and a C9.25 which I pretty much use as a light bucket

The C9.25 with it's bigger aperture does pick up more light ; most notably on the double cluster where it shows more stars than the 127 Apo.  However, for DSOs I'm not certain that it gives a better view. For instance, when viewing galaxies M81, M82, M65 and M66, the views I get from the 127mm Apo actually seem to have more contrast, although the image presnted to the eye is not as large.  Likewise on M42 Orion Neb, the image is bigger in the 9.25 but not more contrasty.  Part of the problem is light pollution, which is not a problem for the 127mm Apo but definitely shows up in the 9.25, robbing contrast.  The central obstruciton reduces contrast too.

Now I've read that the 152 Altair F5.9 achro refractor (also available as a Lyra Optics scope and some others I think) is a stunning DSO scope.  As it's a 6" refractor I am pretty certain it won't suffer from Light Pollution as badly as the 9.25.  The 152 is supposed to deliver as much light as an 8" Newtonian, but with more contrast due to having no central obstruction and no mirrors or spider vanes.  So I wonder whether it would beat the C9.25 as a DSO scope?

Does anyone have any opinions/experience regarding the C9.25 vs the 152 F5.9 for DSOs?

I don't have experience of these scopes, but I can tell you that the 9.25 will give what most people would consider the best DSO views. What counts, though, is what is best for you, and your opinion is weighted by the question of "contrast". This is subtle.

First point: light pollution hurts all scopes equally. Nothing can "cut through" it, no scope is less affected than another.

Second point: the limiting magnitude of a scope (faintest star it can see) is determined almost entirely by aperture: bigger goes fainter. The limiting surface brightness (faintest extended object you can see) is determined by the sky.

Secondary obstructions scatter light, and this leads to a loss of contrast on bright targets such as planets. On faint targets (nebulae and galaxies) there will be no perceivable loss of contrast due to seconday obstruction.

For a uniform (featureless) extended target - a nebula that is a perfect blank disc - magnification enlarges the target and background equally, so lowers their surface brightness equally, leaving contrast unchanged. What changes is the observer's contrast threshold: the degree of contrast required for something to be visible, which is a function of target size and background brightness.

A DSO at low magnification may look small and faint; crank up the magnification a bit and it looks larger and brighter, because you've hit a sweet spot where the size and background brightness are well above your eye's contrast threshold. Go higher and the object disappears - you've made the target too faint iin relation to its size, and it has fallen below your threshold.

None of this has anything to do with which scope you use. For DSOs it's aperture and sky darkness, those are the only things that matter. The Altair refractor may well be a stunning DSO scope, but only as long as you take it to a dark enough site - where 10x50 binoculars will also be stunning. At Altair Astro I find this:

"For rich field viewing of deep sky objects such as comets, clusters and nebulae, the Starwave 152 offers a higher contrast view equivalent to an 8" Newtonian reflector, with similar perceived light grasp, but without the maintenance overhead and need for regular collimation."

 

I don't know how they figure that, but it sounds like complete voodoo to me.

 

"It also sports higher contrast due to the lack of central obstruction which makes deepsky objects appear to "pop" out from the background for very pleasing views."

 

Planets yes, deepsky no, not to any noticeable degree, unless you maybe mean seeing the Trapezium as perfect pinpricks rather than tiy blobs (which is an issue of diffraction, not contast as such).

I've no doubt the Altair is superb, but don't expect it to give better DSO views than a scope of larger aperture, which you've already got. On some DSOs you prefer the view in your smaller scope to views in the larger - they look more contrasty. I think this is just because you're viewing at lower magnification. Try finding a pair of eyepieces that will put both your scopes at the same magnification and compare the views.

 

[t0nedude]

11 minutes ago, acey said:

I don't have experience of these scopes, but I can tell you that the 9.25 will give what most people would consider the best DSO views. What counts, though, is what is best for you, and your opinion is weighted by the question of "contrast". This is subtle.

First point: light pollution hurts all scopes equally. Nothing can "cut through" it, no scope is less affected than another.

Second point: the limiting magnitude of a scope (faintest star it can see) is determined almost entirely by aperture: bigger goes fainter. The limiting surface brightness (faintest extended object you can see) is determined by the sky.

Secondary obstructions scatter light, and this leads to a loss of contrast on bright targets such as planets. On faint targets (nebulae and galaxies) there will be no perceivable loss of contrast due to seconday obstruction.

For a uniform (featureless) extended target - a nebula that is a perfect blank disc - magnification enlarges the target and background equally, so lowers their surface brightness equally, leaving contrast unchanged. What changes is the observer's contrast threshold: the degree of contrast required for something to be visible, which is a function of target size and background brightness.

A DSO at low magnification may look small and faint; crank up the magnification a bit and it looks larger and brighter, because you've hit a sweet spot where the size and background brightness are well above your eye's contrast threshold. Go higher and the object disappears - you've made the target too faint iin relation to its size, and it has fallen below your threshold.

None of this has anything to do with which scope you use. For DSOs it's aperture and sky darkness, those are the only things that matter. The Altair refractor may well be a stunning DSO scope, but only as long as you take it to a dark enough site - where 10x50 binoculars will also be stunning. At Altair Astro I find this:

"For rich field viewing of deep sky objects such as comets, clusters and nebulae, the Starwave 152 offers a higher contrast view equivalent to an 8" Newtonian reflector, with similar perceived light grasp, but without the maintenance overhead and need for regular collimation."

 

I don't know how they figure that, but it sounds like complete voodoo to me.

 

"It also sports higher contrast due to the lack of central obstruction which makes deepsky objects appear to "pop" out from the background for very pleasing views."

 

Planets yes, deepsky no, not to any noticeable degree, unless you maybe mean seeing the Trapezium as perfect pinpricks rather than tiy blobs (which is an issue of diffraction, not contast as such).

I've no doubt the Altair is superb, but don't expect it to give better DSO views than a scope of larger aperture, which you've already got. On some DSOs you prefer the view in your smaller scope to views in the larger - they look more contrasty. I think this is just because you're viewing at lower magnification. Try finding a pair of eyepieces that will put both your scopes at the same magnification and compare the views.

 

Good points, and they might be true, however the bottom line here (which cannot be argued) is that, despite the clear aperture advantage of the C9.25 over the 152, the C9.25 doesn't do Rich Field - AT ALL. The OP has the dilemma of deciding whether the extra aperture is enough to make up for that

Tony.

[Peter Drew]

Well I wouldn't swap my C8 for any achro that I've ever used regardless of object in view.     

[Commanderfish]

Re the Altair 152 having the same light gathering as an 8" Newt, I did some maths on this.  

Actually I did the maths based on an 8" SCT.  I used the aperture diameter of the scope in millimetres to calculate the apreture area by applying pi r squared (diameter = 2r).  I calculated this for both scopes.  I then subtracted the central obstruction from the sct.  Finally I adjusted for the mirror losses of the SCT, assuming that the SCT had the top of the line Starbright XLT coatings for both mirrors, so that accumulated losses from both mirrors and corrector plate are only 16.5%.  The results were as follows:

152 frac: 18,144mm squared

8" SCT: 22,825 mm squared

9.25" SCT: 29,024 mm squared

For a newt with less meticulous coatings, losses would likely be higher than 16.5%, so saying the 152 frac has equivalent light gathering to an 8" newt seems pretty accurate.  In addition, the frac doesn't have diffraction from spider vanes, secondary obstruction etc.

[ecuador]

I don't quite understand the dilemma. First of all, I also love refractors, but when I say that I mean at least ED.

That said, the main reason I don't understand the dilemma is that you already have a scope that gives you about the same field as the 152/5.9 and it is an ED instead of an achro. The one extra inch might make a bit of a difference in dark skies, but the fact that the ED can give a much sharper view by focusing all colors at the same plane is a bigger advantage and I don't really see many (if any) objects looking better on the 152. Also, if I am not mistaken the ED will also have sharper views at the periphery with the same eyepiece since it is an f/7.5. 

Then, any target that fits the C9.25 will look better in that. And the C9.25 has a wide baffle tube, so you can get up to 1.1 or so degrees FOV with a 46-47mm field-stop 2" eyepiece, which is not that bad. And since you mentioned the C9.25 sometimes trades blows with the 127 ED in planets, have you perfected your collimation? I find that collimating using an eyepiece is very affected by seeing, while using a guiding camera (or webcam should do) with the program Metaguide does better.

[Commanderfish]

This was 

On 5/12/2016 at 18:14, ecuador said:

The one extra inch might make a bit of a difference in dark skies, but the fact that the ED can give a much sharper view by focusing all colors at the same plane is a bigger advantage and I don't really see many (if any) objects looking better on the 152. 

Then, any target that fits the C9.25 will look better in that. And the C9.25 has a wide baffle tube, so you can get up to 1.1 or so degrees FOV with a 46-47mm field-stop 2" eyepiece, which is not that bad. And since you mentioned the C9.25 sometimes trades blows with the 127 ED in planets, have you perfected your collimation? I find that collimating using an eyepiece is very affected by seeing, while using a guiding camera (or webcam should do) with the program Metaguide does better.

I was concerned about this, however the 152 actually has 43% more light gathering than the 127.  It's only 6" so it should make a fairly big difference in moderate LP as well as dark sky, unlike bigger aperture scopes anbove 8" where I don't think there'd be much benefit in my garden with moderate LP.  

As for the C9.25, it's great on planets but not much better (if at all) than the 127 ED - but on some galaxies like M81 and M82 I actually prefer the view in the ED127 due to the increased contrast. Most of my viewing is done in my garden with moderate Sky Glow.  The C9.25 collimation seems spot on to me.  It's bad seeing that causes problems for me.

[Commanderfish]

I've been comparing the views between my ED127 and C9.25.  For planetary, the C9.25 produces brighter views for sure, and it might be ever so slightly sharper, but seeing seems to be the limiting factor on both Jupiter and Mars.  For globs,  the C9.25 being brighter, shows more stars than the ED127.  

So I haven't sold that C9.25 yet, but I have managed to source a used Starwave 152, the first that's come up used since I started researching them.  I will test it on DSOs side by side with the sct.   I expect it to be good on open clusters and bright nebs, starfeilds etc, but will be interesting to see whether it can get close to the C9.25 on globs. It doesn't have as much aperture but it will have better contrast.

[t0nedude]

10 hours ago, Commanderfish said:

I've been comparing the views between my ED127 and C9.25.  For planetary, the C9.25 produces brighter views for sure, and it might be ever so slightly sharper, but seeing seems to be the limiting factor on both Jupiter and Mars.  For globs,  the C9.25 being brighter, shows more stars than the ED127.  

So I haven't sold that C9.25 yet, but I have managed to source a used Starwave 152, the first that's come up used since I started researching them.  I will test it on DSOs side by side with the sct.   I expect it to be good on open clusters and bright nebs, starfeilds etc, but will be interesting to see whether it can get close to the C9.25 on globs. It doesn't have as much aperture but it will have better contrast.

...and a wider FOV..

Tony.

[Commanderfish]

16 hours ago, t0nedude said:

...and a wider FOV..

Tony.

Yes, using my widest eyepiece (ES 82 degree 30mm), the Starwave at 2.73 degrees will undoubtedly cover targets that the SCT (1.05 degrees) can't begin to present to the eyepiece.  In this respect there is no competition, the Starwave wins hands down.  The question now is whether the Starwave can handle globs well enough that I feel comfortable selling the SCT, which is a very good scope I've had since new (13 months old).

Looks like clear sky on saturday night so I'm going to give the SCT a proper run against the ED127 on Mars, partly to assess whether to keep the SCT and partly as I've never had a detailed view of Mars.

Steve from ENS is delivering the Starwave on Sunday afternoon

[ollypenrice]

On 12/5/2016 at 12:30, Commanderfish said:

I feel I am becoming increasingly certifiable as a refractor nut too Tony.  

I can recommend an excellent psychiatrist. Dang, hang on, he's a refractor nut as well... Forget it.

Olly

[A McEwan]

On 27 May 2016 at 15:29, Commanderfish said:

Steve from ENS is delivering the Starwave on Sunday afternoon

Ah. You got that one!

 

[John]

2 hours ago, A McEwan said:

Ah. You got that one!

 

That looked a good deal to me. Not surprising that it was snapped up quickly !

[Commanderfish]

Yep.  It's got paint chips on the bottom, fixed with tippex (GRRRRRR) and a little ding in the dew shield though; the paint chips have my OCD meter pinging pretty hard but perhaps I'm being too perfectionist.  No first light of course, because MANDATORY NEW SCOPE CLOUDS.  Apols for early winter folks.  Apparently though, as it's only a second hand scope it's going to be warm next week (whereas new Apos cost 2 weeks bad weather).

 

Incidentally, I did get the 127 Apo out side by side with the c9.25 on saturday night and found something quite surprising.  The 127 Apo was showing the Cassini Division on Saturn's rings but the C9.25 just wasn't showing it.  Saturn was at around 17 degrees.  Mars was around 18 degrees, and I didn't get any real detail on either scope in the time I had between clouds, except that through the C9.25 I thought the topmost part of Mars might have been lighter than the rest (polar cap?) but to be honest the way it looked it could have been stray light messing with the image.  Definitely not conclusive on the polar cap.  127 Apo wins at low angles I would say.