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APM 3.5mm XWA 110 or what else?


Deadlake

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Since we are heading into the planetary season and I've recently been able to make use of a 4.7 mm XWA on Jupiter and Saturn to enjoy a wide field view of their respective systems I was wondering about using a APM 3.5 mm XWA as well.

Anyone made use of such an EP, and what other EP's are there which are similar? 

In the planetary EP types I have a full set of Vixen HR's and a TOE 4 mm.

Thanks

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I guess it depends on the focal length of your scope and the resultant magnification.

The eyepiece has to yield a usable magnification, and that depends a lot on your seeing conditions.

I use a 3.7mm Ethos eyepiece at 495x in my 12.5" quite often for small planetary nebulae or Neptune or Uranus,

but not for anything else.  I rarely go above 300-400x for Jupiter or Saturn.

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I used to have the 3.7 and 4.7 Ethos and used them with my 12 inch F/5.3 dob. Like Don I didn't use the 3.7 all that much. I actually let both of them go but then missed having the 4.7 so bought another one last last year :rolleyes2:

If I want to go above the 338x that the 4.7 gives me I do have the Nagler 2-4mm zoom or the 3.5mm XW. Picking out faint point sources such as supernovae and planetary nebulae central stars sometimes does benefit from these very high magnifications.

I believe that the APM 3.5 is actually a 3.7 ?

 

Edited by John
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John,

I think it is actually a 3.6mm.  At least that's what Stellarvue measured.

If it's 3.55mm, it would depend how you round off as to what you call it.

The APM XWA 100° "5mm" has been measured at 4.7mm, 4.77mm and 4.9mm by different testers.  It might be wise to call it 4.8mm +/- 0.1mm.

Just as apparent fields are rarely exactly as stated, so too focal lengths vary a bit, usually by only 0.1mm which makes little difference in the scope.

My scope has over a 1.8 meter focal length, and the difference between 4.7mm and 4.9mm is only a difference of 16x.  I doubt I could see that if I tried at that high a power.

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I've seen the EP measurement's on CN, marketing over actual dimensions? 😀 

The ~3.5 mm XWA seems a specialist EP then, very happy with the XWA 5 mm. 

@Don Pensack The Ethos versus the APM 3.5 mm.  
   On CN some observers have complained that the lack  of baffling on the APM lets in too much stray light, is that the case with the Ethos as well? 

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6 hours ago, Deadlake said:

I've seen the EP measurement's on CN, marketing over actual dimensions? 😀 

The ~3.5 mm XWA seems a specialist EP then, very happy with the XWA 5 mm. 

@Don Pensack The Ethos versus the APM 3.5 mm.  
   On CN some observers have complained that the lack  of baffling on the APM lets in too much stray light, is that the case with the Ethos as well? 

I've not used the 3.7mm on the Moon, which is where I'd expect to notice.

On Uranus, Neptune, small planetaries and close double stars, I've not noticed any notable level of light scatter.

I've only spent about an hour with the two APM short focal length 110° eyepieces, not long enough to have an opinion about light scatter.

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