ATS 80 and astro 1.25" eyepieces (1 Viewer)

[Boogieshrew]

Hi all,

I just found my APM Swarovski fit astro adapter that I thought I had lost.

Are any of you fine folk using astro e/ps on APS/APMs?

I'm wondering what's out there that works. Particularly for low mag wide fovs but also zooms as I find the wide field Swarovski 25-50x doesn't have enough e/r for my glasses.
Does the APM zoom for 30-60 fit?

All the best 😄

 

[wllmspd]

I would like to know if the wide angle
Baader Morpheus eyepiece come to focus in the ATS, haven’t quite got the courage to ask fellow birders if I can pop this odd contraption into their beloved swaro spotter…. Don’t imagine I’d have much luck. The 12.5mm would give 32x. I like that eyepiece in my celestron hummingbird, very wide.

Peter

 

[Tringa45]

Are any of you fine folk using astro e/ps on APS/APMs?

Do you mean ATM/ATS?
They have focal lengths of 460 mm and the sealing widow in the scope body is 26 mm diameter. That's not much less than the 27 mm maximum field stop on 1.25" astro eyepieces, so even a 32 mm Televue Plössl or 24 mm Panoptic would not vignette severely.
However, the former has a mere 50° AFoV and the latter only 15 mm ER.
Although the Swarovski scopes are very tolerant of astro eyepieces (I have not experienced any that don't focus to infinity in my ATM65) I have dobts about the Morpheus, which also has a 2" barrel. Even if you could remove this, the long 1.25" barrel would bottom out in the scope body and probably impede infinity focus.
A couple of rather expensive possibilities are the 18,2 mm Televue Delite (62°) for 25x and the 17,3 mm Televue Delos (72°) for 26,5x.. Both have 20 mm ER.

John

 

[wllmspd]

To shed some light on this I offer some measurements of the length of the “1.25” pokey bit” and the relative focal position of a range of eyepieces I had to hand. Vernier caliper measurements, focus tested on an 80mm f6.8 William optics zenithstar refractor with erecting 45degree diagonal. I arbitrarily took the 12.5mm Morpheus as “zero” focus position, positive means the eyepiece needs to be pulled further out, negative needs to be pushed further inwards to reach focus. For each eyepiece I give the 1.25mm section length (the bit that would poke into the adapter and the “relative focal position”, all in millimetres.
12.5mm Baader Morpheus, 24mm, 0mm
7mm “nirvana ultra wide”, 27mm, +3.45mm
5mm televue type6 Nagler, 30mm, +6.85mm
24mm APM UFF, 25mm, +1.35mm
18mm APM UFF, 25mm, +3.45mm
Baader mark4 8-24mm click zoom. 25mm, 8mm setting -5.45mm, 24mm setting -3.85mm.


I believe the Morpheus (except the 17.5mm which I believe needs 2.5mm more in travel ) are partocal , as are the type 6 naglers - Televue provides full measurements of their eyepieces and focal plane location.. The televue protrudes the furthest in and focuses the furthest out, and the Baader zoom needs the greatest inwards position to focus.

Hope this is useful, I do wonder if a secondhand 80mm ATS would be a nice (lighter weight) addition.

Thanks

Peter

 

[Boogieshrew]

17,3 mm Televue Delos (72°) for 26,5x

Do you mean ATM/ATS?
They have focal lengths of 460 mm and the sealing widow in the scope body is 26 mm diameter. That's not much less than the 27 mm maximum field stop on 1.25" astro eyepieces, so even a 32 mm Televue Plössl or 24 mm Panoptic would not vignette severely.
However, the former has a mere 50° AFoV and the latter only 15 mm ER.
Although the Swarovski scopes are very tolerant of astro eyepieces (I have not experienced any that don't focus to infinity in my ATM65) I have dobts about the Morpheus, which also has a 2" barrel. Even if you could remove this, the long 1.25" barrel would bottom out in the scope body and probably impede infinity focus.
A couple of rather expensive possibilities are the 18,2 mm Televue Delite (62°) for 25x and the 17,3 mm Televue Delos (72°) for 26,5x.. Both have 20 mm ER.

John

Thanks John. The 17,3 mm Televue Delos (72°) for 26,5x sounds interesting.

 

[Boogieshrew]

To shed some light on this I offer some measurements of the length of the “1.25” pokey bit” and the relative focal position of a range of eyepieces I had to hand. Vernier caliper measurements, focus tested on an 80mm f6.8 William optics zenithstar refractor with erecting 45degree diagonal. I arbitrarily took the 12.5mm Morpheus as “zero” focus position, positive means the eyepiece needs to be pulled further out, negative needs to be pushed further inwards to reach focus. For each eyepiece I give the 1.25mm section length (the bit that would poke into the adapter and the “relative focal position”, all in millimetres.
12.5mm Baader Morpheus, 24mm, 0mm
7mm “nirvana ultra wide”, 27mm, +3.45mm
5mm televue type6 Nagler, 30mm, +6.85mm
24mm APM UFF, 25mm, +1.35mm
18mm APM UFF, 25mm, +3.45mm
Baader mark4 8-24mm click zoom. 25mm, 8mm setting -5.45mm, 24mm setting -3.85mm.


I believe the Morpheus (except the 17.5mm which I believe needs 2.5mm more in travel ) are partocal , as are the type 6 naglers - Televue provides full measurements of their eyepieces and focal plane location.. The televue protrudes the furthest in and focuses the furthest out, and the Baader zoom needs the greatest inwards position to focus.

Hope this is useful, I do wonder if a secondhand 80mm ATS would be a nice (lighter weight) addition.

Thanks

Peter

Thank you Peter for such an in depth reply and for taking time to do those measurements. I will look up all those eyepieces.

 

[wllmspd]

Please feel free to add to them or use them and the ones you have to increase the known list that don’t hit the sealing window and can reach focus. How does the ATS perform with 1.24” eyepieces, I would hope the fixed focal length perform well vs a zoom?

Peter

 

[Tringa45]

17,3 mm Televue Delos (72°) for 26,5x

Thanks John. The 17,3 mm Televue Delos (72°) for 26,5x sounds interesting.

Bear in mind though that the Delos might not correct for the field curvature of the Swaro scope. Pincussion on some astro eyepieces can also be quite pronounced.
If you were able to find a Swaro 30xW eyepiece (65° AFoV), that might be a better (and cheaper) solution. It is almost perfect in every respect, no astigmatism or field curvature, imperceptible rectilinear distortion and 20 mm eye relief.

John

 

[Boogieshrew]

Bear in mind though that the Delos might not correct for the field curvature of the Swaro scope. Pincussion on some astro eyepieces can also be quite pronounced.
If you were able to find a Swaro 30xW eyepiece (65° AFoV), that might be a better (and cheaper) solution. It is almost perfect in every respect, no astigmatism or field curvature, imperceptible rectilinear distortion and 20 mm eye relief.

John

Thanks John.

I have the 30xw. It is a wonderful e/p indeed.
I also have 20x and 45x Swarovski e/ps.
The 20x had limited e/r so I removed the rubber eye cup and made my own with thinner rubber. It now works while wearing my glasses and is a nice e/p although doesn't match the 30x.

It has occurred to me that I should try a 20mm Pentax XW. I used the XW14 on a PF65 eda years ago and it was a really nice to use. The 20mm e/r was great for glasses wearers. And a 70* afov.

All the best

 

[DRodrigues]

...
Does the APM zoom for 30-60 fit?
...

Most probably will not reach focus APM vs. Baader Zoom
There is another wide-field zoom being released that probably will need less infocus than the APM - it seems a clone of the Kowa zoom and I'm waiting to see the first reviews, specially the infocus needs...

 

[Boogieshrew]

A kowa clone sounds interesting. 25-60x appeals much more than 30-60 on the current APM zoom. I prefer low mag and would be happy with a 20-40x actually. I would settle for a 25x start magnification though

I look forward to reading about it.
Thanks