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TV Delos terrestrial use

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#1 sergiun

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Posted 23 January 2020 - 04:23 AM

For terrestrial use, my question is, the delos have rectilinear distortions? the lines of the buildings are not straight like panaoptics?have a apm 82 sd binocular, I like delos 14 mm but it must warking well also for landscape and birds watching, so I need a pair that working well also in day time without lateral color and without rectilinear distortion. thank you.

 



#2 Ernest_SPB

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Posted 23 January 2020 - 06:26 AM

small positive rectilinear distortions



#3 sergiun

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Posted 23 January 2020 - 08:03 AM

thank you, I’m undecided between the delos and the chinese clone of docter astro 12.5, the apm 12.5 FL  with 84* of field, that cost less and have bigger apparent field, but maybe the TV have better quality of view and is 150 grams  lighter. 



#4 Javier1978

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Posted 23 January 2020 - 08:39 AM

IME, the biggest issue with 12 mm Delos for daylight use was that the eye placement became really sensitive. The 18.2 mm DeLite is an outstanding eyepiece for landscapes and birdwatching with a ST refractor. 



#5 Spikey131

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Posted 23 January 2020 - 09:37 AM

I’m not sure, but I think some of the Pentax offerings are better corrected for terrestrial use.  Perhaps someone more informed will chime in on this.

 

Curved lines on buildings don’t bother me when birding, so I use my Panoptic and Delos eyepieces.


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#6 Starman1

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Posted 23 January 2020 - 03:43 PM

For terrestrial use, my question is, the delos have rectilinear distortions? the lines of the buildings are not straight like panaoptics?have a apm 82 sd binocular, I like delos 14 mm but it must warking well also for landscape and birds watching, so I need a pair that working well also in day time without lateral color and without rectilinear distortion. thank you.

Yes, virtually all widefield eyepieces designed for astronomy or mixed astronomy/daylight use have RD in the field.

Eyepieces with no RD have a lot of angular magnification distortion (AMD) instead, which makes things shrink as they near the edge of the field.

It is not possible for a widefield eyepiece to be free of all distortions (i.e. orthoscopic).

 

If you want an eyepiece for daylight-only use, try:

APM 12.5mm 84°

Noblex (formerly Docter) 12.5mm 84°

Nikon NAV-SW eyepieces

Meopta, Kowa, Swarovski, Leica, Zeiss, zooms

Fixed focal length spotting scope eyepieces from the above

or

stick to smaller field (like 50°) eyepieces, which, by virtue of a narrower field, have much less distortion.



#7 Spikey131

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Posted 23 January 2020 - 04:18 PM

Don-

Not Pentax?

#8 Tamiji Homma

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Posted 23 January 2020 - 04:56 PM

For terrestrial use, my question is, the delos have rectilinear distortions? the lines of the buildings are not straight like panaoptics?have a apm 82 sd binocular, I like delos 14 mm but it must warking well also for landscape and birds watching, so I need a pair that working well also in day time without lateral color and without rectilinear distortion. thank you.

 

You may find these shots interesting.  

 

They were eyepiece projection image taken by Fuji X-Pro camera a few years ago.

There is no camera lens.  Camera sensor is directly capturing image through eyepiece.

 

Due to physical challenge, distance between exit pupil and camera sensor plane isn't constant.

 

The longer distance between exit pupil and sensor plane is, the more projected geometrical distortion gets exaggerated.

 

https://pbase.com/ta...oculars&page=95

 

Here is a few examples:

 

large.jpg

 

large.jpg

 

Tammy


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#9 Starman1

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Posted 23 January 2020 - 05:25 PM

Don-

Not Pentax?

Normal RD there.

#10 DRodrigues

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Posted 23 January 2020 - 07:13 PM

thank you, I’m undecided between the delos and the chinese clone of docter astro 12.5, the apm 12.5 FL  with 84* of field, that cost less and have bigger apparent field, but maybe the TV have better quality of view and is 150 grams  lighter. 

Between the AFOVs of the mentioned eps, you have the Morpheus 76°, that are lighter and less expensive. There are both 14 and 12.5 mm versions. I have the 14mm for my cr-birding use and like it.



#11 Starman1

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Posted 23 January 2020 - 08:11 PM

Between the AFOVs of the mentioned eps, you have the Morpheus 76°, that are lighter and less expensive. There are both 14 and 12.5 mm versions. I have the 14mm for my cr-birding use and like it.

Many people tolerate the RD of astronomical eyepieces for birding.  The OP said he was looking for eyepieces without RD, which rules out the Delos, Morpheus, Naglers, XWs, etc.

 

I forgot to mention that Harry Siebert also makes eyepieces with low or no RD.



#12 sergiun

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Posted 24 January 2020 - 09:19 AM

thank you so much to everybody so without RD are nikon nav, pentax xw (but have no completely flat field like I read in this site) and probably the apm 12.5 84* (clone of the excellent docter 12.5). The solution is try in reality wich ones is more nice use for me. thank’s



#13 sergiun

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Posted 24 January 2020 - 09:22 AM

and also the TV Delite have not RD but here narrower apparent field than the others like nikon nav or apm84*



#14 Starman1

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Posted 24 January 2020 - 10:48 AM

thank you so much to everybody so without RD are nikon nav, pentax xw (but have no completely flat field like I read in this site) and probably the apm 12.5 84* (clone of the excellent docter 12.5). The solution is try in reality wich ones is more nice use for me. thank’s

As I said earlier, Pentax XWs have a normal amount of RD for widefields.  They are good astronomical eyepieces as a result.




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