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APM 140 Doublet Owners; What Do You Think?

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159 replies to this topic

#151 Tyson M

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Posted 28 September 2020 - 08:19 PM

I’ve been looking for a used APM 140 for a couple months. No replies and I have seen nothing posted in the classifieds. If that isn’t a testament to how much people like these scopes, I don’t know what is. I may have to throw in the towel and buy a new one.


Sometimes you just have to bite the bullet and buy new. Had to do it with the second 12.5mm Noblex

Edited by Tyson M, 28 September 2020 - 08:21 PM.

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#152 Doug Culbertson

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Posted 29 September 2020 - 10:14 AM

I’ve been looking for a used APM 140 for a couple months. No replies and I have seen nothing posted in the classifieds. If that isn’t a testament to how much people like these scopes, I don’t know what is. I may have to throw in the towel and buy a new one.

PM sent.



#153 Dante 34:139

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Posted 29 September 2020 - 02:47 PM

Would a CEM40 handle this for AP? I guess there'll be no problem for visual only but let me know if I'm wrong. 



#154 ris242

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Posted 29 September 2020 - 04:55 PM

Would a CEM40 handle this for AP? I guess there'll be no problem for visual only but let me know if I'm wrong. 

Where I am the 40 and the 60 are almost on par with price.
I would get the 60.


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#155 25585

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Posted 29 September 2020 - 05:23 PM

Sometimes you just have to bite the bullet and buy new. Had to do it with the second 12.5mm Noblex

So you are bino viewing with Noblexs?



#156 StarAlert

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Posted 29 September 2020 - 05:44 PM

PM sent.

Thanks, Doug! waytogo.gif



#157 emilslomi

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Posted 28 October 2020 - 04:31 AM

My first good Mars with the 140. Started with mono viewing and went up to 6mm. There was a 20+ deg C difference between inside and outside, and, as usual, the high mag image looked like crap during the first 30 minutes. After that, very, nice and further improving until about 45 minutes.

At 150x the 140 is too bright for the brighter planets. There was still a lot of glare, and I switched to binoviewing, which helped quite a bit. Since there seemed to be still more magnification possible, I inserted the 1.25 GPC, which helped a LOT. But the image still seemed too bright. Next I lost heart because a thin veil of clouds started moving in. But to my BIG surprise, the clouds cut out enough light (Mars still visible, but most stars gone) to show a beautiful, well defined pole and the features around the Sinus sabaeus started to show fairly detailed outlines. Oddly, the clouds also cut out (I swear) the atmospheric dispersion. Wow, I got so excited that I forgot everything about trying filters. That was a really good session.

I also tried a Vixen HR 2.4 which arrived last week. With the GPC it would be around 2mm and about 500x. Mars essentially lost its color and turned into an almost featureless grey disk passing rapidly trough the field of view. FOV/transit time were still tolerable (all manual mount), but the image was much worse than before. I will give the HR another chance when there are no clouds, but unless the difference is dramatic, it will have to go.

The GPC helped more than I expected for an aditional 1.25 mag factor. I think it's really the correction of the prisms effects that made the difference at high mags - maybe combined with the 140 doing better with mirrors than with prisms in the first place.

 

Emil



#158 ris242

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Posted 29 October 2020 - 08:05 PM

My first good Mars with the 140. Started with mono viewing and went up to 6mm. There was a 20+ deg C difference between inside and outside, and, as usual, the high mag image looked like crap during the first 30 minutes. After that, very, nice and further improving until about 45 minutes.

At 150x the 140 is too bright for the brighter planets. There was still a lot of glare, and I switched to binoviewing, which helped quite a bit. Since there seemed to be still more magnification possible, I inserted the 1.25 GPC, which helped a LOT. But the image still seemed too bright. Next I lost heart because a thin veil of clouds started moving in. But to my BIG surprise, the clouds cut out enough light (Mars still visible, but most stars gone) to show a beautiful, well defined pole and the features around the Sinus sabaeus started to show fairly detailed outlines. Oddly, the clouds also cut out (I swear) the atmospheric dispersion. Wow, I got so excited that I forgot everything about trying filters. That was a really good session.

I also tried a Vixen HR 2.4 which arrived last week. With the GPC it would be around 2mm and about 500x. Mars essentially lost its color and turned into an almost featureless grey disk passing rapidly trough the field of view. FOV/transit time were still tolerable (all manual mount), but the image was much worse than before. I will give the HR another chance when there are no clouds, but unless the difference is dramatic, it will have to go.

The GPC helped more than I expected for an aditional 1.25 mag factor. I think it's really the correction of the prisms effects that made the difference at high mags - maybe combined with the 140 doing better with mirrors than with prisms in the first place.

 

Emil

At F7  -  I think you should always be using a GPC.



#159 StarAlert

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Posted 29 October 2020 - 08:35 PM

 

I also tried a Vixen HR 2.4 which arrived last week. With the GPC it would be around 2mm and about 500x. Mars essentially lost its color and turned into an almost featureless grey disk passing rapidly trough the field of view. FOV/transit time were still tolerable (all manual mount), but the image was much worse than before. I will give the HR another chance when there are no clouds, but unless the difference is dramatic, it will have to go.

 

 

Emil

I can't imagine a 0.28mm exit pupil would make any planet look good. My crappy old eyes need at least 0.7mm to keep the floaters away. 



#160 emilslomi

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Posted 30 October 2020 - 04:04 AM

At F7  -  I think you should always be using a GPC.

Yes, I will leave it in now. 1.25 is not that much, and the image does look nicer. I have not had the binoviewer for a long time, and mostly used it a low mags and, until Mars, never a really high mags. I does make more of a difference than I expected.

 

I can't imagine a 0.28mm exit pupil would make any planet look good. My crappy old eyes need at least 0.7mm to keep the floaters away. 

I do not have problems with floaters (knock on wood), but I doubt that the image will keep up at 500x. I have a gut feeling that the planetary optimum/max for the 140 with binoviewers and without clouds would be around 250x, i.e. a 5mm eyepiece. But I would like to try the HR at least one more time.

 

Emil
 




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