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Observing Neptune with binos

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#1 clastro8*

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Posted 29 November 2021 - 05:04 PM

I had a pretty good idea where to look using Sky Safari and an atlas (which would show the stars in the vicinity but not the planet itself) and thought I did observe it.

 

But then I checked the visual magnitudes of the objects around there and found Neptune is about 8 mag which is much dimmer than the relative size of Neptune on the app screen.   In other words, on the app screen, Neptune (which is clearly labeled) shows as a larger object than nearby objects but the 'info' button reveals it is really dimmer by comparison.

 

I will try looking again (when the clouds move out), but I am a little surprised by the inconsistency.


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#2 photoracer18

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Posted 29 November 2021 - 06:28 PM

Its not inconsistency. SS if for finding objects not seeing them. If it only showed the actual view of the object you might not see anything at all. The program has no idea what you are observing with so it has no idea if you can resolve it. Uranus and Neptune in smaller scopes and binos are basically a blue dot. Bigger scopes will start resolving them as a blue disc.


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#3 beatlejuice

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Posted 29 November 2021 - 10:45 PM

If you select Neptune and center it on the SkySafari screen,  the size of Neptune on the SkySafari screen is not indicative of its magnitude.  If you saw what looks like a star in the place where Neptune is located on SkySafari , then you likely saw Neptune.

 

As an example search and center Pluto on SkySafari.   Even though the stars around it are much brighter the labelled Pluto (Mag 14.4) will appear brighter on the .SkySafari screen.

 

Eric


Edited by beatlejuice, 29 November 2021 - 10:45 PM.

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#4 sevenofnine

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Posted 30 November 2021 - 12:46 PM

Neptune looked like a very tiny blue dot in my 5" Mak with an 8mm eyepiece so be prepared for Romulan Cloaking borg.gif


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#5 Cestus

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Posted 30 November 2021 - 01:15 PM

I've seen Neptune and Uranus, but they were star like. Not very exciting, but at least I saw them.


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#6 clastro8*

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Posted 30 November 2021 - 01:30 PM

Thanks for your comments.

 

I'm getting more experience using these resources.  

 

I should realize a mag 8 object is not going to be observable from my location using 10 x handheld bino but it looked easy with SS.  I will try a higher magnification bino next opportunity.

 

Perhaps there is a note in the SS documentation somewhere explaining how they depict objects vis-s-vis magnitude, which differs from how an atlas would usually do it.  I noticed in the object info page for planets, they also list arcsec.  For example, for Neptune, it says visual magnitude (7.9) and apparent size (2.3 arcsec).  Does that tell me anything about observability (it's about one-tenth of 1 % the size of the Moon) beyond the listed magnitude?   



#7 aznuge

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Posted 30 November 2021 - 05:04 PM

Good topic.  Here's what I diagrammed for a Neptune view last September, but at 85x with 100mm BTs.  Tonight I will check back with 15x56 or 16x80 binocs to observe it at a much lower mag...

 

med_gallery_347100_16940_8557.jpg


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#8 aznuge

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Posted 30 November 2021 - 06:42 PM

I've seen Neptune and Uranus, but they were star like. Not very exciting, but at least I saw them.

You are right there with Galileo who observed it in Feb of 1619, but did not recognize it as anything other than a star smile.gif


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#9 aznuge

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Posted 01 December 2021 - 12:34 PM

Caught Neptune in my 15x56 Mavens last night.  Had some challenging flood lights coming in at a tangent from the neighbors yard, but was able to fend it off with some strategic hand cupping smile.gif .  Anyway, about 5 degrees NNW of the Psi's of Aquarius, and a degree east of 96 Aquarii, Neptune was easily visible at 15x from my B7 skies.  The planet had moved against the stars over a degree to the WSW since I last viewed it in early September.  I needed to diagram the view for a project, so I am sharing it below.  Neptune's location changes over time were nice to compare and contrast.

 

med_gallery_347100_16940_11698.jpg


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#10 clastro8*

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Posted 06 December 2021 - 07:43 PM

Ok, after 3 1/2 tries I finally made the observation of Neptune early in the evening facing south and using 25 x binos .  

 

The first try I misread the planet's magnification in Star Safari and then started this thread.

 

The second try was cloudy but with a moderate hole to see through in more or less the right place when I started to observe, which quickly clouded over as I should have expected it would.  I'm classifying that as 1/2 a try.

 

The third try I was looking in the wrong place, unfortunately, please don't ask but I just got lost.

 

The 4th try I got more serious particularly after reading aznuge's posts above.  I again reviewed p 74 of my Pocket Sky Atlas to be on the right track, but really began to wonder if that is giving me the picture I am looking for.

 

I resorted once again to SS and, lucky me this time, everything seemed nicely to come together in the following way.  

 

First, the star just below and left of 96 Aquarii in azuge's sketch is HR 8879, it together with 96 forms a nice triangle with Neptune and then, here's the nice part, another star (90 Aquarii), though not shown in the sketch, forms a nice triangle with those two stars but on the opposite side.  So we seem to have a little parallelogram there, in fact, I was thinking of those 96 and HR 8879 as football goal posts and, according to SS, Neptune being on the other side, all I had to do was stand at 90, placekick the football through the goal posts and it would land up in the stands (in Neptune).  

 

Which I first did with 7x 10x, and 15 x binos, but all failed.   I then resorted to my strongest kicker, 25 x, and studied trajectory of the football very carefully and very patiently. 

 

And there it was, a little blue dot just sitting there.

 

I felt great and gave myself 3 points on the board.


Edited by clastro8*, 06 December 2021 - 11:25 PM.

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#11 aznuge

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Posted 07 December 2021 - 01:33 AM

Ok, after 3 1/2 tries I finally made the observation of Neptune early in the evening facing south and using 25 x binos .  

 

The first try I misread the planet's magnification in Star Safari and then started this thread.

 

The second try was cloudy but with a moderate hole to see through in more or less the right place when I started to observe, which quickly clouded over as I should have expected it would.  I'm classifying that as 1/2 a try.

 

The third try I was looking in the wrong place, unfortunately, please don't ask but I just got lost.

 

The 4th try I got more serious particularly after reading aznuge's posts above.  I again reviewed p 74 of my Pocket Sky Atlas to be on the right track, but really began to wonder if that is giving me the picture I am looking for.

 

I resorted once again to SS and, lucky me this time, everything seemed nicely to come together in the following way.  

 

First, the star just below and left of 96 Aquarii in azuge's sketch is HR 8879, it together with 96 forms a nice triangle with Neptune and then, here's the nice part, another star (90 Aquarii), though not shown in the sketch, forms a nice triangle with those two stars but on the opposite side.  So we seem to have a little parallelogram there, in fact, I was thinking of those 96 and HR 8879 as football goal posts and, according to SS, Neptune being on the other side, all I had to do was stand at 90, placekick the football through the goal posts and it would land up in the stands (in Neptune).  

 

Which I first did with 7x 10x, and 15 x binos, but all failed.   I then resorted to my strongest kicker, 25 x, and studied trajectory of the football very carefully and very patiently. 

 

And there it was, a little blue dot just sitting there.

 

I felt great and gave myself 3 points on the board.

I Iike the field goal analogy!  That's having fun with patterns and some creativity to boot (no pun intended smile.gif).  And after a few rounds of frustration - success is sweet. waytogo.gif


Edited by aznuge, 07 December 2021 - 01:34 AM.


#12 Tony Flanders

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Posted 07 December 2021 - 06:17 AM

I should realize a mag 8 object is not going to be observable from my location using 10 x handheld bino but it looked easy with SS.  I will try a higher magnification bino next opportunity.


No, I don't agree. To a first approximation, 10x binoculars show you objects about 5 magnitudes fainter than you can see with your unaided eyes. Under decent conditions third-magnitude stars should be visible naked-eye from even the mostly brightly lit city, so 10x binoculars should show you 8th-magnitude stars and star-impostors like Neptune or Ceres, though you might need averted vision.


Edited by Tony Flanders, 07 December 2021 - 06:18 AM.


#13 clastro8*

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Posted 13 December 2021 - 04:23 PM

In reply to Tony's last comment, we here had cloudy nights all but two in the last week. In the two, I was not able to observe Neptune using 10x binos with either direct or averted vision. I agree my comment about an 8 mag object like Neptune not being observable with 10x binos misspoke, because I have observed objects at that magnitude with 10x. But, I have not been able to observe that object using 10x.

In fact, I did observe Neptune with 15x and averted vision, but it was not a clear view. Had I not observed it using 25x as mentioned earlier, I'm not sure I would have succeeded with 15x.  However, because I knew just where to look for an extended time with patience, I did observe it.

I've seen discussions of magnitude similar to the comment Tony offered elsewhere, so I will continue trying the observation with 10x, but I haven't seen other discussions that Neptune will be observable with 10x and/or absent dark skies; in fact, usually that higher magnifications a la telescopes and dark skies are required.


Edited by clastro8*, 13 December 2021 - 06:32 PM.


#14 clastro8*

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Posted 21 December 2021 - 03:04 PM

I've tried a few more times to observe Neptune using 10x binos without any success, but now I think the reason is that, from my location, Neptune appears in the lower half of the sky and therefore is subject to the dimming which occurs in that region of one's field of view.

 

This explanation occurred to me on seeing a nearby dim star, which I think is HD220134, mag 6.8, which should be much brighter in 10x than I observed it, whereupon the thought popped into my head, both it and Neptune would be subject to this same phenomenon.  

 

According to Star Safari, I was observing these objects around the time of transit, when they would be at their highest elevation vis-a-vis the horizon..


Edited by clastro8*, 22 December 2021 - 01:31 PM.



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