Observation by Paul G. Abel: Neptune, Triton and Nereid
Uploaded by
Paul G. Abel
Observer
Paul G. Abel
Observed
2023 Oct 14 - 22:15
Uploaded
2023 Oct 15 - 12:53
Objects
Neptune
Constellation
Cetus
Equipment
- 305mm Newtonian, x115, x250 and x470
Title
Neptune, Triton and Nereid
About this image
Neptune in very good conditions last night. I have included two lower power drawings. On the left at x115 Neptune can be seen near the 7th magnitude yellow main sequence star HD 222878. What I believe to be Nereid is visible in the 4 o'clock position. In the drawing on bottom right at a power of x250, both Triton and Nereid can be seen in the 4 o'clock position (Triton is closer to Neptune). If this is Nereid, then this is my first sighting of Neptune's elusive fainter satellite!
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Comments
Wouldn't Nereid be a bit faint for visual detection using a 12"?
A background star perhaps?
Possibly. The planetarium software I use doesn't show any faint stars in the correct place. The sky was exceptionally transparent.
It would have to be to glimpse mag 18.
It was a nice night.
Well actually Sky Safari has it listed as Mv~ +19.3 and that really is beyond the range of a 12" telescope! Curious- I'll have a look with some other software to see if I can find a field star in a similar position.
According to the MPC, the coordinates of Nereid at 20231014T2217Z were 23:45:00.7 -03:00:20.
After heading over to https://aladin.cds.unistra.fr/AladinLite/ and pulling up the DSS2 image of that field, it appears that Gaia DR3 2639721332875902848 is located at 23:45:02.2 -03:00:21 and has a g magnitude of 15.90
Glimpsing a 15.9 mag star in a 30cm seems reasonable to me, given good sky and eyesight.
I suggest that is what was seen.
I’m afraid I don’t agree with this at all. There is no way I can see beyond magnitude +13 with my 12 inch Newtonian from my location, and even if one were in a completely dark sky I think magnitude +15.9 would be beyond a 12” Newtonian.
The initial mistake was mine, for some reason I thought Nereid was much brighter that it is- it is in fact well beyond my 12” telescope and what I observed was of similar brightness to Triton. I am looking into this and will report back when I have an answer…
Gaia DR3 2639722565530205824 is g=13.67 at 23:44:55.3 -02:57:18 and
Gaia DR3 2639721951351192832 is g=12.37 at 23:44:46.6 -02:59:56
Triton was V=13.46 at the time.
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