The Moon and Neptune in the same view (just !)

[John]

I've been having a fun few hours with my 130mm refractor starting with Saturn then working through some binary stars while the Moon rose.

I noticed from Cartes du Ciel that Neptune was around 1.5 degrees from the Moon this evening so I thought I'd have a go at getting both in the same field of view. I used my 21mm Ethos which gives a true field of 1.75 degrees with the 130mm refractor. Using Cartes du Ciel to give me a guide to where Neptune would be in relation to the Moon, I set about carefully scanning the sky close to the lunar limb. After my eye adjusted to the lunar glare, stars did start to shine through the moonglow and eventually I tracked down a likely candiate for Neptune. At 57x it looked decidedly "star like" but I switched eyepieces for a 6mm (200x) and that confirmed that it was indeed Neptune with it's tiny but distinct disk shining dimly in the moons radiance.

Swiching back to the hyperwide Ethos 21 I found my calculations had just about been correct and I could indeed get a small segment of the lunar limb at the edge of the field of view on one side and Neptunes shy glowing disk right across on the other side. Nothing of any scientific interest in this really but it was a fun excercise all the same

Using much more magnification (343x) gave Neptune a much more distinctive disk and, despite the moonglow, one that had a distinct pale blue hue to it.

Some lovely features along the lunar terminator tonight as well. Messier and Messier A, my favourite pair of craters, were filled with pools of dark shadow but ther ramparts were well illuminated and the twin rays, which so strikingly extend to the west from Messier A, were bright and clear across the Mare Fecunditatis. The Mare Crisium was split more or less in half by the terminator and it's illuminated and almost perfectly semi-circular western half made splendid a sight.

Good to have a few hours at the eyepiece after some lousy August weather here. Hopefully more of the good stuff to come

Edit: Forgot to mention that I also observed the nova in Scutum again tonight. It's magnitude seemed similar to when I last observed it (more than a week ago ?) at around magnitude 9.

 

[Red Dwarfer]

3 minutes ago, John said:

Neptune was around 1.5 degrees from the Moon

Right , what is the location of Neptune from the Moon , 12 O`Clock , 3 O`Clock , etc ? 

Neptune would be a first for me .

[Red Dwarfer]

Seems to be at 1 O`Clock position on StarWalk app ... gonna have a look now ...

[John]

Cartes du Ciel and Stellarium show it's position better than I can describe it

It's not an easy night to fine Neptune because of the moons glow. Normally I can see Neptune as a dim star in my 50mm finder but not tonight - I needed a low power eyepiece to find the suspect and higher magnfications to confirm it.

Good luck !

[John]

PS: Neptune is now around 2 degrees from the Moon - the solar system has moved on since my earlier observation. I'd not be able to get the two in that FoV now !

[Red Dwarfer]

Okay , I can make out what looks like a star in that 1 O`Clock position , it`s light has a constancy to it unlike a twinkling star ... could be it , but can`t be sure ... 

[MarsG76]

Awesome report.. I'm gald you had some viewing time but not only that but you got a glimpse of something different... ie the Moon and Neptune in the same FOV.
 

[nightfisher]

Very nice report John, i woke for getting up for work and could see the moon through the curtains, after a summer layoff i feel the astro is about to get started again and i have a whole new scope outfit to get used to

[John]

6 hours ago, Red Dwarfer said:

Okay , I can make out what looks like a star in that 1 O`Clock position , it`s light has a constancy to it unlike a twinkling star ... could be it , but can`t be sure ... 

You need to use magnfication to check that it's Neptune. About 200x to be sure I reckon. There were a number of background stars around the Moon last night, some brighter than Neptune.

This is how Cartes du Ciel had things around 1:00 am this morning. The separation between Neptune and the Moon at that point was around 1.45 degrees I think:

 

[Red Dwarfer]

The chances are it was a star I seen as I was looking for the brightest nearby object to the moon - something along the lines of Venus but not as bright - but it turns out to be fainter than some stars ...

Got this last night too after a search for the exact location of Neptune 

[John]

Yes, Neptune is massively fainter than Venus - just magnitude 7.8 last night I think. Thats why I posted earlier that it was hard to spot in the moonglow.