Thanks Fiske for the recommendation to explore the constellations and figure out where their borders are. I did exactly that last night on Serpens and Ophiuchus constellations. I started from 1 Oph and 2 Oph, now an easily recognizable pair of jumping-off stars, and was able to follow the shape of the snake to its head and all the way back. Then I walked up the right side of Ophiuchus to Rasalhague and Rasalgethi (Hercules). I did this using three pairs of Nikon binoculars, Nikon Ell 8x30 (8.8 degs), NIkon EDG 7x42 (8 degs) and Nikon 18x70 (4 degs), in decreasing order of TFOV.
With the Nikon 8x30's 8.8-deg FOV, following the Serpens constellation was almost too easy a task, even for a newbie like me It was decidedly harder to do so with the 4-deg Nikon 18x70, but since I used the biggest Nikon last I was able to manage it just fine. As a bonus, I found a region near Rasalgethi with many stars in the 18x Nikon it immediately gave me the impression of a bouquet of flowers. Checking Stellarium and my Jumbo Pocket Sky Atlas, there's no name for this starry region so from now on I'll remember it as the bouquet of flowers right under Rasalgethi
Lunar viewing was an essential part of my routine nowadays. The moon was pretty low in the sky last night and it took a while for it to come into view near the top of a tree. I was free standing with the Nikon 8x30 in my left hand and the Nikon 7x42 in my right hand. Alternating between the two binoculars, it was hard to decide which one gave the better view. The view through the Nikon 7x42 was decidedly brighter and flatter, but the Nikon 8x30 had the twin advantages of slightly bigger image scale and bigger FOV giving more context. I gave up trying to compare the two instruments and instead just focused on enjoying the magnificent views of the moon hanging between the branches.
I spotted Vega high overhead and proceeded to test the Nikon 8x30's FOV. No problems fitting the Lyra constellation in the 8x Nikon's FOV for a great view. The Nikon 7x42's 8-deg FOV wasn't enough to frame the whole Lyra constellation but nevertheless gave a nice view, if only the background could have been a little darker as it should under darker skies. The best instrument for viewing Lyra was without a doubt the 18x Nikon. The Double-Double and another double star near Vega were easy to resolve in the 18x Nikon. I learned later that each star in the Double Double was a double star but the 18x Nikon didn't have enough resolving power. (It'll be a task for my Kowa Highlander Prominar.)
During my observing session, I spotted many helicopters and airplanes flying overhead. It was really nice tracking those through my Nikon binoculars as they flew across the night sky and disappeared into the distance. I suppose some of those helicopters might have been connected with the ill-fated Tokyo Olympic Games.
Due to my brightly-lit skies, the 6mm exit pupil of the Nikon EDG 7x42 caused the background to be a bit too bright for my observing taste. As such, I found that I reached for the Nikon 8x30 more often than the Nikon 7x42 despite the former not having a flat field. It didn't hurt that the Nikon 8x30 had a larger image scale and a slight larger FOV capable of framing the whole Lyra constellation.
I'll try masking down the Nikon 7x42 into a 7x35 and compare with the Nikon 8x30 again.
Edited by MT4, 21 July 2021 - 08:43 PM.