Linger time

[Weltevreden SA]

Doug Snyder's account of observing the Palomars with his 20-inch mentions several instances where se stayed at the eyepiece nearly an hour to acquire enough glimpses solid enough to log a confirmed sighting. Others seem to spot the object immediately and firmly enough to log it. What are some of your experienced with at-the-limit objects?

[N1]

I try different eyepieces, and go for the high transmission ones if not already in the focuser (I rarely start off a session with any of those).

[Tinderboxsky]

In my view, patience and persistence at the eyepiece are key ingredients to being able to claim genuine observations of objects at or just beyond the limits of observation. Because there are so many variables involved and observations can be very subjective, am always a little sceptical of other’s claims that they have able to spot an object immediately. Indeed, in these cases it can be argued that the object is not at or beyond the limits of observation.
There are quite a few objects that I have logged definite observations for that have required significant time at the eyepiece. I don’t specifically recall “hour long sessions” but certainly I have spent 20-40 minutes at the eyepiece on many occasions to log difficult observations. My discipline is a minimum of 7 sightings before I will log a definite observation.
Obviously one needs to be very comfortable at the eyepiece to achieve these difficult observations. I have a comfortable adjustable chair, freezer suits, light hoods etc - comfort is paramount. Also, I only use eyepieces with at least 20mm of eye relief to ensure eye comfort. I use a TRex mount with Argo Navis with long flexible drive handles (comfort at the eyepiece) which allows me the flexibility to induce motion to improve the chances of detecting the faintest of images.
I get quite a high when I do manage to log these difficult "at the limits" observations.

[glend]

The older you get the less your going to able to see, lingering or otherwise. Once your an adult your cornea begins to deteriourate, and even if you have perfect vision on the wall chart the cornea will start to yellow with age and you will gradually lose sharpness in the central area. No one who is 40 can see the sky as well as someone who is 20, that's a fact.
Once your eyes are dark adapted, maybe 20 minutes max, you get no advantage sitting there staring into the EP. Perhaps you get into a state of convincing yourself, and using adverted vision might help, but its not going to get better by staying longer.
Seeing conditions vary, you may get good results one night, and not be able to see the same object the next night. The quality of the darkness is also a big factor, unless your in a dark site (say 21.7+ on a SQM) then your likely impacted by sky glow of some sort.
The magnitude limitation of your scope is another factor of course.
So in a nutshell, don't waste your precious time, more on to something you can see.

[N1]

I suppose one does acquire some skill over time in seeing things more readily, while one's physical abilities decrease.

On balance I am fairly certain that spending more time on an individual observation will help that observation, regardless of experience or cornea tint. For example, half the time any object spends above the horizon, its observability is improving as time progesses, all other things being equal, simply because the target is rising. More time also means increased odds of catching other favourable but more transient conditions such as good seeing or (for Melbournians) a hole in the cloud deck ;) Light pollution tends to decrease over the course of a night, the Moon might be setting, etc. etc.

So, I'd fully expect two people of equal ability to still take different amounts of time to log a marginal object unless they were looking through the same scope at exactly the same time, which would make for a rare and interesting sight!

[pgc hunter]

I won't spend more than 30 minutes trying to sight difficult objects. Basically, if I don't see several fleeting glimpses of the object in that time frame while trying a number of appropriate magnifications, a black hood and jiggling the scope, I will consider the object out of reach and move on. If there's a couple glimpses of some fleeting variation in brightness with long intervals inbetween, I still won't call it a sighting as it could be just "visual noise". But, if I catch several glimpses intermittently, then that tells me it's a real object wavering in the seeing.

Spending too long staring intently into the eyepiece desperately trying to catch that glimpse has its own pitfalls - averted imagination, eyestrain, visual noise, discomfort sitting/standing in one position too long etc.

To get the best chance of seeing on-the-edge stuff, I'll try and time my obs for after 11pm and when the object is within a couple of hours of the meridian. The latter is less of a concern if it's a far southern target, but when approaching 0* dec and into the northern sky it becomes pretty crucial. All my eyepieces have 20mm ER and feature at least 65* FOV as my scopes are undriven.