Training your eye for faint DSOs

[Littleguy80]

It’s always fascinated me that experience and skill can affect what can be seen through the eyepiece. After all, if it’s there you should see it, right? The answer would appear to be no. Setting aside sky conditions and equipment, how do you train your eye to see more detail? 

I started astronomy using a 130mm scope and built myself from brighter targets and started to push for fainter and fainter objects. I remember struggling to see the intergalactic wanderer NGC2419 with that scope. After many attempts I finally found it. I have often wondered whether challenging myself to go deeper with smaller aperture has improved my eye for faint DSO observing now I use a larger 10” dob.

There’s certainly an element of technique. Mastering adverted vision is tricky in the early days. The eye wants to snap to direct vision when the object appears in averted vision. Fighting that instinct is tricky. Gently nudging the scope to pick out faint targets has also become second nature now. The movement drawing out the change in contrast.

Experience comes in through knowing what to expect when looking through the eyepiece. Deviations from the expected hint at the fainter object waiting to be discovered. Repeat observations can start to bring more detail. A mental image is built. 

I do have some aides. I use an eyepatch and an observing hood and like to observe whilst seated. All stray light is blocked out and I can sit still and comfortable. These undoubtedly help when searching for the fainter DSOs.

I don’t really understand how the eye and mind are working together to make this happen. There are many great deep sky observers on this forum who can see much deeper than I. The secret, as far as I can tell, is practise and experimentation. I’d love to hear from anyone who can explain the how and why of training your eye to deeper when observing DSOs. 

Edited September 11, 2019 by Littleguy80

[Geoff Barnes]

Interesting topic Neil.

Hopefully John will be back soon and contribute, he seems to have mastered the finer arts of observing techniques.

My own limited experience has shown me that spending a decent amount of time at the eyepiece has the most beneficial results. Even when the seeing is good, clear and steady and you are seeing good detail in your subject, there are occasional short times when the atmosphere seems to momentarily disappear and things become so clear you feel you coukd reach out and touch it. This has happened to me mainly with the moon and planets and when it does you can't help but saying "wow".

Averted vision is great for the faint fuzzies out there like galaxies and nebulas, but again occasionally if you give it time even these subjects snap into more detail just for a few seconds.

 

Edited September 12, 2019 by Geoff Barnes

[Doc]

What I found good was tapping the scope very lightly so the eyepiece view wobbled this sometimes made the object appear against the background. Also sweeping the area while looking through the eyepiece had the same effect. Most of the time it's just experience, you get to see the mottled effect a DSO has against the grey/black background.

Edited September 12, 2019 by Doc

[scarp15]

Good topic Neil. During infrequent forays into a dark sky location session, I tend to just maybe get a little bit frantic at the start. It's as though I want to try and hit on things as quick as possible, a reaction perhaps to the lack of times I get to go out to somewhere dark during a new moon and it is actually clear. However this state of mind, quickly evaporates and is steadily replaced by a calmer, composed and more in tune persona, with the environment I am occupying and the circumstance I am in. Free of any other distraction, from then on all that is of importance are the selection of deep sky subjects I wish to pursue.

A calm composed presence of mind, locked onto an absolute focus on particular subjects, a comfortable posture either seated (preferably) or standing, conveys patience and concentration. Some very difficult subjects, require repeated attempts, checking in the finder and the charts. Retaining at all times dark adaption and sometimes requiring afterwards, further clarification, referencing a potential observation to a reputed observers sketch or some verbal /written account. It can almost become a form of meditation, removing all other external concerns and despite a lack of sleep, can get you energised. 

[Paul73]

This may seem obvious, but pointing the scope at exactly the right point in the Sky helps. The micro star hop can yield some really faint stuff. You can spend ages chasing ghosts in roughly the right spot rather than resolving the nearly smudge which is the target. This, together with much averted scope wobbling, finally bagged the Quintet a few weeks ago.

Paul

[jetstream]

17 hours ago, Littleguy80 said:

I don’t really understand how the eye and mind are working together to make this happen

Its a combination of things that add up to seeing deep, including object recognition. After being seen once objects become easier for me even threshold ones. Along the same line, when trying to go for faint galaxies forget nebula viewing first and vice versa.

Another hugely important thing to do is find the objects exact spot and then stare...trying to find very faint things panning is more difficult IMHO. The Sky Commander is helping a lot in my case.

I've read some reports under lightish skies describing some faint objects as "easy" or bright"- I think setting realistic goals for the conditions is important regards of some of the reporting...

One more- when trying a galaxy for instance, knowing its size and magnitude will help visualize what your trying to see instead of searching for a larger brighter object potentially.

[Paz]

I think observing is a skill like any other and that purposeful practice  over time makes a big difference both in terms of looking itself and accumulating all the other tricks and techniques that help to give you the best view in the first place.

[Rob Sellent]

The poet Ted Hughes once asked himself about the purpose of writing. He answered, "It's about trying to take fuller possession of the reality of your life." By like manner, we could ask ourselves, "what is the purpose of visual astronomy?" And we could simply paraphrase Hughes and answer, "It's about trying to take fuller possession of the reality I see."

To my understanding there is one essential feature to this 'possession taking' in visual astronomy: observing. Observing is not just looking-at something. Observing requires active engagement with what is being observed. It is a style of concentrated looking, of picking out features and textures, of training the eye to see more. As @Paz says above, it is 'purposeful practice'.

A useful method for observing in this fashion is to simply adobt what great writers, poets and artists have already done. Turning away from mind chatter and instead asking questions about the object being observed: what is there? what do I know about it? what does it look like? what shape does it have? where does it sit in relation to the other objects in the eyepiece?

If observers wanted to go a step further in honing these skills, they could write about what they see, or talk into a recorder about what they see, or sketch what they see and it makes no difference which method they choose, so long as the objective of such practice is to strengthen their stargazing eye, their observational skills.

This technique is no different to that of any decent artist, writer or poet. Miró, Tolstoy, Dostoyevsky, Nietzsche, Kandinsky, Henry James, Darwin, Monet, Ted Hughes, F. Scott Fitzgerald, Marx, Picasso, Dickens, to name a handful, all used notebooks full of observations. So long as the observers are recording what they are seeing to the best of their abilities, they are training their eye and brain to see more.

It is for this reason that this type of observing has nothing to do with imaging or ticking off objects from some list. Observing is an entirely different experience. It means spending time at the eyepiece to really look at what you can see, training your eye to ever greater detail. If good eyepieces and a seat can add a virtual inch or more to aperture, then concentrated observing must surely help augment that even more.

I feel that although this practice looks simple on paper, in reality it isn't. I too struggle with simply observing!

For one, it can be exhausting. It can also be boring if we want to 'get on with things' and see more objects in our session. Another problem is that actively engaging with what we observe can and does slow us down, so it may appear we're not being that productive. A pernicious condition of modernity is to live life as if it were a continuing series of tasks, chores or emergencies to be dealt with, but it is impossible to develop observational powers if we're rushing around. To observe more we just need to slow down a little and simply try and observe that which is before us.

Edited September 13, 2019 by Rob Sellent

[celestron8g8]

For me it was adverted vision , time and patience , and being later at night and darkness . Living in town i think most ppl went to bed and turned off lights after midnight . But a proper EP is a big help to . I’ve not found alot of galaxies but my favorites were M65&66 . But i never found the one to make the Trio set NGC3628  . It was just too faint . This was using my Celestron C8 with a Celestron 32mm Plossi and sometimes a 2x barlow . But usually just the 32mm did best . Seldom but i did use a dark towel over my head . That’s what help me find M65&66 .  But it is a learned technique the more you observe . 

[niallk]

When I first got a scope I remember reading on SGL someone say 'you learn to see'.  I didn't understand at the time - thinking surely you look into the EP and just see what another person sees!

Now i understand that technique and experience makes an enormous difference.  When I first saw M42, i saw none of the detail and colour that I see now in that same scope... and that's not even a faint DSO 😂

Still learning...

[Moonshane]

I agree that like many things experience counts. I suppose technically you are training your brain to see differences in the background sky that are the fuzzies or clusters etc, not your eyes. The techniques mentioned above are important to this as is keeping out of as much light as you can - even a red torch can affect dark adaptation.

Be careful though. I was once observing the Pacman nebula at a star party and had been for a while. It was in field and someone passing asked if they could have a look. On viewing the field he said "I think I see what you mean but cannot tell if I am seeing it or remembering it" 😁

For this reason I always try to sketch the field and shape of the object before looking at images. This way you can check if what you think you see is the target object. As a side benefit, sketching seems to allow more focused observing and helps see more detail in most objects, even bright ones (like the solar system objects).

[Littleguy80]

20 hours ago, scarp15 said:

It can almost become a form of meditation, removing all other external concerns and despite a lack of sleep, can get you energised. 

I've often thought of it like meditation too. The total focus just makes everything else disappear including time. Hours seems to pass like minutes at the eyepiece.

18 hours ago, jetstream said:

Another hugely important thing to do is find the objects exact spot and then stare...trying to find very faint things panning is more difficult IMHO.

That's an interesting one. I have tended to have a bit more movement to try and catch sight of objects. The advantage seems to be finding the right spot for my eye to catch sight. I'm happier to stare at higher power when the target has a bit more movement as it drifts through the eyepiece. Perhaps something I need to work on

@Rob Sellent Great response. I love the comparison to writing. I can definitely relate to that feeling of rushing. I've gotten much better with that as I've gained experience. I'm often surprised at the apparently low number of targets I've observed at the end of the session. Always feels like I've seen more which I think is a goo sign.

18 hours ago, Paul73 said:

This may seem obvious, but pointing the scope at exactly the right point in the Sky helps. The micro star hop can yield some really faint stuff. You can spend ages chasing ghosts in roughly the right spot rather than resolving the nearly smudge which is the target. This, together with much averted scope wobbling, finally bagged the Quintet a few weeks ago.

Paul

Completely agree with this. I normally spend quite a bit of time comparing star fields to SkySafari to make sure I'm in the right spot

[Nyctimene]

Observing faint DSO's, or details in brighter ones, is mainly a thing of contrast, i.e. a high signal-to-noise (S/N) ratio. A certain aperture given, the signal strength (amount of photons entering the eye) cannot be increased. So it all comes down to decrease the noise. There are external sources of optical noise, that can be eliminated (observing hood/eyepatch, as you, Neil, already mentioned; observing late, in dark sky areas etc.). But there are also internal ones -the need of small muscular correction movements, when observing standing, contributes to the amount of neuronal "noise" in the brain. Therefore, observing seated is to be preferred. Alcohol increases via raising sympathetic nerve arousal neuronal noise in the same way; sleep reduces it.

But in the sensors (=retina) and the processor (=brain) a certain level of "noise" is always present. There are several complex neuronal mechanisms, based on a combination of activating and inhibiting ("lateral inhibition") properties, that enhance contrast perception within the retina and the brain.

Practice is also crucial; repeated activation of neurons in the visual system leads to the forming and growth of synaptic connections ("neurons that fire together wire together"), thus increasing the S/N ratio.

In August 1997 I observed, together with the very experienced comet hunter, Otto Guthier, the comet C/1997 J2 Meunier-Dupouy through his 16". With a visual mag of 12.2 and 3 arc min coma diameter, we both could make out the comet easily, constant in AV, sometimes directly. Another experienced observer (but not so much in DSO's) tried it again and again, without avail. I learned a lot about the importance of experience that night.

Stephan

Edited September 13, 2019 by Nyctimene

[domstar]

I have a small well of tenacity. When I set up it's usually not quite dark but the well is already emptying. I try a few easy targets and then it's time for a challenge. I'm on the ball for less than an hour when I can be quite determined. When the well is dry I tend to just pack up. The end of my session is usually a half-hearted attempt at something only slightly researched and maybe a look at the Double Cluster. It's a necessary step to more concentrated research for another better unsuccessful attempt next time. Then hopefully it's third time lucky. 

So, for me, hunting down faint objects (not a lot of detail in a 4inch) means three times research and then almost willing it into existence. When it reveals itself its like it's just a bit less than not being there. When I'm happy there's a bit more than nothing I usually point away and find it again. With M51 and M82 it's like I can almost see detail at times. I can't but there must be something there to persuade me that I almost can. That's one of the calming joys of dso observation.

[Littleguy80]

21 minutes ago, Nyctimene said:

Observing faint DSO's, or details in brighter ones, is mainly a thing of contrast, i.e. a high signal-to-noise (S/N) ratio. A certain aperture given, the signal strength (amount of photons entering the eye) cannot be increased. So it all comes down to decrease the noise. There are external sources of optical noise, that can be eliminated (observing /eyepatch, as you, Neil, already mentioned; observing late, in dark sky areas etc.). But there are also internal ones -the need of small muscular correction movements, when observing standing, contributes to the amount of neuronal "noise" in the brain. Therefore, observing seated is to be preferred. Alcohol increases via raising sympathetic nerve arousal neuronal noise in the same way; sleep reduces it.

But in the sensors (=retina) and the processor (=brain) a certain level of "noise" is always present. There are several complex neuronal mechanisms, based on a combination of activating and inhibiting ("lateral inhibition") properties, that enhance contrast perception within the retina and the brain.

Practice is also crucial; repeated activation of neurons in the visual system leads to the forming and growth of synaptic connections ("neuron that fire together wire together"), thus increasing the S/N ratio.

In August 1997 I observed, together with the very experienced comet hunter, Otto Guthier, the comet C/1997 J2 Meunier-Dupouy through his 16". With a visual mag of 12.2 and 3 arc min coma diameter, we both could make out the comet easily, constant in AV, sometimes directly. Another experienced observer (but not so much in DSO's) tried it again and again, without avail. I learned a lot about the importance of experience that night.

Stephan

Thanks Stephan. I've not heard it described in terms of signal to noise ratio before. Really good explanation!

[Stu]

Great posts above, not sure I can add that much to it. @Rob Sellent I totally agree about taking the time to observe things rather than just looking. One frustration I have with showing new starters some of the fainter objects is that you just know they are not getting the full experience. They look for a few moments, don't tweak the focus and probably are not properly dark adapted.

My most enjoyable sessions are often when I only look at a few objects, and just spend time teasing out all the detail possible, such as when viewing the Veil the other week. Averted vision is just a thing I do automatically now, I actually have to make myself look directly at the object.

The only thing I can maybe add is about breathing. When observing at high powers for planetary and lunar observing I find that my breathing and heart rate slow down and that helps me focus and keep steady. I think when deep sky observing, taking good deep breaths can help ensure you are getting plenty of oxygen in and that may help see the faint stuff.

There is a faintly amusing section about this in Stephen O'Meara's Messier Objects book, always worth a read. Relevant page attached here from Google Books.

He also mentions not being tired, avoiding alcohol and making sure you are warm and comfortable as key factors in making deeper observations.

[estwing]

Relaxing...hood over the head...scope tapping.....sitting all help here...mainly staying off the vodka with us lot.

[jetstream]

1 hour ago, Nyctimene said:

Observing faint DSO's, or details in brighter ones, is mainly a thing of contrast, i.e. a high signal-to-noise (S/N) ratio. A certain aperture given, the signal strength (amount of photons entering the eye) cannot be increased. So it all comes down to decrease the noise. There are external sources of optical noise, that can be eliminated (observing hood/eyepatch, as you, Neil, already mentioned; observing late, in dark sky areas etc.). But there are also internal ones -the need of small muscular correction movements, when observing standing, contributes to the amount of neuronal "noise" in the brain. Therefore, observing seated is to be preferred. Alcohol increases via raising sympathetic nerve arousal neuronal noise in the same way; sleep reduces it.

But in the sensors (=retina) and the processor (=brain) a certain level of "noise" is always present. There are several complex neuronal mechanisms, based on a combination of activating and inhibiting ("lateral inhibition") properties, that enhance contrast perception within the retina and the brain.

Practice is also crucial; repeated activation of neurons in the visual system leads to the forming and growth of synaptic connections ("neurons that fire together wire together"), thus increasing the S/N ratio.

In August 1997 I observed, together with the very experienced comet hunter, Otto Guthier, the comet C/1997 J2 Meunier-Dupouy through his 16". With a visual mag of 12.2 and 3 arc min coma diameter, we both could make out the comet easily, constant in AV, sometimes directly. Another experienced observer (but not so much in DSO's) tried it again and again, without avail. I learned a lot about the importance of experience that night.

Stephan

Excellent and informative post Stephan.

[rockystar]

I remember being out with @mapstar one evening,  he was trying to persuade me that there was a galaxy in the eyepiece; I remain unconvinced 😁

On another occasion, someone more experienced talked me through observing the Leo triplet; I'd go the two messiers easy enough, but with him talking  me through where the other was and what I was looking for I eventually saw it. Moral of this I think, is that some times you just need to know what you are looking for.

Another occasion I was at an open  evening with the local  astro group looking at M57. It was obvious and clearly visible, yet one person, who had never looked through a telescope just couldn't see it until we told him to look for the smoke ring.

[Stu]

5 minutes ago, rockystar said:

I remember being out with @mapstar one evening,  he was trying to persuade me that there was a galaxy in the eyepiece; I remain unconvinced 😁

On another occasion, someone more experienced talked me through observing the Leo triplet; I'd go the two messiers easy enough, but with him talking  me through where the other was and what I was looking for I eventually saw it. Moral of this I think, is that some times you just need to know what you are looking for.

Another occasion I was at an open  evening with the local  astro group looking at M57. It was obvious and clearly visible, yet one person, who had never looked through a telescope just couldn't see it until we told him to look for the smoke ring.

I have a similar story when observing with Steve ( @swamp thing ) at the SGL10 star party. We were looking at the Crescent Nebula through my 16", and whilst I was seeing the overall shape without much detail, he was able to see structure within it. I could not see this on the night, but have subsequently managed it. It's all about practise and familiarity with the objects, and being lucky with the conditions. I've seen features in the Veil recently which I had never seen before, despite observing over quite a number of years. It's always worth revisiting things I think.

[McNewt]

On 13/09/2019 at 14:15, Stu said:

The only thing I can maybe add is about breathing. When observing at high powers for planetary and lunar observing I find that my breathing and heart rate slow down and that helps me focus and keep steady. I think when deep sky observing, taking good deep breaths can help ensure you are getting plenty of oxygen in and that may help see the faint stuff.

Reminds me of target practice.   I was taught SARA (Swedish military term for Ställning (posture) Andning (breathing) Riktning (aim) Avfyrning (fire).).   It just occurred to me that I've used it without thinking about it in situations with high magnification and a wobbly mount.

Edited September 22, 2019 by McNewt

[pjsmith_6198]

On 11/09/2019 at 19:10, Littleguy80 said:

I started astronomy using a 130mm scope and built myself from brighter targets and started to push for fainter and fainter objects. I remember struggling to see the intergalactic wanderer NGC2419 with that scope. After many attempts I finally found it. I have often wondered whether challenging myself to go deeper with smaller aperture has improved my eye for faint DSO observing now I use a larger 10” dob

I think you are right.  You were training yourself to see faint threshold objects.   The more you observe, the more you will see and the more confidence you will be able to even fainter objects.    When I started observing I could  only see the brightest DSO's.    I started the Messier list, I thought there was no way I could seem them all since I was having trouble with objects like M65/M66,  but I kept at it pushing my limits to see these things and I finished the list.    And that gave me confidence to do the Herschel 400.    The funny thing is,  I had more problems with the Messier's than a lot of the Hershel's.   

Training yourself as an observer is like training as a runner.  Some days you train hard doing intervals on the track (or looking for very faint DSO's) and other days are easy runs (or observing your favorite bright DSOs)  The important thing is just to run/observe consistently.

 

Phil

 

[Stu]

Quite agree Phil. Honing your skills by having to drag the maximum out of a smaller scope certainly helps you get the best out of a larger one later. I personally think the rush to large aperture is a mistake, in some ways it spoils the journey you might otherwise have taken. I started at 6" newt and have spent alot of time with 4" or smaller refractors. I dabble at 8" and 14" now when I have the chance.

Somewhere on the forum is a thread about the supernova in M82 a few years back. I somehow managed to glimpse this through my old Televue Genesis from my light polluted back garden. It was quite a challenge even finding the galaxy, but I spotted it using averted vision. The following night I used my 12", and it was trivially easy. I know which observation was more fun and more memorable!

[John]

Very interesting thread this, full of good tips and techniques to push as deep as you can go

I can recall the evening when I managed, at long last, to see the Horsehead Nebula. I found it an incredibly challenging target and one that pushed my ability and that of my scope to the limit I think.

I spent a long time that evening getting fully dark adapted. Our house lights were all off and the neighbours were all in bed. The sky was very dark and transparent, as good as it gets here. I "warmed up" by observing faint deep sky objects using the views that I was getting of those to guage whether the Horsehead was likely to be possible. I knew exactly where the Horsehead is located and had familliarised myself with the star patterns surrounding it so that I knew my way around without needing a star chart and knew how those star patterns looked through the eyepiece and how the area of sky looked with the H-Beta filter installed. I managed to avoid seeing an artifical light of any type for over an hour I think and by that time the reticule on my Rigel Quickfinder seemed glaring even at a low setting, so I switched that off. After all this the Horsehead Nebula was very, very subtle as I describe in my observing report. It's a weird way of spending a few hours isn't it ?. But, my goodness, its satisfying when it eventually comes together 

 

[Geoff Barnes]

One of the most memorable events posted on the forum John!

Edited September 24, 2019 by Geoff Barnes