This will be my first post. Invited by Suzy. . . Looks like a great community under the greatest of skies! Lots of great advice by experienced observers already on this thread. . . But, at the risk of repeating what some of you have already said, I'll post a list that works for me, in no particular order, off the top of my (bald-ass) head:
1) Be relaxed and rested. A comfortable position at the eyepiece cannot be over emphasized. If caffeine makes you jumpy, don't do it, or do it in moderation. If alcohol makes you drowsy. . . Have snacks on hand, but don't eat a full-blown dinner shortly before observing. Take breaks as necessary: this is not work, it is PLAY!
2) Go at your own pace. Again, relax. Trying too hard, moving from object to object too quickly savors little.
3) Observe with friends! Sharing with novices is always great, but having a buddy with similar equipment and experience to share views with always benefits both (or more) of you!
4) Linger on the view(s). Photons will accumulate on your eye/brain whether the object is bright or dim. Quite remarkable and rewarding to experience this.
5) Definitely use higher power (once you find your object)--your eye/brain will make more sense and see more detail from a more magnified image, even if the lower power image is more aesthetically pleasing.
6) Fine tune the art of averted vision: Don't try too hard. Relax. Massage your eyes . . Jiggle the scope.
7) Make an "eyepiece chart" for really dim objects with your Astro software--that way you can be certain you are in the correct FOV, even if the object itself is too dim/conditions are not ideal and skunks you.
8) Take notes, at the very least. Sketch if you like. Both will force you to see more.
9) Be honest with yourself--don't always trust what you see! I've experienced "averted imagination" in myself as well as with others (especially susceptible in the wee hours when extremely tired). . . Look again. Confirm difficult sightings with others.
And, of course, all the basic stuff: Dim red lights, observing list(s), resource books/charts, play with different filters. . .
Thanks for your contribution, Ray, it is much appreciated by the "locals", many of whom are Australians, but some of whom are far flung all over the world.
Happy to have you join our community.
Experienced observers such as yourself have worked out what works best for them.
Thanks to contributions such as yours, we are building up quite a store of knowledge as to how best to observe the deep sky.
I'll just copy some of my stuff across from the other thread:
For really faint objects on the limits of detectability (rather than faint details in galaxies) where I might get odd flickerings of something in the position, I usually repeat the process in another or even several parts of the field. You quite often get a similar response. Sometimes when you move your eyes back to the target position you get a much stronger response that can be held in averted vision even if intermittently, almost like the exercise sharpened your vision. But if I get the same flickerings of something (all too often!), I'm fairly satisfied that I'm not seeing anything other than a trick of the eye. You really have to hold it, even briefly.
Spending time is essential, and movement helps greatly (tap the eyepiece or jiggle the controls). Provided your eyes are fully light-adapted, I find that coming back to the field later on in the observing session doesn't help all that much unless there is a change in transparency, because you have to pretty much repeat the teasing-out process all over again. May as well spend quality time first-up.
Generally: find a dark place and shield any extraneous light (eg put street lights behind trees). Get light-adapted - never go for really faint objects first. Have (generate) charts that position a faint object precisely in the field - as part of pre-planning pick 'asterisms' or star alignments that you will be able to recognise in the FOV (eg a little triangle of stars or a line of four stars etc etc). Above all, have fun.
While increasing magnification may help by increasing contrast, in a little scope like mine it doesn't generally work - not enough light. Things just disappear!
Anyway, some great tips, thanks to those who've posted. Must admit though, this tip by Doug Snyder has me a little confused!
Welcome to our vibrant little community, Ray, and many thanks for your very useful tips. I really like your emphasis on taking time and having a spirit of play. It is tempting to try to see more objects rather than fully appreciate the one already in view. Also easy to get so focused on the technical that it's possible to lose the magic of observing.
Observing with friends is also such a great tip. I usually observe on my own and really appreciate the several star camps that I go to each year as an opportunity to have friends let me know what they are seeing - opens up whole new vistas, as does comparing the view through different scopes. I think the conversation over the eyepiece also means more coming and going, the revisits revealing more each time.
And thanks Rob for your tips, which I notice you added to - good stuff. And a very good point about the limitations of trying to use high power with a small scope. The double averted vision thing is going to take a bit of thinking about. Does it imply a binoviewer?
Some great tips here ,thanks to everyone who has posted.
I only have a couple to add to the list
My favourite is a dark cloth or hood,I think it can give you maybe a quarter or half a mag brighter as it blocks any stray llight or even the normal sky glow from the millions of stars.
Don't try to see deep sky objects after using the computer for a little while, even with the red screen as dull as it will effect your night vision, wait a few minutes or don't use the computer at all.
Even using a dull red light can can take a few seconds for my eyes to adjust when I am using a star chart.
Print off some charts and use them at the scope with the dullest red light you can see by.
I have an ArgoNavis DTC and set to the bare minimum brightness when observing.
Averted Vision is one of my main tools as well as moving the scope especialy for faint Nebulae which are not much brighter than the background sky.
Put as many stars as possible out of the field if trying to see very faint object as even 10th mag stars can make a difference when trying to tease out very faint galaxies.
Time spent on the object has been mentioned but I think this is one of the main things I get out of observing, trying to tease as much information out of the object as possible .
Try using different eyepieces on each object,it helps you to make up a picture in your brain as you go deeper in magnification.
Have some images handy to see if you have anyobjects in the field that don't belong there Ie Supenova.
And always try to enjoy your observing as it will make you want to come back and observe again and again,as if you dont enjoy it you will soon become an imager
Cheers
Regarding the double averted vision,I can't think of any way that will work without it implying a binoviewer unless by crossing your eyes,the one eye on the eyepiece will be in averted vision.Though crossing my eyes hurts my brain.
It is a tough task to put in writing "what we do" when we are at the telescope, in order to tease out that ultra-faint detail within objects; but I think Ron and Ray and Paddy and Rob K are doing a good job of describing the procedures that advanced visual observers actually do use.
Author's preliminary warning:
(regarding this post , and regarding my next post in this thread)
My comments reflect the approach that I have taken in my own visual observations of diffuse (= extended)(= non-stellar) deep sky objects, such as emission nebulae and galaxies, which is based on my own qualitative observations of what happens when the eye and brain are put behind the astronomical telescope. In no way have I actually put any hard numbers to the various important factors that affect how well we see a diffuse object or feature which is near to the fringes of visibility (e.g. surface brightness, contrast, angular resolution at low light levels, feature recognition by the brain, etc.). As such, everything that I say is very preliminary, and "disprovable".
The Human Brain is the Deep Sky observer's Camera :
Ron and Ray have made the important point (in their recent posts in this thread) that Deep Sky Observers - when they are viewing a very faint nebula or galaxy - are actually trying to gradually build up an image of the object in the human brain. Which is why Ray's point about the utility of sketching (and/or a detailed prose description of what is seen) is so important; the process of sketching and describing an object implies that we are transferring the things that the human brain/mind sees at various times and moments.......onto a piece of paper, which serves as an “accumulator” for the things the brain perceives.
Putting together a mental image of an object :
I do agree with Ron that many and various magnifications should be tried on a diffuse object, because the final result of a deep sky observation is a sort of composite “mental image” of an object, made up of multiple individual views or glimpses of the object.
Therefore, a good approach is to put together, into a single "mental image" and/or a sketch and/or a prose description:
the details that the observer sees over a prolonged period of viewing at a single magnification
the details that she/he sees when viewing at various magnifications
the details seen on various nights
As experienced observers will tell you, some of the galaxy images which are very large in angular terms, such as M101, M31, M33,
NGC 4565, NGC 891, NGC 6744, NGC 5128, NGC 1365, NGC 1313, NGC 253, NGC 55, M83, etc., do contain substantial amounts of detail that is visible to the eye at the telescope, at least if these objects are observed in a dark sky. However, the details within these galaxy images tend to be fleeting, and these details are often seen haltingly because they may be near to the eye's limit. So this is why the approach of "gradually building up a mental image of the target object" can eventually result in the observer getting a really good idea of the structure of the image of an object.
Last edited by madbadgalaxyman; 02-10-2011 at 10:17 AM.
Reason: correction
Tips and techniques that can help I see as a big part of this thread. I posted this originally in the DIY section where I had started a thread on the DIY dob mount that this 8" f/4 OTA.
As I use this scope a lot from home, the ambient light is a real pain in the neck reflecting off the white tube. I had some foam rubber left over from the stuff I used to wrap around the poles of my 17.5", so I used it to cover the top half of the 8" OTA. I cut out the necessary openings to accomodate the focuser, finder shoe and spider nuts. The white markings were done to position these openings.
The foam rubber sheet is wrapped around the OTA and only glued onto itself, not the tube. The holes that the various components poke out from hold the thing in place so it doesn't slip. I made it a snug fit which helps too.
The result works really well to tone down the reflections, . An added bonus was the insulative effect it had on the secondary mirror, protecting it from dewing up for a longer time than before. A bit of a surprise that was. I might consider making a dew shield for it out of thicker foam, much like the ones used on SCTs. Even at a dark site, this simple mod has improved the reflection attenuation off the OTA.
This stuff weighs bugger all, so it doesn't upset the balance.
Below are a couple of pics showing before and after.
---
Another thing I've done was paint the focuser board of my 17.5" matt black, specifically using black coloured blackboard paint. This was considered from the planning stages of the scope, and I've never had the same problem of reflections coming off the board.
Nice modification there, and undoubtedly it puts the unwanted light somewhere away from your eye! Anything that increases the image light and decreases other light reaching the eye is a wonderful thing. (for instance, I am all for getting the the highest reflectivity mirror coatings that I can afford)
I have heard it said by experienced observers and telescope makers that the apparent contrast advantage of traditional (F10 to F15) refractors over newtonian reflectors is simply caused by the traditional refractors having longer tubes and tubes which are well baffled....leading to there being actually less light all over the observed field, and thereby explaining the slight edge that these long-tube refractors had for visual observation of deep sky objects.
Suzy asked if I would contribute some suggestions as I always include size or dimension estimates in my observing notes, so for what it's worth, here are my techniques.
The first method was just mentioned above. I keep a printed page in my notebooks (and sometimes attached near the eyepiece) that includes my various eyepiece focal lengths, magnification and actual field. Using the actual field as a ruler works reasonably well for large objects, such as large open clusters, that take up a significant fraction of the field. Just estimate the percent of the entire field (or the radius) and multiply by the field diameter. I find that this is easier, though, with small to moderate apparent field eyepiece designs such as Plossls or Orthoscopics. Now, I'm using Ethos eyepieces with a 100° apparent field that require peering around to see the edge, and this method is less accurate.
A second technique that's probably rarely used among amateurs is to let the object drift through the field, either by placing it just off the east edge or just on the west edge, and time (using a stopwatch) the number of seconds to enter or leave the field. With a scientific calculator (using a little trig) the seconds can be easily converted into arc minutes (hey, I'm a math teacher ;-)
A third method uses nearby field stars and works well with galaxies and nebulae between say 1' and 5' in size. Often, besides my written notes, I make a rough sketch (I'm bad at accurate sketching) of the object and include some nearby field stars. Then I'll add a comment such as "extends 2/3 the distance between the two 10th mag stars just south". Later when I'm home at my computer, I'll look up the separation of these stars using a program such as Megastar or online with a program such as Aladin. Even this method sometimes fails, though, with compact planetaries and galaxies that are smaller than 1'.
The 4th method is to calibrate your eyepieces to estimate small sizes under 1'. How so? Well, I often start an observing session by taking a look at a few well known double stars that I can find instantly and observe them with the same eyepieces I often use for small galaxies. With my 18" scope, I often use 225x and 285x, and I'll quickly observe 2 or 3 doubles that I know the separations to calibrate my eyes. For example, in the summer/fall northern skies of California, I'll look at Albireo (35" separation), Polaris (18" separation) and Gamma Delphinus (10" separation). By doing this I have a pretty decent sense of these separations using those two eyepieces and feel comfortable making an estimate for a small planetary or galaxy as say 30" diameter. If the object is elongated roughly 2:1, then I log it as 30"x15". My experience is that at 285x, a galaxy that is just 30" or 40" diameter appears larger than most amateurs would probably guess, so it's easy to overestimate sizes.
Thanks for those tips Steve. More to add to the repertoire, especially for the small DSOs. I particularly like the sound of the double star method. I might have to revisit long-forgotten maths for the drift method. A useful mental challenge in itself!
Thanks, SteveG, for some interesting and useful techniques for visual observers.
Wow! As an amateur astronomer, I am always deeply impressed by people who "measure things and put numbers to them".
(a professional astronomer would probably adopt a serious and weighty and grave tone, intoning the phrase "it was a cogent quantitative analysis", very much in the tone and manner of a medieval doctor pompously reciting in Latin, but - in my view - "quantitative vs qualitative" is exclusive language that serves mainly to confirm the membership of a scientist in a secret elite of "those who know".)
I was having a look at some SMC objects last night and was musing on how slowly objects close to the pole move through the eyepiece, which prompted me to wonder about whether there is a need to correct for declination if using transit time to estimate angular size of a DSO and if so how this is done. Steve....?
On simple drawings and tiny object size estimation
First of all Hello SteveG and I think I know who you are ...
I am only now transcribing some field recordings of Abell Planetaries
and assorted Herschel 2 list objects and ran across a case where I
wish I had drawn a crude drawing (yet again). I was trying to describe in words the position of 5 stars in and around Abell 75 so that if one of them were the central star I could then say that it had been noted. I have no idea if one of them was it or not.
Well due to not having a drawing and perhaps poor DSS image back home
I for the life of me cannot figure out what the heck I was talking about.
The observation was from 3am on the 3rd day of a big star party (CalStar in California, USA) so perhaps fatigue caused the description to 'suffer' as well.
Some of my Australia trip from a year and a half ago were also rather difficult to follow. Ever try to verbally describe with some detail the area around the keyhole nebula? Or the whole Eta Car nebula for that matter. Difficult to do with words, very complex but amazing just the same and I hope I get back there again in a year or two.
Anyway, a little drawing sure would prove useful when the description takes more than 20 words or so.
I have heard SteveG in the past discuss the trick of mentioning size relative to nearby stars in the field for tiny objects and that was a nice tip to be sure.
Besides that great set of tips Steve mentions I'll add a tiny bit about one way to increase accuracy on length measurements I tend to use. I'll often bring an object to the edge of the field keeping in mind where I felt it's edge was when it was in the center. I bring it to the side of the view so it's main axis (if elongatted) is radial towards the center then a measurement that is a fraction of the half-field-of-view is noted. This method breaks down when the object is really small. I favor a 7mmNagler or 5mmNagler and the 7 gives about an 18' diameter of fov. So down to 1' is about where it breaks down in accuracy.
Another thing is I have stopped doing the math in my head on fov (too many 3am stupid math errors) and instead I now always note fraction of field of view in my field descriptions to recorder. Then I have a chart (got tired of calculator/head) and this chart is a spreadsheet with eyepieces along the left and across the top I write 1 2 3 ... 20 for the fraction (denominator) So for 7mm 1/8fov I later when transcribing say just that but use square braces and in those place the calculated value which for me I find 7 on the left and 8 on the top and drop down and get 2.21'. Of course before I got lazy I would run the math for 17.7'/8 but I find the spreadsheet printed on a paper at my desk is far more easy to lookup than fumbling with a calculator as I transcribe my recordings.
Anyway, I am sure it is the SteveG I am thinking of, rest assured that he knows basically all 'of the tricks' (or at least 10x more than I will every know).
Thanks,
Mark (Hint to SteveG: I am Marko)
Last edited by astrospotter; 19-11-2011 at 03:15 AM.
Reason: Adding a small tip on measuring object length
Thanks Mark, that's quite a handy way of estimating size. I tend to do something similar, but I can only feel confident with a couple of my eyepieces as I keep forgetting what the TFOV is with the others. a little table would be a very good idea and could sit in the cover of one of my books.
I laugh when I read of your difficulty in deciphering some of your recorded observations - I experience this quite often when trying to transcribe a few days later and wonder what on earth I was rabbiting on about.
I will share how I became able to see super faint fuzzies. It works for me but I can't say it will work for everyone.
What makes this even more amazing is that I suffer night blindness
For the many years I was a full-time Visual Observer (yes, I used to be one). I had 'Trained' my eyes.
Brains and eyes can be trained to know what to look for.
I achieved this by going to an object (or where I believed it should be) and looking, and looking,
and I kept looking.
Then I would walk away from the scope but never look up at any distant light or even the sky, but walk around looking down at the ground for about 2 - 3 minutes, then go back to the scope and keep looking.
Because I was determined to see those faint fuzzies that I saw in books I would do this several times, and eventually I would start to notice things.
Usually (but not always) by the 3rd look I could make out some detail in tiny super faint objects.
Then I would go look at another object (one that I knew well, like NGC 253 or 55 etc, but not a bright object) for about 5 minutes, than go back to the elusive faint fuzzy again and you would be amazed at how instantly you recognise the detail you saw before.
Look for a few minutes then do the walk again, then return to the scope and by looking for another few minutes you will start to see even MORE detail that you thought wasn't even possible with a super faint fuzzy!
If I found that I couldn't quite make out a particular detail I would attempt to sketch the object.
As an artistic person I tend to notice more detail this way.
I would stay on this object off and on all night and each time I went back to it I found it easier to recognise it and any detail in it.
The following night I would start with another object but go back to ones I have 'learnt' on the previous nights. The more I went back to others the more I saw in them.
I did this with many hundreds of super faint fuzzies and after years at it I could recognise then within seconds.
It's not a gift, or a trick.
It is training, and it takes practice, Lots of it.
The many long nights I spent doing this was enjoyable to me as tiny super faint fuzzies are my 'thing'
Even though I don't do visual any more, it pleases me when I do look through Eric's scope about every 2 or 3 months, or look through a scope at camp, and I can still recognise and 'see' detail in very faint fuzzies that many people only see as a very faint blob. It's like recognising an old friend. My eyes still remember what to look for.
Practice, practice and practice.
and then some practice
.
