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m_j_lyons

Deep observing: Going on faith?

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I had a question for the group - for those that enjoy hunting faint fuzzies (those small/really faint fuzzies that show up on charts but are so seldom seen) how much validation do you need before you declare them "observed" during your session? I know that many really faint galaxies will look like stars except under extreme magnification...so do you go on faith and say that if the charts say it should be a galaxy then it must be a galaxy and not a star? (looks like a duck, sounds like a duck, it must be a duck) I know most of the time I've been out "going deep" I rarely see anything where those tiny faint galaxies should be.

I keep telling my wife...it may not be much to look at in the daytime but size DOES matter when the sun goes down.

:shocked:

Happy (deep sky) hunting.

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I assume that if we see something it's there .The starting point is to look for things in the fov which are non stellar. There's a few tricks to help, such as tapping the ota to see if the fuzzy moves ,averted

vision, working through the focus to see if anything suddenly appears.

Best of all is ensuring you eye is dark adapted , relaxed and not affected by any light, including light bouncing off walls. The Moon being up is a big no no.

It's no use squinting or staring hard, you'll just strain and end up seeing less.

I 've heard of folk hyperventilating to get more supplies to the brain and eyes. There's no way that I'm heavy breathing on the patio.

There is a lot of " willing it to appear", really dependant on how much time and patience you have. There is also a tremendous satisfaction when you've succeeded.

I struggle on the edge of town. Visits to dark sites are just a joy, this year it's Skye in the autumn.

Just keep at it, clear skies,

Nick.

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When I spot what appears to be a faint object I'm trying top find, I note it as a "possible" in my log entry - an object that needs more tries on nights with better observing conditions (I note each observing session sky conditions). Some hard objects take several tries over several years to finally rate as a "detected" object. Keeping a observing log is a must for hard objects and saves a lot of frustration from repeating the try again under less favorable conditions.

So I guess my real answer is..the final "yes, I found it", after several tries.

Of course, some I never find after many years of trying :huh:

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That is a great question.

I do place heavy reliance on Cartes du Ciel. My scope can see down to Mag. 12.2 at home (at best) which is a very similar level of brightness to my CdC limit. This leads to my FOV being virtually identical to any detailed map, something which does give me some confidence about what I am looking at.

With regards to DSOs, it is a case of not leaving the eyepiece until something comes through. At the moment, most objects I attempt are not at the very limit of my scope / sky's capability and so my success rate is probably quite high. On odd occasions, I have noticed other nebulous areas to the one I was searching for; most notably NGC 4657 when looking for the Hockey Stick galaxy. NGC 4656 proved too feint but I did notice a very condensed fuzz which I am virtually certain was a busy patch where the galaxies are interacting.

The usual tricks I get up to when something isn't immediately obvious are;

  1. Averted vision (needed often)
  2. Moving the fine adjusters so that eyes can pick up movement of feinter objects (a more effective version of the tip above IMO but used slightly less often)
  3. Swapping eyes
  4. Shielding the eyepiece very closely with hands to blank out even more background light
  5. Breaking away from the eyepiece regularly (I find it can be a strain after viewing something for too long, ie. a minute or two)
  6. Cursing that I have just wasted a half an hour and not added to my tally! :grin:

The dimmest galaxy I have seen (by magnitude) is 11.3. The brighter the object's magnitude becomes, the easier that lower surface brightness objects come through - due to SB being an average brightness per arc second rather than a maximum rating.

I am getting ever closer to exhausting the DSO target list and am resigned to the fact that from now on the failure rate is going to increase..... until I finally convince my wife that I need a bigger scope!

I would say that my nemesis is NGC 5053, the globular cluster close to M53. I have tried to find it at least a half dozen times and always failed. I do think you learn how to see over time (using techniques above and patience). I have looked right through many galaxies in the past (best examples are M101 and M74) but definitely see them more clearly than I used to.

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I agree with DKD

I spent last night out with my 10". I was tired and didn't expect to be out long so left the 16" indoors. It was blowing a gale and so I sheltered at the SE end of the house. It was a great night observing galaxies. Magnitude 11 is not much of a problem for me with the 10". Now, the difference is between locating and observing. I will find the galaxies in the 10" that I wouldn't in the 6". With the 16" I will see detail. With experience, I have found that I will recognise a galaxy from most other things (have mixed up some galaxies with faint globs for instance, i.e. the Intergalactic Wanderer. Now, I'm reasonably confident I can identify something as a galaxy. It might not be anything other than a real fuzz, but it is definitely non stellar. This has come with experience, definitely. For instance, once or twice last night I found a target (I love you, Wixey!) but noticed a fuzz nearby, went to the Skysafari and confirmed there were other, fainter galaxies there. Very pleasing. I suppose what I'm saying is assuming you're not asking way too much for your scope/sky ability, you will know its a galaxy.

BTW, I was nearly punch drunk spending time in Leo, U Major, Coma and Virgo, they were leaping out at me. Absolutely wonderful night, unexpected. Wish I'd wheeled out the big'un!!!

Barry

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The very faintest DSOs can take a considerable time to come into view - I've often spent half an hour or more trying to confirm an object that I know must be in the field of view but can't see. Often it's a case of getting a brief suspected glimpse, then waiting until you can get another glimpse (something that must depend on a number of factors - slight variations in transparency plus changes in visual sensitivity). If I can glimpse the same object repeatedly in the same place, and I'm sure it's not a star, then I log it as a definite observation. If I only get one glimpse then it goes down as a "possible" (and I don't count it as an observed object).

It's very easy to be fooled by faint stars, central brightening of the field of view, and pure wishful thinking. Everyone has to decide for themself what counts as a definite observation.

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This is a difficult issue (not for bright ones, of course). The faintest galaxy I have spotted through my 8" was a mag 13.2 one, which did not appear stellar, but as a smudge, only seen in averted vision. I counted it, because

1) I could move away, and find it again in the same spot several times

2) I could determine its position with respect to two other galaxies, and could verify this afterwards on images taken by big scopes.

The latter stage is important. I do not like to look at images of faint fuzzies before observing, as it may lead to wishful thinking.

I find the smaller planetaries are much more readily confused with stars (as can quasars, of course). In the case of planetaries, there are two reliable ways to tell them from stars: by switching in a UHC or O-III filter, which dim stars, but leave the planetary quite bright (I use a filter-switch diagonal to do this quickly), or by taking a spectrum (a simple grating might work, I would like to try this). Quasars are harder. Here you have to rely on position, and accurate charts.

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I'm very wary of "wishful observing". If I can't do some of the things others have already suggested, such as look away and find the target again, or keep it in view for an acceptable period of time, or pick it out relative to surrounding stars and confirm against charts, then I assume I'm seeing it because I want to rather than because it's actually visible.

James

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VERY good question.

I tend to sketch what I see at the eyepiece and then go back in an compare the view to CDC. If it does not match up then it does not get logged as observed.

I will only include a galaxy if I am sure I have seen it. If there is doubt in my mind I try a few more times on better nights but then after a few goes leave it as not observed.

To be honest I now have a pretty good idea which galaxies will be possible based on their NGC pic and books like Ted Armardas 3000 objects book etc. However the lower elevation ones often stump me.

Mark

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Im glad Im not the only one who has struggled with M101. Took several months of cursing and disappointment, and then one night there it was. Need to go back soon and see if its easier the second time around.

Dave.

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Intriguing question and very useful answers. This is pretty subjective and depends a great deal on the scientific integrity of the individual. I try not to go "Woo Hoo, I've seen Andromeda!" at the slightest hint of fuzziness, but its hard not to indulge a little in the face all the delays and frustrations involved with stargazing.

I claim to have seen Andromeda because I can detect the galactic core in my scope, but I can't claim to have observed it well :grin:

M33 is another matter, as I spent quite a while finding the location, confirming the local asterisms using pictures off the web, but just couldn't pick up anything in the gap. Out of all honesty, I haven't seen it. A borderline case for me is NGC3077. I went after this during a session with M81 and M82, and knew where it is located and thought there was a fuzziness there but only with averted vision just barely. I count this one.........kind of!

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All my messiers were found via Telrad, Stellarium ect, confirmation was simple stick in a DSLR and take a 30 second Image, faint fuzzies then become brighter fuzzies....and the image would also have local stars to check on the Star maps....this will work on Dobs as your not imagine for wall posters but verification so a bit of star trailing doesn't matter...

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If I'm happy in my own mind that I've seen a particular target then that does it for me.

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The very faintest DSOs can take a considerable time to come into view - I've often spent half an hour or more trying to confirm an object that I know must be in the field of view but can't see. Often it's a case of getting a brief suspected glimpse, then waiting until you can get another glimpse (something that must depend on a number of factors - slight variations in transparency plus changes in visual sensitivity). If I can glimpse the same object repeatedly in the same place, and I'm sure it's not a star, then I log it as a definite observation. If I only get one glimpse then it goes down as a "possible" (and I don't count it as an observed object).

It's very easy to be fooled by faint stars, central brightening of the field of view, and pure wishful thinking. Everyone has to decide for themself what counts as a definite observation.

I think this is my way of observing as well. I have a few objects in the Herschel 400 list that I think I might have seen but cannot be sure so they are still not confirmed. These are NGC 3621 (a bit low at -32.49) and NGC 3912 which is close to NGC3900 which I have seen.

Mark

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I have no go-to, and find my fuzzies by star hopping from Uranometria 2000.

I Usually only put it down as observed if I can go away and look at something else and then come back and find it again.

I also need to be sure that there are no stars of similar mag that should be in that location, but in the main I like to be sure that

what I am looking at is not a star so will spend a lot of time using AV and other skills to tease out any non stalla detail before

letting myself feel the warm smugness that comes (sadly) with the quarry found.

In the future I want to get an intelliscope DOB so that I can check pointing precision more accurately.

Mick IOW

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I find if its attained on wishful thinking then it probably didnt count and furthermore if it's that difficult to see then it probably wouldnt be vey excting to look at anyway.

I'm usually content enough that I managed to find the right spot., I never expect much from galaxies in my back garden other than faint smudges. Only M81 and M82 have showed any real detail to me. This is why I hunt globs and open clusters - they give up their detail far more easily.

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Yep, I put a post on ages ago about selecting achievable targets for your situation. A GOTO will find endless objects, I got into the Virgo/ Coma group and just made a note of the really vivid ones and now have a list to go back to for more detailed viewing and sketching,

Nick

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