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Photographs for use in the field

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#1 rinalmj

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Posted 03 April 2013 - 02:01 PM

I've been wanting to start using photographs while observing as a means for (hopefully) being able to detect more detail. I'm looking for a website with images that are comparable to what would be seen at the eyepiece. Does anyone know of something like this?

Thanks

#2 BillFerris

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Posted 03 April 2013 - 03:38 PM

If you can find a copy, the Vickers "CCD Atlas: North" is very useful in the field as a visual observing aid.

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#3 skyquest25

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Posted 03 April 2013 - 04:04 PM

Not a website but a great book is "Visual Astronomers Photographic guide to the Deepsky" by Stefan Rumistrzewicz. (Springer publication)

#4 GlennLeDrew

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Posted 03 April 2013 - 05:46 PM

To be in line with what's visible to the eye, photos should be acquired with a basically green or bluish-green filter that, with the camera, results in a spectral band pass reasonably similar to that if the dark-adapted eye. Otherwise nebulae in particular will be overly emphasized in the red H-alpha emission, and reflection nebulae somewhat too much so when strongly bluish.

The much less strongly hued continuum from star clusters and galaxies is much less affected by a non-matching band pass, and so any images not too strongly color biased will be reasonably faithful.

The foregoing concerns color. But contrast in the image can be important. Best if not too strongly stretched, otherwise subtle contrasts become greatly exaggerated, and brighter parts of the object can become saturated, or 'burned out'.

#5 Tony Flanders

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Posted 04 April 2013 - 05:31 AM

I've been wanting to start using photographs while observing as a means for (hopefully) being able to detect more detail. I'm looking for a website with images that are comparable to what would be seen at the eyepiece.


I don't think that's possible; cameras and human eyes see things very differently. Sketches do a much better job of capturing what you actually see through an eyepiece, but even they inevitably fall far short.

I do find photos of galaxies to be a useful guide to visual observing. However, you have to accept the fact that most of what's shown in the photo won't actually be visible, and learn to guess what will and what won't.

#6 rinalmj

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Posted 04 April 2013 - 07:22 AM

Tony - I agree mostly. However I have seen some short-exposure photos taken with small scopes that look very similar to the view at the eyepiece through my 12" scope. As you mentioned, I mostly have galaxies in mind. Ideally, I would have photographs that show slightly more than what I'd actually be able to see at the eyepiece. I wasn't thinking about sketches, but that might work as well. Thanks.

#7 skyquest25

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Posted 04 April 2013 - 03:42 PM

That's exactly what the book does that I listed. Short exposures and some are done in sketch where a photo wouldn't be sufficient or realistic.

#8 skyquest25

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Posted 04 April 2013 - 03:49 PM

A quote " The images you’ll find in this book are taken using a Watec 120n video camera. This camera is able to give ‘live’ views of DSOs when placed in an eyepiece and seemed the most suitable camera to use in order to give an accurate representation of what the suburban observer may actually see. All the images are, therefore, single frames and completely unprocessed. The only exception is where an odd label has been added here and there to distinguish between several objects in the same field of view. Also included are some sketches, which have been scanned onto computer and the colors merely inverted to give a white-on-black view – i.e., no touching up! Where possible, views of the object are shown through two different-sized telescopes – either through a 72mm aperture refractor or an 11 inch SCT "

Here's a sample page of the Whirlpool.

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#9 MessierScott

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Posted 04 April 2013 - 04:47 PM

I use software called Guide by Project Pluto while observing. If I need to see an actual image of the area, I just overlay a 30' x 30' POSS image on the field.






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