Trouble Seeing

[dougum3882]

I live in Miami and am having trouble seeing galaxies with my new XT8. At first I thought it was just my inexperience, but as I get better at navigating the sky, I am starting to think it is just because there is so much light pollution. Can anyone tell me if I should be able to see at least some of the brightest galaxies or do I need to wait until I get away from the city to see the galaxies? I have seen the orion nebula, which according to Starry Night is higher magnitude than Andromeda, but then again it was higher in the sky and further from the city lights which are closer to the horizon.

 

[tfwthom]

Try these from SAC in Phoenix. They can be seen in just about any scope from just about any city. <br /><br />http://www.saguaroastro.org/content/Objects-Viewable-From-Metro-Phoenix-For-SAC-Award.htm<br /><br />After that try some of their other lists.....awards are for their club members.<br /><br />http://www.saguaroastro.org/content/Things-to-view.htm <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>

 

[dougum3882]

Thanks for the reply. I actually have tried looking for some of the things on the first list, including the Andromeda Galaxy, which I figured should be one of the easiest to see. I tried using binoculars and my XT8 with a low magnitude eye piece and was unsuccessful both times. The only one I have seen is M42. When I found M42, I did the same thing I do when I am trying to find Saturn or Mars. But for some reason, I can't find any of the other galaxies or nebulas. I will search for more objects in the list, but any other suggestions or advice?

 

[dougum3882]

That's disappointing. Before I bought the telescope, I read some reviews that said it should be good for seeing galaxies, but you are the second person to tell me that 8" isn't big enough. For future reference (like when I graduate and get a real job and have money), what size scope should I look into which will allow me to see galaxies?

 

[bbrock]

Don't be dissapointed. Remember, light from galaxies have been traveling through space for millions of years. The light will be quite diffused. On a clear night with no light pollution, you can actually see the core of Andromeda with your naked eye with averted vision. The best view of Andromeda I have ever had is with my 15x70 binoculars. My 10" telescope shows a bright fuzzy patch through the eye piece. All galaxies seen through eye pieces will be dim and fuzzy at best. Most will require averted vision to even detect that something is there. To resolve detail requires an extremely large aperture telescope. How large depends on the galaxy and the transparancey of the sky. <br /><br />The listed magnitude for galaxies is not the same as for stars. The magnitude brightness is the integrated brightness over the entire extended galactic object. The larger the galaxy, the lower it's listed magnitude, but the dimmer it will actually appear. The brightest galaxies to view are the small compact galaxies with moderate low magnitude listing. --- Confusing. I'm not sure I even said this correctly. <br /><br />The best way around this is with astrophotography and timed exposure. Then it doesn't matter how large the telescope aperture is. You can take your 8" reflector and make it perform better then a 30" reflector visually with astrophotography. Just increase the exposure time. <br /><br />In astrophotography, the name of the game is not aperture, but focal ratio. I can afford a 4" refractor with a fast forcal ratio. I can't afford a 24" Obsession Dobsonian. <br /><br />Clear Skies<br />Bill

 

[bobw]

I am glad that I am not the only one who is galactically challenged with an 8". BBrock is right. Using averted vision really helps make them show up better for me; the ones I can find, anyway <img src="/images/icons/smile.gif" /> <br /><br />http://vegas.astronomynv.org/Tutorials/avertedvision.htm <div class="Discussion_UserSignature"> </div>

 

[tfwthom]

This one I'll have to correct you on.....that's a myth.<br /><br />See this post http://uplink.space.com/showthreaded.php?Cat=&Board=askastronomer&Number=393352&Search=true&Forum=askastronomer&Words=Four%20Infamous%20Telescope%20Myths&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=allposts&Main=393352<br /><br />"Large telescopes are more impaired by light pollution than small ones." <br /><br />This claim has no basis whatsoever in truth, but it's pretty easy to see how it arose. The "logic" behind this myth is that since large telescopes gather more light than small ones, they must also collect more unwanted light (light pollution). This is true, but the real issue is image contrast. The brightness ratio between a galaxy like M31 (say) and the background sky is the same regardless of telescope size. All telescopes are equally impaired by light pollution compared to what they would show under a dark sky. A large telescope's advantages — superior light grasp and resolution — are the same under bright skies and dark ones. <div class="Discussion_UserSignature"> <font size="1" color="#3366ff">www.siriuslookers.org</font> </div>

 

[dougum3882]

Thanks to everyone for their replies, but I am a little confused. Under ideal seeing conditions, is an 8" apeture sufficient to be able to recognize a galaxy when I see one or is it too small, regardless of light pollution? I know I won't see amazing detail or anything, but I had expected (and hoped) to at least be able to see the general outline and shape of the galaxy and be able to see the difference between M101, M102, and M105. It sounds like some are saying that my problem is an 8" won't see faint objects like galaxies in an area with lots of light pollution and others are saying that 8" is just too small to really be able to recognize galaxies period. I am just deciding if my objective is to see galaxies, if I should sacrifice a weekend of studying to go somewhere dark (I'm about halfway done with my PhD in math, so every weekend of study counts) or if I shouldn't be in a hurry because I won't find what I am looking for anyway, at least not with the scope I have now.<br /><br />Sorry to anyone who is getting tired of me beating this issue, but I just want to make sure I have my info straight.

 

[bbrock]

Your 8" reflector is more then adequate to see the faint fuzzy properties of galaxies. The problem is your expectations. My 10" reflector will do little better then your 8" reflector on galaxies. <br /><br />Your 8" reflector is higher quality optics then the equipment used by many famous astronomers who first observed the galaxies. Charles Messier would have <br />been astonished. He called the galaxies nebulas with no stars. Through the 1900's, a 6" reflector was the top of the line telescope. An 8" reflector and greater aperture has not been available to amature astronomers until the late 1900s, I think. <br /><br />I have never seen the outline of a galaxy through an eye piece. Usually I see the brightest part of the center core, and then only as a faint fuzzy patch of the night sky. It wasn't until I began imaging that I was able to make out spiral arms, with timed exposure of 10 minutes or more. Looking through an eye piece is real time, with virtually no exposure time. <br /><br />Perhaps you need to change your thinking on this anyway. It is not what you are looking at that is important, but rather, what you are seeing. The closest galaxy ( Andromeda ) is 2.5 million light years away. Most galaxies are well beyond 30 million light years away. Messier 51 ( Wirlpool Galaxy ) is 31 million light years. All will look like fuzzy light spots in the night sky. <br />What you are seeing is ancient history on a galactic scale. Long before humans existed, let alone looked at stars. <br /><br />Clear Skies<br />Bill