How far can i see?

[DJVege]

Hey guys!

You know magnitudes? And how each star/planet is given a magnitude that can range from negative to positive? Well, how do I know how far i can see...to what magnitude with my scope is viewing possible?

+5? +7?? :shrug:

My scope is a MN56 5"!

Thanks.

[Blue Skies]

You don't see distance, you see brightness! (which is what you're asking, no?) Remember, the closest star to us, Proxima Centauri, is difficult to see even in a telescope, but the Andromeda Galaxy, 2.2 million light years away can be seen with the naked eye!

You have a 5" which means you should theoretically be able to see down to +13.0 Whether you can or not depends on the conditions of the night and the quality of your optics, so don't be surprised if you can visually only see down to +12.

And then there's the little problem of surface brightness when observing galaxies and nebulae and other diffuse objects - they might be listed as bright but if they are spread out (diffuse) with low surface brightness you will probably struggle to see those things too.

[DJVege]

Thanks Blue Skies. Yeah, sorry, was talking about brightness. :)

Thanks for that. I was just wondering if I'd be able to see Neptune or Uranus...I know it won't be a great image, but just wondering if I'd be able to make it out. Finding it will be fun! :)

[Blue Skies]

Ah, well then, you should have just asked... Uranus definitely, should be able to see it as a very small disc, that is it will be star like but not quite a star - you'll see what I mean! And you should be able to see a bit of colour in it, the pale aqua blue, much like planetary nebs.

Neptune - you will get it but probably not the colour of it in a scope that small. In a larger scope the deep blue does come through a bit, depends on how good your colour perception is.

[ballaratdragons]

Theoretically, a telescope can see forever! But our eyes and cameras are the limiting factor. As objects get fainter, it's harder to see them. But they are there.

Your limiting Magnitude doesn't only depend on your scope. It depends on Light pollution, Moon glow, seeing, transparency, quality of EP's, etc etc.
So the question has a broad answer :)

[DJVege]

Thanks guys! Appreciate the info. I'm lucky because where I live, it's fairly away from light pollution (except for our front yard timer lights!! Grrr). And I can't use the backyard because we have some renting "Plovers" nesting there. They get quite cranky if you even enter the backyard!! Dunno why, they aren't paying squat to live there! :)

I'll see how I go this weekend finding Uranus and Neptune and report back. Hopefully I'll figure out how to use this TouCam effectively by then.

Thanks again!

[NQLD_Newby]

Hi there DJVege,

I have a 4.5" scope and I can see easily down to 9.5 mag. This was with the standard eye pieces that came with my scope which in my case were not very good quality. I just recently purchased two good quality eye pieces. I am waiting for the moon to go away so that I can try them out and see if I can see any fainter than that. I have already noted a huge difference in what I am seeing (pin point stars in the backround where ever I look that were not visable before).

So what I am saying is you have a 5" scope which doesn't seem much bigger, but it will actually catch quite a bit more light than mine, so if you have reasonably dark skys as you say you will probably be surprised.

As Blue Ski's says though, sometimes magnitude alone is not really an indication of whether you can see it or not. Surface area has a lot to do with it also.

For instance NGC 5128 is a galaxy, near omega centuri, it is listed in my software as being mag7. When i look at it I can just make out a very faint glo, so faint that you almost wonder if you have found it at all. The only reason you know is that when you move the scope the faint glo moves with the other stars etc. Anyway I can see m57 the Ring nebula quite clearly, even with the moon up, and it is listed at mag9. the difference is, that m57 is small and the light is concentrated in that small area, NGC5128 is a galaxy and although the amount of light emitted is more, it is spread out a lot further and therefore appears fainter to the eye.

Moral of this story, as I have found with several objects, is you will never know until you try each object. As Ken has said you have to gauge seeing, transparency etc also, so just because you cannot see it on one night, doesn't mean you will never see it, if the seeing is better on another night you may see it.

Please remember that I am just a beginner, so this advise comes from my experience with my scope and someone with more knowledge may like to correct some of the explanations I have given. However because our scopes are similar in size I thought this info may help.

[Blue Skies]

All that sounds pretty good to me, NQLD_Newby :thumbsup:

[felix]

i only just noticed the importance of the moon in shining too much light in the sky as emphasised by ballaratdragons and NQLD_newby..

i live in a quite densely populated part of the city.. so i guess i hav little hope in seeing much with my telescope (which i hav yet to figure out how to use..) Besides from the moon, i think the general surrounding environment would be very important on whether your eyes could adjust to see the galaxies and stars.. i remember once when in the forest, away from civilisation, the sky was filled with beauties.. back in the city, i could barely point out 5 objects in the sky.

just some thoughts :lol:

[CoombellKid]

Uranus @ mag 5.73 is a naked eye object from a dark site, however (besides
the current moon phase) it is located just NW of Phi Aquarii @ mag 4.21
which will probably wash it out for naked eye. but should be in the same FOV
med/high power ep. Neptune is a lil harder to locate so try a high power on
it to bring out the lil more of it's disc appearance. When I first tried to find
Neptune years ago, I searched for months before some one suggested a
higher power and bingo there it was... and there was me jumping around the
yard with glee!!! Both take on a pale blue kind of appearance and as above
are non stella compared to surounding stars, higher magnification here sorts
the gas gaint from it's stella suroundings.

Oh yeah I believe the most distant odject man can see with the naked eye
is M31 @ 2.9 million lightyears. The most distant object I can see in my
8" is quasar 3C 273 @ 2+ billion light years

regards,CS

[DJVege]

Cheers Rex! Appreciate the info.

Felix, yeah, when I got my scope, i took it out and the moon was FULL! LoL! Never really appreciate just how bright that thing can be!!!

Thanks Rob C! I can't wait to try and find them! Might get the ol' scope at tonight, actually.

[CoombellKid]

If you do, have a look at Jupiter with Vesta close. I've attached a chart for
9pm tonight.

regards,CS

[DJVege]

Oh, cool...I've never seen an asteroid before. (Had to look up just what "Vesta" was. :whistle:

[DJVege]

No idea if I was looking at Vesta or not, and the moon is too bright for me to find Uranus or Neptune. Also, I have no idea where to start to find them! :) I did however get the TouCam workin!! Got a few vids of Jupiter and the 4 moons. Blurry, moving vids...collimation was out a bit, but you could still make out some colour and lines etc... Loved it! :)

[NQLD_Newby]

Well done Djvege, and congrats on your vids. I have attached a PDF file that you can print out to help you locate them. The configuration is shown for 8pm and is for Townsville. You being in Brissy shouldn't be all that different so this should help you out. For me the moon rises at around 9pm tonight so you should have an hour or so to look before it becomes a huge problem. Just in case you have never used these type of charts before, this chart is designed for you to be holding it up with the word east at the bottom, when you are looking east.

Hope this helps and good luck.

Hmmmm file too big, not sure how to compress a PDF?????

There you go, I zipped it and it worked :) Happy hunting

[DJVege]

Thanks Rex! Appreciate it!

I'm sure I'll find it next weekend at Barambah!! :) Tonight...is all about POLAR ALIGNMENT! :scared:

[Ingo]

Good luck on the first try there in the south :thumbsup: :P