object visability in a scope

[MrObvious]

I've got a 102mm mak (skywatcher) telescope, not top of the range to be sure, but better than I expected.
Articles I read indicate that some galaxies can be seen by instruments smaller than this. Yet even from a dark site I've only managed to once see a tiny smudge (a galaxy) that should have been visible with binoculars, according to one article and the software I was using.

The scope is adjusted correctly, its in a dark site, I found the stars around some of the galaxies that were to be observed, but no galaxy :evil:

I knew the scope wasn't meant for observing galaxies, it wasn't bought for that reason. When published articles claim visability in smaller instruments and I can't see any (apart from the one faint smudge) it gets very frustrating not knowing why.

The articles mention brightness and magnitude but how do these get to represent visability in an instrument? Surely there's a way to predict an objects visability in a given scope, I can't imagine being the first to have come against this problem.

[AZgazer]

I have had this frustration as well. I borrowed a 5" Mak 2 weeks ago when I was still searching for a scope to buy myself and I had a hard time with the Galaxies.

As it was explained to me, one of the main problems is most mag listings are not listed in visual magnitude. They are designed for research scopes, which are mainly computerized and are focused in bandwith specific zones.

One of the guys gave me the name of a mag chart that is listed in all visual magnitudes. I will see if I can get that list from him and post it for you. :)

[AZgazer]

Here is a pretty good link (http://www.astronomics.com/main/category.asp?catalog_name=Astronomics&category_nam e=V1X41SU50GJB8NX88JQB360067&Page=1) that will give you a better idea of what you will be able to see in your scope. Hope it helps, I am still waiting for that list for you as well.

[MrObvious]

Thanks for the reply, good articles there too.


Regarding binoculars on galaxies:
Respectable performance in 50mm to 77mm sizes, adequate in 42mm and below

And for cat scopes:
Dark skies and 7" aperture needed for best performance

From my experience a 4" (100mm) mak is not very respectable at all!

Interesting to know that the magnitude limits aren't listed in the visual band, this would make nebula's hard to predict but I thought galaxies emitted an even spectrum of light. Could be quite wrong here though.

I'm surprised that you are having trouble with a 5" Mak, they are advertised from reputable companies to be good on galaxies, glad I didn't cough up the difference to go to 5" for just that reason. At the time I was debating it but decided that I'll get another for just that purpose when the buget gets better.

Would greatly appreciate that visual magnitude listing, would save me a lot of frustration.

Do you know now the surface brightness is derived?

[Kaptain K]

Magnitude limits for stars are easy to predict. It is simply a function of aperature. The bigger the scope, the fainter the object you can see.

For diffuse objects, it gets a litlle tricky, due to the fact that the light is spread out over a larger area. For example, M33 is listed as 5th magnitude and therefore "should" be visible to the naked eye. From my dark-sky site, it is barely visible in 10x50's on exceptionally clear nights!

[AZgazer]

MrObvious I got the reply from my friend. What he has is an Excel Spread Sheet he compiled from NASA ASCII files. He is sending me the SS when he gets home from work today, so if you want to pm me your email address I can forward it to you in turn. He did affirm that it is visual mag's, not photographic, so that will help to some extent.

As the previous post noted, the problem with Galaxies and Nebulas are it's the sum of their brightness that is listed. M33 is terribely faint for me right now as it's on the horizon until later in the night when the lovely humidity takes over. In the 5" Mak it was almost invisible, it was dim enough that if you didn't know it was there you would have just cruised right by. :(

Might I suggest Astromart (http://www.astromart.com/) and see if you can't find a 6-8" Dob that is still highly portable, but will do alot better with even the brighter DSOs.

[aurora]

For diffuse objects, it gets a litlle tricky, due to the fact that the light is spread out over a larger area. For example, M33 is listed as 5th magnitude and therefore "should" be visible to the naked eye. From my dark-sky site, it is barely visible in 10x50's on exceptionally clear nights!

Kap'n is right, M33 is diffuse and has no bright visible central core (like the Andromeda Galaxy does) so it is very hard to find in a telescope even though it "should" be bright.

It's a lot bigger than you expect, which also makes it hard to discern.

Have you tried M81/M82 yet? They are pretty bright.

And you've already discovered that stuff is easier to find when it is overhead versus on the horizon.

[Charlie in Dayton]

It doesn't matter what you're looking at. It doesn't matter what you're looking through.

IT NEVER LOOKS LIKE THE PICTURES!

[Doe, John]

It doesn't matter what you're looking at. It doesn't matter what you're looking through.

IT NEVER LOOKS LIKE THE PICTURES! =D> Hee Hee, maybe you should point that out to Electric Ashalar in his "Cydonia Analysis" thread in the ATM forum

[Kaptain K]

It doesn't matter what you're looking at. It doesn't matter what you're looking through.

IT NEVER LOOKS LIKE THE PICTURES!
Amen! We don't call them "faint fuzzies" just for the aliteration! 8)

[AZgazer]

It doesn't matter what you're looking at. It doesn't matter what you're looking through.

IT NEVER LOOKS LIKE THE PICTURES!

I beg to differ. At our public viewing last weekend I pulled up the Lagoon Nebula for a couple and the guy used a Cool Pix to take a 2 second exposure through the EP and when I compared the Scope view to the Pic...

It looked EXACTLY like the picture.

:P :wink: :lol:

[MrObvious]

Thanks AZglazer.
PM'ed you my email address.

M33, ah yes, the first thing I tried to find, year later still haven't found it!
I am -35deg south though, so its pretty low on the horizon at the best of times.

M81/M82 :( Down south no chance.
Tried to find m83 "bright, easy in view finder" (yeh right!) the other night, I lined up the red dot pointer, confirmed on the laptop, and wow, there it is!!!!! Say to my friend have a look, hmmmm he can't see anything. I look again, nothing, huhhh.

Repeat the process thinking I may have bumped the scope, yep, wow there it is!!!!, Adam looks, nothing. I have another look and nothing.

Lesson is: red dot pointer leaves an image in the eye that looks like a round faint white spot in the eyepiece! :evil: :oops:

Hey, Charlie, not expecting it to like in the pictures, just not expecting it to look like the background either! :D

I'm realistic, not expecting anything in color or bright, not even expecting spirals etc. Just a fuzzy patch of faint white that I can identify as a fuzzy white patch would be fine. A fuzzy black patch on a black background just doesn't do it for me!

[aurora]

I'm jealous, from Melbourne your skies are a lot richer in deep space objects than our skies up north are.

I'd recommend getting O'Meara's book on the Caldwell objects. A lot of the Caldwells are southerly objects that Messier couldn't have seen from France.

[Kaptain K]

Cautionary note - Not everybody's eyes are equally sensitive.

I had the is point driven home to me, in no uncertain terms, when I was in college. Our school had a 12 inch f/15 refractor with a 4 inch f/10 guide/finder scope. Unfortunately, it was right in the midlle of town and the sky (through the scope) was sort of olive green. My room mate could easily see "faint fuzzies" through the finder that I could barely make out through the main scope!

[MrObvious]

Yeh, the skies down south are pretty rich :D

Never heard of Caldwell, I'll look that up, thanks.

Kaptain K, that could be bad news to many people, including me :(
I guess I should have started when I was younger. 12inch f/15 refractor, thats big!

I've heard that shorter focal lengths help, but at the same time I've heard others say it only helps for CCD's or film, being stuck with only one scope at f/13.5 I can't make any personal comparison.

Rain and clouds for the next few nights at least so no chance to try again.

Melbourne weather, cloudy one day, raining the next......

[jt-3d]

What you can see through a scope is not what APOD posts. Most objects are dim fuzzies. Sometimes I even have to wiggle the scope to see anything. What you have to do is look to the side. Then you can see something fuzzy. Case in point, the first time I saw M57. M57 is listed as mag 9 I think, anyway below the mag 8, which is my cutoff point due to light polution. I saw the little bugger though in my 24mm eyepiece (very cool), by looking off to the side. When I switched to the 10mm, which doesn't lose any light, I couldn't see it because there was no place to look off. It filled the whole eyepiece. Such are the vagarities of space watching.

[MrObvious]

I had a look at the list that AZgazer sent, thanks again for that!

The best candidate was NGC5128 listed at mag 7, turns out this was the one we tried to find one night and couldn't. :(

It was listed at 6.6 using the hallo northern sky program.

Might buy a good pair of bino's before I get another scope.

Any suggestions?

[AZgazer]

Apogee (http://www.apogeeinc.com/binos.html) is what I have now. 12 x 60 Astro-Vue and I like them alot.

[Charlie in Dayton]

Apogee (http://www.apogeeinc.com/binos.html) is what I have now. 12 x 60 Astro-Vue and I like them alot.

I have a pair too. How do you like those nebula filters?
Haven't had an adequate time to experiment yet, so I won't comment.

I highly recommend this little gizmo (http://www.helix-mfg.com/binoculars.htm) for binos that big -- scroll to the bottom to the 'bino platform'. A trip to the hardware store for sticks (I found a set of four, threaded to fit, 16" each, and added a rubber crutch tip) and you've got a neato monopod...

[AZgazer]

I have a pair too. How do you like those nebula filters? Haven't had an adequate time to experiment yet, so I won't comment.

I highly recommend this little gizmo (http://www.helix-mfg.com/binoculars.htm) for binos that big -- scroll to the bottom to the 'bino platform'. A trip to the hardware store for sticks (I found a set of four, threaded to fit, 16" each, and added a rubber crutch tip) and you've got a neato monopod...

I actually bought them on your recommendation. :wink: I wasn't 100% sure if I was remembering who told me about them, so I didn't want to name names and be wrong. :oops:

I like them alot. We had a run here of about a month where skies were really clear, but you still have humidity that kicks your butt and halo's you in. So I use them for mainly Milky Way observing after the scope dews over.

The Nebula filters are nice IMO, nothing I would rush out to pay alot more for. However, that doesn't mean I don't like them... They are a nice addition to the Binos, especially at the current price. If that makes any sense? :-? (I must point out that I have not been able to use them in decent dark skies either.)

Man I am going to get that Bino Mount. I have been trying to come up with something almost identical to that. I personally don't like the big tri-pod mount styles for binos. I want something more portable and comfortable to use.

[MrObvious]

Nice bino's, price is good too if you are in the states. Down here they are a lot more expensive. I think even if distributors get them at a cheap price they will pass the savings on to their bank accounts not the consumers :(

Will keep my eye on the prices though.

[jayvinton]

I too experience problems in finding and sighting objects that should be very visible from my dark site on the windward side of Oahu. I have a very modest 3" reflector that usually catches clusters and planets very well but begins to labor for galaxies.

I think it is all in the light gathering of the mirror. For instance, Andromeda does not appear as a disc, rather as a bright point with a small bright point (m33) I beleive, at it's supposed limit.

This is from a very dark, ocean side site. At my home in Honolulu, which is also fairly dark, I can see clusters in Scorpius, planets, and an odd smudge or two. I guess it is all in your ability to gather light, learn indirect viewing and the darkness of your site.