Hi Guys

What is the ideal sized eyepiece for viewing galaxies?
Would it be the 32?
Naturally I think the lower the mag the worse? I am correct

Thanks

Well i'm not an expert on this subject but it all depends on the quality and how much you are willing to pay. A wide angle like the 32 will let you see a bigger wider sky but the size will be smaller, the lower numbers will increase the size of the subject but with a smaller viewing scale. But most important is the size of the scope being used. Now for viewing galaxies you would see a patch of cloud with very little details it would not be like viewing it in a camera plus it will be most likely all grey due to the eye not sensitive to capture the colors that's my 2 cents worth. Any other questions feel free to ask this group it is really good in helping out for those who wants to know.

From NYC you don't have much hope of seeing galaxies very well. Drive out a hundred miles then you can. The eyepiece is good for open star clusters from your location however.

By using high power on small objects like galaxies you can cut through some of the light pollution. Doesn't work for big showpiece galaxies like M31, 33 and 51 however. They need a very dark site. The first two need scopes capable of a far wider field of view than yours can deliver -- that is binoculars will be far better. The 32 from well outside of NYC will start to show you M51 however. Most other galaxies will work better at higher powers, 150 or more from your light polluted skies. Well out of the light bomb of NYC then lower powers may help. You need the high power to cut light pollution's intensity, still leaving enough light to see the galaxy. Not easy from your location no matter what scope you use.

Most galaxies are small, under 20' of arc so low power, even in a dark site isn't all that useful. With my 10" f/8 I often use extreme powers of over 700x to cut out city light pollution and I was only dealing with a town of 200,000 people, not the 10 million in the NYC area. But I was looking at galaxies beyond the grasp of a 6" even in dark skies. Still it illustrates the principle. When dealing with light pollution sometimes high power is better than low even for faint fuzzies. The opposite may be true from a dark site. You have to go with the skies you have.

Your scope works at f/12 and has a small secondary so low power, wide field isn't in its design. It's a planetary scope well suited for NYC use. Not a low power wide field scope.

A 32mm plossl would give about the widest field of view your scope is capable of and would be a bit over 50x. For a 2.67mm exit pupil (32/12). That's really medium power for your scope's aperture. A 5-7mm exit pupil is low power (not achievable with your scope without severely restricting the fully illuminated field of view which negates the advantages of low power. 4 to 2mm medium and smaller than that down to 0.5mm exit pupil is high power. Divide the focal length of the eyepiece by your f ratio to get this value. Your scope is restricted to eyepieces between about 32mm at the low end to 6mm at the high power end. Nearly any eyepiece in that range will work with your scope. Image quality will not improve much with expensive designs. Going longer than 32mm would result in no added field of view. It just doesn't fit down the baffle tube of the scope nor is it reflected back to you by the secondary. It's just too small. This is done to enhance its planetary design. All scopes make compromises, this is one made in this design.

So yes it will work with your scope but unless you get well out of NYC won't show you much when looking at galaxies. They are faint from dark sky sites.

At f/12 you don't need to spring for expensive eyepiece designs made for the much shorter focal lengths of Dobs and other fast scopes. The 32 will serve you far better with open star clusters than galaxies from your location. So it is a worthwhile addition.

Rick

Hi Rick

I am not in the actual bright city part, I am in Staten Island which is darker than the actual city, there is a lot of dark streets and woods around here. Even though the city is only about 8 miles away, will this give me an advantage or will I still be horribly light polluted

Thanks

You can tell how light polluted the sky is by looking up at night. For example, I often use the stars of the little dipper, the dimmest of which is about magnitude 4.5. Can you see that? If so, then you have only moderate light pollution.

If you can't see the little dipper at all, then you have a lot of light pollution.

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Per The Sky the stars in the bowl of the little dipper, when its hanging down from the pole starting from the south west corner and going around counter clockwise when facing north are 2.06, 3.0, 4.95 and 4.29 magnitude. So you have a pretty good scale in one magnitude jumps. Eyesight has a lot to do with it however. I've seen two people vary by over a magnitude when standing side by side looking at the same sky.

You are still well within the light bomb of NYC making faint fuzzies a real challenge. High power will help greatly for small ones.

Even with a 32mm eyepiece, the longest that really works in your scope M31 would require three fields of view so would be just a rather featureless glow in the eyepiece. You will see it get brighter at the center. From well out of the area you will see faint dust lanes.

A bright small galaxy like M82 at 100x or so would be a much better target for that scope in that location. Use binoculars on M31.

Rick

Thanks

Yes I can see the little dipper up there. I am also going to purchase an Oxygen III filter to help me with my light pollution. I will definatley be out with the scope the minute NYC gets a black out, even though a blackout is really no fun, I would however get to see some stars that I usually cant see

OIII helps most in dark skies but will help some under light pollution. I find it works best at a 4mm exit pupil in my skies which is about impossible on your scope. Still there should be some gain at 2.6mm.

It will help with planetary nebula, some are good targets for your scope like M57 and M27. M98 might be very difficult however even with the filter.

The OIII filter only makes galaxies and stars far dimmer however. It will help M42 greatly at larger exit pupil size. Not sure about it at your size. Let me know.

Rick

Hi Rick
I will let you know how it works out
We have this one place here where the ny astronomy society meets to stargaze, I will ask them what they are seeing from the location which is near a boat marina and is very dark.
I will need to see where the galaxies and nebulas you mention are and I will try and see if I can see anything. The Oxygen III will be a nice piece to add to my case, even if it allows me to see only a few spots up there. I have so many gadgets I want to add to my hobby and will start shopping

Thanks

So how do you like the scope. I have not been on in a few days so i probably have missed alot of posts. Any pictures yet ?

An OIII filter is not the best first choice for the majority of nebulae visible to most amateurs. A narrowband filter such as a Lumicon UHC or an Orion UltraBlock is generally more useful.

http://www.prairieastronomyclub.org/filters.htm

http://pages.sbcglobal.net/raycash/filters.htm

Keep in mind that LPR and nebula filters do not, in general, work very well on objects other than nebulae. The best DSO filter is a dark sky.

As far as an eyepiece for observing galaxies is concerned, the vast majority of galaxies are quite small in apparent size and are best seen at relatively small exit pupils, say between 1.5 and 2.5mm. It is, however, a very good idea to have a long focal length eyepiece that provides the maximum true field of view for your particular telescope to locate objects and to view the handful of DSOs that are large in apparent size.

Dave Mitsky

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I'm about to buy an OIII filter, I have the great Baeder Moon and Sky filter which does a lot, and I have an ancient (early 80's) "nebula filter" that does quite well, but its not a 2 inch.

For the nebula that the OIII filter works on, its magnificent, the Veil Nebula is amazing!

As far as eyepiece size, depends on the telescope size. A 30mm on a 10 inch is much more of a light gatherer than on a 6 inch.

Yes, the OIII filter works extremely well on the Veil Nebula complex. It is also better, in general, on planetary nebulae.

I'm not sure what you mean by that last sentence but the aperture of a telescope, and not eyepiece focal length or barrel diameter, determines light grasp or light gathering capability. However, a 30mm eyepiece will produce a "brighter" image in a 10 inch telescope, if it happens to yield a larger exit pupil in the 10 inch.

Exit Pupil = Aperture/Magnification = Aperture/(Telescope Focal Length/Eyepiece Focal Length)

Dave Mitsky

__________________
Chance favors the prepared mind.
De gustibus non est disputandum.
Never attribute to malice that which can be adequately explained by stupidity.

Thanks for your help

I have not been able to use my scope at all, the weather is not cooperating with me at all. The clouds are all over the sky and the snow and rain do not stop. The only night the clouds were not up there, it was clear as a bell and the temp was around 7 degrees and my fingers kinda froze to my eyepiece so I had to pack it up

Please Wish me clear skies so I can use the new scope. I havent even been posting too much as I have nothing to show or write because of this weather