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Galaxy’s and nebula’s

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Biggest one that you can afford / carry / use ...

More important than the size of telescope is dark sky. This is why people often say that tank full of gas is much more important than the size of the telescope. If you can drive away to remote dark location, then even something like 4"-5" will show you all the things you listed.

Take 12" in white zone and you'll be disappointed with views.

Another important thing is to learn how to observe - it is a skill and longer you observe - easier it is to see things.

Eyepiece don't need to be expensive - nice set of BST StarGuiders will be all you really need. Even stock eyepieces that come with telescope will show you these targets nicely under good conditions.

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16 hours ago, Joe beaumont said:

Hi all, what is the best size telescope in inches to see galaxy’s and nebula like andromeda, Orion, whirlpool etc and what is the best eyepieces to use to see these 

thank you 

Of the three that you mention explicitly:
- Andromeda (nebula) M31 can just about be seen with the unaided eye in dark locations. It is certainly visible in small telescopes, though it is a bit of a fuzzy blob, and being very large, it can actually be quite hard to tell that you're seeing it, unless you're using a low magnification/wide field (e.g. decent binoculars)
- Orion (I assume you mean the "Great Nebula", M42). Again, certainly accessible with a small telescope, though light polluted skies may prevent this. A good filter ('OIII' or 'UHC' type) will enhance the contrast.
- Whirlpool, aka M51, is the hardest of the three. It is still a largeish DSO but the "surface brightness" (which describes the amount of light being emitted per unit area of the object) is not so good. Darker skies will definitely improve your chances.

Newcomers are often inspired by, but also misled by, the amazing photos of these objects in books and websites. Bear in mind that these are:
- photos, not actual views through an eyepiece. The camera can capture a lot more light over time than the eye can catch in an instant, and can show colour that the eye will not see, because of the low light levels (DSOs seen visually in a modest telescope are usually grey)
- often taken using larger telescopes than you will be using, with state-of-the-art optics
- sometimes taken from space (Hubble etc.), without the distortions of the earth's atmosphere to contend with
- often taken with filters, may show light that the human eye just can't see at all, and then given false colours afterwards (yes, it's not just influencers on Instagram who cheat)
- usually benefit from a lot of intensive computer manipulation that merges multiple images, intelligently removes the poor ones and combines the rest to give a "best average" picture

If you've not already seen it, you might like to have a read of this item, which describes how objects appear through an eyepiece in an amateur telescope.
It specifically covers the three you mentioned, and shows pictures comparing the stunning press photos with the views that an amateur is likely to see with reasonable skies.


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As @vlaiv remarked above, dark skies are crucially important and cannot be overestimated. You can try and slug it out under light pollution with sheer aperture and a big scope, depending on your situation, but that's an expensive way to get mediocre views. I have a 20" dob, a 12" dob and 15x70 binoculars.

I can see some of the fainter stuff, M51, Flame Nebula, etc from home under town LP (20.3 SQM is about as dark as it gets) with the 20" on a good night when the local lights are down. Andromeda and M42 are both fairly easy under moderate town LP with pretty much any sort of telescope or binoculars, but it's often only a mere shadow of what it looks like under rural skies. You'll want to shield yourself from any direct light from neighbours. Under brighter urban/city lights, I can't say, but that must be difficult going on impossible.

Under fairly dark rural skies here in NE Scotland, I can use the 15x70s to see my best widefield views some of the larger faint objects - the entire E&W Veil and the Rosette last night for example (using UHC or Nebustar filters). The list goes on and on. Pretty astonishing for a pair of relatively small binoculars - using both eyes equates to a 1.4x to 1.8x larger aperture scope with a single eyepiece by most accounts, depending on who you ask.

If you have a car to get you to darker skies, a 10" dobsonian or larger offers the most light-gathering aperture for DSOs and the 10" model is a very popular size. Any size decent scope under darker conditions will be a sheer pleasure to use. Try the light pollution map to find a darker place near you.

If you have the desire, the money, the storage space and the back to lift one, get the largest dobsonian you can within reason, but the size, weight and cost all go up exponentially in a hurry. My 20" fits easily in a small van, but even disassembled, I'd have to take the passenger seats out of my car to fit it in there. And add to that a small ladder on top! It takes a lot of motivation to take one out to dark sites and be prepared for the weather to be uncooperative at times after all the effort. My 300p flextube (a 12" dob) is much more forgiving to use but still gives great views. 

If you don't have a car, perhaps a pair of binoculars like 15x70s, 20x80s, 22x85s or 20 or 25x100s that accepts filters will let you use public transport to get to those elusive darker skies. Filters help tremendously for nebulae, no filters are the way to go for galaxies. I use my 15x70s handheld, or lay on a camping mat for things near the zenith. I rarely use a tripod with them, but they get rather heavy in a hurry. A monopod is another highly portable option. The downside to binoculars is the fixed magnification if you want a closer look at something like M57 for example, it's quite small in most binoculars.

A good 80-120mm refractor might be nice as well. I've never used one so can't comment, but they seem popular for many.  I wouldn't mind owning one someday ;)

Good luck there!



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I was looking at globular clusters in Auriga, and Orion Nebula last night at 11.30 with 8 inch dob class 6 Bortle sky.

Decent views but the nebula appeared blue- grey only.

The globulars I was looking for are classed as easy targets, but I still found them hard to locate.

So dark site, dark adapting, scope cooling should not be over looked.

Doesn’t matter what size scope if you can’t find what your looking for. I used my new Rigel finder for the first time, it was very useful.

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Often repeated however, an 8" dobsonian with a finder such as mentioned above a rigel Quikfinder, a copy of Turn Left at Orion through Amazon, Stellarium app on your devices. Telescope is just the start unfortunately, a few decent eyepieces will be required and then perhaps a nebulae filter or two. As above again, from home presently clusters in Auriga, the Pleiades, Andromeda are possible. Dark skies make an impressionable improvement on everything, particularly galaxies and nebulae, which are often invisible within urban skies. Therefore when covid restrictions ease, look out to join a regional group i.e. via social media or established society. 

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