How many large DSO's are they

[bomberbaz]

So how many objects are they large enough to fill more than 1 degree, Pleiades, Orion Nebula, M31 and Praesepe but how many others.

Reason i ask is i am looking at buying a wide field EP and I have to consider its usefulness. So just trying to figure how many will benefit from such an EP. The EP's being considered range in TFOV from 1.36 to 1.51.

It wont be just for the larger DSO messier etc, I do love sometime just viewing into areas where stars are quite dense against a dark sky and losing myself in its beauty. And it would be very good for Moon viewing too so it isnt restricted to large DSO's.

TIA

Steve

[michael.h.f.wilkinson]

I would add the Veil, North America Nebula and Pelican, M33, the Rosette, the LMC and SMC, the California Nebula, the Flaming Star Nebula, the Double Cluster, the Hyades, and various Melotte clusters (alpha Persei association, etc) to that list. Apart from individual DSOs there are groups of DSOs that look good in wide-field: Markarian's Chain, and the Coma-Virgo region as a whole, M106 and attendant galaxies.

My 31T5 is always the first one in the scope. Very often it stays put for a long time before anything else in inserted in its place.

[pete_l]

Not many Messiers are large. I did a little work on this a while back and came up with this chart

Although there's more to astronomy than Messier objects (there's the Moon, too!). I was primarily interested in what size is sensible for an imaging chip - and the FoV it gave. I concluded that there wasn't much "good stuff" that needed a huge FoV, and than most small chips (and in a visual world: short F/Ls) would be good enough for the vast majority of DSOs.

[bomberbaz]

I would add the Veil, North America Nebula and Pelican, M33, the Rosette, the LMC and SMC, the California Nebula, the Flaming Star Nebula, the Double Cluster, the Hyades, and various Melotte clusters (alpha Persei association, etc) to that list. Apart from individual DSOs there are groups of DSOs that look good in wide-field: Markarian's Chain, and the Coma-Virgo region as a whole, M106 and attendant galaxies.

My 31T5 is always the first one in the scope. Very often it stays put for a long time before anything else in inserted in its place.

Thankyou for the insight Michael, just shows you nothing beats experience. Think Turn left at Orion is on my shopping list. I need to read more and start to learn the skies better when they are murky Its just there is so much of it

Steve

[Moonshane]

Personally I take the view that it's cheaper to buy a new scope than to buy another eyepiece that covers extremely wide fields. E.g. I get 1.1 degrees from my 18" dob and 26mm Nagler (used cost maybe £300+). If I want a wide field low power view I would tend to buy a 6" f5 newt for about £100 used (giving 2.8 degrees) or even (god forbid) an 80mm short frac for maybe £75 used (giving 5.4 degrees) or even a cheap pair of 8x40 bins (giving maybe 6-7 degrees) for perhaps £100-150 new.

As it happens, more often than not, I do none of the above and just look through my 9x50mm finder at very wide things. That said, I recently bought a 12" f4 for the above reasons which just fits in M44 and M45 quite nicely at it gives 1.8 degrees of scrummy field. I'll be converting this to a suitcase dob for my family camping trips this year.

[swamp thing]

Don't forget the Milky Way itself and the Sagittarius star cloud (M24). Both real treasures of the night sky.

[Stargazer_00]

Top advice on using a second scope for ultra wide. This is what I use the explorer 150p for basically. Other than grab and go for nights I want to stand rather than sit, or when its too windy for a dob. The 150p shows really good wide field views.

My widest EP right now is the 24mm which in the 150p shows 2.5 degrees of sky. I've never felt the need yet to get more. The aquisition of this scope as my grab and go recently has stunted my desire to get a 30mm UWA. I picked the scope up (from family granted) for £75 for the OTA. Compared to the price os a 30mm UWA in my dob which will cost £220 and show 2 degrees of sky. Well it's obvious isnt it? I also really enjoy using the smaller newt alot more than the ST120 which was my RFT and now lives in it's original box in the loft!

[michael.h.f.wilkinson]

I also have a second scope for wide field (and third (solar), and fourth (ST80 for guiding and solar modding) by now). This does not replace the wide field EPs in my opinion. The C8 with e.g. and Aero 40 at 1.33 deg FOV is way better at a range of objects than the 80mm with a 12mm T4 at 2.1 deg FOV. However, some real wide-field objects can really only be viewed with the 80mm I have (with its 5.3 deg FOV it magnificent on the North America Nebula and the Veil).

[Stargazer_00]

Just went out in the soup (high clouds washed in LP, still some bright stars visible)

I put the 24mm in my 150p to see what 2.5 degrees shows. I had all 3 main stars of orions belt in the same view. The outer stars were right on the field stop.

An alternative measure is the sword. I put the top bright star of the sword central in the EP and the bottomost set of stars in the sword were inside the field stop with a little bit of room to go.

You have to ask yourself how often you're going to use a bigger field of view than that really.

[bomberbaz]

Actually I do have a small although somewhat cheap skywatcher refractor I bought at F5 80mm (400) and this gives me a great TFOV using a 25mm at 3.75. However the views are not brilliant with quite a lot of colouration on planets. So although it might be useful here and there, its not the answer.

Shane, if another dob turned up in my house then I would be single again, mind you then I could buy anything I wanted for wide field viewing, hmmmm

No stop it, a new EP is the answer I am afriad, hehe

[Moonshane]

well, you cannot change the laws of nature. scopes breed......

I understand what you say about a short frac (I don't like fracs personally anyway) but surely if you want an ultrawide field, some colour on planets is irrelevant? a 6" f5 newt would show good planetary and wide views.

don't get me wrong, I have a number of eyepieces too (and they are easier to get through the door on the QT - not that I do that - we have guilt free spends in our house) but feel that unless you have very dark skies a really wide field quickly gets tiresome and I for one yearn for more detail. personally, 1-2 degrees is plenty I feel but each to their own - there's space for us all in this excellent hobby.

[John]

I agree that the number of DSO's that spill over a 1 degree field is limited but a number of them are, in my opinion, the best DSO sights in the sky.

More than one scope is the ideal but I've found that it's much easier to make a faster scope produce high powers than it is to make a slow scope show an expansive field of view so I've nothing faster than F/7.5 these days

[Moonshane]

slower John, slower

[John]

slower John, slower

Oh, er, yep - slower than F/7.5.

Must type s l o w e r too !

[bomberbaz]

Great info everyone and a bit of a chuckle c/o John hehe .

Stilll a little nearer a decision on the new ep but not there yet. Cost vs quality argument as often is.

[ronin]

Any use:

Wiki List

List 2

Second one has size in minutes.

List 3

Third one has picture of object and the size.

[bomberbaz]

Oh great find Ronin. Just had a quick look through and there is some great info in there. I will bookmark all these and do some planning on my cloudy nights in. Many thanks Steve