Features in some selected diffuse nebulae

Diffuse nebulae are interesting to observe, because their appearance, size and brightness varies a lot from case to case. My impression is that the brightest ones (like M42) and the most difficult ones (Zeta Orionis nebula with Horsehead) get most attention in forums like this. However, there are many moderately easy nebulae out there, and I would like to sharpen your appetite by giving you a small task.

Here comes a list of diffuse nebulae, nebular features and I want you to check them out and give scores according to how difficult/easy they are to see visually. This list is by no means exhaustive, but contains some objects that are well placed in the evening sky at this time of the year. Those of you who have not tried to observe many of these objects may have a surprise or two, even pleasant ones.

Well, here is the list.

1: NGC2024 (Flaming star nebula near Zeta Orionis)
2: NGC1579 in Perseus
3: IC410 in Auriga
4: Dark lane in NGC2024
5: Dark channels (bok globules) in Rosette nebula
6: NGC2174 in Orion (near Eta Geminorum).
7: Obscuring cloud in western part of NGC2174.
8: IC443 (Supernova remant near Eta Geminorum)
9: NGC1788 (In Orion, north of Beta Eridani)
10: NGC2245 in Ophiuchus (west of Christmas tree cluster)

Use the following codes for your scores:

1: Obvious without filter
2: Difficult without filter(maybe averted vistion)
3: Obvious with narrowband filter (O-III, UHC)
4: Difficult with filter
5: Not seen (location verified)
6: Never tried/didn't find object

Good luck!

Inge S

Obviously diffuse nebula don't appeal so much to the participants of this forum. I'll give my comments to the listed objects myself, and still encourage you to use the next opportunity to have a look at least some of them.

1: NGC2024. (Near Zeta Orionis). My score: 1.
The nebula can be overlooked unless the bright star is put outside the field of view.
2: NGC1579 in Perseus. My score: 1.
A pretty bright and large object showing some detail. A narrowband filter will kill it, since it is a reflection nebula.
3: IC410 in Auriga. My score: 3.
Maybe a hint of it can be detected without a filter, but the O-III makes an enormous difference. The nebula is large and is shaped as a letter "C". The cluster involved can hardly be considered a show object.
4: Dark lane in NGC2024. My score: 1.
Just keep Zeta Orionis outside the field. I prefer not using a filter for this nebula.
5: Dark channels in Rosette nebula. My score: 4.
To see these delicate features an O-III filter is neeeded and the sky must be very dark and clear. Still the bok globules of the Rosette are much easier to see than the Horsehead nebula.
6: NGC2174 in Orion. My score: 1.
For some strange reason this object is almost unknown to many observers. I have to admit that I observed it for the first time myself just a year or two ago. In fact it is one of the most interesting emission nebulae of the northern winter sky. Already without a filter it appears as an obvious aura around the coarse cluster, NGC2175. With the O-III it is bright, large and with an interesting shape. In my opinion it is superior to NGC281, the "Pacman" nebula in Cassiopeia.
7. Obscuring cloud in western part of NGC2174. My score: 3.
Although invisible without a filter it is pretty striking with the filter in place.
8: IC443 (SNR near Eta Geminorum). My score: 4.
This is a difficult object. It is completely invisible without a filter, and even with the filter only the brightest part of it can be seen - a rather small segment of the arc visible in photographs.
9: NGC1788 in Orion. My score: 1
Another pretty large and moderately bright nebula. In the same league as 1579 in Perseus.
10: NGC2245 in Ophiuchus. My score: 1.
This object resembles NGC2261, Hubble's variable nebula. It is a bit fainter and has a more delicate (silky) appearance than 2261.

There are many more diffuse nebulae along the milky way. Quite a few of them are small fuzzies best suited for big scopes, but there are some exceptions that are more likely to be detected with a small scope with a wide field of view than with a big one.

Inge S

Thanks for taking the time to make your report, Inge! Your observations confirmed for me that some of these objects are just plain hard to see, and encouraged me to try again on some that will hopefully reveal themselves now that I know what to look for. Very helpful!

Off the top of my head, I believe I've observed all of these objects with the exception of the Rosette's Bok globules. I can't offer any details, however, at this time.

BTW, NGC 2245 is located in Monoceros.

Dave Mitsky