December Challenge Object (OC) - M46

iceman (Mike) · #1 07-12-2005, 10:33 AM

Read all about this object at the December Observing Challenge page.

Post your observation reports and sketches here.

DSO images go in the DSO imaging forum.

dhumpie · #2 07-12-2005, 05:33 PM

This is a very nice "rich" cluster that shows up brilliantly in small wide field instruments with extra wide field eyepieces. It is juxtaposed with M47 which has brighter members but is overall not as pretty to my eyes (I like that stardust feel of M46 in a wide field ep). Plus it has the added "punch" of planetary nebula NGC 2438 which is quite easy to detect even in smallish scopes. This planetary looks like a rather pale and smaller version of M57, the ring nebula as it appears as a ring as well. Best seen with a UHC type filter (for the planetary). Here is my sketch of NGC 2438 and some of M46.

http://www.geocities.com/dhumpie/dastro/2438_m46neg.jpg

Darren

ving (David) · #3 10-12-2005, 04:31 PM

an easy find that shows as a smudge in the finder in reasonable seeing and no moon... alas my seeing was no that great and there was half a moon out. oh well...

it looks like i need to spend more time on this tho as i didnt see the PN imbedded, maybe when the moon goes huh?
i could resolve heaps of stars tho in the 15mm and even more with the higher quality 10.5mm to about 9-10 mag. i didnt stay long tho shifting up to the brighter m47 which was of much more interest to me as one of the brighter stars in the centre is a double with a seperation of about 3" i am guessing (i am no good at judging distances like this

)

must go back...

dhumpie · #4 12-12-2005, 06:41 PM

David the planetary nebula is not that obvious if you did not know it was there in the cluster. If you have a UHC type filter, this will make the planetary "pop" out from the starry background. I have had this effect even in my small Orion 80ST.

Darren

ving (David) · #5 12-12-2005, 09:13 PM

no uhc, might try my broadband

thanks darren

dhumpie · #6 13-12-2005, 03:35 PM

A broadband might help a little although you probably won't get that "popping out of the starry space" effect. Oh and by the way I do have a used UHC filter up for grabs if you are interested

Darren

ving (David) · #7 13-12-2005, 03:51 PM

lol, not at the moment darren

Dobman (Simon) · #8 31-12-2005, 06:12 PM

Went out last night to try & find m41,M50, M46, M47 and M78,& M93. My best views from my backyard are to the N & Ne so these object are nicely placed for me. Did pretty well, found m78, then m41 & m50. Ive just got a new s5000 8.8 UW and its absolutely brilliant for looking at O.C's, really wide field puts the clusters into context in the sky. Next was M46 & M47. Wasn't aware of the PN but thought I could see some sort of nebulosity. So that makes it the 1st PN I've seen

.I'll have to go out and have another look now that i know its there.
While I was looking at m46 &47 I thought I could see another fairly dim small open cluster in the same field. Is there another one there or was it just a random grouping? Any ideas? Didn't get to m93, clouds came in

I'm new to this but one thing I have found very useful is to plan my observing, rather than just going out and roving all over the sky. I think you learn more about the constellations and where things are this way .How do others go about there observing sessions?
Off to Bridgenorth tomorrow nite for a bit of dark sky with the other launcestonians.
Clear skies everyone
Simon

astro_south (Andrew) · #9 31-12-2005, 08:51 PM

nice work and a good haul for the night Simon

.

There is an open cluster near M47 identified as NGC 2423 - not sure if this is the one you saw!

When you get out to your dark sky site be sure to check out the planetary nebula in M46 at high power and you should be able to notice its annular (circle) appearence. Your 12" dob should show the planetary nebula as clear as a bell.

When it comes to observing I have found I usually highlight one or two new objects I want to find and observe (more if I am going to be out for most of the night) and if multiple I try to make them in different parts of the sky. I usually return frequently to the highlights of the sky throughout the observing session - objects that positions are burnt into my memory (revisiting old favourites if you like). Sometimes I will pick an area of the sky such as a constellation and while holding the Cambridge Star Atlas in one hand I just wander from one DSO to the next. Most of my observing sessions also involve sliding in the 31mm Nagler into the focuser and just touring an area to see what I can find. You are totally right about having some sort of plan, but I wouldn't let it rule your observing or make the plan too extravagant. You can always find targets on the fly with some maps if you want to "fill in time".

Hope you have clear skies at your dark sky site.

Sausageman (Mike Boggan) · #10 11-01-2006, 05:30 PM

Is there a January challenge coming up soon?
Up here in SE Qld, the forecast is for clear skies this weekend.
I might even borrow a starlight xpress and give it a go.

Mike

astro_south (Andrew) · #11 11-01-2006, 06:32 PM

Mike

the objects slated are currently :

GX - NGC 1566
OC - NGC 346
GC - NGC 1851
NB - M42/M43
PN - NGC 246
DB - Theta Orionis (the Trap)

We have all been a bit slack in getting organised - except for Rob (xrekcor) who has already done his part. Due to the busy time of year, perhaps we should make these a combined Jan-Feb list. I haven't chatted with the others about this but perhaps there is room to extend the lists to be active for two months. That cuts down on the work for those involved and also gives more opportunity for getting the chance to observe / sketch / and photograph the objects.

AstroJunk (Jonathan) · #12 24-01-2006, 01:19 AM

I had a great view of M46 tonight - always my favorite of that part of the sky. This was the first time I have looked at the cluster in anything larger than 8.75", so I was gobsmacked to see how bright NGC 2438 was in the 20". A lovely ring at 166x with a noticable star in the centre (but NOT the central star if you get my drift - that's way to faint for a night like tonight). I tried to find the magnitude of the said star - any ideas? It seemed a lot fainter than the other stars in the cluster - more mag 12 to me. I know the actual centre star is about 16.

mickoking · #13 28-01-2006, 10:42 PM

M46 and NGC 2438

A fainter and smaller open cluster than M47 but just as attractive. This object has a slight condensation with many outliners and there is a lot of stars of similar brightness approx mv 9-10. In the north part of the cluster there is a small but conspic planetery nebula (NGC 2438). With an OIII filter the planetery shows more detail. The Planetery is slightly elongated E-W and it's brighest at North.

200mm Dob, 26 Feb 2000

I will check it out again tonight, see if the Planetery neb is as easy in the 120mm refractor

mickoking · #14 29-01-2006, 02:32 PM

Quote:

Originally Posted by mickoking

M46 and NGC 2438

A fainter and smaller open cluster than M47 but just as attractive. This object has a slight condensation with many outliners and there is a lot of stars of similar brightness approx mv 9-10. In the north part of the cluster there is a small but conspic planetery nebula (NGC 2438). With an OIII filter the planetery shows more detail. The Planetery is slightly elongated E-W and it's brighest at North.

200mm Dob, 26 Feb 2000

I will check it out again tonight, see if the Planetery neb is as easy in the 120mm refractor

Using the 120mm refractor last night the planetery NGC 2438 is not particually obvious. It showed up easily with the OIII using the 20mm SV eyepiece. The general appearence of the cluster is similar to the view with the 200mm Dob.

TJD (Trevor) · #15 09-01-2009, 01:06 AM

M 46 NGC 2437 is a vast range of stars 300 million years old. They range from 8th to 10 mag and are 5000 light years away 30 light years in diameter and are one of the most beautiful open clusters in the sky i have seen so far.

Smirnoff · #16 09-01-2009, 01:08 AM

I've made a sketch of NGC 2437 at 400x in my 10" dob, I might post it tomorrow if anyone's interested.

AstroJunk (Jonathan) · #17 09-01-2009, 01:12 AM

Quote:

Originally Posted by Smirnoff

I've made a sketch of NGC 2437 at 400x in my 10" dob, I might post it tomorrow if anyone's interested.

I am

Smirnoff · #18 09-01-2009, 01:14 AM

^^ kewl! I'll post it tomorrow

Gargoyle_Steve (Steve) · #19 09-01-2009, 05:52 AM

I independantly "discovered" this cluster and it's planetary nebula (now part of the Steve Catalog as SD33

) during the April 2008 Barambah Dark Sky Camp, and it instantly became a favourite object in my observing schedule.

Shortly after this time I used some of my access time on the GRAS (Global Rent A Scope) network capturing some R-G-B-L images of it.

One of these days I may eventually get motivated again to try and figure how to properly combine these various 20Mb images into one full colour composite (I had a gutful of my lack of success with combining these back then to be honest, I never went back to it. I have several large files of several various objects sitting on a storage drive going nowhere).

If I ever manage to finish the M46 project (and the result is any good) I'll try to remember to post it here.

Smirnoff · #20 09-01-2009, 11:43 AM

Here's my sketch of NGC 2438. Scope was 10" dob, magnification 416x with UHC filter.