Jan 2007 M42/43

[MartinB]

OK so November's targets might not have been that inspiring although Andrew's report on Auriga's open clusters is well worth a read http://stargazerslounge.co.uk/index.php?topic=8036.msg91928#msg91928

however for January we have the big daddy of DSO's. No problems locating, lots of detail even with the most humble of little scopes. So what can you see? How well can you make out the little star cluster at the core of M42? How much of the nebulosity can you see? Can you make out M43 distinctly.

As usual, write down all that you observe giving details of the conditions and the equipment you were using. Please don't be shy!

[FLO]

Good choice

It'll be interesting to see how many stars can be counted in the Trapezium and how much nebulosity is visible. A good one also for experimenting with filters.

[Greg]

Good one Martin,

Steve, Please remind me to use the OIII filter......I don't normally do filters, now I have this in my box I need reminding please

[The Warthog]

Still waiting to get my scope outside in this rotten weather.

[The Warthog]

Well, I got outside and looked at M42 tonight. Can't really say I saw M43, but I have to admit I forgot to look for it. Did see the Running Man right side up for the first time. I was using the refractor. At about 83x the Nebula showed some structure, and I could see all four stars of the trapezium with excellent separation and sharpness, and some apparent colour differentiation, as the brightest of the stars appeared more orange than the other three, although I believe these are all supposed to be blue-white stars. I tried it at 200x, the limit for this scope, and found it a little smeary, making me wonder if I had accidentally breathed on the ep, however lightly. At -8, that's not a good idea. I put in the 8mm (125x) ep, and then added my UHC filter. The filter made the nebula just an eye-popper, but made it harder to see all the stars in the trapezium. The only colour I can see in the nebula is blue. Some hints of structure appear at all the powers I tried.

[MartinB]

Thanks for the clear and detailed report WH. The first and only one.

OK I am holding open January's target for a few more days. Please send in your reports!

[Andrew*]

Sorry, I must pay more attention to try and contribute. Although I must say it's been a bad month for me. The only half good night was totally washed out by moonlight!

Andrew

[Andrew]

This report is from a couple of nights ago (14th Feb). The main target for the evening was M42. I hadn’t really had much of a chance to look at it since getting my new scope (12” Newtonian) and thought I’d better take the opportunity of a rare clear night before it slips away for another year. Conditions were reasonable for my site: Limiting magnitude of approx 5; seeing not great (magnifications >175 a little shaky).

The dominant feature of the nebula is the wedge-shaped core (4' x 4'), centred on the trapezium. The boundaries of this extremely bright region are very sharp on the west and south sides, pretty distinct along the edge of the fishmouth embayment and perhaps a little more diffuse to the north. Reduced nebulosity in the hole around the trapezium was very clear. To the west a small bright patch is adjacent to the core and curves away to the south for a short distance. With direct vision this patch appeared to merge with the core, while with averted vision the two areas were separated by a region of markedly lower nebulosity. At high power (x159) the bright core of nebulosity was a mass of fine detail (wispy, cloud-like structures), while faint fingers of brightness extending into the fishmouth were apparent at the inner end of the embayment. Wings of nebulosity extending to the southeast and northwest gave the nebula a maximum visible diameter of about 25-30’. The former wing was the more distinct, particularly along the edge closest to the centre of the nebula. Interestingly, the sharp boundary of this wing also stands out clearly on photographs. M43 was very clear and approximately circular although with faint extensions to the southwest. Large regions of faint nebulosity were clear to the south and west of M42's core and behind the wing extending to the northwest. Judging the extent of these areas was tricky because of the low brightness gradient away from the core. Views with both UHC and OIII filters were dimmer but with greatly enhanced nebulosity (more in terms of the level of detail visible than the apparent extent). Of the two filters the OIII improved the views by most.

[MartinB]

Great report thanks Andrew and very interesting to read about the view through a 12" scope.

[FLO]

Nice one Andrew, interesting to hear the comparison between UHC-S and OIII