Sunday, March 8, 2009

Good deepsky conditions, even with moon!

The sky looks very transparent, but unfortunately the moon is already quite bright. Without moon I guess we would have more than 5,5 nelm. I estimate it now to be 5,0 but deteriorating at the end of the session due to upcoming clouds.

Date: March 2, 2009
Location: Boutersem
Equipment: Obsession 18”
Eyepieces: 24mm; 16mm, Powermate 2,5x
Nelm: 5.0
Seeing: moderate
Time 19:15Hr UT to 22Hr15 UT

Comet Lulin was the first observed object. Same vision as on Saturday, meaning I could not glimpse the tail of the comet. At 84x the faint halo is around 15’ big, the coma is 3’ with a nucleus.

The usual program of Herschel II is next topic:

NGC 5879 – galaxy in Draco
At 84x I can see it as an elongated spot of 3’x1’, without core. It’s not that easy to see (visible 30% of time) because it’s still quite low on the sky. At 211x I can see it almost continuously. (Something went wrong with the planning as I have seen this object on 14/2/2009)

NGC 6015 – galaxy in Draco
At 124x this galaxy is a large oval of 5’x3’ which is just visible with averted vision. No structure to see. There is a star close to SE edge (does not touch the galaxy). Higher power does not provide more details.

NGC 6340 – galaxy in Draco
A round spot of 2’ with a faint core is visible at 124x. The view is nice at 211x: the galaxy, of which the core is now clearly visible, is located close to a double star. The 2 IC galaxies in the neighborhood (IC 1251 and 1254) are suspected at 316x.

NGC 4236 – galaxy in Draco
This is a huge galaxy of 23’ in Draco. I tried this one already a few times, but today, I’ve got it without any doubt. At 124x I can see an extremely faint, large spot of 15’, of which the northern part seems to be brighter. At lower power, 84x and with a deepsky filter the objects is easier to spot. I can see 2 somewhat brighter patches (northern edge and southern edge).

NGC 2610 – planetary in Hydra

Last time I saw only a stellar object. Today I can see clearly the planetary nebula at 211x as a disc of 30”. It’s a faint disc, almost round with a star at the northern edge. A bright orange star is located north. UHC filter provides much better contrast. The edges are sharp and the southern part is fainter than the northern one. This is the nicest object of the evening.

NGC 2525 – galaxy in Puppis
I tried NGC 2525 already several times, but today I finally got it. This is an extremely difficult object. I can only see it at 211x when the scope is moving a bit. It’s around 3’ big with an undetermined shape. Once located it became visible even when the view is not moving. This object requires “heavy” averted vision and extreme concentration.

I missed NGC 2283, a galaxy in Canis Major, as it was already to low on the sky. Bad planning!

NGC 2805 – galaxy in Uma
This is a galaxy which I was not certain I had seen it (logged as Perception of object is very questionable). But today I could see it at 211x with averted vision. It’s a spot of 2’ of undefined shape. The 2 other galaxies NGC 2620 and NGC 2814 were also visible.

NGC 3145 – galaxy in Hydra
Again a difficult target. At 124x I can see it a few times as an oval of 2’. It’s located a slightly north of a line made by a bright orange star and a fainter star. Does not become easier at 211x. The bright orange star which is quite disturbing.

All Herschel II objects of Uma have been observed by now so I need to start hunting in a new constellation. Leo is the most appropriate one at this time. It’s not yet culmulating but it’s high enough to look for the remaining 18 HII objects.

NGC 3162 – galaxy in Leo
NGC 3162 is a round spot of 2’ with a faint core (124x). It is continuously visible with averted vision. A faint star is located close to the eastern edge.

NGC 3177 – galaxy in Leo
NGC 3177 is a small bright circular spot of 1’. It contains a bright core. The galaxy, visible with direct vision, is located in an area with a lot of bright stars.

NGC 3274 – galaxy in Leo
This is a round or oval galaxy (it’s not clear) of 1,5’, located in the middle of a triangle of stars. It has no core. A double star is located 7’ south.

NGC 3301 and NGC 3287 – galaxy in Leo
NGC 3301 is an oval of 2’ with a bright centre and a stellar core. It become larger up to 3’ with 211x. Nice! NGC 3287 is located 30’ SE of NGC 3301. It’s an oval of 2’x1’ without core. Also this one is located close to a double star, of which the primary is white and the faint secondary blue. Nice combination!

NGC 3338 and NGC 3357 – galaxy in Leo
NGC 3338 is an oval spot of 3’x2’ without core (124x). NGC 3357, located towards NE, is a round spot visible 20% of time at 211x. It contains no core. Arp 291 was not visible, although I tried at all possible powers. I think the sky conditions were already deteriorating at that moment.

NGC 3507 and NGC 3501 – galaxy in Leo
NGC 3507 is a round spot (211x). A star is located at NE edge. A core is visible at 211x. NGC 3501 is difficult. I could see it only twice at 124x and estimated a size of 3’. The view changes completely at 211x as now I can see a nice but faint needle of 3’.

I ended this session with M81, M82 and M51, of which I could see only 2 spots. Clearly sky conditions are not good anymore. In fact, half and hour later, the sky was completely covered by clouds.

Anyway, this was a great evening, with one comet, lots of galaxies and one planetary nebula (and I forgot, a few double stars)

Herschell II: 220 seen.

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