Obs Report, 22 October 2008

[Rob_K]

Had a good (if cold!) time last night at our group’s monthly get-together!

Time: 9pm-10:30pm, Wed 22 Oct 08 (UT+11)
Location: Porepunkah airstrip, Porepunkah, Vic
Telescope: Tasco 4.5" f8 reflector on Alt-Az mount
EP: 21mm Celestron X-Cel
Transparency: Excellent
Seeing: Poor – fair, wind blowing

M31 Andromeda Galaxy in Andromeda, mag 3.5 – always special to look at, though it never gets high in my northern sky! Despite the abundance of binoculars on the field, I didn’t actually get a peek at it through them, the best view IMO. Through the telescope, the large bright core showed up well, and the faint extensions were visible, extending for more than two FOVs. Its companion galaxies NGC221 & 205 were visible, the former small, bright and round, the latter a dim, elongated diffuse blob that really required averted vision. This galaxy blows me away so much that I always seem to forget to check out the nearby Triangulum Pinwheel galaxy M33 at mag 5.7 – never seen it!!

M27 Dumbbell Nebula in Vulpecula, mag 7.3 – best view I’ve ever had of it, very strong & bright with dumbbell shape clearly showing. Called the others over & they were impressed (or said they were, LOL! )

NGC7293, Helix Nebula in Aquarius, mag 7.3 – very large planetary, but strangely the view was pretty ordinary despite it being very high. My eyes couldn’t seem to focus on it properly, and bits of it would come in and disappear again. Perhaps it is more prone to poor seeing? After M27, I was expecting great things and I’ve seen it really well through this set-up before…

NGC253, Sculptor Galaxy in Sculptor, mag 8.0 – superb, a bright cigar-shaped smudge that spanned nearly half the FOV. Called the others over again for a look, and then we all had a look through binocs. A large bright smudge even through them.

NGC55, galaxy in Sculptor, mag 8.4 – superb again, a long bright smudge, more elongated than 253, and showing a lack of symmetry in having more of the faint extension on one side. The galaxy extended for about half the FOV.

NGC1527, galaxy in Horologium, mag 11.7 – a supernova has recently been seen in this one. The galaxy showed as a tiny faint smudge in my scope, and seeing the supernova is well beyond my set-up. But I satisfied myself with the thought that a proportion of the light entering my eye came from a catastrophic detonation that occurred millions of years ago!

Nova Musca 2008 – after imaging this one over the past few weeks, it was good to make an acquaintance with it visually. I know the field like the back of my hand, LOL, so it was easy to find. Dimming right off now after climbing up to mid mag 8s.

Galaxies in Dorado: After imaging this field a week ago, thought I’d try visual on the tiny fuzzies that showed up on that shot. My charts weren’t crash hot and I only had the brightest galaxies marked. The transparency was so good that I saw lots of other tiny, very faint galaxies, but it was just too difficult to sketch the fields for later checking and I didn’t bother. These are the ones I identified – descriptions are limited, but you don’t see all that much in a 4.5" scope anyway:

NGC1566, mag 10.2 – Impressive, one of the largest galaxies observed, quite bright, slightly off-round (oval)
NGC1553, mag 10.0 – quite bright with a bright core, oval to cigar shaped
NGC1549, mag 10.6 – Close to 1549, this appeared smaller, rounder and a little dimmer. Both these galaxies ‘grab’ your eyes as you pan through the field.
NGC1546, mag 11.9 – A small faint blob that was easier to see in averted vision
NGC1617, mag11.4 – Close to Alpha Dorado, this galaxy showed as one of the larger ones, oval-shaped and quite bright. Viewing was easier with A Dor out of the field.
NGC1596, mag 12.1 – not far off half-way between 1566 and Alpha Dorado, this galaxy was small and dim, but nonetheless appeared as an edge-on spiral
NGC1533, mag 11.7 – Not sure what happened here. My notes say it was clear though small and dim, and very edge-on. This doesn’t seem to tie in with the shape Starry Night showed when I checked later. Possible that I saw a different one, don’t know
NGC1672, mag 10.5 – Very impressive, largest galaxy seen (still small of course!), face-on spiral with lots of faint extension in averted vision, even conning myself I could faintly make out arms…

All in all, a great night!

Cheers -

[dannat (Daniel)]

seems like you were busy Rob, did you catch any orionids later?

[§AB]

Fantastic report Rob and you sure did find alot of stuff in your short timeframe! Makes me wanna go out but ofcourse there is some bull**** moving in from the west, Melbourne style.

The Helix doesn't look as bright as M27 because it is actually much larger and consequently suffers from low surface brightness. It looks great in an OIII though!

[Rob_K]

Thanks guys - Daniel, I had an "Orionid night" the night before, very good too!

Originally Posted by §AB

The Helix doesn't look as bright as M27 because it is actually much larger and consequently suffers from low surface brightness. It looks great in an OIII though!

Yep SAB, my point was I've seen it well through this scope before and with the top-flight transparency I was expecting better again. Instead, it was very poor, all over the place. Just wondered with the LSB whether it might be particularly susceptible to poor seeing...

Cheers -

[§AB]

I don't think that with an object so large (and with low power) you'd notice any difference between poor and good seeing. Poor seeing will crap up extremely small and faint DSOs and Globular Clusters, but large Nebulae like the Helix wont be affected to a noticable degree. I'd say it was your memory fooling you

[ngcles]

Hi Rob,

Geez I'm impressed with what you do with that pretty small Tasco, excellent report!

Teriffic galaxy list that most would find a challenge in an 8" -- well done!

I like the galaxies of Dorado, Reticulum etc too -- the Cloud isn't the only thing in Dorado.

Best,

Les D

[§AB]

Originally Posted by ngcles

Hi Rob,

Geez I'm impressed with what you do with that pretty small Tasco, excellent report!

Teriffic galaxy list that most would find a challenge in an 8" -- well done!

I like the galaxies of Dorado, Reticulum etc too -- the Cloud isn't the only thing in Dorado.

Best,

Les D

Just goes to show what a difference dark skies make. NGC 1566 is a great object, it looks like a telescopic Magellanic cloud and I suspect that if I were to go as far as possible from this light polluted and above all cloudy Iceland, I could detect some of its HII regions (I've seen 1 under awsome transparency from here).

[Rob_K]

Spot on SAB, it's not the scope or my modest skills, it's the skies. Last night was exceptional. I've never really tested what mag skies we have - from home it's pretty good, but Porepunkah is always better.

When the transparency is that good, a million viable targets open up for you even with a 4.5". For instance, there was a mag 12.1 galaxy in the list above that even though faint was quite easy to pick up scanning through the field. However it was positively 'bright' compared to other tiny, very dim ones I saw while scanning around Dorado. Now I only identified the ones that were on the chart, and these were the brightest. What mag were some of these others?

But if I lived in Melbourne I'd probably battle to see OC, and have to go out and get me one of them there cannons, LOL!

Cheers -

[§AB]

Originally Posted by Rob_K

Spot on SAB, it's not the scope or my modest skills, it's the skies. Last night was exceptional. I've never really tested what mag skies we have - from home it's pretty good, but Porepunkah is always better.


When the transparency is that good, a million viable targets open up for you even with a 4.5". For instance, there was a mag 12.1 galaxy in the list above that even though faint was quite easy to pick up scanning through the field. However it was positively 'bright' compared to other tiny, very dim ones I saw while scanning around Dorado. Now I only identified the ones that were on the chart, and these were the brightest. What mag were some of these others?

I might check those galaxies out for you on sky-map.org, see what those other little fuzzies were . 12.1 for a galaxy is a good effort for a 4.5", Ive seen mag 15.9 stars from my place with the 12" so I certainly wouldn't be surprised if you were pushing 13 from your location. Yeah 4.5" scopes do an admirable job from dark skies, the one time I had mine out in the sticks I got a fantastic view of the Flame Nebula and other objects that I had no hope of seeing from melbourne.

But if I lived in Melbourne I'd probably battle to see OC, and have to go out and get me one of them there cannons, LOL!

Cheers -

I'd like to flop my cannon out on the porpunkah airstrip

[Starkler (Geoff)]

Originally Posted by §AB

Yeah 4.5" scopes do an admirable job from dark skies, the one time I had mine out in the sticks I got a fantastic view of the Flame Nebula and other objects that I had no hope of seeing from melbourne.

I had a memorable evening about 2 years ago with my little 130mm newt in dark skies with the best transparency I have seen. The flame neb stood out like the proverbial dogs bollocks with dark lane resolved in the 30mm finder scope

[goober (Doug)]

Rob, excellent stuff. I love reading obs reports, where the eye tells the story, not a CCD chip and stack of processing

Must... get... out ... there.

[erick (Eric)]

Originally Posted by goober

Must... get... out ... there.

Yes, hangin' out for it. Hopefully tonight briefly and a full night tomorrow night!

[§AB]

Originally Posted by Rob_K

NGC1533, mag 11.7 – Not sure what happened here. My notes say it was clear though small and dim, and very edge-on. This doesn’t seem to tie in with the shape Starry Night showed when I checked later. Possible that I saw a different one, don’t know

I just checked this one out on skymap.org, and it appears there is bright central bar enveloped in a fainter circular haze. You would've been seeing the bright bar, hence the 'edge on' appearance.

[Rob_K]

Originally Posted by §AB

I just checked this one out on skymap.org, and it appears there is bright central bar enveloped in a fainter circular haze. You would've been seeing the bright bar, hence the 'edge on' appearance.

[/size]

Ahh, thanks SAB, couldn't for the life of me work out what else I could have been looking at within the field or a bit. There is a thin edge-on nearby, but at mag 15+ it is a few mags dimmer than I could ever see.

And good luck Doug & Eric, hope you have a great time!

Cheers -

[markus.a.bergh]

Thanks for your reports. I always enjoy them. They give me a lot of inspiration.

You must have very dark skies. I can barely see NGC253 using a 12"dob.