NGC 300, 11.3hrs, done!

[codemonkey]

Edit: This is now 11.3hrs total integration time, my longest yet. Larger version available on Astrobin (http://www.astrobin.com/218794/).

---

This is 30x480s subs. I was hoping to get another hour or two last night, but the clouds came in early. Can't complain too much though, we've had a good run up here over the last week.

Anyway, I found something interesting doing this one. My dodgy pier doesn't hold alignment very well, and all of last nights (10 used here) subs I thought were throw-aways due to field rotation. I should have checked my alignment, but I didn't.

After stacking these less than great subs with the other 20 from the previous night, the eccentricity was still only 0.44 (as opposed to mid 0.5s to high 0.6s). I just integrated them to see what would happen, but I think in future I'll be using more of my "bad" subs. Honestly I wouldn't even know if I didn't know ;-)

This is a pretty dodgy processing job (I even used USM instead of decon), I'll do a better job when I get more data. Pretty happy with it so far considering there's only 4hrs of data here.

[Placidus]

Coming along marvellously! A great result and fantastic for the circumstances.

There's no sign of field rotation there. Stars look great. If the polar alignment is off along the same hour angle as where you are photographing, then you not only get nasty field rotation, your guiding can get lost in the dec backlash. Conversely, if by good luck your polar axis is off along an hour angle that is at 90 degrees to where you are photographing, then at least for an hour or so you get no field rotation and consistent guiding. Perhaps the pier moved in a direction that was harmless or even helpful given where you were photographing. (With our fork mount, we intentionally put the polar axis 0.04 deg west of the SCP. That gives excellent behaviour when photographing say 60 deg either side of the meridian. And 2.5 tonnes of steel reinforced concrete in solid rock makes it stay put!)

Best,
Mike

[gregbradley]

Awesome Lee. You must be happy with that. Lovely round stars too.

Greg.

[codemonkey]

Thanks Mike! :-)

There's definitely some movement in the subs from last night, which I believe to be rotation. PHDLab estimates a misalignment of over 29' and there's visible elongation in the subs, either NE or SW. PI reported quite high eccentricity; two which didn't even make it into this were 0.7+. All's I know is that when stacking the 10 "bad" frames with 20 "good" frames, the elongation disappeared and I was left with pretty round stars. Happy days!

I think I'm going to have to do some more work on the pier. In trying to save myself some money I've got a clearly inferior solution. I think it's the mounting to the pier that's the problem; I'll be looking into buying a proper pier top plate to hopefully sort this out. I've seen alignment change as much as 70' in a week; whereas parking the tripod on the same footing I'd end up about 15' after several weeks.

My footing is okayish, it's mostly just the dodgy DIY pier. Pier footing is 110x110x60cm (only 60 deep). It's in clay mixed with granite, but to get below that point in our soil would require the footing to go down over 3m. It moves a little but it's not too bad, certainly not 70' in a week bad.

I also intentionally misalign to improve guiding; I've got 2884ms (thanks PHD2!) of backlash in DEC so I try and keep corrections to one side. I'm going to be trying PHD's new backlash compensation feature to see if I can use that to correct in both directions whilst dialling in better alignment.



Thanks Greg! :-) Pretty happy with the stars! You wouldn't think 1/3 were bad throw-aways eh? Could be a bit tighter like yours and and Mike/Trish's, but I'm still pretty happy.

[Shiraz]

very tidy hi res image - that scope is delivering!

[codemonkey]

Thanks Ray :-)

Forecast says it'll clear up this evening so hopefully I can get some more data. If the forecast is right over the next few days I should be able to finish it up completely.

The scope really is delivering; though you wouldn't guess it from the review thread, I'm really happy with it. By far the sharpest images I've ever gotten.

Moonlite should be here for the scope in the next couple of days; it'll be interesting to see whether I have to keep refocusing with that. If not, I think my shaft couplers are at the post office and I'll start work on building automated focusing.

The better news, equipment wise, is I've found out my recent issues with RA and major, major backlash (and hopefully the high-frequency noise I was seeing): the pulley on the RA worm had come loose. Ripped it apart again yesterday and fixed that up.Looking forward to seeing how it guides again now. The other night I did some PE analysis and found a really smooth curve, so hopefully with this fixed up PEC will make a huge difference.

[codemonkey]

Got another ~3hrs of data last night, making this now the longest L integration I've done; 6hrs, 56min. Micro data for some of you, but a big effort for me :p

Pushed this pretty hard (see second attachment of original post)... might have overcooked it.

Hopefully the weather will hold and I'll get some RGB tonight.

[AlexN]

Coming along really nicely Lee.. I agree it might be pushed a little hard however you're showing great detail in the arms and plenty of background galaxies... How did you go for clouds last night? I was imaging for a couple of hours until an abundance of wandering clouds sent me packing at about 10:30... Ironically, one of my kids woke up and kept me awake until nearly 4:30am, and from about 12 onwards every time I looked outside the sky was clear as a bell...

To say I was kicking myself was an understatement...

[codemonkey]

Thanks Alex :-)

Yeah, after reviewing it I definitely pushed it too hard. So now I've redone it, pushing it hard in a different way lol. Happier with this one though. I've replaced the overdone one in the original post now.

Cloud cover last night was great; had a small patch come up just after it cleared (and I thought "yep, here we go, typical!") but then nothing until I packed up around 11:30pm.

[AlexN]

That's the ticket. Looks awesome.

[codemonkey]

Thanks mate :D

[strongmanmike]

Looks pretty sweet Lee, lovely contrast. Sometimes in images of NGC 300 it is had to tell what is noise and what is actual resolution of the galaxy and I think many processors like to kinda convince'emselves that some of the noise is stars, but I recon you have done a good job here :thumbsup: Looking at your image I can see why it is such a popular target this time of year.

Mike

[Paul Haese]

The latest version looks pretty good Lee. I like the detail levels of the later version.

[gregbradley]

Looking good Lee. I hadn't noticed those 2 dark areas in my subs. Are they processed or in the RAW data? They look like dust areas in the galaxy.

Greg.

[codemonkey]

Thanks Mike! It's definitely tricky to identify the noise from the detail in this one. I've probably still pushed it a bit hard, and when I do the RGB I'll likely dial it back a bit.

To be honest I just wish I had a smaller (FL) scope for this... bit too up close and personal for my tastes, but I only have the one scope now and no reducers, so it is what it is.



Thanks Paul!



Thanks Greg :-) They're definitely in the raw, but they have also been enhanced with local histogram equalisation which I used to bring out the arms a bit more.

I did get some RGB last night, but haven't had a chance to give it a real go. First impressions are that I may need more data... back to work now (just been on leave) so I'll have a play when I get home tonight.

[AlexN]

On leave over new moon weekend you cheeky devil. ;)

[codemonkey]

haha, yep, I have to confess the moon phase did factor in when planning the leave ;-)

[AlexN]

My last annual leave was 5 days each side of new moon. 10 nights, I imaged for 7 of them. Hahaha

[codemonkey]

Niiiice. I had one week off and I think I imaged on 5 of the nights? Best run I've had in forever though, so it was most welcome. In fact, I actually welcomed the two cloudy nights so I could relax lol.

[Atmos]

Loving the colour version :-)

[codemonkey]

Thanks Colin :-)

Side note to all:constructive criticism is (as always) much appreciated.

[Camelopardalis]

Looking good Lee :thumbsup:

Is that diffraction spikes I see on the brighter stars?

[strongmanmike]

Colour looks good Lee :)

Mike

[alpal]

Hi lee,
nice job on the colour version.
I am surprised that you could get such a good picture with
only 120mm of aperture.
well done

cheers
Allan

[codemonkey]

Thanks mate; yep there's definitely some kind of artefact around the brighter stars that resembles diffraction spikes. I'm not sure what it is, but I don't mind it to be honest... if only they were bigger :p (yes, I'm one of those heathens that likes diff spikes)



Thanks Mike! :)



Thanks Allan; appropriate sampling, sensitive camera, dark skies and an unobstructed 120mm does alright I think. I'm happy with the compromise, having less things to constantly tweak, and the budget won't go any higher than a 120mm triplet.

I've uploaded a corrected version (http://www.astrobin.com/218794/C/) to Astrobin now, fixing the colour a bit.

[Placidus]

Hi, Lee,

The colour is both rich and plausible. Well done.

I continue to be surprised by how blue NGC 300 is, not just in your shot, which is great, but in APOD and ESO publication shots. I wonder a bit whether this is "We always throw the best looking person in the tribe into the volcano, and we always make NGC 300 very blue. Otherwise the crops won't grow, everyone knows that", or whether it is undergoing a round of intense starburst activity. There's no sign of tidal distortion that might suggest a recent encounter with another galaxy. I should love to know. Wikipedia says it forms a gravitationally bound pair with NGC 55. That might do the trick!

Best,
Mike

[topheart]

Very nice rendition!

Tim

[Camelopardalis]

:lol: I was about to say I kinda like it :D

[codemonkey]

Thanks Mike, appreciate the feedback and the info, very interesting.

I always struggle to get colours right and it's hard to know what's right, so when I don't know I'll usually go with convention unless I've got a good reason not to.

The one in the original post is definitely too blue.. I tried to reduce a green cast and ended up going blue instead of magenta. I fixed it up in the Astrobin version.

Thanks again!



Thanks Tim!



haha. Ah, good to find another heathen.

I'm a bit low on targets at the moment so I may continue to add more to this. The colour data is particularly poor, I really need more than 5 subs per channel.

[Shiraz]

It's very detailed and beautiful Lee - what a result. The colour is sure a bit tricky, because this is fairly dim, but you have nailed it. interesting to see how you go with more data.

[codemonkey]

Thanks Ray, appreciate it! :-) I definitely need more colour data at the very least.

I had a quick play last night, spawned by Mike's comments and some I received elsewhere and produced one that's a lot less blue than is typically done for this subject. Thoughts on it? Ignore the over-saturated background galaxies.

[codemonkey]

Got a couple of hours more data last night and reprocessed it (see original post, or Astrobin (http://www.astrobin.com/218794/F/)). The colour is a bit different, hard to say what's right and wrong given the colour variations I've seen, but I think I'm happier with this.

Right now I'm gonna say I'm done with it... mostly 'cause I'll never think it's right and I want to move onto other targets :p

[alpal]

Hi Lee,
You've done so well on a tough target.

I think I'll have a go tonight even though a 5 minute test shot
I did - that was a bit out of focus hardly revealed anything.
see the attached test shot.

I noticed you mixed 1x1 binning & 2x2 binning.
I think I'll have to do 2x2 binning & 15 minute subframes to pick up anything in those faint arms.( for all LRGB )
A 30 minute subframe of Ha binned 2x2 would also be nice.
I am undecided on how to do this one?

cheers
Allan

[codemonkey]

Thanks Allan, appreciate it! :-)

I'm lucky to have dark skies, which makes this a bit easier for me. Hard to say what's appropriate for you without having a lot more information. All I'd say is try and find out how long you need to expose for before you're sky limited (at least for luminance) and then aim for that. If you go above that you're risking more subs to environmental issues and all you're getting for your efforts is reduced dynamic range (blown out stars).

I initially did 2x2 for RGB because for me to get sky limited in the blue channel I need 38min exposures when binning 1x1, and I'm not prepared to do broadband subs that long.

I ended up with a lot of artefacts around the blown cores of the brighter stars with the 2x2 images, so I went back to 1x1, which helped with that. I could have (to some extent at least) processed it out, but I'd prefer not to have to. I think I'll probably just stick to 1x1 in future... if I throw out some resolution by software binning the results don't seem to differ much so I don't think it's worth it for me.

For your reference I've attached a single 480s luminance sub, stretched to hell and back.

[alpal]

Thanks Lee,
Your dark skies pulled the arms out of noise.
I'll see what happens with a 2x2 Luminance at 10 minutes & judge what to do from there.

cheers
Allan

[E_ri_k]

Looks great Lee, lovely colour variation in the galaxy, I must give this one a crack myself.

Erik

[codemonkey]

Good plan Allan. Look forward to seeing the results :-)



Thanks Erik! :-) You've certainly got some nice gear, that extra aperture would go a long way on this one.

[AlexN]

This is looking fantastic Lee. That 120 is focusing the photons beautifully upon your sensor. I'm out again tonight collecting more data. Missed last night due to daddy daycare duties.

I'm waiting for orion area to get up, for my rig there is not much in the sky of interest at the moment.

[AlexN]

Ps. Look at all your background galaxies. Hundreds of them. That heavily red shifted lot to the left look interesting.

[codemonkey]

Thanks mate! Friday night was awesome, at least over here... last night was about average.

Did you end up getting anything? Clouds were due to roll in around 12; they appeared on the horizon here at 11 just as I was packing up.



That's half the fun! Not sure what that little cluster is but it's one of the cooler features in the image (imo). When I did the RGB initially I rotated the camera too much and had to crop half of it out, but after doing the second run I was able to bring it back in.

[AlexN]

I got a couple of hours in until I was interrupted by patchy cloud. Stuck it out till 1am hoping it would clear then woke up sitting on my backyard at 1:45. Packed it in and went to bed. Haha