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The Eagle finally lands in Baginton...

Tim

By Tim
in Imaging - Deep Sky

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Tim

Tim

Posted
Posted

As usual when chasing this target, there were tales of woe

http://stargazerslounge.com/astro-lounge/83073-bin-bag-over-streetlight.html#post1247681

It all ended at 2am when my laptop had a BSOD, something I haven't seen for ages, it just went blue, gave the error, and shut down, leaving the kit in all sorts of mess.

So this is the initial stack of 16 x 10 mins

OTA = C9.25 @ f6.3 using TS Off Axis guider in conjunction with a Trutech supaslim filter wheel. (first time used this config)

Imaging = SXV-H9 via Nebulosity 2 with Baader New 7nm Ha filter.

I'd dearly love to add sufficient OIII and SII data to this, but given what it took to get this image, that's looking unlikely. To compensate I have done a false colour image in PS to try and accentuate the detail a little. Not sure If I prefer the mono or the false colour.

In case you missed it, M16 was APOD for today too, check out this pic, its a beauty!

http://antwrp.gsfc.nasa.gov/apod/image/0907/m16_colognato_big.jpg

Thanks for looking.

TJ

post-14037-133877384443_thumb.jpg

post-14037-133877384452_thumb.jpg

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bazza

bazza

Posted
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TJ,

Aaaaaah....the Eagle Neb...it just stands for Astrophotography, does it not?

I've got no chance with M16 - trees and just too low.

Glad to see the gear giving you some return.

I think it's a super image given what you were battling against!

Yes, that APOD is a beauty, but I bet he didn't have half the battle you did - which must make yours doubly satisfying.

I think I prefer the mono version, either way, you can see the detail in the columns.

Anyone who produces an Eagle Neb from the Midlands in the UK has raised the bar IMHO.

Well done mate......will I have to move house?!

Regards,

Barry.

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ollypenrice

ollypenrice

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Sharp and then some! Great stuff. I have a curious optical reaction to some nebulae, and certainly this one in your excellent rendition here; they flip from negative to positive depending on how I catch them.

Olly

PS Good link to APOD. Boy, that one will take some beating...

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roundycat

roundycat

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can't say that I care for the false colour but the mono pic must have been very gratifying. The two doubles have come out as very clear doubles, not something that everyone manages to do. Maybe even better without the white point pushed so hard. Lovely work.

Dennis

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Tim

Tim

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can't say that I care for the false colour but the mono pic must have been very gratifying. The two doubles have come out as very clear doubles, not something that everyone manages to do. Maybe even better without the white point pushed so hard. Lovely work.

Dennis

Thanks Dennis. It seems tricky getting "sharp" with an SCT. I have the collimation as good as I can get it, but I think to get the very best out of it i'll have to get it bench collimated.

I never touch the white point though, just bring up the rear. In fact, the mono pic looks pretty much like it did rolling out of the camera in nebulosity, which auto adjusts the black and white points for you on the preview. Maybe should have taken some shorter exposures to get the stars?

Cheers all.

Tim

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steve51450

steve51450

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very contrasty Tim, and the strange thing for me is i prefer the false colour one, even though its very unusual colour :)

its to low down for me unless i take my chainsaw to the neighbors roof so i can understand the faffing you had to do to get such a good image

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roundycat

roundycat

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Tim, I have the same problem with my LX, the collimation is good but the stars always seem to suffer. I'm beginning to think it is just the magnification/seeing issue and I'm stuck with it. Very clear nights are noticeably better. I am also playing with using one filter at a time at the moment, put the filter in the nose piece and the filter wheel in its box.

I know nothing about Nebulosity; does it make adjustments for you or is the preview just the preview as in Maxim? If you have Maxim and can do a line profile of a bright star does it have a flat top? It's all still nit-picking, the mono pic is a blumming good one

Dennis

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Tim

Tim

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The image that comes off the camera in Nebulosity looks pretty much like a stretched pic. I do have Maxim, but still shy away from it as the other apps seem to do the job with a simpler interface.

The new Baader filter certainly seems to have eliminated the halo around bright stars at least.

Out of interest, how do you collimate your LX Dennis?

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roundycat

roundycat

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Tim, If you ask me (I know you didn't!) if you get a stretched looking picture from Nebulosity then it has taken control. If your starting point is with that stretched picture then you don't know how much damage has been done. Maxim provides a screen stretch to a pre-determined ratio but the picture that gets saved as a TIFF and then opened for surgery in PS is not stretched at all. If you have Maxim I would definitely recommend that you get to grips with it.

Incidentally, I stole your picture and cropped it in Maxim and then looked at the brighter stars using the Line Profile tool. The stars show a 5-6 pixel flat top which means saturated whites. Whether this happened as part of the jpegging or Nebulosity did it without asking I know not. I have a screen grab of it if you care to have a look.

I know most people seem not to give a toss but if your stars are smaller then the whole picture looks sharper.

I collimate my LX by trial and error, at least I think that is what the method is called. Highish power, slightly de-focus a dim star and then play with the three screws one at a time whilst running around the back to have another look. If the first movement does not improve it I return the screw to where it was and then try the next one. I did this ages ago and check it regularly and it hasn't needed adjusting for ages.

Dennis

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Tim

Tim

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Thanks Dennis. The output from nebulosity is a FITS file, untouched.

This pic was stacked in DSS, and using their recommended for Ha "Super-pixel" mode, which essentially takes 4 pixels and averages them, as I understand it, meaning the output is a lot smaller.

I havent had a chance to look at the full size stack yet, nor have I properly gone over each FITS to look for problems. So in this stack even the several pics that had the 500w security light reflecting in the primary are in there. When I get time i'll take a good look at each one. That tool in maxim sounds useful, does it work live, on the fly as well?

Cheers

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roundycat

roundycat

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Tim, with 16 subs I would definitely go for a combine in Maxim using an outlier rejection method, either Median or SD Mask, not average.

The Line Profile tool does work on the fly, you can have several frames open and just click on each one, position the line and then read about it as shown here.

Dennis

post-15519-133877384678_thumb.jpg

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Tim

Tim

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Me too Richie!

Dennis, that tool does indeed look nifty. Would I be right in thinking it would help determine the maximum useful exposure time before stars became saturated?

I'm going to go over the files now and see what is what.

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minimalist

minimalist

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Btw Tim, in DSS, the equivalent of the stacking methods Dennis mentioned is the Kappa-Sigma methods. I usually use the second one which I believe replaces the outliers with the median instead of average.

Still, an excellent image Tim, I'd be very happy to get something like that. :)

Daniel

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Tim

Tim

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Yes, I usually go for KS stacking, or the auto-adaptive one, which seems to give similar results.

When I went over the files, 4 of them showed a lower score, were less contrasty, and stars more bloated, it may have been clouds or the security light. The restack without them looked quite nice, but I fell asleep at the laptop and havent dared look at what state I saved it in yet :)

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RobH

RobH

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Great image Tim, especially from where you are :)

Practical Astronomer had a very interesting article in Feb(I think) 2008 about using a Hartmann mask for collimating an SCT. I used the method on my 14 and although it only needed the slightest tweak, it made a lot of difference.

I'm away at the moment but I'll be happy to send you (and anyone else!) a copy when I get home if you like.

Cheers

Rob

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