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ollypenrice

More refractor galaxies - M101.

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Big scope with big pixels or small scope with small pixels? Here's a 5.5 inch scope with an Atik 460 mono on M101.

2 hours per colour, unbinned. 12x10 per colour.

Luminance 19 x 15 mins.

Ha 7 nm 5x20 mins (grossly abused in photoshop and made to talk!)

TEC 140 Apo, Mesu 200.

Taken and processed over two nights with guests Peter Goodhew and Richard Miller.

M101%20TEC%20HaLRGB%2012%20HRS%20WEB-X3.

Olly

 

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Oooo, nice! I like that. I like the galaxy colours and the arms are all there..... well done to you and your guests :)

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lovely image Olly and guests - gosh im gona have to get a pasport

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Really nice image and lovely natural colours. I see you are using two hours with 10 minute RGB subs. In discussing this with Peter he said that you were using 10 minutes to get above the noise factor. Do you consider this to be an issue with your dark skies? After getting some horrible RGB skies in some of my subs I have been looking at extending my normal 1-1.5 hours from 5 minute subs per channel to 10 minutes subs, and then of course you want enough of them, so two hours seems about right. Just wondering what your thoughts were ;-)

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Very nice. I like that you can see detail almost to the very center as well as the faint outer arms as well. Plus excellent stars. I would love to be able to get the same range of star colours in my images as well.

Cheers, Ian

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4 hours ago, ampleamp said:

Really nice image and lovely natural colours. I see you are using two hours with 10 minute RGB subs. In discussing this with Peter he said that you were using 10 minutes to get above the noise factor. Do you consider this to be an issue with your dark skies? After getting some horrible RGB skies in some of my subs I have been looking at extending my normal 1-1.5 hours from 5 minute subs per channel to 10 minutes subs, and then of course you want enough of them, so two hours seems about right. Just wondering what your thoughts were ;-)

Hi! From a dark site you don't have to worry about skyglow so you can expose pretty much for as long as you like. For me 5 minutes would be too short to get the faint stuff safely above the noise floor so I work in 10 minutes for colour and 15 for lum, usually. If going after very faint things like tidal tails or the IFN I'll use 30 minutes in lum and usually I do Ha and OIII in 30 minutes as well.

It is much easier to process an image with 2 hours per colour than just one. The luminance tends not to wash out the RGB when you have plenty of colour. There are processing workarounds but I'd far rather have plenty of data.

Olly

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Masterful Olly, Peter & Richard.

I especially like the exquisite Ha detail as it spirals into the centre :thumbsup:.

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Thanks Olly, I managed a good session last night and upped rgb to 10 minutes each and will see how that processes; i have to say they look better 

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With less tired eyes I've done a little more work on the core detail and continue to be delighted by the performance of the 5.5 inch refractor. This is within a gnat's crotchet* of what we managed with the 14 inch.

5ada1aefbdc99_Coreweb.jpg.905fe936963fcac3f90fa3bb1f7d21a1.jpg

Olly

* An expression well known to admirers of the late great Humphrey Littleton!

 

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I’ll be awarding points for this – and points mean...

Edited by AKB
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That TEC combined with the Atik 460 certainly does the job.  Not to mention the expertise of the operators and the processing of course....

Chris

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Beautiful. You got so naturally what I had to over process to get (and you still got more).  Oh for those 21.98 skies (or whatever it is you have over there!).  Is the first image a crop?  The scale is bigger than I expected.

Rodd

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37 minutes ago, Rodd said:

Beautiful. You got so naturally what I had to over process to get (and you still got more).  Oh for those 21.98 skies (or whatever it is you have over there!).  Is the first image a crop?  The scale is bigger than I expected.

Rodd

Yes, a crop. Thanks for the comments, Rodd.

Olly

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Olly, will you please stop making my life so difficult.......

So tonight i have turned down a good deal on a Tec 140 in favor of buying a smaller TS Photoline 130mm apo and with the money left over buying a 12" newt for galaxies and Dso's thinking it will be ideally suited and here you sre posting a stunning galaxy image and telling us it's not far off your 14"

My head is literally about to explode.  Just as i've convinced myself that it's right decision you throw this spanner into the works and bring my metaphorical carousel to a grinding halt

Ahhhhhhh.......  😋. 😉

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1 hour ago, Northernlight said:

Olly, will you please stop making my life so difficult.......

So tonight i have turned down a good deal on a Tec 140 in favor of buying a smaller TS Photoline 130mm apo and with the money left over buying a 12" newt for galaxies and Dso's thinking it will be ideally suited and here you sre posting a stunning galaxy image and telling us it's not far off your 14"

My head is literally about to explode.  Just as i've convinced myself that it's right decision you throw this spanner into the works and bring my metaphorical carousel to a grinding halt

Ahhhhhhh.......  😋. 😉

Oh dear, sorry! Tonight we're running the TEC on a galaxy for which I have some not quite finished older data from the 14 inch (which was never mine, it belonged to Yves Van den Broek but lived here.) Again it will be interesting to compare them. The idea is to combine them this time. I wonder if the TEC was Darren's? If so anyone can buy with confidence because he's a great guy.

Olly

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Yes, it was Darrens Tec. The plan was to get the Tec which would have been my one and only scope, then i was discussing it on another forum under the topic of 130mm vs 150mm apo, where a few people jumped in and suggested going for a cheaper 130mm and using the money saved to buy a larger decent quality newt,

So spoke to TS and they offered a cracking deal, a TS photoline 130mm triplet which gets good reviews & the TS 12" carbon UNC newt for around £2700 which seemed  like a no brainer, but now I'm having doubts again as the Tec 140mm is a dream scope.

That said, the TS 130mm uses FPL53 ohara and reports say they are very well colour corrected, so it should hopefully be 75-80% as good as the Tec and i would be happy with that.

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Wow that is a nice piece of work there. I wish I had the same gear and location :)
well done Olly

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Great job Olly, Peter & Richard.Yet more evidence that a large refractor coupled with the right camera can cut the mustard on galaxies. 

How big a part does the imaging location and the processing play in this? With the former, quite a lot, I would think. 

Looking forward to seeing what the 150 can do on these targets from a Bortle 4 location, assuming we get a look in before Astro darkness disappears.

 

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