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Old 24-08-2019, 05:14 PM
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Atmos (Colin)
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Messier 55

My second night out with the Mewlon 250 imaging and I must say I'm quite enjoying the whole longer focal length thing. I'm way over sampling at 0.4"/pixel but as I've only got one camera to work with at the moment I just deal with what I've got.

The seeing wasn't great last night, the best I could achieve with 5s focusing images was about 2.5" around 11pm and with the stacked images being 3", it was interesting watching how much the FWHM varied between 300s subs going between 7.25 pixels all the way out to 12 and back down again. After 1am best focus was at 4" with 5s focus images. On nights like that I do see why wide field imaging is so forgiving

Coming from a fast refractor it's great seeing no kind of discolouration around stars except for that induced by the atmosphere. So here is Messier 55, one of several globular clusters I imaged throughout the night. It also has my longest integration of the night at a whopping 2 hours!

24x300s unguided at 0.4"/pixel.

High Res Link

One night I'll get the Mewlon out under good seeing and see what it's capable of.
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  #2  
Old 24-08-2019, 06:19 PM
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multiweb (Marc)
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Great colours and resolution.

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24x300s unguided at 0.4"/pixel.
Show off!
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Old 24-08-2019, 06:31 PM
Merckx (James)
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Really like those colours Colin. What is the blue item in the bottom left of the image?
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Old 24-08-2019, 07:12 PM
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Nice one, Colin. Lovely colour. I also quite like the diffraction spikes you get with the Mewlon. I'm imaging at 0.5"px and that's tough; I don't think I'd want to try 0.4"/px

Finally got a clear night here that's not blowing a gale, nor a full moon, and coincidentally I set my sights on M55 early in the evening, moving onto NGC 253 when it hits 45 degrees. Unfortunately I have no idea if any of the data is any good because I forgot to plug my ethernet cable back in and the observatory is all the way up there. Probably garbage seeing, knowing my luck.
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Old 24-08-2019, 08:43 PM
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Great colours and resolution.



Show off!
Thanks Marc
The mount does all the work. I learnt a few things from my first night out with the camera attached to the Mewlon, made imaging an absolute breeze. In saying that, it is not something I'd have EVER wanted to have attempted with the EQ6 I had. It guided well and I could get 1 hour subs in Ha at 1.5"/pixel but it certainly wasn't smooth!

One night I would like to see how long I can push the exposures without guiding. Wouldn't mind seeing how 20 minutes would go with this setup, good to know if I ever do some dark site imaging with it.

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Really like those colours Colin. What is the blue item in the bottom left of the image?
Colour wise this is my favourite image of the night, it's also the one that I had the best seeing on so everything looks a bit less washed out.
The blue spike on the bottom left is a star that is just out of view, just out beyond the edge of the field.

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Originally Posted by codemonkey View Post
Nice one, Colin. Lovely colour. I also quite like the diffraction spikes you get with the Mewlon. I'm imaging at 0.5"px and that's tough; I don't think I'd want to try 0.4"/px

Finally got a clear night here that's not blowing a gale, nor a full moon, and coincidentally I set my sights on M55 early in the evening, moving onto NGC 253 when it hits 45 degrees. Unfortunately I have no idea if any of the data is any good because I forgot to plug my ethernet cable back in and the observatory is all the way up there. Probably garbage seeing, knowing my luck.
I agree with you, I quite like the 6 spikes. They tend to not be quite so intrusive as the four spikes brightness wise.
I would much rather be at 0.7-0.8"/pixel as it matches me average seeing a lot better but if this is what I've got then it's what I've got.

Here's hoping you had 1" seeing and everything is going perfectly while you have no connection
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Old 24-08-2019, 09:05 PM
Startrek (Martin)
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Thatís a really nice M55 Colin
One of my favourite globs
Well done !!
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Old 24-08-2019, 09:39 PM
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Nice detail well captured and great colours
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Old 25-08-2019, 07:41 AM
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I agree with you, I quite like the 6 spikes. They tend to not be quite so intrusive as the four spikes brightness wise.
I would much rather be at 0.7-0.8"/pixel as it matches me average seeing a lot better but if this is what I've got then it's what I've got.

Here's hoping you had 1" seeing and everything is going perfectly while you have no connection
Yeah, I think I'd prefer 0.6", I think it's rare that I really leverage 0.5"

Looks like SGP focused rather poorly on my attempt at M55, which is one of the reasons I rarely shoot globs. I haven't checked all the subs, but the ones I did check didn't have a single one below 2.5", most over 3" ... which I checked NGC 253 I had many at 1.8". According to SGP's forum, improved AF will be a focus (pun not intended) of the next major release, which I greatly look forward to.
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Old 25-08-2019, 08:44 AM
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Thatís a really nice M55 Colin
One of my favourite globs
Well done !!
Thanks Martin, I've wanted to capture globs for years so I'm glad to be able to do that now.

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Nice detail well captured and great colours
Thanks Dave

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Yeah, I think I'd prefer 0.6", I think it's rare that I really leverage 0.5"

Looks like SGP focused rather poorly on my attempt at M55, which is one of the reasons I rarely shoot globs. I haven't checked all the subs, but the ones I did check didn't have a single one below 2.5", most over 3" ... which I checked NGC 253 I had many at 1.8". According to SGP's forum, improved AF will be a focus (pun not intended) of the next major release, which I greatly look forward to.
.6" even requires reasonable seeing but it looks like you get it with 1.8" subs so that's good to know.
One thing I cannot do with the Mewlon at the moment is auto focus. It seems to hold its focus reasonably well but I wouldn't like to see it in falling temperatures. There is a fair bit of mass that can suffer from shrinkage

I knew there was a jet stream coming over from the west but I was curious as to how that would show in FWHM. I'm only just venturing into an image scale where anything more than worse than 2.5" is even detectable Wide field imaging has it perks.
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Old 27-08-2019, 07:47 PM
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Nice image Colin. Star colour is excellent. Resolution what you would expect from a Tak. I think despite your sampling you produced a good image. Seeing is always king though.
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Old 28-08-2019, 11:21 AM
willik (Willik)
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Enjoy your Mewlon 250 very nice image Colin
Martin
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Old 29-08-2019, 09:51 AM
PeterSEllis (Peter)
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Hi Colin,
Nice image and good colors, certainly show the quality of the Mewlon 250.

Cheers
Peter
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Old 29-08-2019, 10:26 AM
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Quote:
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Nice image Colin. Star colour is excellent. Resolution what you would expect from a Tak. I think despite your sampling you produced a good image. Seeing is always king though.
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Enjoy your Mewlon 250 very nice image Colin
Martin
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Hi Colin,
Nice image and good colors, certainly show the quality of the Mewlon 250.

Cheers
Peter
Thanks
I am very happy with the performance of the M250 so far, it makes star clusters look so much better than my wide field refractors.
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Old 29-08-2019, 07:20 PM
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That looks great Colin.

Greg.
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Old 29-08-2019, 09:15 PM
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I agree with all the comments about the great colours in those starts, Colin. A lovely image!

Are you going to try the ASI094 and the modded Nikon with the Mewlon. Would be very interesting to see the results.

Cheers,
Richard
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Old 30-08-2019, 12:00 PM
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Very nice Col; M55 Sooo neglected even visually.
Bigjoe.
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Old 30-08-2019, 07:48 PM
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Good resolution, good colour, right sized field and good processing. Fits all the criteria for a perfect GC shot. Nicely done.
Geoff
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Old 31-08-2019, 01:22 PM
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Atmos (Colin)
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That looks great Colin.

Greg.
Thanks Greg

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Originally Posted by Decimus View Post
I agree with all the comments about the great colours in those starts, Colin. A lovely image!

Are you going to try the ASI094 and the modded Nikon with the Mewlon. Would be very interesting to see the results.

Cheers,
Richard
Thanks Richard
Don't really have any plans of putting the D810 on the Mewlon as the ASI094 is just a better astro version

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Very nice Col; M55 Sooo neglected even visually.
Bigjoe.
Thanks Joe, I don't think I've ever checked it out visually either :/

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Good resolution, good colour, right sized field and good processing. Fits all the criteria for a perfect GC shot. Nicely done.
Geoff
Thanks Geoff
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