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!
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.
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.
Quote:
Originally Posted by Merckx
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.
Quote:
Originally Posted by codemonkey
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
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.
That’s 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.
Quote:
Originally Posted by dave_galera
Nice detail well captured and great colours
Thanks Dave
Quote:
Originally Posted by codemonkey
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.
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.
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.
Quote:
Originally Posted by willik
Enjoy your Mewlon 250 very nice image Colin
Martin
Quote:
Originally Posted by PeterSEllis
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.