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  #1  
Old 11-04-2017, 07:33 AM
markas (Mark)
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Tak Mewlon 250

Has anyone used a Tak Mewlon 250 for deep sky photography.

Because of its light weight it appears attractive as a mobile astrograph, but there is very little about it in such a role, even though it is not new .....

Mark
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  #2  
Old 11-04-2017, 08:06 AM
AnakChan (Sean)
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My Mewlon 250CRS is my main scope. Whilst it may be light, it still does require a decent mount. I use the Vixen AXD.

I use it for DS such as galaxies, globular clusters, and planetary nebula. For nebula, it's got kinda of a long focal lengh at 2500mm so NGC 6888 Crescent Nebula would fit in.

Being an F10 scope though somewhat longer exposures would be beneficial. I do use a cooled Sony A7S and have gone as long as 30 min subs (with a nebula filter).
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  #3  
Old 11-04-2017, 08:25 AM
markas (Mark)
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Sean,

Thanks for the feedback. I would be using it to complement an ASA10 so the 2.5m is fine. I understand re the mount - at that focal length it needs to be good!

I would be using a KAF16200 class camera.

Any comments on image quality?

Mark
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  #4  
Old 11-04-2017, 09:10 AM
AnakChan (Sean)
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I think for my setup, there's room for improvement. I find my stars to be a little bloat and that could be a combination of the environment I take my photos (I'm in Tokyo so I go to Chiba which is about 1-1.5 hrs but still distant factories with hot/cold air rising/dropping so a little turbulent), and the A7S as good as it is for low light has its own issues.

i.e. I don't think I'm getting the best out of my 250CRS.

However I am shooting full 35mm frame so edge to edge it's stars are pretty sharp. Mind you the 250CRS has the corrector built in already. I don't know whether your proposed 250 has a corrector or not.

Light falloff-wise, it does vignette somewhat so flats required.

NB: Using the 250CRS for visual though, really nice .

Last edited by AnakChan; 11-04-2017 at 09:11 AM. Reason: adding site note
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  #5  
Old 11-04-2017, 09:31 AM
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multiweb (Marc)
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Quote:
Originally Posted by markas View Post
Has anyone used a Tak Mewlon 250 for deep sky photography.

Because of its light weight it appears attractive as a mobile astrograph, but there is very little about it in such a role, even though it is not new .....

Mark
I got a 210 because I didn't want to have to lug my C11 in the bush due to its weight. For similar FL the Mewlon is light weight and great to image with. Unfortunately I haven't been able to get out much because of the weather lately. I've used it only once on the field at Snake Valley couple of years ago.
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  #6  
Old 11-04-2017, 10:46 AM
loc46south (Geoffrey)
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Hi -

Used one with the reducer on a G-11 for a while. Can be wildly frustrating -
It has a definite lack of backfocus distance and I had to get special adapters machined for a FLI PDF - that was the only focuser I could use with a ST10 with CFW10.

In saying that as a portable scope it is amazingly robust and once collimated and locked it maintained it's collimation to the present day - I have had no need to touch it and we are talking in a time frame of years.

The only other problem was it's cool down time - but once cooled down it gave excellent pictures.

Cheers
Geof
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  #7  
Old 13-04-2017, 07:48 AM
markas (Mark)
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Geoffrey, Marc, Sean,

Thanks for the input, particularly the heads up on backfocus distance.

Mark
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