The morning of March 1 saw me finally able to get my Mewlon 250 into serious imaging action on the Moon. Seeing was good and I took a few captures just before dawn of the waning Moon.
Images are taken at f/21.6 with the DMK21AF + TMB 1.8x barlow + Astronomik G filter, stacked and wavelet sharpened in Registax and LR deconvolution in AstraImage.
Here are the first two I've processed, Pythagoras with a favourable NW libration and Gassendi:
I was giving serious thought a while ago to upgrading from my 9.25 to an M250.
I wasn't sure it was worth the additonal $$$ to gain a mere 15-20mm aperture...but the superior quality of the optics (1/4 wave Vs 1/20 wave) certainly had me thinking long and hard about it.
Thanks Craig, the telescope is a Takahashi Mewlon 250, which is a 10" Dall Kirkham folded reflector.
You wouldn't see that much detail through an eyepiece though, each of those images is a composite of the best couple of hundred frames from around 1500 frames taken using a CCD webcam. The best frames are then stacked to average out the effect of atmospheric turbulence and the detail enhanced using wavelet sharpening and LR deconvolution.
There's a good article on this site by Mike Salway which explains the process, albeit in the context of imaging Jupiter, but lunar imaging is similar save that you do it in black and white:
A couple of terrific images, well done! I have the M180 so it’s nice to see what the bigger brother can do – very impressive indeed. I’ve often thought that a Barlow less than x2 would sometimes be useful, so what do you think of the TMB x1.8, its performance looks excellent. Is there a supplier in Oz?
Matt – go get one, you know you want to and you will not be disappointed! LOL.
Stephen those images are just amazing. The one on the left is one of the best images that I have seen of the moon. Just superb. It looks as thou you could just jump in to it
Ian
Now where did I put that Tak180 when the clouds rolled in.
...so what do you think of the TMB x1.8, its performance looks excellent. Is there a supplier in Oz?
I like it a lot. It's a few mm shorter than a TV 2x barlow but a bit heavier and much more solidly constructed, it feels likes it's been carved out of a solid block of metal. Optically it's excellent. I don't know of anyone who sells these in Australia, I ordered mine direct from Markus Ludes at APM though I note OPT also have them listed on their website.
wow!
that first shot is absolutely amazing!
just amazing
you'd be proud of that...
now you've got ME thinking! how good would that be on DSOs !!!
:]
frank
What a shot, it actually almost looks like the focus is sharper in the foreground than in the background! The Melon can't be THAT good can it?
I'm seriously reconsidering my dream of an SCT 14" now!
frank
People don't tend to use Mewlons for DSO imaging, at least I haven't seen many DSO images taken through one. At f/12 it has quite a narrow FOV and while Tak do make a reducer for it it only takes it down to about f/9. The other issue is that while Dall-Kirkhams are extremely sharp on-axis they do have a problem with coma towards the edge of the field. Anything longer than about a 20mm EP in my scope and you will see that coma start to creep in.
The Mewlon does make a nice visual DSO scope - at least on any target that's not wider than about 40 minutes. Because it is so sharp and contrasty DSO tend to stand out very well against the background.
I think the apparent focus depth in that image is an illusion. I suspect its because the terrain in the foreground is more cratered and pitted than the smoother terrain around Pythagoras (which I guess is molten ejecta from the impact) and because the foreground is closer to the terminator the shadows stand out more. The other relevant factor might be that when you do multi-alignment point stacking and wavelet sharpening in Registax the regions of higher contrast do seem to benefit more than low contrast regions.
Thanks for that,
Without a doubt the focus issue is an illusion or as you say a result of processing. The image is stunning.
I keep thinking it would do a superb job on smaller DSOs, perhaps it could be tried on M104 (hehehe, here I am putting in an order for an image :] )
thanks for the info keep up the great work
frank
