some WL close ups, 2nd July

[Joseki]

Had my first go solar imaging with my evostar 120 this morning, despite constant high level cloud.  Using a lunt wedge + continuum filter + baader UV/IR filter and a GSO 3x barlow, + ASI120MM camera.

1000 frame captures, stacked in AS!2, keeping 10%, tweaked in GIMP

I'm pretty pleased with the granulations, they're my best images so far.  I was tempted to false colour them green in honour of the continuum filter but I'm not sure it would look 'proper'

I had a go Ha imaging with my Quark but the images are no good - mainly because of newtons rings.  I took a flat, but not very carefully since the images looked fine on screen and I think I'm just going to give up on that data, especially since I haven't found the best setting of the Quark for that scope yet.  Imaging is quite fun but I've also been enjoying the view.

Aligning my mount in daytime is another skill I seriously need to work on.

[DrRobin]

Fantastic white light close ups John.

I have only tried an ASI120MM on my Quark once. Directly connected there was Newton Rings, but I put a 0.5x focal reducer on the ASI and they went completely. Just for the record, my DMK41 shows slight Newton Rings without a focal reducer so I was pretty impressed with the ASI.

I want to see how close the FR can be to the ASI, so it gets rid of the NR, but keeps the high magnification.

Robin

[Joseki]

Thanks Robin, I've been reading your Quark posts with interest (and the rest of them).  I don't have a focal reducer to try and I wondered if the effect of it on Newton Rings would be consistent across different scopes.  Also for just twice the price of a focal reducer I can get a tilt adaptor,

http://www.365astronomy.com/t2-camera-tilting-unit-from-teleskop-service-p-3653.html

which ZWO specifically mention as a solution to Newton Rings, Ha imaging and  the AS120MM.  

and seems to work okay:

http://zwoug.org/viewtopic.php?f=24&t=1395

[DrRobin]

The pictures on the ZWO site are pretty impressive with the tilt adapter.  If you get one post a comparison, I might be interested.

I don't fully understand what causes the Newton Rings, they look like they are generated by diffraction, but do appear to be caused by internal reflections.  I have found that as the magnification is pushed up they seem to get worse.  With my Lunt 60 double stack and a DMK41, they are not visible.  Add a 1.5x barlow and I can just see them depending on the tuning.  Add a 2x Coronado barlow and they are very visible, although poor tracking and averaging usually gets rid of them.

Just one more thing to throw in, I often look down the blocking filter without an eyepiece, just to check that the scope is aligned before putting the camera in.  I noticed Newton Rings in the Quark and have never seen them before.  Now I do wear reading specs and it could be that the Quark and scope has a much longer FL than my Lunt, but I was a bit surprised.

Robin

[Montana]

Superb!! very fine work indeed :)

Alexandra