Full Solar Disk 5th Jan - High Surface Activity

[Star Catcher]

Hi All

This is my second attempt (and best) at doing a full H-Alpha solar disk. Conditions were not quite good enough to do my usual imaging at 2800mm focal length, so I decided to move down in magnification and do a mosaic.

The image is made up from 12 panels taken with the Lunt LS80Tha, DMK41 camera and 2.5x powermate. I have embedded two smaller images to meet the upload limits.

I have also included two Flickr URLs for larger versions (50%) so that you can better see the lovely structures the sun is currently displaying. Thanks.

Higher resolution mono image: My Flickr Photo Mono Version (http://www.flickr.com/photos/74075989@N00/8352703758/sizes/h/in/photostream/)

High resolution colourised image: My Flickr Photos Colour Version (http://www.flickr.com/photos/74075989@N00/8356378065/sizes/h/in/photostream/)

Ted

[Larryp]

Great images. Ted!

[Peter Ward]

Top shelf images Ted.

Hard to do better, if at all. :thumbsup::thumbsup::thumbsup:

[Solar]

Those High Res images are Keepers.
Very nice work Ted, you must be very pleased with the result. :)

[alocky]

Same to you Ted - top stuff! We'll have to swap dmk41 settings sometime. There were a couple of really bright proms when I did mine and I'm surprised they don't show up in yours - are you single or double stacked etalon?
Cheers,
Andrew

[Paul Haese]

Nice Ted. Now there are three of us at Hi res doing mosaics. This should lead to some nice coverage.

Just a minor thing. One of the panels is just barely visible on my screen. Top left area looks like around the second lot of panels down and one from the left. Some minor levels in the midtones will get rid of this during assembly of the mosaic.

[Star Catcher]

Thanks Paul. Mosaics are still a pain for me. Thanks for the pick up. I think you meant the patchiness in the dark background areas top left. Fixed that. Otherwise it might be a little bit of blending error on the disk panels.



Hi Andrew, no I only ever operate in SS mode even though I got the DS. Too much illumination issues with DS. I was focussing on surface features to minimize white level clipping, therefore the proms got lost in the background.



Thanks, yes they came out better than I hoped. I have stuffed up several in the pass and generally avoided doing them.



Thanks Peter, there is a little headroom left for improvement :)



Thanks Larry.

[Steffen]

Fantastic high-res images Ted! When did you venture into solar imaging?

Cheers
Steffen.

[Paul Haese]

Yes I know what you are saying. Mosaics are a pain. I am looking at yet another upgrade to the camera just to eliminate this issue. Mid year Point Grey will be producing USB3 CCD cameras with the same size or larger sensors that Peter and I have. Something larger will produce almost almost two panel mosaics at hi res.

I think what I am seeing also is one panel has better seeing than another and I often see this myself. It is really hard to remove these issues, but it can be done.

That said, this is exceptional work Ted. I need a morning where the seeing is this good myself. :thumbsup:

[Star Catcher]

Hi Steffen, thanks. I have been doing it for about 18 months now. It has opened up my astro opportunities, especially since I am in the Sydney suburbs with light polluition and the weather has made it declining option in my view.

Ted

[gbeal]

Wonderful shots Ted, I applaud your persistence with the mosaics, I don't seem to have the time or inclination.
Gary

[Poita]

Are you using the 2.8MP Grasshopper Express currently Paul?
What size sensor would be required to get the whole disc in 2 panels?

[Paul Haese]

Not to take over Ted's thread, just in short I will answer.

yes currently using it.

The 6mp will currently the whole disc with a 2x, but with a 2.5 would require two panels.

Now back to Ted's fine image.

[Solar]

I am still stoked with those images. Might have to get one of them thar cameras. What size is the chip Ted.:eyepop:

[Star Catcher]

Thank you. I use the DMK41. The DMK41 chip (1280x960) is physically smaller than the DMK51, so my mosaic needs more panels than you would need with the DMK51.
Ted

[Poita]

Thanks Paul, I've started a thread re the cameras in the Astrophotography and Imaging Equipment and Discussions
http://www.iceinspace.com.au/forum/showthread.php?p=932733so as not to derail this thread any more :DTed, how much time passed between starting to image the first panel to when the 12th panel was finished imaging?

[Star Catcher]

umm, let see. I think it was about 900 frame avis per panel gives roughly 12-13 minutes in total. Then there is positioning for each panel say 3 minutes in total. So all about about 15 minutes. There is some risk from surface changes causing minor dislocations, but blending usually sorts it out. As Paul indicated I have a panel which exhibits some variation from the average. It is the variable seeing from panel to panel that has always caused me the most grief, not to mention insufficient or too big overlaps. With the larger sized chip you minimize these headaches.
Ted

[Merlin66]

Ted,
Just a question....
If you're trying to record the full disk features why use a x2.5?
Would you not get a lot more sun in a prime focus image and less # to build a mosaic.....

[alocky]

The DMK41 will do it in 2 panels with the Lunt 80mm and I believe the dmk51 can do a full disk. I use an Antares reducer to get a single frame per disk. Unfortunately, even dithering and decon fails to produce a result comparable to a mosaic in terms of spatial resolution.
Mind you I haven't tried it in autostakkert - could be a job for the weekend.
Cheers,
Andrew.

[Star Catcher]

Thanks Andrew, I agree.



In my basic understanding and explanation, I think it is all about the ability to view the disk as a whole, and then be able to zoom to the native level of resolution as imaged at 2.5X. You have the best of both worlds. If I were to image the disk at prime focus (560mm) on a chip 1280x960 pixels, any attempt to zoom into the disk would pixelate on the details as there are too few pixels to represent the surface structures, remembering that the sun's disk spans 1800 arc secs.
Ted

[Paul Haese]

Exactly. :thumbsup:

[Merlin66]

I agree.
The 900 pixel height would give a sampling of 2 arc sec/ pixel whereas if you use a mosaic to cover 900 x 2.5 = 2250 pixel you get a sampling of 0.8 arc sec/ pixel for a final resolution of 1.6 arc sec.
It really depends on the seeing conditions.

[Matt Wastell]

Excellent!