H-Alpha Sun 9th Sept in Better Seeing

[Star Catcher]

Hi All

Managed to get some better seeing in between moderate winds this morning. Grabbed this image of some nice active regions with the usual gear: Lunt LS80, DMK41 and TV 2.5X. Thanks.

Ted

Image HA Sun 9th September (http://members.optusnet.com.au/extraspace4/HASun9thSept2012.jpg)

[AstroFlyer]

Fantastic Ted!
Super sharp & love your processing.
Any hints for us beginners?

Arek

[nandopg]

Hi Ted,
Great mosaic showing the ARs 11562, 11563 and 11564. Very well captured and processed.

Fernando

[Paul Haese]

Man that is sweet.

[Star Catcher]

Thanks Fernando, including the AR information. I am lazay in not including such information. This was a single frame shot, not a mosaic.

Ted

[Star Catcher]

Thank you. There are a few tips that come to mind and my apologies if it is telling you how to suck eggs.

1) Seeing is king. Even the best processing won't overcome poor seeing. The solution is to image when you have the best chance of stable thermal conditions. Mornings are usually best but late afternoon can be just as good. If your line of site is close to nearby roof tops, you'll likely get disturbed air, wait till sun gets higher.

2) Variable conditions that show a slow wobble but with occasional clarity of details means that you are likely to grab some good quality frames in your AVI. Stacking programs will sort these qualiy frames for stacking.

3) Sometimes you may pause the capture during more unsteady monents and restart when things settle. You get more good frames. Alternatively extend the number of frames captured.

4) If conditions are not so good, go with the widest field possible. Alternatively if they are great and you need clsoeup views, use a 2X.

4) Precise focusing is hard to achieve in variable seeing and strong daylight. Shade your screen and eyes from direct sun. Focus on fine structure details rather than hard edge of disk.

5) Be careful to ensure the expsoure histogram has sufficient range to take in the lightest and darkest part of the image. This will vary on if you are chasing proms versus surface.

6) Avoid turning up the gain too high as it will show noise in dark parts of the image. Gamma ia adjusted to suit surface or proms or indeed both proms and surface.

7) Always try to achieve the highest frame rate possible.

8) Grab data in avi file. Check file to see if it has captured during reasonable conditions. If you have caught bad seeing, redo.

9) Then you will need to crunch the data through your favourite stacking program. These usually have many settings and some work better than others depending on the data.

10) Run stacked frame through favourite sharpening prrogram e.g. photoshop. Trick is to not oversharpen or to introduce too many artifacts. You may need to correct for uneven illumination, adjust contrast with curves etc etc.

Ted

[Peter Ward]

Fantastic stuff Ted !

[Derek Klepp]

Great pic Ted and good advice.Unfortunately I don,t have a histogram with the Gstar so I just wing it.I can see that it obviously helps when using the DMKs especially in regards to the contrast range.
Derek

[Star Catcher]

Thanks Derek. Yes you can wing it by eye and have done it many times in the past :)



Thank you Peter



Thanks Paul

[AstroFlyer]

Great info Ted.
Thank you very much.

Arek