IC 1396 The Elephant Trunk

I LOVE the amount of nebulosity! :shock:

How did you find using the H-Alpha filter? Any issues with guiding? Any blooming on the 15min exposures?

Michael, There was no problem using the H-Alpha filter. The exposure time for guiding was 7 seconds through the filter, but still the guiding errors were under 1 arc second with the CGE mount. There was no blooming at all.

Cool. Good to hear. I always fancied the idea of getting a set of Ha, OIII and SII filters instead of RGB. Only problem is deciding whether to get 2" or 1.25" ones.

Michael according to Ian King you only need the 1 1/4" for the SBIG ST8-XME, which is what I have

Thats one hell of an image. :mrgreen: I always hate imaging with H alpha due to increased exposure times and sleep deprevation.

I would comment on that some of the fainter stars look over sharpened and some of the dark bands look too black.

Have you seen Russel Cromans 'big unsharp mask' method? It works very well for nebula

Perform a "big unsharp mask" on the luminance image:
First, drop the output white level to about 200 using the levels command.
Invoke the unsharp mask filter. Set the radius to 250 pixels and the percentage to between 20 and 40.
Make sure nothing important (e.g., core of galaxy) got clipped. If it did, undo, drop the white level again, and repeat the filter.
Perform smaller unsharp masks as desired to increase contrast in features of interest. I usually do a 100- or 50-pixel radius unsharp mask, followed perhaps by a 10-pixel radius, all at fairly low percentages. Again, the image should not "look processed."

www.rc-astro.com/resources/index.html

Thats one hell of an image. :mrgreen: I always hate imaging with H alpha due to increased exposure times and sleep deprevation.

I would comment on that some of the fainter stars look over sharpened and some of the dark bands look too black.

Have you seen Russel Cromans 'big unsharp mask' method? It works very well for nebula

Perform a "big unsharp mask" on the luminance image:
First, drop the output white level to about 200 using the levels command.
Invoke the unsharp mask filter. Set the radius to 250 pixels and the percentage to between 20 and 40.
Make sure nothing important (e.g., core of galaxy) got clipped. If it did, undo, drop the white level again, and repeat the filter.
Perform smaller unsharp masks as desired to increase contrast in features of interest. I usually do a 100- or 50-pixel radius unsharp mask, followed perhaps by a 10-pixel radius, all at fairly low percentages. Again, the image should not "look processed."

www.rc-astro.com/resources/index.html

Thanks for that Kieran, I'll give it a try later.

Having never heard of the Elephant's Trunk Nebula till Kieran's forst image last month, you're all at it now, with spectacular results. Even for a black and white image Gary, it still has the WOW factor to the extreme.

Seanie.

Gary,

As others have noted, this is a very good result. Please be careful with the unsharp masking, for it has added a small black halo around your smaller stars suggesting that you were slightly overaggressive in sharpening the image.

Either way, good stuff!