Two new images

by Richard Crisp

Bill Drelling dropped by last night to visit and watch me doing some imaging. His relocation from The Big Easy to Alameda was Louisiana's loss and our gain. Bill's an interesting guy that's doing good work keeping our ports safe and secure (commander in the US Coast Guard in charge of homeland security for our seaports). I'll tell you I sleep better at night knowing we have top caliber people like that out there protecting us from the bad guys, but I digress.

While we were chatting it up in the backyard, I was finishing my Halpha data of CED90/lower end of the Seagull Nebula.

Here is that effort: three hours of Ha shot from my AP180/IMG6303

http://www.narrowbandimaging.com/cederblad_90_ha_page.htm

Also a new image, is this shot of M109.

I have been trying to shoot M109 for a few days using the 18" f/12.6 cassegrain.

The seeing just hasn't been what I was getting back in late November / early December. The best I've been able to get is low 3s versus high 1s to low 2s back then.

Still I wanted to try it anyway using my ST10XME and AO7 self-guided.

I had believed when I took this data that I was using a luminance filter. After all the data was taken I discovered I was using a blue filter! That explains why I was unable to get a bright enough guidestar when I was able to just a few days before when I was shooting luminance binned 1x1

This time I binned 2x2 in hopes of avoiding oversampling so badly and in hopes of getting a guidestar that would permit the AO7 to run faster than 1.2 Hz

Well as I mentioned I was unable to get the AO7 to guide at all so I just guided with the built in self guider of the ST10XME.

I sort of think that I would have been able to get decent results had I been actually using the Luminance filter but I guess I will have to wait until another night rolls by that is clear and has reasonably steady skies. Hopefully this tiny guy is still in season.

I ended up shooting 13 shots of 10 minutes each binned 2x2 though an Optec Blue filter (IR blocking). I used that filter because that's what is in my filter wheel. Someday I'll probably buy a set of Astrodon 2" ones to replace these ancient Optec ones.

This is not a very large galaxy. But it is too big to fit onto the ST10XME sensor and have a guidestar using this focal length.

If I were able to rotate the camera 90 degrees it would have fit the FOV better but there would be no guidestar if I were to do that. This is what I call the self-guiding blues. I'm not bashing SBIG but this is exactly one of the problems with self-guiding that I have in mind when I state that self-guiding is not the end-all be-all solution for guiding. There are scenarios where you cannot get a guidestar and frame the image properly. This is one of them.

The data is a bit thin but now that I realized it was shot through a blue filter it makes sense.

I discovered the blue filter was used on the following morning when I happened to look down the aperture of the scope and saw the filter.... It wasn't clear!!

here's the image

http://www.narrowbandimaging.com/m109_spiral_galaxy_in_blue_light_page.htm

I am really eager to get some good seeing again so I can take some decent images with this monster. It can deliver but it needs good seeing to do so.

No flattener or reducer was used. Straight up 5760mm f/12.6

Posted on sf-bay-tac Mar 16, 2005 20:52:08 PT
Converted by report.pm 1.2 Mar 18, 2005 20:45:39 PT