Hey all,

I was trying last night to capture some Ha data on (to quote Wikipedia) "Jones-Emberson 1 (PK 164+31.1), also known as the Headphone Nebula". I got the JNow coordinates from Stellarium and entered it as a user-catalog object. Slewed, plate-solved, nothin'. Tried the J2000 coordinates. Nada. I was using the "mount control" dialog to search and Goto, followed by Capture and Solve on the Alignment tab with "Slew to target" checked.

Ten-minute Ha exposures at high gain revealed...stars. Which, you know, stars are pretty, but I was hoping for more.

So for a target that's not in any of the downloadable catalogs, exactly how is it best to proceed? Should I enter JNow coordinates in the Mount Control dialog, or J2000? Is the MC Goto + Capture and Solve process the best workflow? If the time is incorrectly set, that would of course make the Goto inaccurate, but won't the plate-solve fix that?

So many things I think I understand, only to learn better once I look closer. Pretty much the story of my life, come to think of it.

The Mount Control window defaults to JNow (I think it is the only part of Ekos that does so, making it a potential gotcha-point). There is a radio button to change it to J2000 (though it is hard to see in the particular color scheme I usually use). I normally standardize everything on J2000. I frequently write down J2000 coordinates from framing something in Stellarium and type them into either the Mount Control window (after making sure MC is in J2000) or into the Scheduler (which defaults to J2000). It works, so you may have gotten Epochs swapped somewhere there.

Thanks Ron! Heh. Speaking of epochs, when the next one rolls around and I have clear skies again, I'll have to try it out...

I've never imaged that target before, so it's also possible that I was spot-on and just didn't get enough signal in ten minutes to see anything. Surface brightness of 20.52 is not a lot.

Rick,

According to Stellarium, the difference between JNow and J2000 for the headphones nebula is several arc-minutes--I'm guessing not enough to put it out of your field of view.



So, the real question is did you actually point to where you were hoping to point?
You could solve the image (e.g. by uploading to astrometry.net nova.astrometry.net/upload)
and see if it agrees.

After some careful inspection of some online photos of the Headphone, I determined that I was, in fact, pointing in the right place. The issue appears to just be that the thing is so darned dim that it wasn't showing up even with pretty long sub-exposures at high gain.