Thwarted By Christmas.....LIGHT POLLUTION

So, betwixt the howling winds and numerous cloudy fronts, I've been trying to shoot some targets on my to-do list.  One of those objects is a large, faint structure known as the "Angel".   I last tried back in February, but I didn't realize how faint the structure was.   In the meanwhile, I figured that if I hit it with maybe 70-80 subexposures, I'd get something decent.

So I started taking exposures in the early morning hours of the 24th.  Unlike the night of the 22nd, it was a calm, decent night with okay transparency and seeing.   I shot about 24 frames at F/4, 1600 ISO, 600 sec -- all through the 135mm lens.

After stacking the images and having a preliminary look, I discovered a problem I dreaded:  a light pollution gradient !!!     Normally, light pollution isn't much of an issue unless you're shooting directly over the neighbor's houses.   But starting about a week ago, everyone had their Christmas lights on.   The neighbors to one side (directly under my target) have strung a bunch of lights in their front yard.   After letting my eyes get dark adjusted, I could see the air glowing above their house -- presumably from all the moisture.  It really didn't occur to me until I started shooting that it would be an issue.  The 135mm lens has a hefty, solid metal lens shield that extends about 3 inches out from the front of the lens.   But it didn't matter.

The image has been heavily stretched in Photoshop to bring out the faint nebulosity.

Most of the subexposures for this image were about 40-60 degrees up in the air.   Yet the left-hand side which corresponds to the ground is swamped with light pollution.

Here's a negative version to see the structure with a little more contrast:

So, I thought about getting a light pollution filter, but I think the better option is to simply wait 3 weeks and start shooting after the lights are down.

BOO for Christmas light pollution!  

....a little while later:  

I wanted to note that during the night the exposures started showing a slight oblong shape to the stars.  The guiding was perfect so I attribute it to some sort of flex.   Last Feb when I tried shooting this on the Orion Sirius mount, I had the same problem.  

This last time, when I brought the camera in, I noticed that the locking knobs that hold down the dovetail were slightly loose.    I assumed it was just the locking screw that holds the camera down, but it may be a combination of things.

Note to self:   Cinch down everything really tight AFTER slewing the scope AND BEFORE starting another run.