The Lightbox and the Leo Triplets

 Here is an image of the Leo Triplets, M65, M66 and NGC 3628, the same one shown earlier. At that time, I was not shooting "flat" frames properly, and the vignetting is pretty obvious-ruinous, in fact. Simply put, the scope is able to send far more photons to the center of the image than around the edges. This was from a single night's subs, with no PhotoShop work done to even out the background. In fact, that was pretty much out of the question anyway, since each galaxy lies more or less on the boundary between light and dark backgrounds; efforts to flatten the background all looked artificial.

One of the principal purposes of flat frames is to measure and correct this, by essentially underexposing the bright areas and overexposing the darkest. There IS an increase in noise caused, so more subs are needed to get the same detail.

This is last night's set...and no background monkey business with Photoshop was used. Before the actual pictures were taken, the light box is placed over the scope and about 20 shots taken of white light through a few layers of translucent white plexiglass. This not only tells the software what the vignetting is, but also defines things like dirt on the CMOS, which it also corrects for.

I shot 160 30 second frames, and tossed about 40; this is roughly an hour exposure. ( I say roughly-stacking is not exactly the same as taking longer exposures.) The result from this single night, however. is better than the combined results from ALL previous shots. Since I don't have the proper flats for the previous nights, I likely won't try adding them to this, but will use this as a new foundation to start building more detail. Also, with the nearby floods off for the night, I was able to capture FAR more detail, especially of NGC 3628 at the top.

In the next few days, I'll also make and process crops of each galaxy; all three are very different and don't really look their best when processed together. Like I said before, the lightbox is a great leap forward, especially compared to the old method of putting a T-shirt over the scope and shooting some shots of the sky the next day.