Comet Lovejoy (C/2014 Q2) with DSLR on Motor EQ-1 Mount

I'm getting better at polar-aligning my motor driven EQ-1 mount, and increasing the total exposure length I can achieve without star trails. However, now I'm running up against another barrier - I'm getting to the point where my sky conditions have too much light pollution to even merit longer exposures.

My longest single frame without star trails (left) straight from the camera. I love the aqua color of the comet without any processing! Stacking always seems to make it a dull green.
ISO 1600, 300mm, f/5.6, 20 seconds, Canon T5i on motor driven EQ-1.

With the sky beginning to wash out even after 20 seconds, you can tell that my techniques are advancing up against another ceiling, the sky conditions themselves. Even if I did have a super fancy tracking mount, would it even be worth it if I can only get exposures of 20 seconds?

Comet Lovejoy C/2014 Q2 with Canon T5i on EQ-1 mount
Stack of 31 light (ISO 1600, 300mm, f/5.6, 13 sec), 21 dark, 23 bias, and 15 flat frames
Processed in DSS

Comet Lovejoy C/2014 Q2 with Canon T5i on EQ-1 mount
Stack of 31 light (ISO 1600, 300mm, f/5.6, 13 sec), 21 dark, 23 bias, and 15 flat frames
Processed with layers from both DSS and Photoshop

And yes, I'm using flat frames like a good boy! Every time I learn something new it seems to make my imaging procedures longer not shorter! Flats make a big difference though, it's like the "eating your vegetables" of astrophotography. I used the same technique I talked about in this previous post.

Flats should be gray, not white. Below is a sample of one of the flat frames (left) and that same frame with the contrast turned WAY up (right) to show that there really is some gradient and vignette information there even though to the naked eye it just looks like an even gray wash. The purpose being that the image processor, such as Deep Sky Stacker, will remove the hot spot gradients and corner vignettes.

One of my flat frames with contrast boosted on one side to show gradient information hidden within. Adjust exposure time until you get a good histogram just to the left of center. This one happens to be ISO 1600, 300mm, f/5.6, 1/640 seconds.

Taking flat frames with DSLR - I actually took them hand-held as close to the screen as possible while moving the camera around to make sure I didn't get a dust spot in the same place each time.

Comet Lovejoy Shines Green on New Year's Eve

One last post in 2014 ya'll! Here is Comet Lovejoy C/2014 Q2 at 10pm ET tonight, taken with my DSLR on a fixed tripod and stacked in Deep Sky Stacker. In spite of the bright moon, the skies were completely clear and the green color showed up without cheating the saturation up at all!

In Photoshop, I stretched the histogram in levels by sliding the gray slider to the left, then used the eye dropper in Curves to identify the grays and turn them up. Next, I created a Gaussian blur layer and subtracted it to get rid of the slightly red hot zone that I had from not taking flat frames.

Canon T5i on fixed tripod, stack of 46 light, 21 dark, 12 bias, 205mm, f/5, ISO 3200, 1.6 sec

Crop of the above image

Happy New Year everyone! See you in 2015!

Comet Lovejoy C/2014 Q2 in Lepus

Comet Lovejoy C/2014 Q2 is currently in the constellation Lepus, and the celestial rabbit's bunny ears made excellent pointer stars to help locate the comet last night! The comet was visible with binoculars and with my DSLR even through thin clouds. Tonight is supposed to be crystal clear, so I might make another attempt to photograph it since I don't really have any NYE plans.

Brightness, contrast, and saturation adjusted in Photoshop

Original image, single frame with Canon T5i, ISO 3200, 75mm, f/4, 6 sec

Comet Lovejoy (C/2013 R1) November 14, 2013

Comet Lovejoy: 107 subs, 29 darks, 42 bias, 300mm, 1.3 sec, f/5.6, ISO 1600

I heard Comet Lovejoy was showing up better than Comet ISON, and boy is it! Because Lovejoy is higher in the sky, there's a lot less atmosphere between this dirty snowball and my camera. I took these photos at 6:00am ET on the morning of November 14, 2013.

My stack of 107 light frames shows a bright coma but not much color due to the short exposure time (1.3 sec for each frame). In a longer exposure, the comet and stars form streaks across the sky, but the cool emerald color of Lovejoy's coma is very nice.

Comet Lovejoy: Single frame 8 sec, ISO 1600, f/5.6, 300mm

Looking at the individual frames, I noticed the comet is very close to a 9 magnitude star which creates the appearance of a dense point of light in the center of the coma. Sadly, the comet is all green fuzz from my perspective, but the adjacent star makes it look like it has a visible head.