Here’s another image of Comet 41P/Tuttle-Giacobini-Kresak taken from a Bortle red zone location which is in the middle of a larger city.  No filters and a stock camera on a F/5.6, 480mm focal length telescope were used.

I was able to shoot 2 minute exposures at ISO 400 before it maxed out the light pollution (LP.)    This is the StarFreeze version of the data.   I have lots more data, too.   There is another set of 40x120sec shots and some 90 sec, ISO 400 sub-images I did early on when the comet was lower in the sky and deeper in the LP muck.

For now, this doesn’t look too bad to my eye, considering the conditions.  I would estimate the coma is twice the size we see here from a dark-sky location.  I’m glad the sky was nearly transparent this night.   It made processing easier.

Here’s the obligatory star streaks version:

One thing I’ve found out with using electronically assisted methods to view dim objects in bad LP conditions is this:   Live stacking generally improves things, but only at first.  If you want something as dim as Comet 41P to show any more than just the inner coma, you have to stack with lots more subs using more advanced stacking methods than just average and additive.

So, I shot 103 subs-images, along with 30 darks and about 30 bias images for this object.   I brought them into IRIS and used only the first 60 because that is all I could get to align.   The usual methods of aligning based on the drift per hour in x and y coordinates doesn’t work if the sub-images are not timestamped.      This is another deficiency in the low-end capture and stacking program, RisingSky (ToupSky.)  Not sure if SharpCap has the same issues.

Anyway, at least I was able to obtain a basic image and considering the conditions, it is not too bad.  Compare this to my previous effort with the Aptina AR0130 sensor.   This would probably work lots better at a dark sky site.   But, I don’t know if I would waste time on shooting with the RT224 when I could use the Canon T3, which is more sensitive when it comes to comets and captures a much larger field of view.

I was fooling around with the Toupcam from a red/white LP zone and trying to get Comet 41P to show up.   I ended up using SharpCap and doing live stacking with between 10 to 23 x 8 sec exposures for each stack.  Then, I combined those stacks in IRIS and aligned them on the comet.  It came out to be a total of 18 minutes worth of exposure, albeit in a heavy LP zone.   So, I got it to show up, but the color and faint details of the tail and coma got lost in the noise.

I was able to catch 4 comets on the night of Feb 25/26th, 2017.  Comet Johnson was the last one of the night and I got some good data on it this time.

I have processed the data like usual and included both a star freeze and star streaks version.    I cropped these close at 100% full size.

The full frame is below:

Update Feb 27, 2017:
I actually made a mistake on processing these and the exposure time involved.   There are only two (2) sub-images that were shot for 3 minutes at ISO 3200 (the first two) and the remaining sixteen were all 5 minute subs at ISO 1600.   Doh!  😮

Update Feb 28, 2017:
I had processed them with the 180 sec, ISO 3200 darks and offsets and it still came out.   I wrongly stated to myself (and this blog) that I would not reprocess them with the right calibration data, since it looked good enough.  However, I’m glad I changed my mind:

This was much cleaner in the reprocess.  I have two layers here.  One is the comet and one is the star background.  I didn’t have to slice and dice 10 different processing attempts and put together an image.  I only used the minimum needed.   Nothing from the first processing job was used.

Because of weather, I missed out on imaging Comet 45P when it was near a famous galaxy pair recently.    I finally got to image it from a relatively dark sky location on Feb 26, 2017.   There were no “famous” galaxies in the vicinity this night, but there were sure lots of faint fuzzies in the image to make it interesting.

The star freeze version above came out OK.  Not too bad.  I also did a star-streaks version and I’ve included that below.

Keen observers will note that there is an asteroid in the tail of Comet 45P.   It can be seen in both versions.   I’m pretty sure that is 5081 Sanguin (1976 WC1).

At about 11:00 PM CST on Saturday night, Feb 25th, I decided that I’d hit Comet 41P again.   This time with a longer session, more exposure and a higher ISO.    These images are the results of that endeavor.

I managed to get off 2 shots on Encke before it sank too low to shoot.  One shot was 5 minutes @ ISO 1600 and the other was 5 minutes @ ISO 800.   I added the two together and it came out like you see it above.   Not great, but you can see where it stands.

A different comet is out and about now.  Periodic comet 41P is coming back around and is conveniently placed in Leo and so is up most of the night.    I shot it from a darker sky location and it turned out OK, I guess.   It was a little dimmer than I expected.

I was pressed for time this session, so I went with 2 minute ISO 1600 exposures to match the darks I had already taken for another object.   It really needed a little longer exposure and more ISO.    Next time, I’ll hit it with 3 minutes and ISO 3200, which I hope will be in two days after this was posted.

They say this comet will get better during March, so I’ll probably be shooting it again soon.