Here’s one of those images I’ve been playing with over the last few weeks. It combines a number of shots into one image and I try really hard to minimize the blending errors. Doh! 🙂
I have two versions of it. The 2nd version below has better resolution, but is cropped tighter and is not quite the field of view I was hoping to encompass like in the 1st one above.
I took the very good Feb 2017 version of M45 and combined it with 3 other good images taken with the same scope as far back as 2011. I still have more that I can add to it, but for now this will do.
Not satisfied with the first version above, I worked up a darker version with more contrast and noise reduction.
It was Friday, March 3, 2017 and the weather was iffy for imaging at my dark sky location. So, I decided to stay in town and try some short-exposure imaging with the Toupcam color planetary/guider cam I have.
I also wanted to try out an adapter I purchased for the Orion Star Shoot so that it can work with the Orion Ultra-Mini, 130mm, F/4.3 guider scope I’ve been using. This worked better with PHD2 than I thought it would. It seemed more accurate than the Toupcam with less dropped frames. In fact, I’ll probably leave this as the permanent guider setup.
For the Toupcam, I used a two inch extension on the TV-85 at F/7, but I still had to let the cam and extension hang halfway out the focuser to even reach focus. But, it was stable enough to try some simple targets like the Orion Nebula.
I used a software program called SharpCap for acquisition, dark subtraction and stacking. It worked well enough for M42, but it had trouble with stacking dimmer objects like M46, an open cluster with plenty of stars in it. I used IRIS to stack the individual frames manually for that one.
The last two images were tests of a relatively dim galaxies, like NGC 4565 and M64. I only got 16 frames for NGC 4565, so it is not too special. But, it shows the galaxy well enough to recognize what it is. Like the previous image, it was also stacked manually in IRIS.
For my M64 dim galaxy test, I accumulated 38 frames @ 8 sec each. It was also a test of using a video file format called .SER that was designed for astronomical imaging. It is like a video file. After I downloaded a SER viewer/player, which also let me export the frames out as TIF format, I was able to bring the data into IRIS and stack.
I really didn’t have time to shoot this like it should. But, I just had to get a minimum of 3 shots of it since I could see it with my naked eye. It was calling me. lol
Later, I reworked the image to bring out more of the blues in terms of color balance:
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.
It was a beautiful evening and I just had to shoot the Pleiades (M45) from my new dark sky site. They just looked too good from there.
I wanted see how much I could pick up with the unmodified Canon T3. It is definitely a camera that is sensitive to blues and cyan. It does comets and galaxies well enough. It is not as good as a modified camera on nebulae, unless its a reflection nebula like M45.
This is about 2.58 hours of integration – about the minimum needed to bring out that faint background nebulousity I’ve always tried to get. It is difficult to decern the true background if there are any gradients, unfortunately. There were a some here and I tried my best to minimize them. Towards the end of the set, M45 moved into the muck and a little LP from a small neighborhood to my northwest. Plus, the zodiacal light was contributing a gradient, too. It was interesting to see that, though. 🙂
Below is the normal orientation for M45 with some noise reduction thrown in. I didn’t do any to the first image. That was pretty much how it came out after stacking.
And finally, the gaudy, maxed out version:
🙂
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.