Except for the galaxy M74 these are all clusters. Except for M56 they are all a dozen or so 80 second ISO 800 shots with the canon t3i through the william optics z61(360mm, f/5). M56 was accidentally done at 10 sec ISO 6400. I’m not sure it suffered all that much for the skimping.




These are crappy, pro-forma, messier sweep images but I like them. I was shooting for M73 which was too close to my roof and getting closer so i grabbed a dozen shots 10 seconds at iso 6400. The one above with the roofile out of focus at the bottom has a nice sky colour. It’s cropped below to show M73 – an asterism of four stars near the left – and M72, a larger globular cluster on the right.

And How About That Takumar!

One of he objects I was excited to shoot with the Z61 was M57 the Ring Nebula. I had captured it with the Takumar 200mm f/4 lens and I thought the larger scope and longer focal length would improve it. It did, sort of, but the Takumar image is still prettier.

On the left above is the Takumar 200mm f/4 11 shots, iso 800, 25 seconds. On the right is the Z61 360mm f/6, 12 shots at iso 800 60 seconds. Both processed about the same way in siril and cropped to the same area then the Z61 image was resized 66% to compensate for the focal length. The Z61 shot clearly show more stars but the image has lots its charm. Maybe I just blew out the ring with too much exposure.

The two exposures are not that different though. The formula is something like L=f^/(iso*time) and 4^2/(25*800) is not very different from 6^2/60*800. So maybe processing.

M14 and M92


These don’t amuse me nearly as much as nebulae and galaxies but i guess i’m going to work through the messier catalog as they wheel past me. M14 and M92 are both about 30,000 light years away so part of our galaxy.

These are both low effort images – 9 or 10 exposures at 60 seconds for M92 and 90 seconds for M14 all at ISO 800 with the canon t3i on the William Optics Z61(360mm f/6).

M102 is Shy But Has Distant Companions.

M102 is a small galaxy considered to be the same as NGC5866. It’s visually small even as galaxies go but it was in an easy part of the sky last night so i captured 30 subs of 60 seconds ISO 800 with the canon t3i and the william optics z61(360 f/6). The usual processing in Siril. The second picture below shows a broader crop where two other galaxies are obvious – NGC5879 on the lower left and NGC5905 on the right. M102 is about 50 million light years away. The third picture is a screencap of wikipedia’s image of M102 and the final one is wikipedia’s NGC5907 both of which blew me away.

M104 – Sombrero Galaxy

Thirty lights 60 seconds each at ISO 800 with the canon t3i through the William Optics Z61(360mm f/6). Processed in Siril with photometric colour calibration and asinh.

I took it for the Sombrero Galaxy but my eye is always caught by the patterns formed by stars in these images. Toward the top right is what feels like a cartoon of a rocketship fleeing the frame and near the middle left there’s kind of an arrow pointing to it. It’s all just perspective though – the sombrero galaxy is 30 million lightyears away and the individual stars are all in our own galaxy but nowhere near each other some are as “close” to us as a few hundred light years and some over 1,000.

My rocketship though is apparently well known as the “Stargate” asterism STF 1659.

M3 – I’m Dithering!

Over-processed as always, this is 40 25 second shots at ISO 800 through the Z61(360mm f/6). Processed with siril’s photometric colour calibration then the black point raised .2. Of the 40 shots, 30 had dithering applied. That’s easy to do, just a button in Backyard EOS, but i can’t see that it made a difference.

Below is a comparo where i processed 10 images with no dither(ND), 10 with dither(D10), 30 with dither(D30) and the whole lot(ALL40).

M63 – The Sunflower Galaxy

You just get a sense of the shape and colour of the Sunflower Galaxy in my cropped and over-processed image. It’s bright but you can see how small it is in the original below. I’m sure I could do better but it was quite a bright night with the moon near full and high in the sky.

This is 35 lights at 50 seconds ISO 800 through the Z61(f/6 360mm) with 5 darks, flats and biases from earlier work. Basically trouble free shoot limited only by conditions. Processed in Siril with per-image background removal. The blackpoint raised with ASINH and colour fully saturated. The speckles you see in the galaxy are really just noise that was all over the image but drowned out elsewhere by the processing.

The image below is from an Astronomy Picture of the Day and you can see the same star patterns around M63.

APOD: 2017 July 12 - Messier 63: The Sunflower Galaxy

The Rosette Nebula

This has been my great white whale for the last couple of months. It’s in the south in the winter which makes it tricky from my back yard. Last night I went to a nearby park where I have a view to the south over farmland. With the snow gone I was able to get 30 100 second subs at 800 ISO through the william optics z61(360mm f/6). I had to stand for the better part of an hour blocking a streetlight but it seemed worth it. There was a pretty strong gradient in the subs but I found a new siril script that seems to do a good job knocking down gradients. Probably a few weeks ago at the last new moon would have been better but i’ll take this for now. The blotch at around 2 o’clock is dust that wasn’t mitigated by my flats. Besides the script I would have used siril’s auto-stretch histogram, the asinh function to raise the blackpoint and colour saturation to boost the colour.

I’ve been looking lately at all-in-one astrophotography solutions like stellina or the EVscope. It’s not that i can’t get decent results but it’s a lot of hacking around in the field and after the fact.

Polarissima Cluster

Another pretty name, the polarissima cluster is also just a few degrees away from polaris opposite polarissima borealis.I seriously just bagged it for the name. The bright star to the right is not polaris – it’s 2 uMi, magnitude 4.

This is 30 60 second shots at 800 iso through the william optics Z61(360mm f/6).