Star101

1 hour ago, Davey-T said:

Nice one, whizzing along, meant to have another go at it last night but got side tracked.

Dave

Thanks Dave, Yeah I saw the moon rising and thought of experimenting

Thanks GiorgioF.

I will leave it for now. I just had the urge to image M81 for a few weeks now. I knew last night was not a great night, with the moon so bright, but I still went ahead.

I will image again when we have clear DARK skies

Tried again last night for about an hour. I used the ZWO183mm as guide cam....Not as easy as I expected. Lodestar X2, I think, would have been a better choice. Very difficult to get PHD2 to show much detail with the ZWO camera. Maybe I should have used Darks Library!

Anyhow, I cut the GIF down as the original is 300Meg. This one is 33Meg, if it allows me to upload

I should have said that the GIF image was created using GIMP. 

Deconvolution and a few tweaks.

M81 take 2 

From WiKi- 

Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a spiral galaxy about 12 million light-years away, with a diameter of 90,000 light years, about half the size of the Milky Way, in the constellation Ursa Major. Due to its proximity to Earth, large size, and active galactic nucleus (which harbors supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for amateur astronomers.

Taken with a very bright moon shining in a very hazy sky.

9 x 600s and 11 x 300s Lights

Master Darks/Flats/Bias

C11 with Celestron FR. Atik 4129EX OSC  camera on a Mesu 200 mount.

Collected using SGPro and Processed using PixInsight.

Thanks for looking.

Dave

Very nice Carole.

1 minute ago, geoflewis said:

Nice capture, but curious why it’s posted under solar? Geof

Thanks Geof.

Yeah, I should have put it in Special Events. Could Mods move it please!

Thanks Davey-T. I wish I had remembered it sooner. Could have spent a few hours on this. Maybe tomorrow if its clear I will give it a better shot

Managed 6 x 1 minute subs before rain stopped play.

C11 with focal reducer. Atik 4120EX OSC processed in PixInsight.

Not the best and I know some of you can do better. The tail is there, just needs more time to bring it out. See Inverted Lum.

Great image David.

On my laptop the stars appear to have a green tinge.

If I may suggest one more process to try if you are using Pixinsight. - NoisReduction/SCNR/Green.

Dave

Quick process of data from last nights session where I left the rig imaging while we went XMas shopping

Not the best night as lots of low foggy cloud as can be seen in the final image. Also need new Flats...I'm not sure what the black triangle shade is in bottom right hand corner as this is not on the lights!. Oh well, just a test shot.

I found 600s is too long for the Atik 4120EX with the C11 and FR. The center core is blown out. I will try 300s next time.

16 x 600s Lights 

I think the definitive answer is to process, to the best of ones ability, both images and see which comes out best.

The green cast, in the first image, does not help and is easily removed in processing.

Dave

Having double clicked both images to zoom in on the noise. I think that the second image is better. 

On a normal scale, on my laptop. Both images look the same. Very nice work.

Thanks for sharing.

Dave.

Thats a very nice Helix MG.

This is way too far south for me to see, let alone, image.

Thanks for sharing.

Dave

🧘‍♂️

Very nice images. Well worth the time spent.

I switch between full FL and Hyperstar quite a lot. I also use a hairdryer sometimes to blow out condensation. Its possible dust actually gets blown into the OTA.

The scope is 10 years old now. Its the first time I have ever cleaned the primary. I have cleaner the corrector plate once before. I have not yet touched the secondary mirror. At close inspection, it still looks good to me  

The second image appears much better on my phone. 

I've always found M33 a very difficult galaxy to image. It takes a lot of imaging time to get any detail. I find it has the usual three areas of bright centre dimmer mid drift and faint outer reaches of its arms. 

I think you have done well to get the detail here.

Ditto on flats. They will clear up the vignetting and making it look smooth right across the image.

I have the same camera. Its a great camera. I recommend Darks/Flats and Bias ( I use 1 second Darks as Bias )

Why not give it a go with this image and post it here ?

Are you dithering ?

Dithering makes a world of difference. If you are just imaging and taking shot after shot with no movement of the mount, the bad parts of the chip get highlighted. If you dither ( move the scope very very slightly, between shots. When you come to stack the subs, the image will be slightly moved so the stacking software will align the images on the subs. By doing so, it will move, blend, the chip defects. Making them hardly, if at all, noticeable.  This way, improving the final image  

It took me a while to work out what the issue was. I have had a few late nights but easy days as it was a weekend.  Last night, I looked up, the sky looked fairly clear but my subs looked very dim. Even at 10 minutes. subs. So, I parked the scope up. Removed the camera and filter. Everything looked OK there. Looked at the corrector plate ( that's the front end or the C11 ) Boy was it dirty! Not sure if someone had lit a smokey fire during the previous night or something. Looking further inside, I could see the primary mirror looking dull and dusty too. So, decided I would strip the scope down and clean it up the first chance I get!

The forecast for tonight was not so great. It was a busy day at work but in my way home I called at the shops and got a bag of pure cotton balls and de-ionised water. 

I have read lots and watched many videos on how to clean a SCT scope. My preferred method is to mark up and remove the corrector plate. Have the scope pointing slightly downwards so water falls out and not in   Set about with wet, soggy, cotton balls and clean the primary mirror. Dab it dry with new cotton balls and then finish off with a cool hairdryer. I washed the mirror and  dried it. Cleaned the corrector plate, both sides. Put everything back together being careful not to disturb Bobs Knobs ( Oh Er!! ) .

Tested the scope in the amazing clear skies I had for 20 minutes (edit!.. or was it that I had just cleaned the scope !! ), lol. Did a de-focus test to check collimation and WOW! I could not have gotten a better circular doughnut if I tried. A great success. And all under two hours work  ...Including a perfectly timed stop for tea  

So....whens the next clear sky forecast ?  

Dave

If I take my NEQ6 and scope somewhere there is no mains power. I take my Ring 12v 17Ah 2.0L Engine Power Pack with Inverter. I has USB, 12V cig socket and 3 pin 240V AC socket. So I can plug most things into it. It generally lasts me with my NEQ6, Cameras and laptop about 6 hours. Long enough for most sessions.

I actually used it to help start a Hybrid car last weekend too   That was interesting in itself   ( Youtube is a godsend  lol  

5 hours ago, rl said:

I'm intrigued about the whiteness of the nebula not characteristic of emission lines; is this a processing artefact ?

I decided to go back and reprocess this image as I too was intrigued by the colour. I found that using the STF drag to HTF in Pixinsight can reduce the colour in some images. So I went back to my old method of manually adjusting the Histogram. Adjusting separately the RGB, to align each peak to the others. Stretched and Noise reduced. Colour enhanced. AutomaticBackgroundExtractor applied.

Here is the resulting image.

Thanks for looking.

1 hour ago, rl said:

Nice shot.

I'm intrigued about the whiteness of the nebula not characteristic of emission lines; is this a processing artefact ?

I also like the other incidental features like the galaxies to the left and the fan shaped nebula around the star on the right.

The whiteness is a combination of the camera and my processing. Stretching the image too much can and will reduce the colour of somethings and make them whiter than they are. Bleaching the colour sometimes. I have another camera that gives different colours again. Also, it has been shown several times recently that if you give 10 people the same image data to process then you will get 10 different coloured and contrasting images. I tend to prefer a brighter background than some others. I can make the background darker to make the image prettier but I do prefer detail and not so much aesthetics   

Christophe has posted the info on the other galaxies and artifact on his M97 here

The wonderful weekend continues

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From WiKi - 

The Owl Nebula (also known as Messier 97, M97 or NGC 3587) is a planetary nebula located approximately 2,030 light years away in the constellation Ursa Major.[2] It was discovered by French astronomer Pierre Méchain on February 16, 1781.When William Parsons, 3rd Earl of Rosse, observed the nebula in 1848, his hand-drawn illustration resembled an owl's head. It has been known as the Owl Nebula ever since.

The nebula is approximately 8,000 years old. It is approximately circular in cross-section with a little visible internal structure. It was formed from the outflow of material from the stellar wind of the central star as it evolved along the asymptotic giant branch. The nebula is arranged in three concentric shells, with the outermost shell being about 20–30% larger than the inner shell. The owl-like appearance of the nebula is the result of an inner shell that is not circularly symmetric, but instead forms a barrel-like structure aligned at an angle of 45° to the line of sight.

The nebula holds about 0.13 solar masses of matter, including hydrogen, helium, nitrogen, oxygen, and sulfur; all with a density of less than 100 particles per cubic centimeter. Its outer radius is around 0.91 ly (0.28 pc) and it is expanding with velocities in the range of 27–39 km/s into the surrounding interstellar medium.

The 14th magnitude central star has since reached the turning point of its evolution where it condenses to form a white dwarf. It has 55–60% of the Sun's mass, 41–148 times the brightness of the Sun, and an effective temperature of 123,000 K.The star has been successfully resolved by the Spitzer Space Telescope as a point source that does not show the infrared excess characteristic of a circumstellar disk.

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This morning, around 01:30 I started imaging M97. I managed 14 x 600s and processed in Pixinsight.

Equipment was C11 @2800mm, Atik 4120EX OSC, Lodestar X2 Guide Cam on ZWO OAG. All mounted on the Mesu 200.

Thanks for looking.