M101 plus UFOs

[Kaptain Klevtsov]

Last night there were loads of triangular UFOs in front of M101, you can see their Nav. lights in this shot. :D

Captain Chaos

[FLO]

We're being invaded :shock:

[OXO]

Nice pic, i used to get those pixels too

James

[FLO]

What is causing them?

[MartinB]

You've also got some Turquoise pacmen - the wind I reckon. Had a little play cos I need all the practice I can get. Filters/noise/dust & scratches, radius 2 and move the threshold as far right as possible before the hot pixels reappear. This smooths out the wonky stars a bit. Then a bit of a histogram stretch, hue reduction and despeckle. A little bit of lassooing.

I guess from looking at the pixels that you used 3 subs. It's so tricky M101 - there is so little light showing up against the background sky.

Showing up well CC - just need a few more subs. Well done for perseverance grabbing the opportunity to get out

[Kaptain Klevtsov]

Thanks for the repair Martin. What makes you think it's the wind, rather than out of focus? I had assumed that the fault was with me again.

Perseverance? After a combination of Big Brother and Eurovision I had to leave the house!

Captain Chaos

[MartinB]

Your M101 looks pretty sharp and the shape of the stars suggests some movement. Only guessing.

[Kaptain Klevtsov]

Steve, the coloured dots are hot pixels on the DSLR chip. The pattern comes from Registax lining up the image rather than the frame so the pattern gets repeated throughout the image.

Captain Chaos

[OXO]

CC, is there a hot pixel removing piece of Software for your Camera? i ask as i had one for my Nikon coolpix and it worked a treat!

As Martin has said it does look like the image has been affected by wind rather than out of focus, those stars look too tight really for it to be out of focus..

James

[Kaptain Klevtsov]

James, yes there is and I could do dark frame subtraction but I decided instead to ditch the image and try again another time. The wind wobble is too severe to rescue anything I think. I just posted it as I thought it would a) give us a laugh and show some hot pixels to talk about.

Thank goodness its the wind and not me making a mess of the image.

Next job, do shorter subs and / or try the noise reduction in camera and, of course, try again when its not windy.

BTW, anybody know if Newts are prone to wind movement more because of their size? I'm guessing yes, 'cos it's like a sail, and would a solid pier help, or does the OTA flex?

Captain Chaos

[MartinB]

Next job, do shorter subs and / or try the noise reduction in camera and, of course, try again when its not windy.

I think you need the longest exposures your set up will allow for something like M101 in order to bring out faint detail and to keep the noise down.

[FLO]

Steve, the coloured dots are hot pixels on the DSLR chip. The pattern comes from Registax lining up the image rather than the frame so the pattern gets repeated throughout the image.

Thanks CC,

Thats a lot of hot pixels! (Even allowing for Registax having duplicated them).

[OXO]

CC, the software i used for my Nikon coolpix let you RE-MAP the hot pixel array on ya imaging chip, after the first go all Hotpixels were removed from the camera and i didnt get any Hot pixels anymore(Even 1yr later). The software wasnt devoloped by Nikon it was a third party software company maybe worth a look arounf the Net for one CC...

James

[Kaptain Klevtsov]

I've considered a remap but that could mess up the normal working of the camera. At less than a minute exposures the hot pixels aren't a problem and can be sorted out easily if they are. The remapping for several minute exposures might not be all good.

I'm currently working out a way to get the Newt. to focus with a 2x focal reducer when using the SC3. This would then let me snap this fuzzy (albeit in monochrome) once and for all.

Captain Chaos

(laser collimater in the post for moving the primary up the tube)

[CELESCOPE]

very good CC this is a very hard target to get , and you have done very well there mate , got some nice detail in the outer arms to , keep at it mate ,

Rog