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M32 Andromeda Galaxy Wide Field

Stub Mandrel

By Stub Mandrel
in Imaging - Deep Sky

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Stub Mandrel

Stub Mandrel

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Bit concerned about the star colours, but it will do for first processing :-)

I had to crop out coma at top left, and there was a fair bit of violet halos (expected with a modded camera) reduced by blending in a sharpened version of the green layer as partial luminance. Still not bad for a £25 lens!

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tooth_dr

tooth_dr

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25 minutes ago, Stub Mandrel said:

Bit concerned about the star colours, but it will do for first processing :-)

I had to crop out coma at top left, and there was a fair bit of violet halos (expected with a modded camera) reduced by blending in a sharpened version of the green layer as partial luminance. Still not bad for a £25 lens!

Hi Neil

Thats interesting about the blue halos.  I recently took an image of the seven sisters and thought that there was more to the blue halos than expected.  I put it down to being taken with a doublet, but the modded aspect of the camera must have contributed to it.

 

The star colours are a little pink maybe, but the galaxy looks well.

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Stub Mandrel

Stub Mandrel

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12 minutes ago, happy-kat said:

Nice framing. Did you stop the lens down much? 

That was wide open. I had to mod the lens to focus with my modded DSLR so stopping down means unscrewing the bottom plate and manually adjusting the iris before reassembly!

The motivation for 30mm was (1) because my 400mm lens is a bit tight on big targets and the 135 is too short and (2) because I was getting miserable contemplating the price of a WO61 + flattener.

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Stub Mandrel

Stub Mandrel

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17 minutes ago, Swithin StCleeve said:

Andromeda using a Tokina 300mm.

90% of 206 frames at 35s, unguided, EQ3 cooled Canon 450D.

I'm a newbie to astrophotography, so excuse my ignorance, but does that mean you took 206 photos, at 35 seconds each? If so, how did you not get trailing if it was unguided?

The mount is driven, but just polar aligned. Guiding corrects for small errors in mount alignment or accuracy.

Without guiding my EQ3 will track accurately enough for 1-2 minute exposures if well balanced and aligned, but as teh exposure length increases I have to drop a proportion of subs. At 30 seconds I was able to stack 90%.

I have now got a guiding setup, so I can take much longer exposures for faint objects, but it wasn't worth setting it up for such a bright target especially on a horrible humid night when the laptop would have been dripping with dew!

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Stub Mandrel

Stub Mandrel

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I've had ago just stacking 50% of my subs. The DSS scores were very consistent and lower scoring subs seemed to be totally randomly distributed, but I think they might just have been affected by patches of light cloud as the smaller stack was less affected by CA/haloes but a tiny bit noisier. As it was now much easier to get nice stars, I went with using a bit more noise reduction rather than masking in the galaxy from the earlier image, and kept the colour a bit more subtle.

I haven't cropped this image as the stars at top left are less obviously distorted.

I may try stacking higher percentages until the 'bad haloes' return, I suspect I can improve the noise ratio that way.

59c6a51217c6c_AndromedaBest.thumb.png.c98dca2447a279ea47b890c8a72c59ba.png

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Shera

Shera

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I have to ask seeing as you have used a 300mm lens...how is it not blurry?! I am a newbie and I have borrowed a Canon EOS 400d camera and on of the lenses is 70mm-300mm and everything at 300mm is fuzzy! And my Andromeda is tiny! Did you zoom in on the stacked image to get this close up of Andromeda?

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Shera

Shera

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5 hours ago, Stub Mandrel said:

Are you using long exposures, stacking them and then stretching them? If you are taking short exposures and not stretching them you will only get the fuzzy core which is much smaller.

Not at the moment, I'm hoping to buy a Skywatcher Star adventurer tracker but I was concerned that the lens wasn't up to it based on just doing tester shots of 15-30 secs (not stacked). So I have to stretch the image...is that like cropping an image? Is it possible to do on GIMP or do you stretch an image on DSS? Thanks.

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Stub Mandrel

Stub Mandrel

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Stretching is done with the histogram and curves tools, it can be done in any package.

There are lots of tutorials online, this one is fairly short, its for PS but Gimp is almost the same.:

https://www.awesomeastronomy.com/tutorials/dso-astrophotography/59-processing-your-images-in-photoshop

I suggest you consider buying a copy of Every Photon Counts (I should be on commission...)

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