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Galaxy Quest and SLL v3.0

HiloDon

By HiloDon
in EEVA - Reports

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HiloDon

HiloDon

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Hi All,

Had some clear skies at my home observatory last night, so I though I would test out Paul's new version of Starlight Live.  I decided to keep it simple and used my mono Lodestar X2.  I was particularly interested in how the defective pixel removal worked.  I found it to work well for general EAA/NRT viewing, but on close examination of saved images, there appears to be a pattern noise that gets streaked by stacking.  Using darks together with the DPR seems to eliminate the pattern noise and produces a cleaner image.  Attached are some examples of galaxy captures with just the DPR on.

Paul's software is a dream to use and made for a wonderful night of galaxy viewing.  

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HiloDon

HiloDon

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Toward the end of the session, I decided to try capturing Seyfert's Sextet low in the eastern sky.  At a focal length of about 1000mm, even the Lodestar wasn't producing a large enough image scale, so I went with F10 native on my Meade 8" SCT.  The pattern noise was objectionable, so I took some darks and made the capture.  I then decided to try M51 and M104 at the larger scale as well.  Here are the results.  What a fun night it was indeed!  Moon rise was pretty nice, too.

Seyfert's at F5:

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Seyfert's at F10 (Forgot to change caption):

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M51 at F10:

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M104 at F10:

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Ain Soph Aur

Ain Soph Aur

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Lot;s more but looks like my new Astrobin account hasn't fully set i as I can't upload any more for now. Ya know, you can't beat VA/EAA for Galaxy viewing. I viewed more galaxies Tuesday night x 10 that I have viewed in an EP in decades of visual.

 

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Hibou

Hibou

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16 hours ago, HiloDon said:

there appears to be a pattern noise that gets streaked by stacking.

Great images as usual Don. You say that pattern noise is apparently produced by defective pixel removal. That would be important, but I can't see that from your images. It would be great if you could link to a raw FITS file (no dark subtraction) both with and without defective pixel removal.

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HiloDon

HiloDon

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24 minutes ago, Hibou said:

Great images as usual Don. You say that pattern noise is apparently produced by defective pixel removal. That would be important, but I can't see that from your images. It would be great if you could link to a raw FITS file (no dark subtraction) both with and without defective pixel removal.

Thanks, Hibou.

I didn't mean that the pattern noise is caused by DPR, but that there is some noise, fixed may be a better word than pattern, that is not being removed by DPR.  When the images are stacked, there appears to be some streaking evident.  M100 and ngc4725 are probably the best examples when blown up a bit. It became very apparent when I captured Seyfret's at 2000mm.  I then took darks, and the artifacts were gone, but I still used DPR.  As I indicated, the DPR works very well for general EAA viewing.  I should take some fits so Paul can better determine what's going on.

Don

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Martin Meredith

Martin Meredith

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Great images Don and Brandon! Forced to select one to like I selected the Abell cluster as I'm a sucker for the edge-on galaxies that are really impressive in this grouping. That 'little' 6" scope is doing really nicely.

I have a question for both: are you using SLL's nonlinear modes much in these images? Also, it might be interesting to see an occasional screen grab showing the settings. I was quite surprised watching Dr D's broadcast the other night how differently we used the contrast setting, for instance (probably sky-glow related). I always end up with a very narrow histogram and a black point really tight up against the lower edge or eating into the lower part of the histogram; then I use the nonlinear modes to 'expand' the dynamic range and get the graylevel variations. But I imagine there are other combinations of settings that produce similar results.

Martin

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HiloDon

HiloDon

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Thanks, Martin.

I did not use any non linear scaling on the posted images.  I usually try it when I have a significant bright area in the object such as M51, but it tends to make the object look flat like an underexposed b&w photo with film.  I found that the linear setting makes the image pop more.  With Paul's new stacked fits save, I plan on experimenting more after the fact.  I should have saved some and sent one to you to play around with.  Next time.

My settings are similar to yours.  I always have the black level close to the peak of the histogram signal, but always to the left.  Paul's keyboard controls make fine adjustment much easier now.  The width of the histogram varies but is usually narrow.  I adjust the white level and contrast to get the desired effect, all depending on the brightness of the object.

Don

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Astrogate

Astrogate

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44 minutes ago, HiloDon said:

Thanks, Martin.

I did not use any non linear scaling on the posted images.  I usually try it when I have a significant bright area in the object such as M51, but it tends to make the object look flat like an underexposed b&w photo with film.  I found that the linear setting makes the image pop more.  With Paul's new stacked fits save, I plan on experimenting more after the fact.  I should have saved some and sent one to you to play around with.  Next time.

My settings are similar to yours.  I always have the black level close to the peak of the histogram signal, but always to the left.  Paul's keyboard controls make fine adjustment much easier now.  The width of the histogram varies but is usually narrow.  I adjust the white level and contrast to get the desired effect, all depending on the brightness of the object.

Don

Hi Don

Those are some really good galaxy image you captured. I was wondering if there was a way to maintain the brighter regions like the cores from blowing out while still bringing out the fainter regions (dynamic range)?

 

Chris

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