Ngc253

[Peter Ward]

Originally Posted by Alchemy

during the processing did you use a high pass sharpening filter, not the variety in photoshop but one that sharpens just the high values,....

i noticed a sattelite trail to the lower right, what stacking mode did you use was it average mode, ive being using median of late although i usually run most of them just in case one gives a better result initially,....

......which brings me too how many exposures and length of time for each exposure and the camera.

cheers Alchemy

I sum frames, as I have found median, SD clips etc, simply do not let you extract the full dynamic range from the data......like satellite trails !

I also use a high pass layering technique in PS3, so that just the fine detail is ramped up a tad.

Barb also made the comment the "stars have harsh blue haloes"....well, the two near the galaxy are certainly that...because they really are hot blue stars! you'll see elsewhere in the field the vary in colour, some yellow, some more white. I actively try to emphasize star colour in my images.

....Stars are never all white

The image is a LRGB exposure, around 5 hours of data. If I shot from a dark sky, I could get the same S/N in about 1/3rd that time, and not have to deal with light pollution gradients......one the joys of deep imaging from the 'burbs' !

I'm still playing with the data on this one, and appreciate the feedback. While I doubt I'll finally come up with a "one size fits all" version...this one's not quite done yet

[Geoff45 (Geoff)]

Originally Posted by Peter Ward

Barb also made the comment the "stars have harsh blue haloes"....well, the two near the galaxy are certainly that...because they really are hot blue stars!

Hi Peter
Are you sure they are not reflexion halos in the camera? This is certainly the case with beta crucius here .
Geoff

[Peter Ward]

Originally Posted by ghsmith45

Hi Peter
Are you sure they are not reflexion halos in the camera? This is certainly the case with beta crucius here .
Geoff

In the case of the Jewel Box image I have about a 15 magnitude spread between Beta Crux (mag 1.3) and the faintest stars in the image (according to The Sky/Hubble GSC around mag 16 ).... that's just shy of a million to one in brightness levels (!!) ....yep, there is some flare there! but given the dynamics I think the camera/scope did a great job

As for Ngc253's close companions, CCD guru's much more skilled than myself have found them to be blue... so I figured, who am I to change them?

[Tamtarn]

Originally Posted by Peter Ward

Barb also made the comment the "stars have harsh blue haloes"....well, the two near the galaxy are certainly that...because they really are hot blue stars! you'll see elsewhere in the field the vary in colour, some yellow, some more white. I actively try to emphasize star colour in my images.

....Stars are never all white

I'm still playing with the data on this one, and appreciate the feedback.

I may be female Peter but I'm not stupid!!!

Yes I do know that there are different colour stars and they are not all white.

I didn't comment that the stars were the wrong colour just that they had harsh blue halos.

My point was that the stars in your image were very over saturated and compressed giving the harsh dark blue halo. They looked very unnatural.

I'm pleased to see you have reprocessed the data and they do look a little better now

Barb

[Peter Ward]

Originally Posted by Tamtarn

I may be female Peter but I'm not stupid!!!

I'm pleased to see you have reprocessed the data and they do look a little better now

Barb

Jaaaysusssss H ...I didn't call anyone female or stupid so where did that come from?

None other than Jay GaBany also determined those little suckers are blueish.

Harsh blue? Duck-egg blue? I'm still trying to figure out sky blue......

[Satchmo]

Originally Posted by Peter Ward

....Stars are never all white

This does come across as a little condescending. I can understand Barbs reaction. Wink emoticons can make a post look more condescending , intentional or not.. ( annoying arent they ! ) ......

[Peter Ward]

This was not my intent...which was "you already knew/understood that"..but agreed: better to use precise English.

Originally Posted by Satchmo

This does come across as a little condescending. I can understand Barbs reaction. Wink emoticons can make a post look more condescending , intentional or not.. ( annoying arent they ! ) ......

[Kal (Andrew)]

Nice picture.

BTW - those stars definately don't have halo's around them. If you look at what a reflection halo looks like you will see it doesn't look like the blue around those bright stars. IMO, those starts look perfectly normal.

My only critique is the satellite trail, which detracts from the overall image a bit.

[Kal (Andrew)]

Originally Posted by Tamtarn

I may be female Peter but I'm not stupid!!!

This can soooo be misinterpreted by many a male chauvinistic!!!!!

[Garyh]

Very lovely image Peter, sooo much detail in this one,
but I have to agree in what other have mentioned, being a little red in the background.
I gaussian blurred a small selection by 5 pixels that was rather free from stars and the red is up a little?
The diffraction around the brighter stars doesn`t worry me as I know its pretty unavoidable when you stretch your data hard to get the most from it.
But its a cracker image I enjoyed looking at!..
cheers Gary