M101 Luminance

[Rocket Pooch]

Hi,

6x15 minute subs, flats applied, I have RGB, just thinking about processing it, but I'm well chufed with this.

Chris


M101-Luminence by chrissuddell, on Flickr

[RobertM]

That looks really nice Chris with plenty of detail.

[JohnP]

I bet you are chuffed - that looks superb & massive - the galaxy near on takes up the whole 3000 pixel frame. Tons of detail & very smooth.

Impressed - John

[PhilB]

Impressive. There's a fantastic amount of detail, you've every right to be chuffed.

[MarkS]

Very good image, that.  What focal length are you using?

It would need a large number of subs to start bringing detail to those very faint outer arms.

[Rocket Pooch]

Hi Mark,

I think its about 1.5 meters, I need to meausre the FR to chip distance to work it out properly.  But its an SCT so that will not be too accurate..

Chris

[The Thing]

Hi Chris,

If you get someone to solve the image in Maxim 5.x it will give you the size of the field of view and you can work out the focal length from that. I did it once for my set-up and with my Baader Telecompressor, DSLR at prime focus, the focal length came out to about 1250mm. I must have done the same with an image with no FR in the train and then worked out the ratio of the FoVs. I assumed that the base focal length was 2000mm, but that depends on where your mirror is in the OTA (8" SCT of course). There is probably an accurate way of using this information to work out the actual focal length for a given FoV with a DSLR at prime focus.

Duncan

[Fay]

Looking very nice indeed, Chris

[RobertM]

Hi Mark,

I think its about 1.5 meters, I need to meausre the FR to chip distance to work it out properly.  But its an SCT so that will not be too accurate..

Chris

I can plate solve to get you the f/l in MaximDL when I get home if you like ?

[Whitters]

Real nice image Chris.

[mickw]

very nice, loads of detail in the arms

For some reason the image on the forum looks blocky and horrible, but the full size on Flikr is perfect (on this machine anyway)

[Rick]

For some reason the image on the forum looks blocky and horrible, but the full size on Flikr is perfect (on this machine anyway)

Looks fine here. Is it a progressive JPEG? Maybe your machine gave up half way through?

[MarkS]

For some reason the image on the forum looks blocky and horrible, but the full size on Flikr is perfect (on this machine anyway)

I have the same problem at home with "blocky images".  At work it looks fine but at home it looks blocky and horrible.  I strongly suspect the reason is that, in my case, I am using mobile broadband at home (until my "proper" broadband is installed).  I bet there is some kind of "bandwidth optimiser" that doesn't download the highest resolution of a progressively encoded image.

BTW the blockiness is just as bad using either IE or Firefox browsers.

[Rick]

BTW the blockiness is just as bad using either IE or Firefox browsers.

Weird. Makes me wonder whether the server is doing something different when it thinks it's talking to a mobile phone...

[Rocket Pooch]

It's not the server its bandwiidth Nazi's pn mobile devices then de-res images so all the little iPhone people don't swamp the mobile internet with images.

Look fine here, but hey I have the origional..

[mickw]

My laptop is hooked up to "50 meg broadband"  via gigabit ethernet and it still looks blocky on the forum but ok on flikr

[MarkS]

I've got my fixed broadband connection now

With the fixed connection I don't get blockiness.
Going back to mobile broadband I get blockiness.

Hypothesis supported ...

Mick - going back to a fixed connection, you might need to refresh the images to download the "non-blocky" version.

Mark

[MarkS]

My laptop is hooked up to "50 meg broadband"  via gigabit ethernet and it still looks blocky on the forum but ok on flikr

Your browser has probably cached the low resolution version. Try refreshing the image - it worked for me.

[mickw]

Cleared the cache - sorted - Thanks