Big images of DSO

[ollypenrice]

One useful way to think about the size of the object on your PC screen is to think about how many pixels its image has landed on in the telescope.

The question of useful sampling rates is so intractable that I've given up on it. I simply don't know the point at which it stops being useful to go for fewer arcseconds per pixel. I'd have said that going down to about 0.4 was pointless until Julian Shaw kindly gave me this data to process...

By the way, this was at F15...

At the moment I'm imaging galaxies at about 0.9"PP using a refractor and separate guidescope. Even this is very sensitive to seeing, though. I may do only colour when the FWHM values are poor.

Olly

[Analysis Paralysis]

7 hours ago, ollypenrice said:

One useful way to think about the size of the object on your PC screen is to think about how many pixels its image has landed on in the telescope.

The question of useful sampling rates is so intractable that I've given up on it. I simply don't know the point at which it stops being useful to go for fewer arcseconds per pixel. I'd have said that going down to about 0.4 was pointless until Julian Shaw kindly gave me this data to process...

By the way, this was at F15...

At the moment I'm imaging galaxies at about 0.9"PP using a refractor and separate guidescope. Even this is very sensitive to seeing, though. I may do only colour when the FWHM values are poor.

Olly

Wow! That image is fantastic. I wonder what aperture he used? I have seen a wonderful M51 taken with a Mak at F12, but I believe it was a 12 inch aperture, and I believe aperture is important, although I have seen very good 150 mm F12 M51 images, so I know it's possible. 

Mark

[ollypenrice]

2 hours ago, Analysis Paralysis said:

Wow! That image is fantastic. I wonder what aperture he used? I have seen a wonderful M51 taken with a Mak at F12, but I believe it was a 12 inch aperture, and I believe aperture is important, although I have seen very good 150 mm F12 M51 images, so I know it's possible. 

Mark

6 inch refractor plus Astro Physics Advanced Barlow.

Olly