Why is saturn so dim???? 31st Dec

davidpretorius · #1 31-12-2007, 05:38 AM

Paul was telling me the other night how dim was saturn was and so I decided to give it try this morning.

I could only capture at 7.5 fps and with the clear filter.......the histogram may have topped out at 140 max i reckon.

Anyway, the bands are viewable.......it may be a good excuse to go a 16" mirror

h0ughy (David) · #2 31-12-2007, 07:12 AM

yes it sound to me as though you may indeed have to go to a 16" David

would it be because the rings are moving to edge on

iceman (Mike) · #3 31-12-2007, 08:44 AM

That's a massive image scale, David! Is it enlarged?

I know what you mean about it being dim - very difficult to capture.

You've done a great job to start the season, I love it.

John K · #4 31-12-2007, 09:06 AM

Nice going Dave, yep, due to the tilt of the rings I suspect. Massive scale there!

davidpretorius · #5 31-12-2007, 09:40 AM

you might be right there houghy...........i do need a 16"......seriously, the rings may not be reflecting as much light our way.

Mike and John, i used the 100mm extension tube, which i think gave me 7.7x.......i better check birds calculator.

I then did a 1.5 upscale using ninox

RB (Andrew) · #6 31-12-2007, 10:16 AM

Wow nice image scale David, even taking into account the x1.5 upscale.
Surely it must be dimmer due to the shallow ring angle.

OneOfOne (Trevor) · #7 31-12-2007, 10:33 AM

I would expect the angle will reduce the brightness overall, making it appear dimmer to the eye, but the brightness of the planet itself should remain the same.

bird (Anthony Wesley) · #8 31-12-2007, 10:23 PM

Nice scale there DP. Your image scale pretty much matches with mine for the saturn data I grabbed this morning, I'm also using a 3/2 resample before processing.

Here's my capture settings:

Image scale: 14m focal length, pixel size 7.4u
Red channel: 17fps max gain
Green channel: 17fps max gain
Blue channel: 15fps max gain
camera: PGR dragonfly2

The image is very dim at this scale, so the 12-bit data from the camera is likely to be 10 or 11 bit, not too much of a loss and the seeing has been bad enough around here to want the higher fps. Just means I have to capture 2x as much data :-)

Saturn will get a bit brighter and larger near opposition.

cheers, Bird