First Stacking Attempts

trufflehunter (Wayne Robinson) · #1 03-06-2005, 10:18 AM

My first post on the upgraded forums. Great improvement. Thanks to all involved!

Just playing around with Photoshop to start to get the stacking process sorted out. I was put off for a while because of reports that photoshop doesn't offer an 'additive' blending mode. It does offer a 'screen' mode, though, which is what I used here and it seems to work. I've also hit on a nice, easy, nifty set of photoshop steps to remove field derotation from a series of short exposures with an alt-az driven mount. I might work on a little 'how-to' when I've polished it up a bit!

After stacking, I flattened the image and adjusted the levels.

I'd love to hear from anyone who uses photoshop for stacking, especially regarding the 'screen' layer blending mode. Is there a better alternative?

Early days yet... still trying to make a "silk purse out of a sow's ear". These were taken a few weeks ago with the moon up.

Omega Centauri: 4 x 30secs
Jewel Box: 2 X 30secs
Nikon D70, iso 1600 with noise reduction on
Meade LX90, F10, fl 2000mm, alt-az mode

[1ponders] (Paul) · #2 03-06-2005, 10:24 AM

Way to go Truffle. Nice shots.

Now that you're hooked we'll get you up and wedgemounted in no time

iceman (Mike) · #3 03-06-2005, 10:41 AM

Both great shots Truff, well done!

Looks like a bit of trailing on the jewelbox shots, but nothing that won't be overcome!

acropolite (Phil) · #4 03-06-2005, 12:47 PM

Nice effort Wayne. I think I can see some tracking coming on.....

atalas · #5 03-06-2005, 02:33 PM

Good work Wayne ,your on your way!

Louie

trufflehunter (Wayne Robinson) · #6 03-06-2005, 04:31 PM

Thanks guys for the encouragement. I don't think I'll ever be able to use a wedge though, Paul... my neighbours like to turn their lights on without warning! so it's snatch a few seconds here, snatch a few seconds there for me! Also I live near the train lines and everytime a train goes past the ground shakes! That's what caused the problem that looked like poor tracking with the jewel box... I only took two frames and the second frame had a bit of 'train-shake'!

I've got to say I love the idea of stacking several short exposures from an alt-az driven system. I'm going to stick with that and explore all its possibilities! ... for a while...

[1ponders] (Paul) · #7 03-06-2005, 04:36 PM

Do you have a higher ISO setting on your camera? If you do, maybe take half a dozen or so at that speed, yes they will be very grainy, and a couple at a lower ISO (800-1600) stack the faster ones in registax to achieve a single image then stack all of them in PS to remove some of the graininess but still keep your brightness from the higher ISO.

Don't know how well it would work but just a thought

trufflehunter (Wayne Robinson) · #8 03-06-2005, 04:49 PM

1600 is the highest iso on the D70. Good idea!
I tried stacking in registax but gave up in frustration! I've been doing it the 'hard way' in photoshop.

[1ponders] (Paul) · #9 03-06-2005, 04:58 PM

I know what you mean about stacking large kb images in Reg. It tends to choke. Maybe settle for medium sized images but still at "fine" setting (that's how it is in 300D anyway), take 10 or 15 and try it that way. Might be worth a go.