According to Deep Sky Stacker...

[Apollo XX]

...there are about 8500 stars in this image - six of which I can see naked-eye from my backyard. All this past week there were clear skies predicted, but the funny thing about meteorological clear skies is that they can actually be quite cloudy - like in full cloud cover. Anyway, it finally cleared nicely so I broke out the hinge tracker last night. I pointed my Nikon D5000 at Cassiopeia and flicked the little plastic wheel 600 times while the exposures rolled off. That's one flick per-second for ten minutes. The secret is to become one with the metronome. I didn't wind up using all ten exposures, as the skyglow in my area outweighed any advantage gained by stacking additional exposures. There's just too much signal loss when looking over multiple cities and towns that won't turn their lights off.

Cassiopeia, Nikon D5000, [email protected], ISO400, 60s, stack of 5, Registax and GIMP,



Mike M.

[Mark G]

OMG Mike that AWESOME

I understand just what you did to get this FINE image.

FWIW I used my Nikon 2020 35mm film camera to catch my avatar image at Stellafane in the mid 90's. The camera was piggy backed on my C8 on my LXD500 with a WF lens on it at the time. I used the C8 with a 27 mm cross hair EP to hand guide the camera for 10 minutes while keeping focused on the guide star in the X hair The phrase "patience young grass hopper" comes to mind

TY for sharing your most excellent image with us

[AndyG]

Very nice, Mike. Your tracking, focus, and optics are perfect giving pinpoint stars from edge to edge. I like how you can see the Milky Way flowing up through the middle.

[Apollo XX]

Thanks guys! I'm hoping to keep going with some more constellation photography.

Mike

[Apollo XX]

Bill, I'm in the infancy of sky photo processing. Actually, I'm in a good place right now to take advantage of some tutoring from some of our more experienced members. Steve L. and Tom H. have talked in the past about putting together a workshop or two on basic image processing, and I could definitely benefit from that right now.

Mike M.

[NGC7000]

Very nice, Mike. I admire the results you achieve with the tracker. That's actually quite an achievement.

And yes, we should do a workshop. When Andy decides to give one I'll be attending.

[Apollo XX]

Bill, I noticed that you used a lot more exposure time in the Cygnus region than I did in my Cassiopeia image. I went with 60 second exposures at ISO400, F2.8. Even at those conservative settings it amounted to a somewhat over-exposed sub. I blame the skyglow, which there is plenty of when looking NE from my yard. I'm not sure how you able to keep any stars at 6 & 8 minutes. Were you using a very low ISO setting? A tight F-stop? Were you in a dark sky area? I know myself that even at 1 minute @ ISO800 with an open F-stop I'm getting a very washed out result, even more so than your original subs.

No, I didn't do any calibration procedures on this image. I didn't shoot any darks, flats or bias images. I just shot the ten lights and worked with that. I think if I was working from a very dark sky area I would go to the effort of calibration. Perhaps I will try from home as well to see what the result will be.

Mike

[Apollo XX]

Yes, I have seen the special procedure for preserving pure RAW files in Nikons, but that isn't going to work for me while I'm using the hinge tracker, which is hand driven. I'd need four hands to keep the tracker going and turn the camera off and on after every exposure. As it is I am just sure to have turned off any noise reduction features in the menus, which include standard long exposure dark subtraction and high ISO noise reduction.

Believe it or not, my one minute light frames at ISO400 from the other night fell right into the 1/3 range on the histogram. You mention it and it is also something that I heard from Al Takata during a talk at Stellafane last year. I am able to set the dark point in the grey-black range using levels as you mentioned, but I'm getting the bluish sky background when I'm stretching the contrast a bit in either curves or contrast. Yeah, it's a little much, but I do like how it seems to brighten the stars somewhat and I like to it's not too detrimental on such a wide field image. Right now it seems kinda purty to me, but that'll probably change as I progress.

I'm glad you mentioned stacking issues, because I'm doing battle with it myself. I've had results at times where some frames have been skewed 30* apart! I have no idea what I'm doing here and would like to get a handle on it. I see that a lot of imagers use Deep Sky Stacker, so it must be an effective tool. I'm very new to it, but I do wonder if anybody makes something that is a bit more intuitive to the person with a very limited understanding of the processes involved? Maybe if I had more time to play with it...

What's that I've heard about the steep learning curve?

Mike

PS - Now the other Bill, Bill G, suggests using a tungsten white balance to cut through the skyglow, which I have been using. It did seem to cut back on that orange cast I was getting before.

[WCGucfa]

Hey! Did I see my name mentioned?

Mike, believe it or not, I was shooting in daylight WB mode last night, instead of my usual tungsten.
It is rare whenever someone actually follows my rebel ways! I thank you!

Anyway, whenever I don't care about having the stars in the scope show their true colors, I shoot tungsten. This
usually gives a nice space blue to the background and, as you suggested, eliminates sodium vapor yellow/orange.
Last night was different because I got word that Nova Delphinii 2013 had turned a beautiful red as its magnitude
dropped, and I wanted to image this, making daylight WB the way to go.

By the way, the Nova is alive and well at magnitude 9. The change in brightness and hue is impressive in the scope but an image
really shows it in all its splendor, catching the little devil among a million neighboring stars (no averted vision necessary).
As usual, once again I digress!

Bill G.

[Apollo XX]

I'm glad you weighed in BG, because I do like the colors of the stars to be in the picture. I'll have to work at finding a nice balance between exposure and skyglow artifacts while using Daylight WB.

Mike