Those are simply hot pixels in the individual subframes...when you align the stars, they give a history of how your mount tracked over the duration of the session.

I use Maxim which has Hot Pixel removal tool which wipes out errant pixels.  Barring that, you can use image processing programs to clone them out.

Darks won't always wipe them out.

Rick

Thanks, guys...I was very happy with this one...

That's exactly the filter I used for this one.  And I didn't use any gradient correction or flatfielding.  I still don't buy that the 13nm pass filter is less than ideal for moonlit conditions.  I've never seen a Moon gradient on any of my images.
With the DSI Pro, you've just got to get a long enough exposure to overcome the read noise, particularly with narrowband. 

I've got a bit of light pollution...
http://cleardarksky.com/lp/JCVnOBMIlp.html
I'm just to the left of the central crosshair, on the border between the Red and Orange.  I'm about 3 mi from an international airport.  Due to this (as well as my severe tree situation), I can only image in the East.  It's a limitation, but one I can plan for.  I can only get to about 30-40 degrees of the horizon, so things like the lagoon, eagle...are out.   It's forcing me to think a little differently, and I'm orienting myself more towards higher resolution imaging, where the target selection is more varied.  Luckily, I was able to do a lot of widefield and southern stuff in Arizona.



SD Mask is essentially Ray Gralak's Sigma combine that's built into MaximDL.

I just made up the pseudo dark subtraction thing.  THe ST2000 with the 2020 chip has very little thermal noise, similar but not quite as good as the SXV-H9.  I can get rid of the bright spots with hot pixel removal like  with the SXV, but there is still some lower level noise that I like to call "thermal rumble".  I find that I get best results by doing the hot pixel removal on both the light frame and the dark frame and then do the dark subtract.  With normal dark subtract, I'd tend to get darker "pits" in the image.  Being lazy, I didn't want to do a load of 8 minute darks, to I just used some very smooth 2 minute darks I had around.  It didn't get rid of all the "rumble", I'm sure, but it likely helped.   

This kind of stuff drives those who do everything by the books crazy.  That coupled with the fact I've never done a formal G2 color calibration draws a lot of "why not"s from many, and I can't argue with them because it's just laziness.  But it's laziness chosen to minimize time and effort with minimum expense of image quality.


Rick

Here's an approaching full moon Ha image I was able to grab last night.   Gotta love narrowband imaging!

http://www.ricksastro.com/DSOs/NGC6888_TEC.shtml

Regards,

Rick Krejci

The 8" doesn't have the bigger threaded backplate that the 10 and 12 have, so the eyeopener, even if it did any good, wouldn't fit.

Rick

Here's the SCT Users Contest site:

http://www.rothritter.com/contest/2005/

I'd also like to congratulate Ted...he did a lot better than I did (second vs. 4th)!


Here's an excerpt from the results message:
---------------------------------------------------------------------------------------------------------------
Category #1 - Best astrophoto of a solar system object

First place - P. M. Heden - lunar eclipse - William Optics
ZenithStar 80 donated by Astronomics

Second Place - Barre Spencer - first quarter moon - $50 gift
certificate donated by Astrotec

Third Place - Monroe Harden - lunar eclipse - Celestron SMA 12mm
1.25" eyepiece donated by Anacortes


Category #2 - Best prime focus astrophoto of a deep sky object

First place - Rick Thurmond - M8 - Tandem 14 Bar donated by ASTRO
Accessories

Second Place - David Gimenez - M101 - 11mm Bird's Eye View - 1.25"
eyepiece donated by Anacortes.


Category #3 - Best CCD image of a solar system object

First place - Eddie Trimarchi - Moon - Meade DSI Color donated by OPT

Second place - Ted Wilbur - 30mm Bird's Eye View - 2.0" eyepiece
donated by Anacortes

Third place - Adam Stuart - Moon - Celestron SMA 12mm 1.25" eyepiece
donated by Anacortes

Fourth place - Dennis Persyk - Comet Machholz - Cloudy Nights T-shirt


Category #4 - Best beginning CCD image

First place - Jason Hissong - M83 - SAC 8 CCD camera donated by OPT

Second place - Bob Runyan - M51 - "The New CCD Astronomy" donated by
Ron Wodaski

Third Place - Rufus Kendall - M57 - Celestron SMA 12mm 1.25"
eyepiece donated by Anacortes

Fourth place - Francesco Corrao - M57 - Anacortes Telescope Logo T-
shirt


Category #5 - Best Prime focus CCD image

First place - TO BE ANNOUNCED IN A SUBSEQUENT E-MAIL

Second place - Sean Walker - M33 - "Image Processing: The Zone
System for Astro Imaging" donated by Ron Wodaski

Third place - Dennis Persyk - Rosette Nebula - 11mm Bird's Eye View -
1.25" eyepiece donated by Anacortes.

Fourth place - Rick Krejci - M81 - Celestron SMA 10mm 1.25"
eyepiece donated by Anacortes


Category #6 - Best digital camera image of a solar system object

First place - Mike Lecza - lunar eclipse - Celestron C-130 Maksutov-
Cassegrain telescope donated by OPT

Second place - Nicholas Carbajales - Moon - Astro Chair donated by
Buy Astro Stuff

Third place - Don Joski - Moon - Celestron SMA 12mm 1.25"
eyepiece donated by Anacortes

Fourth place - Jacques-Andre Regnier - Moon - Anacortes Telescope
Logo T-shirt


Category #7 - Best digital camera image of a deep sky object

First place - Jeff Crilly - M81 - Meade DSI Pro with color filter
set donated by Astronomics

Second place - George Gajdos - M42 - Astro Chair donated by Buy
Astro Stuff

Third place - David Goodin - NGC 4565 - Celestron SMA 10mm 1.25"
eyepiece donated by Anacortes

Fourth place - Wayne Fukunga - M42 - Anacortes Telescope Logo T-shirt


Category #8 - Best Webcam/Video Capture of a solar system object

First place - George Lamy - Saturn - Meade DSI Pro with color filter
set donated by OPT

Second place - Joe Shuster - Moon - Celestron NexImage donated by OPT

Third place - Wah - Moon - Celestron SMA 10mm 1.25" eyepiece donated
by Anacortes

Fourth place - Gerald Weckselberger - Sun - Anacortes Telescope Logo
T-shirt


Category #9 - Best Webcam/Video Capture of a deep sky object

First place - Steve Brodin - Ghost of Jupiter - Celestron binoviewer
with 2 eyepieces donated by Astronomics

Second place - Jacques-Andre Regnier - M57 - 30mm Bird's Eye View -
2.0" eyepiece donated by Anacortes

Third place - Brent Maynard - M5 - Celestron SMA 10mm 1.25" eyepiece
donated by Anacortes

Thanks, guys...

For the DSI, I mainly set out to show that an el-cheapo scope and an el-cheapo camera can take some nice pics...I was truly amazed I won 2nd!

On the SCT users...I try to enter that one and encourage others (should have announced it here!).  So few people enter it and theres some great prizes.  With so few people, I wouldn't be surprised if the sponsorship goes down next year...

Rick

Looks interesting!

It's a bit expensive for a non-cooled camera, though (about $1k), but it's hard to argue with the results!

Rick

I think that's New Mexico Skies...a place where they have a bunch of robotically controlled scopes.

Rick

The ME2 wouldn't be the best choice for planetary imaging.  It's basically like a SBIG ST-402ME, which is actually cheaper ($1500 including an internal filter wheel).

The chip (KAF-402ME) on these imagers doesn't have an electronic shutter, and thus are limited in their ability to take short exposures and freeze seeing.

To be honest, some of the very best planetary images out there have been taken with the Phillips webcams...you just have to make sure yours is the CCD version rather than the CMOS.

The only one I think could be a better performer would be the just released SAC10...it has smaller pixels, is one-shot color and will be lower noise (with no compression).  You wouldn't even need a barlow with it. And it's very reasonably priced.
http://www.sac-imaging.com/sac10.html

Rick Krejci

Super start...very smooth and 3d/fluffy looking!

If you want something for a target, you should check out Tony Hallas' recent shot:
http://www.astrophoto.com/M27.htm

It's amazing what lurks in the depths out there!

Rick

Jake,

That's better than "not bad"...that's a great image!  To capture the Ha detail you did with an unmodofoed rebel is nothing short of incredible.  Your processing looks prefect to me...I tend to like the lighter backgrounds and nice, gaussian shaped stars.   Not overdone at all!

You could get rid of the satellite trail by using Sigma combine if you'd like, but it doesn't bother me at all...

Great work!

Rick

Yes, I mean replace the green channel with a mix of green and blue and leave the blue alone.  Whe I did mine, I think I actually ended up with a green channel consisting of about 75% of the blue channel and 25% of the green...and it's still a little too blue!

Rick

Backlash is incredibly tricky!  If you're going to use the backlash compensation in the comtroller, you want to make sure you have it just less than what is necessary.  If it's the tiniest bit more, you will go unstable...

A new mount will likely not help your woes as much as you may think...there's backlash on virtually every mount out there!

Good polar alighment is a good goal, but it's one that I seldom aspire to.  I get it close enough and use longer guide exposures (4-8 seconds) and use very low agressiive settings.  Remember, generally DEC driftis always in the same direction and the same amount for a given point in the sky.  Basically, I set it up to allow the drift and correct it always in the same direction.  I could turn one of the DEC guiding directions off and would get the same results...in fact if you can do it, you can wire a few switches to turn one or the other off.  This can work miracles on making a system stable.  I can do this in software (using Maxim)...I usually turn one direction off, see if it still drifts...if it still doesn, I switch the direction I've turned off.  Takes less than a minute.  For long exposures, sometimes the direction gradually changes...you then just need to switch which direction is off.

Rick

Very good results!!!

I'm seeing exactly the same thing with the DSI Pro...no green for any OIII type objects (m57,m27). 

You might want to try what I did for some recent DSI Pro shotsI posted on the Meade_DSI group...mix the blue and green exposures together (if you have PS, use the lighten to get the OIII core but not effect the stars too much).  This will yeild a much better color balance.

The advice on using Sigma combine is right on target...it should help the bright trailers.

Rick

Was able to take advantage of the super weather last night...actually was able to get almost 4 hours of exposure time on one of my favorite objects...the eastern portion of the veil.   I used Ha to enhance the Luminance, but I chose not to add it to the red since it would de-emphasize the blues, which are my favorite part.

http://www.ricksastro.com/DSOs/Veil6992_T140.shtml

I can see my sleep if going to suffer in the next few days, as the forecast remains wonderful...

Rick Krejci