wimvb

Since you're testing PI, here's a tip from a dark lord: PI has a noise evaluation script, and you can do image statistics (process -> image -> statistics), which you can use to evaluate the three stacked images. The difference between the images should be in the background noise, and any hot pixels. You should also examine the stacks for any "walking noise" or streaks left over after stacking. If you want to test stacking in PI, I suggest you use the batch preprocess script, since you're only on the trial version. The feature that should win you over to the dark (dark) side is DBE. Crop the image, apply DBE, and see the magic force.

I agree with Neil, that's a good start. The easiest way to proceed from here is to expose more frames, download deep sky stacker to combine them, and use whatever image processing software you have to increase contrast. Good luck, and have fun

That would be a great challenge, if it were not for one tiny detail: the mount used. Non autoguiders range from poor students/kids using an alt az or eq3 mount, to semi-professionals having mounts that don't need guiding. The challenge would be unfair. But who am I to stop people from taking this challenge?

Great, Neil. Much better than my attempt at ngc2903. What camera settings did you use & nr of subs?

I know that seeing can be bad, but this bad? I guess you meant "no flats" Nice catch, anyway. Cheers

Nice catch. Ha nebs are difficult witj an unmodded camera, the results depend very much on camera make and model. With this target you did very well. Thanks for sharing

I don't think the horzontal lines are from dew. Have a look at a single sub and see if the dark lines emanate from bright stars. I have a issue with dark lines like this when stars are becoming over exposed. http://wimvberlo.blogspot.se/2017/01/correcting-dark-lines-in-dslr-astro.html?m=1

I have found that a longer dew shield can be better than a dew heater. My guide scope dew shield extends about 30 cm in front of the lens. Haven't had dew or ice yet, despite not using a dew heater. Otoh, I have had dew and ice when using a heater alone.

Nice result. You'll notice that being able to do 3 minute subs will vastly improve your image quality. Unfortunately DSS seems infamous for sucking the colour out of images. Sometimes it helps to blur a copy of the image and turn saturation all the way up. Use this as the colour information in an LRGB combination. Thanks for sharing,

Done that, been there. (Never got the t-shirt ). Made a dew heater for my st80 guide scope, but didn't really solve the dew problem until I also made a dew shield, which extends about 30 cm or more in front of the scope lens.

Dunno, one could argue that the Ha emits red, so it should be red. Otoh, it will probably also emit some Hb, which is blue. That would pull the colour towards magenta. Your Rosetta and Veil have a more traditional look. I would leave it the way it is, even if it isn't the way it "should be". I like it.

Impressive. Never seen such a red pelican.

Great catch. As you already noted, more data will improve the result. If you can increase exposure time to 1 minute, and catch 60 good frames, I think you can have a great image. It also seems to me that you are at the limit of what the Gimp can do. You can probably improve the image in photoshop or PixInsight. Thanks for sharing

Wow, those tadpoles really stand out. Great. If you can do that in a 2 hour gap, you must have a permanent setup, I guess. It usually takes me an hour at least to set up my rig and align. Thanks for sharing.

I don't think it was phd, but rather me. As it turned out, phd was already in an ubuntu repository, so installing was much easierthan in Raspbian. No need to check dependencies, just link to the ppa. Now I need to learn ekos/kstars. Sounds familiar?

Snowing here, after yesterdays short cold spell. (Why does this site lack an emoticon for snow?) Enough opportunity to tinker, but never enough to test what you tinkered with. BTW, as you may have read from a recent post of mine, I managed to get a Raspberry Pi working with Ubuntu mate, INDI and PHD2. For some reason I had less luck with Raspbian + INDI + PHD2. Maybe because I installed INDI after PHD2???

?? Can you elaborate? The center spot of my mirror came off during cleaning, and I replaced it as per numerous articles on the interweb. Was this not right? What's the cause if the difference?

The primary isn't too difficult to remove. The whole cell is held in place with just 3 - 4 screws. To center the center spot, it's good to have transparencies with a circle the size of the primary. For collimation I use a self made cap and a barlow with my laser. It does require a center spot on the primary, however. If you google "barlowed laser collimator", you should reach a few explaining articles on the matter. Good luck

Dare I say that I enjoyed two nights in a row with clear skies. Just enough to get some images of Bodes galaxies before moonrise. But now the gap has closed. Hope some gaps find their way to your site as well.

Thanks. Have you seen this site? http://www.deepskycolors.com/archivo/2010/04/21/formulas-for-Photoshop-blending-modes.html It may help finding the right blending method.

Can you post a link? (assuming you read it online) TIA

If scnr takes too much, I usually turn down the amount to .25 - .5. Scnr differs from mere curves tweaking by the way it treats highlights.

Great images, Gina, even if they're only screendumps. What causes the increased noise in the bi-colour (rh image)? Due to weak O signal?

TGVdenoise is a marvelous noise reduction method, if applied right. Here's a link to my recipe, which I only use to reduce noise in luminance. http://wimvberlo.blogspot.se/2016/07/noise-reduction-for-dslr-astroimages.html?m=1 For the origins of this recipe, follow the links in the article. ABE is automatic background extraction, as opposed to DBE, dynamic background extraction. Both are processes in PixInsight to even out gradients in images. Generally, DBE will give you more control, but sometimes ABE just works better. Some astrophotographers invested in PixInsight just for these processes, it seems.

It seems to me that you still have a lot of vignetting left, which indicates that your flat calibration isn't working. Three things that are important when taking flats: Keep the optical train exactly the same as when shooting light frames. The same camera with the same optics, in the same orientation. Dust can move around on the sensor, so take flats directly after or before lights. Do not use the sensor clean function of your camera between taking light frames and flat frames. Exposure should put the main peak of the histogram at or just below the midpoint on the lcd display (dslr). Forget about "adu counts". Flats need to be taken in the linear range of the camera sensor. An image stacked with flats should have a more evenly distributed background than one stacked without flats (when stretched the same), if your system has vignetting (which most systems do to some extent). Hope this helps