wimvb

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.

Thanks, Gina. I've set up RPi's a couple of times, both Ubuntu and Raspbian, but always need to have a tutorial next to me, so I don't forget steps. It's great to have a complete setup walkthrough in one place.

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

That's a nice start. With the weather the way it has been, you may be able to do another sub before it disappears untill next season. If / when you do manage to add to this, also take flats, bias frames and darks. With some gentle processing, this can become a great image. Good luck

The whirlpool looks nice. If you can add flat frames, you can improve the vignetting near the corners. You also caught a nice flame and horsehead. Alnitak and the flame/horse nebulae will always be difficult due to the huge dynamic range of this target. I would be inclined to reduce ISO, because it should give you more dynamic range. ISO is the DSLR equivalent of gain (and offset). Lower gain will generally give more dynamic range and less noise. As long as you stay above the read noise floor, you should be able to stretch the image to compensate for the lower ISO. As always, try to go for the longest single sub exposure that your gear can handle. Adjust ISO to get the best possible trade off between signal and noise/light pollution. If you can collect data for 3 hours in one night with 1 minute exposures, this means that you can collect about 150 frames. Even if you need to throw out 50% of these due to trailing issues, that leaves you with 75 stackable subs. It usually pays off to investigate time in setting up your scope. Polar alignment, star alignment and balance (with probably an intended off balance to improve tracking) have to be spot on for best results. Thanks for sharing, and good luck

Kstars apparently also does the guiding, but it seems to use lin_guider on the client as its native guider. That must put a heavy load on the network, I think. According to the docs/forum, it's possible to do the guiding in the driver on the server side, but I wonder how that works. Do you have any idea? Atm, I use lin_guider on a RPi strapped to my mount. (Actually, not at THIS moment, since it's solid clouds for the next week, and has been for the last two weeks.) Seems to work ok, but lin_guider is very basic, more "just push here dummy" than PHD.

I heard a loooong, loooong time ago, that weather prediction models, when left to their own devices, predicted a white earth, where the weather stabilized to an equilibrium of a snow covered earth. Maybe those models weren't so far off after all ... And totally unconnected to this: Gina, congratulations on your latest victory over Raspberry Pi. I have been following your struggles, but had nothing to contribute.

Since you already have PixInsight, why not use its noise reduction methods. They do wonders with most images, and retain detail. Here's my noise reduction recipe http://wimvberlo.blogspot.se/2016/07/noise-reduction-for-dslr-astroimages.html?m=1 If you have Warren Kellers book, he describes his method in detail. I've tried it, and it works just as well.

You are too modest. It's not just a touch. Besides a new mount, I also invested in a coma corrector last summer, after this image. Next major investment will be a camera to replace my box brownie (aka Pentax).

Here's an image I took last April, and which I hope to revisit in March or April. NGC 2903 is a barred spiral galaxy in Leo. It is sometimes called the galaxy that Messier missed, since it is as large and bright as certain Messier objects. This image was captured with my 150PDS on the EQ3 Pro, unguided 80 and 120 seconds exposures at ISO 1600, 24 subs in total. 120 seconds means that this target is underexposed, but in this case the mount was the limiting factor. Processed in PixInsight. The fuzzy on the left is another NGC object. Next time I gather data on this target will be with my AZ EQ6 and guiding. That will make for a nice comparison.

For an alternative to the lrgb method that I suggested earlier, here is one that may be more suited for photoshop and gimp. The blending methods may have different names (value instead of color?) As always, DO try this at home. (As opposed to what they say on tv shows)

You're right. I had seen one example of it withe the asi, but it seemed much weaker. It must be the sensor that is the culprit then. I wonder if all Sony exmor sensors suffer from this. Prior to the qhy image, I hadn't noticed it.

To be honest, I think the noise you still have will come into the way of processing this image properly. Your best option is to gather more data to bring the noise down. If you can increase your single frame exposure time at a lower iso setting, your data will have less noise. With this image I would forget about the stars, and concentrate on the nebula. One option you have is to create a b/w copy of the image and process this (mainly noise reduction and some very gentle stretching and local contrast enhancement). Then blur the colour image and do an lrgb combination. In PixInsight there is a function for this. In photoshop/gimp there is very likely a layer blending mode that can achieve the same. Good luck.

Morphology transformation (MT) in PixInsight is your (/my) best friend for star reduction. Deconvolution would work, if the stars are round and regular. But I've always had more success with MT.

Great result for this little camera. Since you are using PixInsight: the vertical bands are easy to remove with CanonBandingReduction (just rotate the images 90 degrees first). As for the ASI1600 vs QHY163, they both use the same chip, so as long as the back focus is similar, they should both accept 1.25" filters. There is a thread with images from the QHY163 somewhere in this forum. Here, actually: You might also want to check out the published dark frames from both cameras. It seems that both suffer from amp glow, but the QHY possibly a little more. The QHY also has some (in my opinion) ugly diffraction patterns from its microlenses, that shows up when imaging bright stars I very much like the new CMOS cameras, but results like these would make me hesitate to buy one. Cheers,

... more of the same. Lots more It's a good start.

Lovely image. Nice to see these two targets together. They seem almost the same size, but one is of course MUCH larger than the other. Flats will take care of the vignetting. Adjusting colour sliders should clean up the green colour cast, but scnr in PixInsight or hasta la vista green in photoshop work better.

If 10 min subs @ iso 1600 is too much, why not decrease iso? That should give less noise, and slightly more dynamic range. Somewhere in my collection is an image of the california neb at 4 minutes per sub. It shows the nebula, and I was also able to reveal just the slightest hint of dust. Unfortunately, I had too few subs at the time, and haven't been able to add more data yet. But it is high on my to do list. If you can get guided 10 min exposures, then my advice is to go for it.

Then the 80ed may be the one. There is a difference in fl and speed (f-ratio), but with coma correctors, field flatteners and focal reducers, this different may not be so much.

Do you like or hate diffraction spikes? 130pds has them, and the 80ed lacks them.

Great start on Leo. If you have the possibility to increase exposure time (to 60 secs perhaps) and double the number of subs, you will still be under 1 hour total, but have a massive improvement in image quality. Decrease iso if your sky is the limit.

NGC 1499, Jan 2016, SW EQ3 Pro, 135 mm @ f/5.6 Pentax K20D (unmodded) 4 minutes subexposures, unguided M31, Jan 2016, SW EQ3 Pro, 135 mm lens, Pentax K20D, 3 and 4 minutes sub exposures, unguided NGC 7000, Aug 2016, SW 150 PDS on AZ EQ6 with Pentax K20D (unmodded), 4 minutes subexposures, unguided NGC 7635, Nov 2016, M52, SW 150 PDS on AZ EQ6 with Pentax K20D, 10 minutes subexposures, guided On my drive I have data from a grand total of 41 imaging nights during 2016. That's an average of 5 nights per month (May - August it's too bright to do any imaging). In August I upgraded my mount (from EQ3 to AZ EQ6) and in November I started guiding.