wimvb

Very nice first image. What does the with-flats image look like when processed as the original image? Most dslr images have colour (chromatic) noise that can be dealt with very efficiently using MMT on chrominance. And any gradient can be reduced, if not removed, with the help of dbe.

I just stumbled across this article by the Dragonfly team https://scholar.google.com/scholar?start=20&q=Ngc2841+galaxy&hl=sv&as_sdt=0,5#d=gs_qabs&u=%23p%3DWjSypV0skbIJ It seems that the structures extend a lot further out than what is visible in the 100 minutes exposure that I processed. Cool! I wonder how deep amateur gear would allow one to image this object. Maybe a challenge for galaxy season?

From binoscopes to fish physiology; I just love this forum. Thanks for the lesson, Göran. Btw, if we could preserve the phase relationship of the light entering each half of a binoscope, there would be a true advantage, because the resolving power would increase.

I agree, and I use it from EKOS. But unless you need special functions (predictive pec in my case), I think that "plain" guiding works equally well in the native guider.

This is a non-commercial, family friendly forum. I don't want to get banned. If ever we meet irl, I'll buy you one.

The native Ekos guider works fine enough, it's based on Lin_guider which is more Push-Here-Dummy than PHD. But PHD has more functionality and allows for more guide analysis than Ekos. I've used Ekos, Lin_guider and PHD, but prefer the latter. They all work on RPi.

I maintain, it should be the grouse cluster. 😋 Skål.

Thanks, Gina. It is a bummer to lose mobility just because of a wet spot. I'll get my revenge on that rock next spring. I've never used these in earnest.

Put a priority on that, Gina. A week ago I went out to my obsy (not operational yet) to do some work on the wiring and slipped on a muddy patch. Broke my knee cap on a stone I never removed during construction. Now I'm waiting for surgery.

Not me. I have an Opticron Omega. Because I'm severely nearsighted with my left eye only, and have an unhealthy dose of astigmatism, super binos are probably lost on me. Now, a dual imaging rig, that would be something else.

Ha, ha. Nice! Now, if you combine the chicken and the long neck, you end up with a grouse. Or have I been staring at that bottle for too long? 😉

Always something to tweak or one more bug to remove, I guess.

CurvesTransformation in PI works the same as curves stretch in PS. Also, have a look here for repairing stars that are blown out: http://pixinsight.com/tutorials/NGC7023-HDR/index.html#High_Contrast_Small_Scale_Structures

If the difference is in the flats, it makes more sense to look at the background model as extracted by DBE. As Vlaiv noted in an early reply, the difference is in flat application. If a master flat doesn't correct properly, you see the difference in the background model. Just apply DBE with identical parameters to either image and compare the result. Set "none" for image correction method. Then stretch the two background models exactly the same. Or you could use PixelMath to compare the background models: BG_model1 / BG_model2 and the other way around: BG_model2 / BG_model1.

While clouded in and waiting for knee surgery, I started playing with data from the Liverpool Telescope (http://telescope.livjm.ac.uk/). I downloaded all the NSO data on NGC 2841, a very nice flocculent galaxy in Ursa Major, and started processing in PixInsight. While I couldn't get anywhere with the colour of this galaxy, the luminance created from the combined filters revealed structures that I've never seen before in an image of this galaxy. I combined a colour image of NGC2841 with an inverted superstretch of the combined SDSS-r, Bessell-V, and Bessell-B filters. RGB image: Red: 35 frames SDSS-r' Green: 16 frames Bessell-V Blue: 20 frames Bessell-B L image: integration of all 71 frames, approximately 100 minutes total exposure time. Field size: roughly 10 x 10 arcminutes. The arrow points at a weak loop, and the circle shows a slight density increase in the weak structure.

Had never heard of that before, but it looks interesting as an alternative. It's all about value for money.

Ooh, nice one. How big is that telescope?

Telltale sign of darks not matching: light - dark < 0. However, if you do need darks for other reasons, you could add a small positive offset to the lights. Personally, I'd only do that when needing darks for other corrections. Otherwise I wouldn't bother.

Maybe, maybe not. You have to experiment. Darks don't always work for dslrs. Dslrs don't have temperature control, so it will be difficult to use darks for anything temperature related (faulty pixels, possible amp glow). There's only one answer: experiment. Adjust clipping parameters during stacking, apply cosmetic correction (deep sky stacker and pixinsight allow that), etc.

Excellent rework, Andrew. I like this palette more than the original. Just for kicks: apply scnr green with default settings on that last image and see where that leaves you.

What am I missing here? What is the advantage of a bino telescope over a bino eyepiece? Other than comfort, that is.

Did you read the edited reply? Unless you get the synscan upgrade, you won't have goto. This upgrade is more expensive than the other offers. But regardless of which upgrade you get, if it includes dec, you won't have to touch the mount to center a target. Hence less vibrations that can throw pointing off. Also check which upgrades allow guiding (st4 port).

If you have an osc, and only occasionaly want to spice up your images with nb from a light polluted site, then why not. But I wouldn't recommend it as a replacement for individual nb filters. Usually the three components, Ha, Oiii and Sii are at very different intensities and need individual treatment to get best results.

Go for dual. Only if polar alignment is spot on, will tracking in RA only suffice. You need dec control if you want to guide. Dual motors also make it easier to slew to targets. Without the dec motor you still have to touch the mount in oder to point to a target. This introduces vibration. Dual motors should also increase the resale value of the mount.

That's a nice little gem, but I agree, a longer fl would be a better fit. If you deemphasize the surrounding stars, the double cluster will stand out more. To do this, create a star mask. Erase its cluster stars. Then apply and shrink the stars. This will shrink the stars that are not part of the clusters. A bit of artistic license. 😉 I wouldn't shrink the largest stars much. Leaving those will create a more natural night sky look.