MarsG76

Awesome detail... makes me want to visit Barnard 33 for a close up also...

Weather is a pain for all of us that is why I built a permanent setup, so that I can be imaging within 15 minutes of noticing a clear sky, this luxury makes exposing more subs or re-shooting data is easier... and if I stars and clouds come, than it's not as much of a infuriating event as spending a hour setting up for every imaging session... and we all know that weather forecasts are hardly ever accurate. I find that processing each seperate channel independently gives me more fine details in the images as each filter records different details or parts of the details/feature. The luminance is one of two... either a "De-Saturated" version or a Grayscale version of the separately processed SHO image. Believe it or not those two versions do look different, more contrast than anything else tho. One looks better than the other, and this changes with images, so I keep the best looking version.

I imaged these regions in particular to compare the difference in detail recorded and overall image quality between my 8" SCT @ f6.3 and the same region imaged with my 80mm f6.25 refractor 2 years ago, almost to the month. The first image is a comparison of the same area of the Carina nebula photos between the image completed recently and the cropped section of the same area from the full resolution photo taken back in 2021. The image taken with the C8 at f6.3 was scaled down to match the actual full resolution image from 2021. The second image is a resolution and scale comparison of the same area of the Carina nebula photos between images taken with the 80mm refractor at f6.25 on the left and the C8 at f6.3 on the right. The image on the left is an unscaled full resolution image as recorded back in 2021 and the image on the right has been scaled down to 60% from the full resolution for presentation, effectively "BIN 2x2". Both images were taken with the QHY268M. and using the same filters. I think that the bigger mirror makes a bit of a positive and sensitive difference.

Hi Simon, My workflow is quite simple as I do not want to muck around with my data too much and always aim for the best original stack I can record, always manually quality controlling all subs and rejecting all but the best of the night. I re-expose subs if I my data is all particularly poor or if I do not have enough for me to be happy with the integration time. I like to aim for more than 30 subs per channel for more difficult objects or if imaging at over 1280mm focal length with my SCT. The difference is visible in these latest 4 images... the first two were made up of exposures: Ha:50x300s, OIII:46x600s & SII:49x600s (20h00m), the third (Carina's Face Profile) exposures: Ha:35x300s, OIII:28x600s & SII:38x600s (13h55), which delivered quite a noise free stack even though the object is fainter than the first two BUT on the other hand the Southern Tadpoles were made of of exposures of only : Ha:26x300s, OIII:22x600s & SII:31x600s (11h00m), and it's a much fainter object. The stacks resulted in being much dimmer, particularly OIII and SII was even weaker, and the stretched channels had a lot more noise which had to be dealt with... this particular nebula needs at least double the current image spent integration time and I will re-visit this object in the future. Anyway, here is my processing work flow point form: 1. I align all of the stacked channels in Nebulosity 2. Crop the aligned stacked channels to crop out undesirable elements such as stacking artifacts. 3. Run all cropped channels through Starnet V2 4. In photoshop create starmasks using "Difference" between the Channel and starless channel.. I do this for all channels. 5. Stretch and process each Starless channel. 6. Combine into RGB.. these images were SHO... (Red<-SII, Green<-Ha & Blue<-OIII) 7. Generate a luminance channel before any color balancing 8. Color balance the RGB channel with using the generated Luminance channel. 9 Add the stars from the generated starmasks. 10. Final blacks and gamma level adjustment before exporting the final image... noise reduction as necessary, but at this stage I rarely have any noise in the image which needs to be removed. Hope this was helpful, Clear Skies, Mariusz

Fantastic image...

Hi Astronomers... Sharing with you my latest completed astrophotography project which spanned across February and into March, targeting some close ups into nebulae within the southern sky constellation of "Carina". I imaged 4 images concurrently all with my C8 at f6.3 with the QHY268M and tracked on a hypertuned CGEM mount. All images are of objects within the constellation "Carina" but three of these images are closeups of the Great Carina Nebula, NGC3372, and the last image is the southern counterpart of the northern object in Aurgia, the "Tadpole Nebula", known as the "Southern Tadpoles" nebula, NGC 3572. Total integration time for the first two closeups into the Carina Nebula were 20 hours, the third close up (one that looks like a profile of a face) was 13 hours and 55 minutes, and the Southern Tadpoles was 11 hours (and would benefit with a few more hours exposure through the SII and OIII filters... next time.) All images were imaged in SII in the red, H-Alpha in the green and OIII in the blue channels. Clear skies, MG

Good choice.. I've been using APT for at least 10 years, since version 1.91, it has come a very long way and I'm not looking to change using it anytime soon. I wouldn't call it "only for beginners" anymore either.

Awesome

Hello, I haven't come across a app that stacks on an iOS device.

Absolutely fantastic image.. the extra hours shows...

Hi All, I don't know if you're interested in deep southern objects but here is another close up into the famous deep southern sky object, Large Magellanic Cloud. This region contains star clusters, double clusters, a super cluster, emission nebulae and a globular cluster (NGC1850, 1854, 1855, 1856, 1858) in the Dorado constellation, located in the northwest part of the bar of the Large Magellanic Cloud at a distance of 168,000 light years from the Sun... location of the imaged area is shown in the thumbnail image of the LMC. This is an unusual cluster system because the main distribution of stars is like a globular cluster, but unlike the globular clusters of the Milky Way it is composed of young stars. This object was imaged from a Bortle 4-5 quality sky and the inset shows the location of the frame in a 150mm focal length wide field image I imaged a few months ago. Integration time was 10 hours and 35 minutes in bi-color, Hydrogen Alpha and OIII narrowband color with a C8 SCT at f6.3 with a QHY268M astronomy camera. Summer down here is quite warm, and we have mostly blue skies during the day.. but unfortunately it's quite humid and more often than not the night is either clouded over, or some high altitude haze is rendering the sky transparency and seeing to such a level where subs look as if they're imaged through some wierd soft focus filter.... hoping for some drier weather soon. Clear Skies, Mariusz

Yeah, I know.. sometimes it feels like the clouds are going to collide with the corrector plate and I'm imaging as fast as I can... currently I'm limited only by the speed of clouds but occasionally can accelerate to the photonic boost.

The bottom image is the one (first imaged taken) before the back spacing tweek... both images are imaged with exactly the same equipment... and my small filters do not help the vignetting side, but if I can achieve a perfectly flat field.. ie nail the perfect back focus than cropping out the 5% around the edges is not much of a loss. As you can see, the top image is better at the edges even though the bottom image was more severely cropped... I believe that a perfectly flat field is possible but requires a bit of trial and error... but I feel that I'm close. Theres also that tilt... although I'm suspecting the plastic shims with that problem....

I don't find it to be expensive when you consider the price of other astronomy gear.. but it improves images while "speeding" up you optics by halving the needed exposure time. But yes, a Christmas gift is a great idea.

Fantastic Mars....

I'd say that this experiment is a success...

Greetings Astronomers, After imaging a wide field of the Large Magellanic cloud at 150mm FL... ... I imaged a couple of close ups of the more interesting regions of our Satellite galaxy... the Tarantula nebula and the Dragon's Face nebula. Both of these photos are imaged with the C8 at f6.3 (Hirsch focal reducer/flattener) with a QHY268M. The first image was a SHO narrowband image of the Tarantula Nebula region, total integration time 12 hours and 35 minutes. The second image was a result of not being anywhere happy to the "flat" field quality I am getting with the FR... the stars at the edges are ugly and I have to crop a lot of the frame to have a sort of acceptable result... but even than the field curvature is obvious. When I try to research the reason, I find explanations like that the FR light path is too narrow for a true flat field with a APS-C sensor size, even when my back focus is set at around the (recommended) 105mm distance (testing the sensor further and closer didn't help)... using 1.25" filters probably isn't helping either... but I wanted to try and exhaust all possibilities before giving up... but also was not keen on losing any of the few and far between clear nights for this so I accepted that cropping it will remain for a while. A long story/short is that I had a clear night but of particularly poor seeing, so imaging was not going to result in any quality images and so that night was spent on setting up the FR in a "out of the box" kind of thinking... and on that nights 180 second test subs, the (bloated) stars were round all of the way to the edges... but thats a story for another post in the "equipment" section. I imaged the "Dragon's Face" region during the next clear night of decent seeing in HOO, total integration time of 5 hours and 10 minutes, and the stars were indeed closer to a flat field than previously, although there is still room for improvement... vignetting still has to be dealt with as flat frames don't completely remove it but the stars are still a lot better. Sorry for the novel, thanks for looking and clear skies, Mariusz

The 8SE is capable of some great images... the long focal length is a challenge but doable... I imaged with a 8SE and a astro modded Canon 40D for years... Adding a f6.3 focal reducer will get the whole moon into the frame with a APS-C sensor sized camera like the D3100. Now I'm still imaging with a 8" SCT, same spec as the 8SE and with a QHY268M, same size sensor and still happy with some of the images I can get with that setup. There was a total lunar eclipse visible from here on 8th November and the images I posted were taken with the C8, a f6.3 reducer and a unmodded stock Canon 40D... definitely doable.... the only change I did with my 8SE was to put it on a CGEM mount, but that more for long exposure DSO rather than moon photography. Controlling that focal length comes with practise and is also more effected by seeing quality. MG