AMcD

That is an amazing result for such a faint target under Bortle 8 skies!

I have been endeavouring this winter to concentrate on reflection nebula. Over the course of the winter, I have managed to complete three such targets. I had also hoped to image the 'Running Man' Nebula, but as Orion processes inexorably West I think this target will now have to wait until next season to complete. Each image was taken with my QHY268M using Antlia Pro LRGB filters on my TS Optics Photoline 130 APO mounted on a Losmandy G11. The data was acquired with SGPro and processed in PixInsight. I set out below a summary of my Pix|Insight workflow used on these images. NGC1333 in LRGB comprising a total of approximately 24 hours of 120s integrations. The Iris Nebula in LRGB comprising approximately 22 hours of 120s integrations. vdb14 and vdb15 in LRGB comprising approximately 15 hours of 120s integrations. PixInsight Workflow: Blink frames to remove integrations with high cloud etc. Stack L, R, G and B in WBPP Script Align resulting L, R, G and B images using StarAlignment. Dynamic Crop L, R, G and B to same dimensions. Dynamic Background Extraction (DBE) on L. Evaluate PSF on L. Remove stars from L using StarXterminator to create L starless. Perform deconvolution on L starless using BlurXTerminator and measured PSF. Perform Linear Fit on R, G and B channels. Combine R, G and B in Colour Combination in PixInsight. Perform DBE on RGB image. Perform Background Neutralisation on RGB image. Obtain Astrometric solutions for RGB using Image Solver Script Perform SpectroPhotometric Colour Calibration on RGB image. Stretch a copy of RGB image using Masked Stretch and remove stars using StarXterminator Generate Star Image to generate RGB stars. Evaluate PSF of master RGB image. Remove stars from master RGB image using StarXtermninator to create RGB starless Perform deconvolution on master RGB starless using BlurXTerminator and measured PSF. Stretch L starless and RGB starless to non-linear with Masked Stretch: Add L starless to master RGB starless to give LRGB starless using LRGB Combination. Perform Noise reduction on LRGB starless with Noise XTerminator. Perform stretches on LRGB starless using Curves Transformation on LRGB starless. Set black point on LRGB starlesss and balance channels in Histogram Transformation Curves Transformation to reduce / enhance stars on RGB stars image. Add back RGB Stars to LRGB starless using Pixelmath. Adjust saturation using Colour Saturation Reset Blackpoint with Histogram Transformation. Integer Resample.

Continuing with my winter project on reflection nebula, this is my LRGB image of vdb14 and vdb15, a pair of reflection nebulae in Camelopardalis. vdb15 is the larger of the two nebulae surrounding the magnitude 5 star C Cam. The image comprises 8 hours of luminance data and three hours each of red, green and blue for a total integration time of approximately 17 hours. It was taken under Bortle 4 skies with a QHY268M through a TS Optics Photoline 130 APO and Antlia Pro LRGB filters mounted on a Losmandy G11. The data was gathered using SGPro and processed in PixInsight. I have picked up some annoying halos around a few of the brighter stars, which I think is down to high cloud across a significant number of the nights on which the data was gathered. Constructive criticism always welcome 🙂

Thank you. Really honoured that my effort was recognised amongst such an array of amazing images. Looking forward to drinking late night coffee from my mug 😊

I had been having problems with getting my flat frames to work with my H-Alpha integrations and produced this image of IC1848 in the process of working out what was going wrong. It turned out that I had inadvertently taken the flat frames I was using at a different gain/offset to my light frames. With the same gain/offset it has now worked. This image represents 4.5 hours of 600s integrations under Bortle 5 skies taken with my QHY268M and TS Optics Photoline 130 APO on my Losmandy G11, using an Antlia Pro H-Alpha 3nm filter. The data was gathered with SGPro and processed in PixInsight. Constructive criticism always welcome 🙂

There is no such thing as "too far" in this hobby 😂

The quite unprecedented number of clear nights over the past week or so allow me to get another one in under the wire from my current period concentrating on reflection nebula. This is my LRGB version of NGC1333 taken across a number of nights in January with my TS Optics 130 Photoline Triplet APO and QHY268M with Antlia Pro LRGB filters, mounted on my Losmandy G11. A total of 26 hours under Bortle 5 skies comprising 11 hours luminance and 5 hours each of RGB. Processed in PixInsight.

Many thanks @Elp. Yes, the processing is a challenge. I have to contend with an old sodium streetlight shining directly onto the observatory, as well as the more general light pollution in the city center. Even with high SNR from the large number of integrations I still have to wrestle an image out of the data when imaging these fainter targets.

I am concentrating on trying to image reflection nebula this winter. This LRGB image of NGC1333 comprises 11 hours of luminance and 5 hours each of red, green and blue, for a total of 27 hours of 120s integrations. It was taken under Bortle 5 skies in Worcester city centre over a number of nights in January using my TS Optics Photoline 130 Triplet APO and QHY268M with Antlia Pro LRGB filters, mounted on my Losmandy G11. The data was captured using SGPro and the data was processed in PixiInsight. As always, constructive criticism is most welcome.

In circumstances where you are using an AZ mount it may be field rotation, as mentioned by Malcolm, rather than a difficulty with the back spacing, that is causing the elongated stars in the pattern seen in the photo. I think if your back spacing turns out to be per the measurement given online, then the odd shaped stars in the corners are more likely to be field rotation, especially if you were using longer exposures.

I think this is a target needs a very large number of integrations. I cannot imagine anything would be visible on a 5 minute Ha sub. I have seen what are described on SGL as “short” attempts at this target run to 13 hours or more and longer attempts range up to 26 hours or more. I think it is a target that benefits from as much integration time as possible 🙂

It would be useful to know a little bit more about the equipment you used and how you processed this image. From the nebulosity, the focus does not look too bad, albeit it is not completely sharp. The blue rings around the brighter stars look to me like processing artefacts. Depending on the type of telescope you have, the brighter stars will tend to develop blue/violet halos around them that can be exacerbated during processing, particularly if the image is stretched hard to bring out the nebulosity. There are also ways to reduce the blue / violet halos during the processing stage. It also looks to me like you might have an issue with your back focus (the distance from the camera's chip to the first piece of glass in your optical train). If you zoom in on your stars towards the four edges of the frame, they are elongated in a manner that suggests the camera's chip might be too far from the first piece of glass in your optical system after the camera: There will be information online about the correct back focus for your camera / telescope combination. The picture is a good start. Very nice composition. 🙂

I have had this experience regularly recently. It looks clear to the eye but when I fire up the all sky camera on the observatory there is a clear pall of high cloud. I then try to resit the temptation of imaging anyway, knowing I will regret it when I come to processing the integrations 🙄

With SGPro, I run the autofocus routine on the first filter I am using during the session and thereafter have SGP set to refocus for every 1.5-degree change in temperature and immediately after each filter change. I have filter offsets entered for each filter so that the autofocus after filter change starts from roughly the right point for the new filter. This seems to work pretty well. Not much time is lost to the autofocus routine when taking LRGB images as the autofocus routine for LRGB requires only nine 15 second exposures at Bin 1x1 plus download time. It is, however, a different story with narrowband filters. The autofocus routine can take up to five minutes with the Ha filter, even at Bin 2x2. For LRGB I am using Antlia Pro LRGB filters. Whilst Antlia state that "The uniformity in substrate thickness delivers good parfocal performance across all Antlia filters" my understanding has always been it is a good practice to refocus between filters to account for any slight shift between them.

My LRGB version of the Iris Nebula. This image represents a total of 25 hours of 120s integrations, comprising 9 hours Luminance, 5 hours Red, 5.5 hours Green and 5.5 hours Blue. The data was captured over a number of nights in December 2022 using my TS Optics 130 Triplet APO and QHY268M with Antlia Pro LRGB filters, mounted on my Losmandy G11. It was taken under Bortle 5 skies. The data was acquired with SGP and the mount was guided with PHD2. It was processed in PixInsight.

I think this image of the Iris Nebula for me, as it was the first time I have managed to get some kind of handle on mono imaging and mono processing in PixInsight. I also like it because it is the culmination of so much kind and valuable advice received from SGL members over this year on getting going with my QHY268M and gaining experience with processing in PixInsight. In that context, this image is really one taken 'standing on the shoulders of giants'.

This a further attempt at processing my LRGB version of the Iris Nebula (with thanks to @ONIKKINEN for valuable tips on the last version). This is a total of 25 hours of 120s integrations, comprising 9 hours Luminance, 5 hours Red, 5.5 hours Green and 5.5 hours Blue. It was captured over a number of nights in December using my TS Optics 130 Triplet APO and QHY268M mounted on my Losmandy G11 under Bortle 5 skies. The data was acquired with SGP guided with PHD2. It was processed in PixInsight . Happy New Year to one and all at SGL 😀 Iris_Nebula_LRGB_Final_Final.xisf

I use Antlia LRGB 2" mounted filters and am very happy with them.

I am extremely pleased with the imaging performance of my TS Optics Photo Line 130mm F7 FPL53 Triplet Apo, that I picked up second hand.

Many thanks indeed @ONIKKINEN, I really am very grateful to you for this extremely helpful advice. I will try a further version incorporating your excellent feedback. Many thanks again.

This is my LRGB version of the Iris Nebula (also attached the full size TIFF file). This represents a total of 25 hours of integrations comprising 9 hours Luminance, 5 hours Red, 5.5 hours Green and 5.5 hours Blue. It was captured using my TS Optics 130 Triplet APO and QHY268M mounted on my Losmandy G11. The data was acquired with SGP guided with PHD2. It was processed in PixInsight (Pre-processing, Linear Fit on L, R, G and B, RGB channel combination, DBE on L and RGB, BTX on L and RGB, SPCC and SNCR on RGB, NXT on L and RGB, Masked Stretch on L and RGB, StarXT on L and RGB, Curves on L and RGB, LRGB combination and addition of stars with Pixel Math) and Photoshop (to tweak black point and saturation). This data was a bit of a challenge to process as much of it was captured before, during and after the full moon under Bortle 5 skies. Constructive criticism always welcome - I am really trying to improve my processing skills. Master_LRGB_Final.tif

That is an entirely reasonable request, and I have done so. But the content on your site does rather demonstrate the problem that @ollypenrice describes. Under your most recent article titled "How to Clean Your Telescope Mirror Like a Pro", you say as follows: "Based on what I have learned over the last few years, I will show you a quick and easy way to clean your telescope mirror without all the fuss that I see so many other YouTubers and content providers in the astronomy world encouraging." Thereafter, with your "last few years" of experience in the hobby, you appear to dismiss the entire, and extensive, body of information concerning the very delicate task of cleaning a telescope mirror, including it would appear the extensive information from telescope manufactures (the "Pros" you speak of in the title) that are presumably encompassed in your term "content providers". To quote again from your article: "Others usually advise something like this: To clean a telescope mirror, first, make sure the mirror is cool and not exposed to sunlight or any other source of heat. Gently blow any loose dust off the mirror, then carefully moisten a soft, lint-free cloth with a mixture of warm water and a mild, alcohol-free detergent. Wipe the mirror in a circular motion, starting from the center and working your way outward. Avoid pressing too hard or using too much liquid, as this can damage the mirror. Once you have finished cleaning the mirror, use a clean, dry cloth to carefully remove any excess moisture. Allow the mirror to air dry before using the telescope again. That’s way too complicated! I’ve got a much simpler method for you to try. It worked for me." In a sentence, you dismiss all other learning on this topic and invite readers to follow your own method (immersing the mirror in slightly soapy water / spraying it with water and detergent, wiping it very carefully with a lint-free cloth, rinsing it t with distilled water and letting it dry in a vertical position). Thereafter, you go on to further dismiss with one categoric word, again on the basis of your "last few years of experience, the generally accepted learning that telescope mirrors may not need cleaning for years: "I have looked at a number of videos and read many online articles that tell you your mirror may not need cleaning for years. One person I watched even stated that he hadn’t cleaned his telescope in ten years and that this is not a problem. Wrong! Why do I say this is wrong? Based on my own experience. The best research anyone can do is to actually try different methods and learn by experience. " The difficulty here is that you are offering categorical, inflexible advice on cleaning incredibly delicate optical surfaces in very expensive instruments based on no more than your unparticularised experience of short duration. Advice that many would argue is simply wrong, or at least dangerously generalised given the nature of the task in respect of which you are offering your categoric advice to people who will have spent a good deal of money on their gear. I do not mean to single you out as I know this kind of thing is seen all over the Internet. However, as @vlaiv says, rather than using SGL simply to harvest the knowledge of those on here in order to produce content for your site, try engaging in detailed discussions on these topics with members. I strongly suspect it will benefit you, and your site, in the long term.

Well @scotty38, I think you were right after all. I have spent the past couple of days noodling away at this and have traced the issue to the application of Local Normalisation to the light frames. Even though the scope did not dip below the wall of the observatory, and therefore no edge shows when the frames are blinked, I think it did indeed get close enough to cause a subtle shadow over the objective lens, which is in turn confusing the Local Normalisation algorithm when that algorithm comes to be applied on the lower part of the frame. Essentially, I think the algorithm thinks that 'normal' in that area of the frame is the shadow from the observatory wall rather than the sky. Many thanks for your responses to this post.

Whilst tidying my study this morning I came across my first ever astro photos. The first, of M31 was taken with, I think, a Tasco 3” refractor and a Pentax film camera. The second, of M45 and NGC1499, was with the same camera and, I think, a 35mm lens. I believe they were taken on Kodak colour slide film in the early 1980s (likely developed at Boots!) and then printed some years later when it became possible to scan slides onto computer discs and do basic processing. They were taken in Suffolk under very dark skies. Film cameras and manual guiding - those were the days...

I found PI absolutely infuriating to begin with, and walked away from my desk in disgust multiple times muttering darkly about user interfaces. However, once I found the Light Vortex tutorials and video tutorials from the likes of Adam Block and Visible Dark, and worked through them methodically, things got less frustrating quite quickly. My understanding of the nuts and bolts remains limited, but I have noticed that many of the game changing processing applications, like BlurXTerminator, that are emerging seem to require linear data, so I suspect learning PI is going to be a good investment of my time.