SH2-101 The Tulip Nebula

The Tulip Nebula after some very bad processing in PixInsight.
It goes to show that all the tools in the world are no good if you don’t know how to use them!

I imaged this nebula over 2 nights, several weeks ago in August but I had a terrible time processing the data. I was convinced I had some issues with my flats and then my subs. Then I was sure I had some light pollution leaking into the camera. I was at a loss for a solution but then I happened to read a post over at Forum | Backyard Astro that suggested to me the problem was how I used the Weighted Batch Processing script. I had recently updated PixInsight and was just using WBPP script with its out of the box default values.

That was a stupid newbie error, correcting the configuration of WBPP for the flats and light processing completely resolved the problem. As a result, I went back through all my recent images and began a methodical reprocessing.

And here is the result of more care and attention in processing the image.
This is 6hrs total, 300s subs @ Gain 200. 2hrs each for Ha, S2 and O3. Imaged using my trusty Orion Optics 250mm Newtonian with the ASI1600mm Pro.

I don’t want to go through that pain again so I have written down the steps and will publish what has worked for me.

One thing you will notice if you pixel peep the image is that the stars are vertical short lines. Guiding was close to perfect for this target so I believe the problem is caused by the RA motor drive board of my CEM70G which is a 2020 vintage, later mounts have improved RA and DEC boards. At least I hope that is the root cause as I’ve ordered replacements from the iOptron factory and I dont really want to use an OAG. [The last I heard the factory airport was in lock down due to covid so I don’t know when to expect them.] Because of the star shape it is a little more difficult to use my star reduction technique that worked so well for my IC1396 image. I shall have to see how others do it.

One thing I have learnt as a result of writing my steps down is slavishly following a process does not work well for all images. Sometimes you have to deviate from the path and experiment too. But still, a written down process is a good place to start from.

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IC 1396 The Elephant’s Trunk Nebula

This is a narrow band S2, Ha, O3 image taken over 6 hours (2hrs each) in one night.

Imaged with my Altair Astro 70mm ED-Triplet and my ASI1600mm pro camera.

This image is a reprocess of the same data with slightly less green removal and a different crop.

Finally worked out that Automatic Background Extraction was causing my vignetting in processed images and not poor flats or something else in the data. I’ve had another go and produced an almost full-frame image (minus the few pixels for dithering) with better colour control and handling of the stars:

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Caldwell 33, The Eastern Veil

This is the result of 4 hrs each of S2, Ha and O3 subs taken over three nights, I was lucky to have excellent conditions. I have been able to pull out the gas from the background with very little processing. So more (good) data = easier processing. I need to play with the colour balance it takes some getting used to.

This is the first processing of the data as a simple Red = S2, Green = Ha, Blue = O3 combination. I am still exploring the process and have quickly learnt I need to do some colour balancing or in general the Ha signal will appear too strong and dominate the image. But still here you can see the Ha wisps surrounding the main
This is with Red = S2 * 0.2 + Ha * 0.8, Green = O3, Blue = O3 * 0.85 + Ha*0.15
I believe this is with Red = S2 * 0.15 + Ha * 0.85, Green = O3, Blue = O3 * 0.85 + Ha*0.15
I believe this is with Red = S2 * 0.15 + Ha * 0.85, Green = O3*0.8+Ha*0.2, Blue = O3 * 0.85 + Ha*0.15
This is the original SHO combination with heavily neutralised green.

Imaged using my Altair Astro 70mm triplet, ASI160mm Pro and filters on my HEQ5. Each sub was 5mins @ gain 200.

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Caldwell 34 – The Witch’s Broom and Pickering’s Triangle in HOO

Rare are nights of clear skies and then two in a row allowed me to capture over 7 hours of data of the Western Veil or Filamentary nebula – it has many names.

The imaging was done on my “portable” rig powered by my Baudens 240WHr power tank. It’s the first time I have used it seriously for an imaging.

Guiding with the ASI120mm and 30mm guide scope was fantastic, the ASIAIR reported sub 1 arc-second all night with periods of sub-0.6. The HEQ5 really works well with a short focal-length refractor.

This was the first time I levelled the tripod before levelling the mount. If that is the trick, I’m sticking to it. The ASIAIR PA routine is very quick and simple too.

Image Details: 300sec subs @ gain 200, 40x Ha, 45x  Oiii, ASI1600mm Pro and filter set, Altair Astro 70mm ED-T + 0.8 FFFR, on my ageing but trusty HEQ5 managed by an ASIAIR Pro.

Processed in Pixinsight.

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Messier 51 and first light for my Orion Optics 250mm rebuild

M51 May 2021
M51 May 2021, ASi1600mm Pro, Orion Optics 250mm, CEM70g

This LRGB image is the result of 3 hrs of imaging with many lost subs due to cloud and some RA imbalance issues. Probably only 1.5hrs with most of those softened by clouds. This results in a noisy and more washed-out image than I would have liked. Still, compared to my first attempts, 14 yrs ago, it’s not bad.

Imaged with the ASI1600MM-Pro, ZWO filters, Lacerta Komakorr Coma Corrector. modified Orion Optics 250mm Next on the CEM70G.This was first-light for my refurbished scope. I had the mirrors re-silvered in 2020, I flocked the tube and replaced the focuser for a Skywatcher low-profile Crayford. I’ve just finished making a brace for the rings – to stop ring wobble – which it does very well. The Lacerta Komakorr Coma Corrector is a big improvement over Skywatcher 0.9 CC. Sharpness has improved across the image, its very noticeable.

I should try and revisit this target again and give it the time it deserves now that my equipment can capture more detail.

Some of my earlier attempts:

M51 May 2017
M51 21x300s @ISO800 260517. HEq5, OO 250mm, 550d.

A guided session using an HEQ5. Manual focusing is a bit dodgy so lots of detail lost.

M51 April 2012 Canon 350d
M51 April 2012 Canon 350d

An early guided session using my HEQ5.

M51 April 2009
M51 April 2009

Taken with a Canon 350d, OO 250mm on an EQ5 unguided.

M51 May 2007
M51 May 2007

Taken with a modified webcam using my OO 250mm on an EQ5.

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Messier 63 – LRGB

M63 LRGB May 2021
M63 LRGB May 2021, ASI1600mm Pro, Orion Optics 250mm, CEM70g

I had a few things to crack like the differential flexure and misting up of the camera that trashed most of the subs I took in a 3hr session. As a result, I don’t have much colour in the galaxy itself. All things considered this is not a bad image. (First posted May 27th, 2021)

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M13 imaged over the years

I have been fascinated by astronomy ever since I was a boy (even making a telescope with simple lenses) but it wasn’t until 2005 that I really started taking astronomy and astrophotography seriously. But as is common with me, my interest peaks and wanes with extensive periods of inactivity (often associated with challenging work commitments and I now suspect metal health dips).

M13 is a very bright object and so it’s been an obvious target over the years. This post contains images taken over the years with different equipment and improving results and techniques.

M13 2005
M13 2005 Modified Toucam, Orion Optics 250mm, EQ5, unguided.

The Toucam was a basic way to start astrophotography long before low-cost CMOS cameras existed. The Toucam was a CCD webcam that produced surprisingly good results for planetary images. With the long exposure modification (and Peltier cooling) you could even attempt some deep sky imaging. It had a very small sensor with just 640×480 pixels. Getting a target on to the chip was a real challenge.

I remember being very pleased with the results all things considered; using the large Newtonian on a wobbly over stretched EQ5, manual focusing, basic polar alignment, star hopping and lots of 1-5 second images.

M13 2010
M13 2010, Orion Optics 250mm, HEQ5, Canon 350d. Guided.

By 2010 I had invested in the HEQ5, a Canon 350d DSLR and a guide camera. But even the HEQ5 is pushed to its limits by a fully loaded 250mm reflector. Good results were possible but exposures had to be short when the DLSR really needed longer, it was a challenge even for bright targets. This led to some frustration that ultimately meant the hobby was parked for several years.

M13 June 2020 imaged with Canon 550d DSLR, Bresser 150mm f5 on HEQ5.

In 2020, when lockdown really started to bite, I restarted my hobby and invested in a new small Newtonian, the Bresser 150mm f5, that was better suited to the HEQ5. This allowed substantially better-quality guiding and the shorter focal length was more forgiving. It was worth taking longer subs and building up the data to get a deeper image.

For this image conditions were not great and I did not take enough subs to control the noise (dark hours are short in early summer).

(If you pixel-peep you will notice all the stars are D shaped. This is because the focuser tube extends into the light path when the scope is used with the Skywatcher 0.9 Coma Corrector. I eventually resolved this by sawing off 16mm of the focuser tube!)

M13 June 2021
M13 June 2021, ASI1600mm Pro, Orion Optics 250mm, CEM70g

At the back end of 2020 I decided to comit more to the hobby updating my 250mm Newtonian with re-silvered mirrors and flocking. In early 2021 I replaced the focuser for a more robust low-profile Skywatcher focuser. At the same time, I purchased the CEM70g and finally after some 15 years or so I had a mount that could handle the weight of the 250mm easily! Swapping out the DSLR for a dedicated mono camera has allowed a much more detailed, deep and less noisy image. This final image shows just how far the globular cluster extends.

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NGC 6888 LRGB + HOO

This is composed of LRGB+SHO as one image, I found this quite tricky to do satisfactorily.
This is the same data reprocessed some week later as a pure SHO image. This time the subs have been corrected by the flats properly in WBPP. The data is beginning to look good but that O3 is very faint. I may try to reduce the stars a little.

This is my first image of this season after a long break. It’s the result of two nights of roughly 1hr total for LRGB, 2hrs Ha and 5hrs Oiii. I’ve been practicing with methods to combine the images… This final image is LRGB normally processed combined using a star mask and pixel math with an HOO image. The result is fairly balanced but the regions extensive Ha is not as pronounced as I would like. I seem to have bit of light leakage in the corners, some I managed to clone out but I need to track down the source.

LRGB subs were 30sec @ gain 0, Ha and Oiii subs were 120sec @ gain 200.

ASi1600mm pro and filter set, scope was the OO250 newt.

Even at 30 seconds and 0 gain I still manage to clip some stars.

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