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Flying Bat and Squid nebulae Sh2-129/Ou4 narrowfield (m-sho, c-shorgb) - 131 hours!


ramdom

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Also includes LBN445, LBN449, LBN453, v419 Cephei.

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  • Total integration: 7876 minutes/131+ hours (153/204 x 300/420s or 37h for Ha + 632/47 x 300/420s 58h for O3 + 153/185 x 300/420s or 34h for S2 + 60 x 120s for OSC).
  • Cameras: QHY163M (16mp mono) and QHY247C (24mp OSC) CMOS cooled to -20 and -15 degrees C.
  • Telescopes: Takahashi FC100DF Steinheil fluorite doublet and Stellarvue SV70T triplet apochromat refractors @ f/4.9 and @ f/4.8.
  • Reducers: Takahashi FC-35 (0.66x) and SFFR70-APO (0.8x).
  • Mount: Paramount MyT.
  • Filters: 1.25" Astrodon 5nm Ha, 3nm O3, 3nm S2 and 2" Baader UV-IR-Cut
  • Software: TheSkyX Pro, Sharpcap, PixInsight, Topaz Studio 2.

Thanks for letting me upload the original files (at least JPEGs). I was going to upload the inline versions.  Full resolution images of all images in the series are available at https://www.astrobin.com/hg1c5d/ and https://www.astrobin.com/jdaa90/ and of the primary images at http://ram.org/images/space/scope/1.4+7.4.5+6/ou4_sh2-129_nf_c_shorgb_2193m+3489m+2060m+120m_7876m_131h.jpg and http://ram.org/images/space/scope/1.7.4.5/ou4_m_o3_632x300m_3160m_53h.jpg

The Squid nebula (ou4) occupies over one degree of the night sky, representing the largest angular extent ever found in a planetary nebula. Known colloquially as the giant squid nebula, it is physically nearly 50 light years across.  This bipolar nebula could be one of the nearest of its type known, situated around 2300 light years away, though its possible planetary nebula nature needs confirmation.  Even though it is big and close, you're not likely to find it easily. It is an extremely faint nebula emitting primarily O3 signal and resides within the larger Flying Bat nebula (sh2-129) which tends to overshadow it, making it a challenging target to image.

The Squid shape is created by the outflow of material driven by a triple system of hot, massive stars catalogued as HR8119 (blue hypergiant) as well as the pulsating variable star v419 Cephei (red supergiant) seen near the center. While their shapes do their names justice, to me, the Squid seated within the Flying Bat more resembles a hand holding an infinity stone (viewed sideways) rather than a Bat carrying a bejeweled Squid on its back.

Seeing the Squid situated within the Flying Bat (which apparently has been confirmed) brightly light up in Ha and S2 emissions makes for a fascinating study in contrast and perspective: Most people prefer to assume the head of the bat shape to be part on the bottom left when it is viewed right side up (aka sideways) but to me it's more natural to have the head be where the small blobq of O3 is. This is especially so in the narrowfield framing of my second image, and viewing it sideways, small O3 blob pointing down, and pointing up, all offer something to contemplate. In the widefield framing however it is clear that what most people think is more correct since the wings of the Bat go back a long way.

The Flying Bat and Squid project/series became a huge undertaking for me, ending up with a total of more than 131 hours in the final integrated widefield image of both objects and three series of images, with a few versions in each, depending on the data set used for the integration.

In the first series of images, I am showcasing the Squid nebula by itself using only the O3 filter data, with and without RGB stars.  The mono Squid imaged with the Takahashi FC100DF consists of ~53 hours of total exposure in O3, making it my single longest total exposure of a target with a particular framing with a specific filter/scope/camera combination.  The RGB data collected using the QHY247C with the SV70T adds another two hours to the exposure.  The total integration for the version with RGB stars is ~55 hours.  I also captured another 5.5 hours of O3 data using my SV70T which I added in while creating the narrowfield version by reprocessing using LocalNormalization and Drizzle (which were a big help to me in combining the data for narrowfield and widefield series).

There are several versions of the Squid only framing with full capture details at https://www.astrobin.com/jdaa90/ --- the difference between the two monochrome versions of the Squid is the application of HDR Multiscale Transform which reduces the halo on the central star as well as the amount of data used: (A) is based on the full ~53 hours whereas (B) is based on the best 40 hours.  (C) and (D) are corresponding versions that combine O3 in the blue channel with RGB stars along with changes in the amount of saturation and brightness. Similarly with (E) and (F), but the Squid is in monochrome mixed with the RGB stars background. Finally, the last image is the re-processed O3 version without and without RGB stars representing ~58 and ~60 hours worth of data.

Following the Squid-only series, I worked on the narrowfield (https://www.astrobin.com/hg1c5d/) and widefield (coming soon) series where it is situated between the wingspan of Flying Bat. I started with data from the FC100DF/QHY163M combination which results in a total exposure of 78+ hours for SHO. The SV70T/QHY163M data used for the widefield framing representing another 51+ hours was also integrated in. The RGB data using the QHY247C with the SV70T adds another two hours.  The total exposure of the final image with the narrowfield or widefield framing is 131+ hours, my longest to date!

For the narrowfield series, I struggled with colour. The Ha (A), the S2 (B), and the L versions that include the O3 data (with and without stars, C and D) are my favourites.  The final colour versions were processed additionally using TopazStudio (with and without stars, E and F).

As always, thanks for looking!

--Ram

Edited by ramdom
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  • ramdom changed the title to Flying Bat and Squid nebulae Sh2-129/Ou4 narrowfield (m-sho, c-shorgb) - 131 hours!
52 minutes ago, Kinch said:

It certainly stads out......but in truth, I am not so sure you needed to spend that amount of time on it. 

I agree, I could get something very similar with about 75 hours total for this particular image but this is the total data from two framings/OTAs and there's one more framing left to go and all three framings are using the same data so per image on average it is like 43 hours. Instead of doing 3 separate images I did them all at once but with different OTAs (squid only, narrowfield bat, widefield bat). The main requirement is the ~60 hours of O3 for the Squid region - I think I could've doubled that to 120h and I'd have still noticed a discernable change (I compared the ~40 hour integration to the 60 hour one and I could see a difference).  Then for the narrowfield I added some Ha and S2 which brought it to 76 hours ( + 2 for the RGB stars). Then I switched scopes and shot more Ha and S2 but with a greater field to get the FULL bat (but at a lower resolution).  I then integrated all this data for both the narrowfield and widefield versions (i.e., both images use the same data but they cover different parts of the framing) since I had it all anyway. 

This is the only framing where there's nearly 100% overlap (two of the corners are actually about 80 hours worth, and without the O3 data, only 20 hours).  

Perhaps this image will make more sense, this only about 20 hours worth: http://ram.org/images/space/downloads/Image40.jpg and this is the FULL image from both scopes (just one night's session of each filter from each scope is there as a trial run - you can see the lines and how the framing shifts, and what I mean by "corner" etc - this is NOT present in the final images, the last series I'm still doing). This is also 131 hours total but the parts OUTSIDE of the above framing are only about 40 hours (only Ha and S2).  Now I could've done the lower resolution image only  and then blown it up for the same result  but my goal was to get the Squid and surrounding Ha/S2 in a higher resolution first and THEN do a low resolution  of the surrounding areas. It's a technique I've been playing with using drizzle and local normalisation which removes those lines in the test image instead of doing mosaics.

I posted this question a long time ago.  One reason I'd like to do a mosaic is to get a higher resolution version of a target. For instance, my SV70T setup has a resolution of 2.4"/pixel (a bit soft) and the FC100DF has a resolution of 1.7" (not bad, could be better, I aim for 1"/px). If I wanted to do the full bat with the FC100DF, I'd have to do four panel mosaic but yet what you see above is the main region and typically I want to do a mosaic, 80% of the target fits n my scope but another 20% doesn't not. There's a lot of "wasted space". So I select a region like above and do it at the highest resolution and then do the whole surroundings (see Image40 link) with a lower resolution but integrate all the data together.  So I feel I am getting away with doing something less (at least less work) than doing a mosaic which is mostly going to be empty space.  

I hope all this makes sense.  Sorry for the long winded answer but I did have a reason for doing it this way.

--Ram

 

 

 

Edited by ramdom
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Fabulous work and I admire your work ethic.  The squid is so faint and it is great to see it with such good SNR.  My only quibble is purely aesthetic.  On the one hand you could say, "if you've got it flaunt it!" but, for me, a slightly more subdued squid would be preferable.  The SNR would still shine through.

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Thanks Martin! It's not so much "if you've got it flaunt it" as much as "flaunt it whether you've got it or not"!  :) At least when it comes to AP (and perhaps many things, we have rooms in our home lit up like a nightclub) I'm more of a psychedelic bright colours person - if it even half works I'll take it. The actual image I produced via PixInsight is quite subdued but then I got a bit carried away in Topaz.  I understand not everyone appreciates that and it constantly surprises me (this colour combination is one of my favourites for instance: http://ram.org/images/space/scope/1.7.4.5/ic1396_sho.v0221.jpg) but it makes my twelve year old daughter happy... 

The Squid itself could be subdued as the image (not mine) I was following for the colours does  but I was following this video on getting your O3 data to "pop" (https://www.youtube.com/watch?v=5M3zB7-Llhw&ab_channel=RockyMountainAstro) so that was partly responsible for the less subdued O3. 

--Ram

 

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