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A Merry Christmas Tree and Cone Nebula to Everyone


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My last image for 2022, got family arriving for Christmas later in the week and weather forecast does not look that good for imaging over the Christmas/New Year holiday so I will probably bring my kit indoors and sit it  in a cupboard with a dehumidifier for a day or so.


This image has been quite a challenge for a number of reasons - but Astro imaging is all about soving problems... I started in late November grabing data inbetween the very heavy rains and cloud cover then recent clear skies had the full moon to contend with and also very low temperatures in my back garden -7/9degC , not as low as some other areas of the country but did impact imaging - my mount aquired a lot of backlash, and I assume the low temperatures contracted the metal in the worm gear and as the tolerances are quite fine, I had to stop and dial down the backlash mid-session - it worked but as temps increase I may get binding and have to adjust the backlash again...

I also did not begin with intention to build a mosaic, but the gas cloud formations around this area are so full of detail ,  I used the mosaic function in ASIair and setup the plan and over the last 3 anda bit  weeks captured about 35-36 hrs of subs . However about 3hrs of the Ha was not useable as the full moonlight shone directly into the objective and wiped out most of the contrast , and the rest were binned due to clouds/poor guiding and horrible stars.


I didn't intend to take so much Sii, but for some reason, possibly user error rather than software bug, but I did set the plan to use Oiii filter, but after I had completed the first run of the plan and reset and start again , the plan reverted to Sii - the autofocus  kicked in on plan start and so I did not notice until I reviewed the subs the next day and wondered why I had so many Sii.....

My EAF also was losing focus very quickly and I noticed I could move the focusser about 1-2mm even when the EAF was powered - wonder if that was temperature related as well ?

I moved from focus every hour to focus every 30mins to compensate.


I processed 29hrs of data.


I have applied the new Rus Croman tool BlurXT to each of the channel integrations, not too much and certainly not the defaults, around 0.15-0.2 for star deconvolution and about 60 on the sharpening function using auto PSF. I used StarXT and NoiseXT all post-processed in Pixinsight, integrated with APP and mosaic stiched using APP
Stars are a HOO pixel math combination and screened back into the SHO image with ~((~starless)*(~stars))


I have also posted up a crop of the Cone and Christmas Tree




Image Detail

    23 Nov 2022 ·  7 Dec 2022 ·  8 Dec 2022 ·  9 Dec 2022 ·  10 Dec 2022 ·  14 Dec 2022 ·  15 Dec 2022 ·  16 Dec 2022 ·  17 Dec 2022
    Antlia 3nm Narrowband H-alpha 2": 164×300″(13h 40′)
    Antlia 3nm Narrowband Oxygen III 2": 68×300″(5h 40′)
    Antlia 3nm Narrowband Sulfur II 2": 116×300″(9h 40′)






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