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Post by ChrisV on Apr 30, 2016 13:45:41 GMT
Local star party cancelled. So persisted in my backyard but had to give up after a few hours as the clouds were too much. All done with GT81 80 f5.9 refractor, no focal reduction, either UHC filter or no filter for the two galaxies. 20sec shots stacked in sharpcap, darks subtracted, and fiddled black levels later in fitswork. Antennae galaxies. A bit of Eta Carina. Ghost of Jupiter. Sombrero galaxy. Omega Centauri. Pearl Cluster. Tarantula (colour a bit weird for this = green). Hmmm, stuff seems darker when posted. Still haven't figured out what to set colour at in the camera controls. If anyone can tell me how you go about this ? Had to do 20 sec shots, even though others seem to use shorter, otherwise the histograms were cutoff in sharpcap.
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Post by davy on Apr 30, 2016 14:06:16 GMT
Wow,,cracking images chris.
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Post by Dragon Man on Apr 30, 2016 17:44:00 GMT
Fantastic results Chris!!!!! Don't panic about Tarantula. It IS green, with some pink bits. I sometimes alter the Hue in my Live views to make it look more pink but it is actually green, so you have it correct. Many astrophotographers make it pink because they believe pink nebulas look correct. Here's one of my Tarantula in it's normal colour:
and a pic from the European Southern Observatory (ESO): European Southern Observatory (ESO).
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Post by howie1 on Apr 30, 2016 19:57:59 GMT
Top shots Chris. Nice combo the asi and sc hey! Interested to know ... are you doing your own thing gain vs exp times, or following astrojedi's cloudynights thread on high gain and lots of stacked short exp less than 15 sec? Lovely scope you are using too.
cheers
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Post by ChrisV on May 1, 2016 0:30:38 GMT
Thanks guys. So that's why it looked green, it is green.
Howie. Have tried to follow Astrojedi's tips to the letter. Highish gain and short exposures stacked. But had longer exposures (20sec) last night as I was working at f5.9, no reduction. If I went shorter then the histograms got cutoff so I asusme I was missing some stuff. Other nights when I used the 0.5 or 0.33 reducers I was doing 5-10sec exposures. I also think that capturing with RAW16 rather than RGB24 was a good tip. Much more depth to play with so finer detail.
I thought the number of 20s stacks was in the filenames, but it isn't. Antennae (12) Eta Carina (6), Ghost (4), M104 (5), Omega (3), Pearl (2), Tarantula (12).
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Post by howie1 on May 1, 2016 6:46:36 GMT
Yeah, thanks Chris ... I wondered cos AJ's method is short but takes lots to stack and when I have tried SharpCap it doesnt even find stars! Firecapture saved for AToaster to stack does work for some reason!? But like I said lots of shots stacked. I can get something at 10 x 15 secs and that I am prepared to wait. After 5 or so stacked I tweak the image to 'something' ok ... then I start reading up facts on the object so I can learn stuff (terrible with names and constellations!) and just let it keep building the stack in the background while researching.
Thanks for the info Chris. Again great shots. Carina is tops!
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Post by ChrisV on May 1, 2016 13:27:15 GMT
And tonight with Meade f3.3 reducer, but with short spacer so maybe 0.5, so overal f3 on my scope. With the smaller focal ratio, I only needed stacks of 5sec, otherwise camera saturates. All with UV/IR filter. Cat's Paw Neb (96x5s). Centaurus A (80x5sec). Eta Carina (92x5s). Lagoon Neb (72x5s).
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Post by howie1 on May 2, 2016 0:45:45 GMT
Dang, clear skies again Chris ... I'm moving to Sydney! Cloud n rain in Brissie ... again!
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Post by Rick in NWArk on May 9, 2016 15:59:28 GMT
Top notch results Chris, just fantastic!
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Post by ChrisV on May 9, 2016 22:02:58 GMT
Its a great little camera Rick.
Howie. You might need a visa to move from Qld. And we a forecast of a few clear nights. Just enough before the moon comes back too much. Hah !!!
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Post by howie1 on May 10, 2016 0:40:54 GMT
Yup Chris ... crazy up here in the North. Was 23C (73F) this morning at 6:30am! Forecast today of 30C (86F) and its nearly June! Where's Winter!!??!!? And with the heat .... cloudy as, and mucho rain. Rained last night, again! Though the farmers out west are happy as they have had best rain in May since records began. Having said all that, did get out with the Astro club to Lake Wyaralong 2 hours from me on Saturday night. Didn't save any images, was too busy hopping from here to there and checking out two guys with 16" f/4.4 dobs! But had a good clear night. First in a while where weekend coincided with good weather here in Brisbane. We had a ball. 28 scopes and around 60 people. If it doesnt cool down/clear up soon I'll have to call my Neice and hubby down there in Sydney and tell her I'm heading down for a visit. lol Current view outside ...
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Post by howie1 on May 10, 2016 1:00:42 GMT
Hey Chris, just saw you ask re color balance .... gee, never had to adjust my ASI224. And currently using FC and not SC. But in the SC histo, doesnt it show the 3 channels? Or maybe its in the Stacking window where the histo shows RGB lines? Sure I saw them there back when I used SC. Anyway, adjust the R B channels settings to move the R B lines/curves so they are as close as you can get to the G one. Have not tested this so warning ... note your initial settings before mucking about with them.
Maybe some other WB guru's will chime in with more info for you.
cheers
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Post by ChrisV on May 10, 2016 1:30:10 GMT
Howie. Yes its still warm here, even at night. I don't think we are going to get a winter this year.
Thanks for the pointer about the colour. Yes, sharpcap has the RGB in the histogram (not when stacking). I'd fiddled the colour levels as I was getting massively more R than B/G, so had adjusted colour to get their histograms closer. But wasn't sure if this was the way to go, as whatever I'm looking at isn't going to be white. Hey I could point on a few known stars and sort of match to their colour/temp. In sharpcap you can select a small portion of the viewing screen for histograms,& focusing with FHWM. I've got a few clear nights - so might just try this out.
I googled Lake Wyaralong. Looks like a nice spot !
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Post by howie1 on May 10, 2016 2:10:46 GMT
No probs Chris. Glad to help. Yup zoom on star or you could try what I had to do with an old Canon 450D which I modded for astro. You have to set a custom WB for them after doing it. You could try the same process on the ASI224.
Go out in daylight with a piece of white paper and orientate it so the bright sun is shinning down brilliantly lighting the surface of the paper. Set Auto WB, auto exp and auto gain, and point the camera at the illuminated paper. Adjust R and B so the white looks as close to the same white as you see ... or maybe there's a auto WB ... think there is actually. Can't recall. Then note the settings for R and B which it sets to. Use those settings as 'balanced' as a start point for astro work.
I've also heard to put a blank white empty document / webpage on an iPad and hold that over the scope objective end and adjust WB using that.
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Post by ChrisV on May 14, 2016 13:19:10 GMT
Howie. Thanks I'll try that. Half moon tonight so not great. But I wanted to try my new old Optec f3.3 FR. It has a really short focal length - I got a set of thin delrin spacers which I'm still fiddling with. Anyway I've set the spacers so my 80mm f5.9 refractor is at ~f2.6. Can't go too much further or I run out of focus and the edges of the shots get a bit weird. So with the Optec, Eta Carina with fov = 1deg 11min x 53min (according to nova.astrometry). 34x 5 sec.
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Post by Dragon Man on May 14, 2016 14:29:39 GMT
Looks great Chris.
I like that FOV. It's about the same as I try always use. I try stick around 1 degree.
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