Galaxy NGC 2403 (C7...
 
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Galaxy NGC 2403 (C7)

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(@greg-erianne)
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NGC 2403 (Caldwell 7) is about 8 million light-years away and some 50,000 light years wide.  It is an intermediate spiral galaxy in the constellation Camerlopardalis and contains numerous star-forming, HII regions (pink-red in the photograph).  The lower spiral arm in the photo connects it to the very large (940 ly across) star forming region, NGC 2404.

In the non-cropped version, you can see numerous other smaller galaxies and other structures as well (which is why I posted this version as well).

Askar 107PHQ
ASI2600MC Pro (OSC camera)
ZWO AM5 mount with guiding via ASIAir Plus using an ASI178mm mini and a 60mm F4 guide scope
Antlia RGB Triband Ultra filter -- 300s x 43 [Total Exposure 3:35]; calibrated with dark, flat, and bias frames
Pre- and post-processed in PixInsight
Additional post-processing in Photoshop for color balance and generation of jpeg (for reduced file size)


   
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Terri Zittritsch
(@terri)
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Posts: 327
 

Posted by: @greg-erianne

NGC 2403 (Caldwell 7) is about 8 million light-years away and some 50,000 light years wide.  It is an intermediate spiral galaxy in the constellation Camerlopardalis and contains numerous star-forming, HII regions (pink-red in the photograph).  The lower spiral arm in the photo connects it to the very large (940 ly across) star forming region, NGC 2404.

In the non-cropped version, you can see numerous other smaller galaxies and other structures as well (which is why I posted this version as well).

Askar 107PHQ
ASI2600MC Pro (OSC camera)
ZWO AM5 mount with guiding via ASIAir Plus using an ASI178mm mini and a 60mm F4 guide scope
Antlia RGB Triband Ultra filter -- 300s x 43 [Total Exposure 3:35]; calibrated with dark, flat, and bias frames
Pre- and post-processed in PixInsight
Additional post-processing in Photoshop for color balance and generation of jpeg (for reduced file size)

 

Hey Greg, glad to see you got out for a bit of A-P.    Very nice capture.  I've never looked at this one or thought to capture it.  It looks like a neat galaxy based on the detail and knots in the arms.     Great imaging, processing.   

 

Terri

 

 

 


   
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(@greg-erianne)
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@terri Thanks, Terri.  Last night was a total, but very nice, surprise!  The only forecast that was accurate was the Candian RDPS.  The sky was clear when I looked out after dinner, but all the other forecasts were calling for solid cloud cover.  Go figure.  Seeing that, I just went ahead and set up and it was clear until I stopped my run at about 11:40 pm (because the moon was starting to come up from behind the cloud bank in the east).  

C7 is really a pretty galaxy with all the HII regions in it. I'd bet your setup would capture a gorgeous image of it with much more detail than I can get.

Greg


   
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Terri Zittritsch
(@terri)
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Posted by: @greg-erianne

@terri Thanks, Terri.  Last night was a total, but very nice, surprise!  The only forecast that was accurate was the Candian RDPS.  The sky was clear when I looked out after dinner, but all the other forecasts were calling for solid cloud cover.  Go figure.  Seeing that, I just went ahead and set up and it was clear until I stopped my run at about 11:40 pm (because the moon was starting to come up from behind the cloud bank in the east).  

C7 is really a pretty galaxy with all the HII regions in it. I'd bet your setup would capture a gorgeous image of it with much more detail than I can get.

Greg

I will add it to my list.  I spent last night debugging a mini pc setup and working on sensor tilt.   It’s amazing how 20 to 60 um effects sensors off axis and how hard it is to adjust this out!!   Reynolds aluminum foil is 20um measured!!   I was chasing my tail last night because my adjustments were too big.   Now that I have a better idea I’m still not sure it’s going to be easy!

terri

 


   
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Terri Zittritsch
(@terri)
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One more reply on the forecast.   Astrospheric showed a clear night starting yesterday after noon.   I set up just in case it was going to be real even though it was clouding up as it approached 6pm. Cleared up right after and was a nice night.  Perfect for what I was doing. 


   
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(@greg-erianne)
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@terri Yes, the RDPS showed clear all night, while the others (NAM, NBM) showed clouds.  Seeing that it was clear out, I prepared as well. Glad I did!

Happy you're making progress on the tilt problem.  From what I understand and from what you just said, it seems like a tough thing to work out and it's a lot of trial and error.  Stupid question (and I keep burying my head in the sand on this so I don't have to deal with it), but what is an obvious sign you have a tilt problem, misshapen stars?

Greg


   
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Terri Zittritsch
(@terri)
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Tilt will be seen in different star shapes across the frame, typically in corners.  This is typically a full frame sensor issue, although I expect it can happen in an APS-C, but it is significantly smaller area.   With the ASI1600, no worries at all.   With the larger sensors you have both tilt and back focus issues which become more prevalent.    So once I figure out tilt, I can see if there is residual back focus to fix.    Right now it says my sensor could use around 40um of added back focus, but until I'm done fixing the tilt, that would be a waste of time.     I'm using a tilt plate that has 3 push pull screw systems not aligned to any axis... it's a real pain.    Luckily I didn't feel any particular need to get it done quickly else I'd probably have gotten frustrated.  To give you an idea, the tilt plate uses .5mm or .7mm pitch threads so one full turn is 500um to 700um.  With such small amounts of movement, even the amount of tightening I apply to the lock down screws affect the amount of spacing because the plate is aluminum.   I may bite the bullet and buy one of the more elegant solutions but given the expense, I'll try this first.    The current solution forces me to do a focus run, evaluate the tilt, remove the camera/FW/FF and cap it up, take it into the garage where there's good light, remove the field flattener to get at the adjustments, make a small adjustment, cap it up, take it out back and plug it into the scope, go back inside, start another focus run, evaluate, then rinse and repeat.    I can't make the adjustments inside because I'd create a mess with condensation on the sensor, filters, etc.    

 

Terri 


   
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(@greg-erianne)
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@terri Wow, that sounds like tedious work, Terri, and I imagine it can be frustrating.  

I have some odd star shapes in the corners when I use a 0.8x reducer/flattener with my AT60 and I want to try and track down what it is, but I never seem to make the time to do it.  🙄 About the only thing I have planned for the little scope plus the reducer is the Spaghetti nebula, but that's down the road a ways.  (Reprieve!)

Yes, I've seen those rather expensive solutions!  Good idea to try to resolve it yourself first.  

Greg


   
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