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Old 10-01-2022, 03:09 PM
Stephane
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My first galaxy NGC 2997

Hi all,

Below is my first ever image of a galaxy. No filters used based on IIS advice (galaxy filters post). I am happy I followed the advice as this image came out better than I expected given the light pollution in Melbourne.

In regards to processing, I think I am slowly getting the hang of star reduction and masks. I used masks to clear up that terrible Nikon background noise. Tried deconvolution for the first time too. I had some dust showing up because I used some old flats, but I think I managed to "hide" them. Post-processed a little in Lightroom too for further noise reduction and a little sharpening. The stars are a little bright for my taste with some unnatural looking haze around them.

Please feel free to comment and critic so that I can improve. Thanks again for all your help and encouragement.

Many thanks and clear skies,
Stéphane


Integration: 80 x 180" = 4 hours
Callibration: 30D, 40B, 20F
Camera: Nikon D7000 (ISO: 800)
Guiding: ASI120 MC (PHD2 error < 0.7)
OTA: Bintel BT200 f/5
Mount: EQ6-R pro
Filter: None
Coma corrector: MPCC MkIII
Process: PixInsight, Adobe Lightroom
Attached Thumbnails
Click for full-size image (NGC 2997 cropped.jpg)
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Click for full-size image (NGC 2997.jpg)
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  #2  
Old 10-01-2022, 04:19 PM
Startrek (Martin)
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Stephane
Gee you love a challenge, taking on a tiny dim 9.5 magnitude spiral galaxy , good on you
Well done !!!
A few observations -
1/ Moon is half phase at the moment and disappears on the western horizon around midnight. Did you image this galaxy after midnight or before ? If before the moon glare even at half phase will add some nasty gradients which are hard to mitigate
2/ Try to take new flats for each image session , it’s worth the effort. Darks and Bias you can reuse masters

3/ Stars are a slightly eggy or elongated across the field so either you have a bit of tilt in your camera at the focuser , possibly your polar alignment error is too large causing a bit of frame shift across the field. They appear to be worse on the right hand side. It could also be a bit of coma but I don’t think so as in the left side corners the stars appear to be fairly round. Tight guiding won’t eliminate these issues.

4/ Can’t help you on the post processing side of things as I don’t use PI or Lightroom

Overall a great first attempt

Your definitely heading the right direction and have made great progress in the hobby in such a short time

Clear Skies
Martin
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  #3  
Old 10-01-2022, 04:40 PM
Stephane
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Thanks Martin! I was hoping for an easier galaxy, but couldn't find one on Stellarium. My back garden has mostly an Eastern and Northern view. South and most of the West have obstructions.

I started imaging at 10:30 pm and finished around 3:30 am. So I guess I had the moon for a couple of hours.

For the first time my mount successfully performed an automatic meridian flip which was great to watch.

I will take new flats each imaging session. I learnt this the hard way today.

As for the elongated stars, I am also confused. There were serious issues with my polar alignment and I am not sure what was happening. NINA was telling me that I was perfectly polar aligned one moment, but 15 minutes later, it was telling my I was a degree off in both RA and Dec. Not sure how I can be polar aligned one moment, then off the next. I made sure everything was tight, couldn't find any issues. I re-polar aligned, and same thing happened. So I did it a third time, and hoped for the best. Tilt is also a possibility as I did take the camera off to remove the L-Extreme filter and perhaps repositioned it with not enough care. I also tightened the focuser lock screws which I don't usually do. Any thoughts??

Also, I am a little worried about my Dec gears. The mount is making a slight grinding noise as it rotates. RA gears do not make this noise, just the high pitch "normal" noise. Any thoughts there? I haven't ever opened the mount up, and don't really feel confident doing so...

Thanks again for all the encouragement.

Clear skies,
Stéphane
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  #4  
Old 10-01-2022, 05:55 PM
AdamJL
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Martin's made some great points. Definitely take flats, every time, unless you have a permanent observatory where your setup doesn't change. Flats (and dark flats) are mandatory.

For your elongation, as the stars are going in a north/south direction that definitely indicates polar alignment issues. Did you use the 3 point polar alignment routine in NINA?

For processing, this is a very blue image. I don't think the NGC 2997 group is coming towards us, so if anything it should be redshifted (interestingly, that's why Andromeda appears blueish in many pictures... proof it's coming towards us)
How did you process the colours in this? 4 hours might be enough to get colour data from this dim galaxy, but you should definitely have star colour with that much data.

edit: just to make an additional point... if your stars elongate when you rotate your camera, then that would indicate tilt issues in my view. You can chuck a sub into ASTAP and it will show how much tilt you have. Or CCD Inspector. Expensive software, but you can trial it first.
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  #5  
Old 10-01-2022, 06:03 PM
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Top effort Stephane on your first gaxaly,
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  #6  
Old 10-01-2022, 06:08 PM
Startrek (Martin)
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Quote:
Originally Posted by Stephane View Post
Thanks Martin! I was hoping for an easier galaxy, but couldn't find one on Stellarium. My back garden has mostly an Eastern and Northern view. South and most of the West have obstructions.

I started imaging at 10:30 pm and finished around 3:30 am. So I guess I had the moon for a couple of hours.

For the first time my mount successfully performed an automatic meridian flip which was great to watch.

I will take new flats each imaging session. I learnt this the hard way today.

As for the elongated stars, I am also confused. There were serious issues with my polar alignment and I am not sure what was happening. NINA was telling me that I was perfectly polar aligned one moment, but 15 minutes later, it was telling my I was a degree off in both RA and Dec. Not sure how I can be polar aligned one moment, then off the next. I made sure everything was tight, couldn't find any issues. I re-polar aligned, and same thing happened. So I did it a third time, and hoped for the best. Tilt is also a possibility as I did take the camera off to remove the L-Extreme filter and perhaps repositioned it with not enough care. I also tightened the focuser lock screws which I don't usually do. Any thoughts??

Also, I am a little worried about my Dec gears. The mount is making a slight grinding noise as it rotates. RA gears do not make this noise, just the high pitch "normal" noise. Any thoughts there? I haven't ever opened the mount up, and don't really feel confident doing so...

Thanks again for all the encouragement.

Clear skies,
Stéphane
No problem glad to help where possible, we all need encouragement
The Dec axis “may” have some slight binding on the worm gear
Both my EQ6-R mounts sound similar in Ra and Dec ( high pitch like a mosquito) as I have adjusted both Ra ad Dec worms. If it’s a harsh grinding sound, a shudder sound or even a clunking sound ( Binding of worm gear ) I would stop using the mount as it could do damage.
Adjusting the worms are fairly straight forward
Here’s my procedure below plus Cuiv the lazy Geek has a YouTube video on how to do it

EQ6-R Dec backlash adjustment

This procedure is only required if you have “binding of gears” or any minor back and forth movement or rotation movement in your Dec axis with the Dec clutch locked and the same with the Ra axis.It may be only a slight amount of movement ( less than 1mm ) but there should be almost no movement in your Dec and Ra axis with the clutch locked position and also no binding of the Dec and Ra worm gears when slewing the mount around.

Tools required
5mm Allen key long shaft short end ( I had to cut off 10mm on the short end of the Allen key wrench so it would fit behind the Ra clutch lever )
2mm Allen key long shaft short end

NB: Make sure your Telescope is installed with all equipment and mount is in the “Home Position” with the Dec and Ra clutches secured and locked

Dec Axis
1/ On the Dec axis or Dec shaft housing loosen the 4 main fixing Allen screws pointing down the Dec shaft ( 2 x rear and 2 x either side ) just half a turn not too much
2/ The Dec adjustment screws are small Allen grub screws located either side of the Dec axis or Dec shaft housing ( one at the front and one at the rear )
3/ “Very important “ do not tighten or loosen both adjustment screws together the same way otherwise you may damage your Dec worm gear inside the housing. You must tighten one side and loosen the other side during all adjustments, these adjustments must be small , just a quarter turn or less. Start off with tightening the top or front grub screw and loosening the back or bottom grub screw
4/ Make sure you a make small adjustment in the adjustment grub screws ( one side screw in and the opposite side unscrew out )
5/ Then retighten the 4 main fixing screws
6/ Now check for backlash in Dec by trying to rotate or move the telescope back and forth. If there is no movement at all , then your ready to test the mounts powered movement or slewing
7/ Power up your mount and slew or rotate the Dec axis through nearly 360 degrees using your mounts hand controller or direct from your Laptops telescope control ( eg EQMOD). If you hear a binding or scraping or shudder sound it means your adjustment has been slightly to much one way or the other , stop the mount and return it to the Home Position.
8/ Repeat item 1, item 4( adjust back a little bit ) and item 5 again and rotate or slew the Dec axis of the mount again through 360 degrees until you hear no binding , and the mount is smoothly rotating around with just the high pitch noise of the mount.
10/ Return the mount to the “Home Position” again and check for Dec backlash again. Once your satisfied, just double check your 4 main fixing screws again
11/ A tip is to only make small adjustments one way or the other with the adjustment screws.
12/ The main objective is no backlash and no binding in the Dec axis.
Ra Axis
Repeat the above procedures for the Ra axis

Cheers
Martin
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  #7  
Old 10-01-2022, 06:33 PM
Startrek (Martin)
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Quote:
Originally Posted by Startrek View Post
No problem glad to help where possible, we all need encouragement
The Dec axis “may” have some slight binding on the worm gear
Both my EQ6-R mounts sound similar in Ra and Dec ( high pitch like a mosquito) as I have adjusted both Ra ad Dec worms. If it’s a harsh grinding sound, a shudder sound or even a clunking sound ( Binding of worm gear ) I would stop using the mount as it could do damage.
Adjusting the worms are fairly straight forward
Here’s my procedure below plus Cuiv the lazy Geek has a YouTube video on how to do it

EQ6-R Dec backlash adjustment

This procedure is only required if you have “binding of gears” or any minor back and forth movement or rotation movement in your Dec axis with the Dec clutch locked and the same with the Ra axis.It may be only a slight amount of movement ( less than 1mm ) but there should be almost no movement in your Dec and Ra axis with the clutch locked position and also no binding of the Dec and Ra worm gears when slewing the mount around.

Tools required
5mm Allen key long shaft short end ( I had to cut off 10mm on the short end of the Allen key wrench so it would fit behind the Ra clutch lever )
2mm Allen key long shaft short end

NB: Make sure your Telescope is installed with all equipment and mount is in the “Home Position” with the Dec and Ra clutches secured and locked

Dec Axis
1/ On the Dec axis or Dec shaft housing loosen the 4 main fixing Allen screws pointing down the Dec shaft ( 2 x rear and 2 x either side ) just half a turn not too much
2/ The Dec adjustment screws are small Allen grub screws located either side of the Dec axis or Dec shaft housing ( one at the front and one at the rear )
3/ “Very important “ do not tighten or loosen both adjustment screws together the same way otherwise you may damage your Dec worm gear inside the housing. You must tighten one side and loosen the other side during all adjustments, these adjustments must be small , just a quarter turn or less. Start off with tightening the top or front grub screw and loosening the back or bottom grub screw
4/ Make sure you a make small adjustment in the adjustment grub screws ( one side screw in and the opposite side unscrew out )
5/ Then retighten the 4 main fixing screws
6/ Now check for backlash in Dec by trying to rotate or move the telescope back and forth. If there is no movement at all , then your ready to test the mounts powered movement or slewing
7/ Power up your mount and slew or rotate the Dec axis through nearly 360 degrees using your mounts hand controller or direct from your Laptops telescope control ( eg EQMOD). If you hear a binding or scraping or shudder sound it means your adjustment has been slightly to much one way or the other , stop the mount and return it to the Home Position.
8/ Repeat item 1, item 4( adjust back a little bit ) and item 5 again and rotate or slew the Dec axis of the mount again through 360 degrees until you hear no binding , and the mount is smoothly rotating around with just the high pitch noise of the mount.
10/ Return the mount to the “Home Position” again and check for Dec backlash again. Once your satisfied, just double check your 4 main fixing screws again
11/ A tip is to only make small adjustments one way or the other with the adjustment screws.
12/ The main objective is no backlash and no binding in the Dec axis.
Ra Axis
Repeat the above procedures for the Ra axis

Cheers
Martin
Stephane,
So as not to alarm you I’ll attach Cuiv the lazy geeks YouTube video which clearly demonstrates what binding of the worm gear sounds like and how to rectify and clear any backlash in your mount

https://m.youtube.com/watch?v=1hzAh6ro8YU

Cheers
Martin
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  #8  
Old 10-01-2022, 08:17 PM
Stephane
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Quote:
Originally Posted by AdamJL View Post
Did you use the 3 point polar alignment routine in NINA?

For processing, this is a very blue image. I don't think the NGC 2997 group is coming towards us, so if anything it should be redshifted
Adam, thank you for the tips. Yes, I did use the 3 point polar alignment in NINA. Fairly straightforward, but as soon as I was within half an arc minute, every 3 second exposure would result in a larger and larger error, until I was an entire degree off. Really weird. I wasn't touching anything.

As for colours, yes, I messed around with the colours a lot, bumping up the blues and reducing green. I didn't touch the reds, but my colour calibration is definitely off. I haven't quite mastered that yet, but am watching videos and reading articles. I think I was just so happy to see "something bright" that I didn't really care at the time, but that will definitely be my next goal for improvement.


Quote:
Originally Posted by Startrek View Post
Stephane,
So as not to alarm you I’ll attach Cuiv the lazy geeks YouTube video which clearly demonstrates what binding of the worm gear sounds like and how to rectify and clear any backlash in your mount
Thanks Martin, I'll watch this video. RA sounds like a mosquito like yours. Dec has a slight grinding noise. Not that bad that I am panicking, but enough for me to mention. I might try your procedure if I muster up the courage. I am getting nervous just thinking of the damage I might do...

Quote:
Originally Posted by Kuz View Post
Top effort Stephane on your first gaxaly,
Thank you, Kuz
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Old 11-01-2022, 01:07 AM
raymo
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Adam, when the colours are properly balanced when imaging 2997 with
a non astro modded DSLR it is grey/blue, but an astro modded camera will
of course show quite a lot of Ha [red] areas, so Stephane's image is pretty much the right colour, just too saturated.
raymo
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Old 11-01-2022, 08:52 AM
AdamJL
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Agreed, Raymo. But there should be star colours at least.
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Old 11-01-2022, 11:34 AM
Stephane
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Thank you all for the tips. It gives me a few things to try to work on in coming weeks.

Clear skies,
Stéphane
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Old 11-01-2022, 12:45 PM
raymo
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Absolutely, Adam, but as Stephane said himself, he's not full bottle at processing yet.
raymo
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Old 11-01-2022, 01:02 PM
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Awesome work mate, love the details.
Can you link the 'galaxy filters post' you reffered to please i can't seem to find it
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Old 11-01-2022, 01:12 PM
AdamJL
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Quote:
Originally Posted by raymo View Post
Absolutely, Adam, but as Stephane said himself, he's not full bottle at processing yet.
raymo
very true, mate. It's hard to provide feedback sometimes. Usually in the beginners forum I don't do it unless asked.

Stéphane said

Quote:
Originally Posted by Stephane View Post
Please feel free to comment and critic so that I can improve.
Hence the comments and the one about star colour. If this isn't accepted, I'll just provide feedback in the DSO section instead. Not trying to ruffle any feathers.
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Old 11-01-2022, 01:29 PM
Stephane
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Quote:
Originally Posted by AdamJL View Post
very true, mate. It's hard to provide feedback sometimes. Usually in the beginners forum I don't do it unless asked.
Adam, please comment freely. I really appreciate your comments and need them if I want any hope of improving. You are not ruffling any feathers on my end! In fact, if you have any further points for me to work on, please let me know.

Quote:
Originally Posted by Tony Leece View Post
Awesome work mate, love the details.
Can you link the 'galaxy filters post' you reffered to please i can't seem to find it
Tony, the link is: https://www.iceinspace.com.au/forum/...d.php?t=196103

Quote:
Originally Posted by raymo View Post
Stephane's image is pretty much the right colour, just too saturated.
raymo
Thanks Raymo for your feedback too. Will try to take all these points on board. I agree the colours are too saturated, and need to draw the red out somehow.
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Old 11-01-2022, 05:55 PM
raymo
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All criticism is usually well accepted here Adam, please continue to offer it.

Stephane, you can't draw the red out of images if the red is not detected
and recorded by your unmodded DSLR. In other words you can't bring out what is not there.
raymo
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