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Tarantula Nebula NGC 2070 - Askar FRA400 L-extreme Filter ASI533mc

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#1 robonrome

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Posted 21 November 2020 - 11:05 PM

Trying a lot of relatively new things here, new scope Askar 400 FRA and L extreme filter and using NINA for the first time...well first time I manage to get it to work and when it works it's great. Used APT before, but really appreciating a lot of the features and the AF is great.

 

This is 5 hours of data taken over three nights mostly 180s exposures, ASI533mc pro (unity gain and -5deg cooled). This is with the Askar 400 without it's reducer. It's a Petzval like quintuplet so don't need any specific spacing except when using reducer.

 

This is in the deep south for me (i'm 27 deg south but this is near the pole) and it's right in the middle of the SKyGlow of Brisbane city, pop 2Million, Bortle 7.

 

The new L extreme filter from Optolong extreme is amazing for this. Don't get the full colour range, but otherwise would never be able to do extract this detail. 

 

I may add more to this but suspect it's probably diminishing returns from here?

 

comments, advice, critique welcome.

Attached Thumbnails

  • Tarantual_3nights_5h5mexp_Askar400_lextreme_533_unity_lowres.jpg

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#2 MikiSJ

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Posted 21 November 2020 - 11:44 PM

A very nice image of something I will never see. You get so much more and different in the Southern Hemisphere.

 

My personal taste and please ignore if not warranted: you may want to darken the brighter parts, especially in the right of the image.



#3 robonrome

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Posted 22 November 2020 - 04:42 PM

A very nice image of something I will never see. You get so much more and different in the Southern Hemisphere.

 

My personal taste and please ignore if not warranted: you may want to darken the brighter parts, especially in the right of the image.

thanks Miki, the grass is always greener. I'm always gazing in envy at all the norther hemisphere subjects I never get to see and image ;-)

 

You're right I could wind brightness back a bit at the right. The brightness variation is quite massive in this complex however. That brighter right area I've had to work hard to restrict while bringing out fainter areas...it's a bit like the central trapezium area in the great Orion Neb for brightness (well not quite but up there)



#4 Huangdi

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Posted 22 November 2020 - 05:29 PM

thanks Miki, the grass is always greener. I'm always gazing in envy at all the norther hemisphere subjects I never get to see and image ;-)

You're right I could wind brightness back a bit at the right. The brightness variation is quite massive in this complex however. That brighter right area I've had to work hard to restrict while bringing out fainter areas...it's a bit like the central trapezium area in the great Orion Neb for brightness (well not quite but up there)

That's what masks are for :p

Nice image BTW!

Edited by Huangdi, 22 November 2020 - 05:29 PM.


#5 robonrome

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Posted 25 November 2020 - 01:24 AM

I've added some data to a total on 6.5hrs integration time and reprocessed a little trying to bring out some fainter detailed here.

Attached Thumbnails

  • Tarantula_5nights_6h49m_Askar400_ASI533_unity_Lextreme_lowres.jpg

Edited by robonrome, 25 November 2020 - 02:33 AM.

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#6 imtl

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Posted 25 November 2020 - 01:37 AM

Its interesting to compare it to SHO palette. Here is something I put together quickly. No real image processing, just channel combine and a bit of enhancing the nebular regions. I want to collect a lot more data on this.
I rotated my image to compare to yours. I think you got some nice data! I think though that if you really want to pull the faint stuff out, you should collect a lot more. I think its worth it.

gallery_259665_13682_11304308.jpg


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#7 DRK73

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Posted 25 November 2020 - 08:56 AM

Thanks for posting - this is actually very reassuring. I've got the same system (Askar FRA 400, ASI533mc-pro, L-extreme), but the one night I've been able to get it out I used the 0.7x reducer. With the reducer (maybe), it doesn't look like I'll be able to get red and blue wavelengths parfocal. When I separated channels, I had blue and green very tightly focused but the stars in the red channel were poofy little doughnuts. Based on your (fantastic!!) image, it looks like this is not an issue at the telescope's native focal length? Great job!



#8 robonrome

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Posted 25 November 2020 - 03:46 PM

Its interesting to compare it to SHO palette. Here is something I put together quickly. No real image processing, just channel combine and a bit of enhancing the nebular regions. I want to collect a lot more data on this.
I rotated my image to compare to yours. I think you got some nice data! I think though that if you really want to pull the faint stuff out, you should collect a lot more. I think its worth it.

gallery_259665_13682_11304308.jpg

eyal, the detail here is sublime and something to aspire to. I intend to keep adding data as you suggest but I think I need to master and use channels based processing to make the most of it. BTW how do you attach such a large detailed image here...i had to drop the jpeg quality to just "2" to make it under the required size limit here which has softened my image a lot.



#9 robonrome

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Posted 25 November 2020 - 03:52 PM

Thanks for posting - this is actually very reassuring. I've got the same system (Askar FRA 400, ASI533mc-pro, L-extreme), but the one night I've been able to get it out I used the 0.7x reducer. With the reducer (maybe), it doesn't look like I'll be able to get red and blue wavelengths parfocal. When I separated channels, I had blue and green very tightly focused but the stars in the red channel were poofy little doughnuts. Based on your (fantastic!!) image, it looks like this is not an issue at the telescope's native focal length? Great job!

I've used the 0.7x reducer a fair bit with this scope as well but mainly with the ASI071mc (apsc sensor) for wide field also with Lextrreme or Lenhance. There is a slight amount on CA I think toward the edges even with native FL, but the 0.7x reducer really exacerbates it - tilt in my system makes it worse and critical focus is well critical to avoid it. I haven't noticed CA so much with the ASI533.oh and with the reducer backspacing is critical. Nominally 55mm and when using lextreme more like 55.7 but for my system found I needed 57mm

Edited by robonrome, 25 November 2020 - 04:17 PM.


#10 imtl

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Posted 25 November 2020 - 04:03 PM

Lets focus on your image. I think the L extreme is a duo band filter so with this object that pretty nice since Ha and OIII are mutually strong. The SII that I captured is much fainter.

 

The "problem" of course with this is that your OIII data is mixed between blue and green but that's OSC. If you are using PI then look into colormask script to help you process the different color channels to your liking.

 

The jpeg is within the allowed limits :O its 1600x1060.


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#11 robonrome

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Posted 26 November 2020 - 06:56 PM

Lets focus on your image. I think the L extreme is a duo band filter so with this object that pretty nice since Ha and OIII are mutually strong. The SII that I captured is much fainter.

 

The "problem" of course with this is that your OIII data is mixed between blue and green but that's OSC. If you are using PI then look into colormask script to help you process the different color channels to your liking.

 

The jpeg is within the allowed limits :O its 1600x1060.

Thanks. I'm just using DSS and then Photoshop. I am going to start with watching a tutorial on using channels in PS and see how I go. I may have to make the move to PI or something similar at some point but will see how I go with PS first. Just posting a reduced size but increased jpeg quality image to see if it shows better here as well. EDIT...it doesn't seem to retain the sharpness and detail I see when looking at the same jpeg on my pc direct...hmmmm.

 

Tarantula_5nights_6h49m_Askar400_ASI533_unity_Lextreme_lowres.jpg



#12 imtl

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Posted 26 November 2020 - 08:16 PM

You can upload to flickr or abin and share a link. But I think you are on a good path. A lot to learn especially processing nebulae.

The star colors are off, to get them right you might consider taking some exposures with just your Uv-ir filter and replace the stars with the RGB ones.


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