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NGC 281 without filter and with my "special Duo-filter"

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#1 hobbyknipser

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Posted 22 September 2019 - 12:53 PM

Hi,

here a comparison!

I imaged in January 2017 NGC 281 without filter, at cold temperatures, with a Canon T3i; 26x6 min at ISO 200...

...and now in September 2019 with my "special Duo-filter": that's an Astronomik UHC-Clip-filter and a 2" Idas V4-filter, together in the image train.

So I have 30nm Green/Blue and 16 nm Red; taken with a Canon T7i, 17x10 min at ISO 800 and warm temperatures (16°C; many hotpixels).

Telescope was every time the TS APO 80/480 at f/4.8.

Here a similar field of view for comparison; what is what, will be clear quickly. lol.gif

By the way, all pictures, as ever, guided with a 500mm guide tube and manual guiding with a double cross eyepiece. So I'm the guider. smile.gif

If I look at the image below, with the smaller stars, ca. 2"/Pixel, I ask myself, is this a sensefull border in resolution for my polluted place, to use this combination the most time...undecided.gif

I believe, in the image below, the Pac-Man has eaten up completely. lol.gif

 

cheers

Andreas

Attached Thumbnails

  • NGC_281_26x6m_384mm_200_050117_8gausx5.jpg

Edited by hobbyknipser, 22 September 2019 - 01:10 PM.

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#2 hobbyknipser

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Posted 22 September 2019 - 12:56 PM

...here the image with the special, wide Duo-filter:

NGC281_17x10m_220919_fits7gausx5.jpg


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#3 Tom K

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Posted 22 September 2019 - 07:33 PM

I love the manual guiding - I did a bunch of that in the 80's and 90's.  You are clearly doing a great job!


Edited by Tom K, 22 September 2019 - 07:33 PM.


#4 Devonshire

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Posted 23 September 2019 - 11:09 AM

So... the UHC narrows the blues, and the IDAS narrows the reds?  Very nice!   :-)

 

I'd wondered about combining filters as well.  Currently thinking about combining a Baader 610nm longpass with either my  UVIR cut filter, or my Optolong CLS-CCD.  Haven't decided to commit to the 610 yet, but you did just give me a nudge!   Thanks for posting this.



#5 hobbyknipser

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Posted 23 September 2019 - 01:26 PM

Hi, Tom,

 

Thanks for your nice comment!

All longer single exposures I did by manual guiding. In any case it was rational with my C9.25 because of the mirror shifting.

I think, no guider can correct the sudden big jumps.

 

cheers

Andreas


Edited by hobbyknipser, 23 September 2019 - 01:48 PM.


#6 hobbyknipser

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Posted 23 September 2019 - 01:45 PM

Hi, "Devonshire",

 

Thanks for your words!

What do you want to reach? For which DSO ...or for planets?

Baader 610nm + uvir cut  = the area 610-700nm that is nearly a normal red filter  (is it right?)

Baader 610nm + CLS  = no Green/Blue and (the CLS begins at 630nm?) 630-700nm (is it right?). That's a narrower red filter (without orange)?

 

greetings

Andreas



#7 Devonshire

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Posted 23 September 2019 - 04:04 PM

Andreas,

 

Oh, just thinking that nebula shots with my unmodified camera using CLS-CCD , combined with some red-enriched shots (mix of Ha, SII, etc.) might be interesting and use time-on-target to compensate for my lack of a mod.


Edited by Devonshire, 23 September 2019 - 04:06 PM.


#8 hobbyknipser

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Posted 28 September 2019 - 12:04 PM

Hi,

I added the images with fitswork to increase the depth and come now to 326 min total exposure time.

Thanks for looking! A new Crop.

 

regards

Andreas

 

Attached Thumbnails

  • NGC281_17x10m_26x6m_220919_2add1897.jpg


#9 hobbyknipser

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Posted 29 September 2019 - 06:36 AM

...and a little more stretching to reach 20.0mag lol.gif

 

 

Attached Thumbnails

  • NGC281_17x10m_26x6m_220919_2add2893.jpg


#10 hobbyknipser

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Posted 29 September 2019 - 12:43 PM

In the overall pictures, as a waste product, Abell 2 was to be seen, but only at 384mm and with too long single exposure times.

Abell 2 is rather unexciting: here a link:

http://www.deepsky-v...e/AbellPN_E.htm

 

In the filterless image, it was a blue dot.

In the image with the 2 filters is was a green dot.

Here, just for fun, the sharper image with the filters:

 

cheers

Andreas

Attached Thumbnails

  • NGC281_17x10m_220919_fits7gabell28.jpg

Edited by hobbyknipser, 29 September 2019 - 03:27 PM.



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