Andromeda Galaxy Mosaic

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  • Member since
    September, 2007
Andromeda Galaxy Mosaic
Posted by lothar22 on Wednesday, October 30, 2013 2:20 PM

My first attempt at a mosaic.

Imaged over 3 nights.

Each frame: 22 x 2 minute exposures.

Took darks before and after each frame and used all of them together to calibrate (Dark subtract) all frames when combining.

Used same exact settings in FITS Liberator to stretch each frame.

Pasted each frame into the same image in Photoshop, but kept them on separate layers.

Stretched each frame with the same exact settings, going back and adjusting any frame that didn't match background and/or forground brightness.

Flattened image into single layer for final stretch and touch up.

I've imaged another mosaic (still processing), and have learned a few things:

Imaging all frames in one night is ideal, as varying sky conditions can make it difficult to match frames from night to night.

I didn't need as much overlap on each frame as I thought I would. I overlapping by 20% at least. I think only about 10% is needed.

 

 

 

 

 

Andromeda Galaxy


Imaging: 8" f/5 Newt on a Celestron AVX mount

Meade DSI Color with ATIK .5 focal reducer / Celestron UHC/LPR filter.

Guiding: 60mm Meade Telestar refractor

Logitech Quickcam Pro 3000 / PHD Guiding

http://www.chrislester.net/astro/

  • Member since
    November, 2009
Posted by Poppa Chris on Wednesday, October 30, 2013 2:32 PM

Excellent "Firstie".

Don't hold back... Tell us a bit more about how you took the images and how you compiled the mosaic.

(Enquiring minds want to know... Wink )

 

---Poppa Chris---

Denham Springs, Louisiana USA

"Second star to the right - Then straight on until morning!" - Peter Pan

Celestron CPC1100GPS (XLT) - 279mm aperature, 2800mm Focal length. (f10) Celestron Ultima LX (70deg AFOV) Eyepieces 32mm thru 5mm, Canon EOS Rebel T2i DSLR, Backyard EOS imaging software, Orion Star Shoot Planetary Imager IV, Celestron Skymaster 15x70 binoculars

 

  • Member since
    December, 2005
Posted by Oliver Tunnah on Thursday, October 31, 2013 12:46 PM

Looking good.

A good 'manual' mosaic is always rewarding. Can't wait to see what's in the works.

  • Member since
    November, 2009
Posted by Poppa Chris on Thursday, October 31, 2013 2:00 PM

So you took darks before and after each series of light frames?  Interesting.  I can see how that could help you average out sensor temperature most effectively.   Did you take any Flat and/or Bias frames?  How did you stack them?  Deep Sky Stacker? (I am assuming the manual work in Photoshop was only on the mosaic segments of the final image.)

 

---Poppa Chris---

Denham Springs, Louisiana USA

"Second star to the right - Then straight on until morning!" - Peter Pan

Celestron CPC1100GPS (XLT) - 279mm aperature, 2800mm Focal length. (f10) Celestron Ultima LX (70deg AFOV) Eyepieces 32mm thru 5mm, Canon EOS Rebel T2i DSLR, Backyard EOS imaging software, Orion Star Shoot Planetary Imager IV, Celestron Skymaster 15x70 binoculars

 

  • Member since
    September, 2007
Posted by lothar22 on Thursday, October 31, 2013 5:48 PM

As my DSI is uncooled, "bracketing" lights with darks for each frame/segment is recommended.

Basically, take darks often, and a lot of them. 

For the entire mosaic, I took 174 lights, and 144 darks.

I did take flats and Bias frames, and used them to calibrate the darks.

I tried using just the darks from each segment for each segment, but they didn't match color and brightness.

When I used all the darks for all the lights, they matched right up.

I used MaximDL to Calibrate and Combine, then FITS Liberator.

I do a full range stretch in MaximDL to get all data. Then after combining and opening in FITS Liberator, I use the same exact stretch settings for each segment. Then save as a .TIF for Photoshop.

 


Imaging: 8" f/5 Newt on a Celestron AVX mount

Meade DSI Color with ATIK .5 focal reducer / Celestron UHC/LPR filter.

Guiding: 60mm Meade Telestar refractor

Logitech Quickcam Pro 3000 / PHD Guiding

http://www.chrislester.net/astro/

  • Member since
    September, 2011
Posted by RayM0506 on Thursday, October 31, 2013 11:39 PM

Very cool.  Well done!  I am going to be trying a mosaic myself here soon so I is good to see this!

Celestron 8 SCT F/10 to 7.5 to 6.3-C-GEM Mount-Starizona Power Pack II+-Bahatinov Focus Mask-Canon 60Da-Nexguide Auto Guider-Orion Short Tube 80mm Guide Scope- Baader Planetarium UHC-S/L-Booster visual/photographic 2"-Capture Software Backyard EOS-Deep Sky Stacker-Adobe Photoshop/Registax 6 for post work

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