Sunday, July 16, 2023

Tarantula Nebula & NGC 2070 from CT?

The Tarantula Nebula, also known as 30 Doradus, is an immense hydrogen emission nebula in the Large Magellanic Cloud - a satellite galaxy to the Milky Way approximately 160,000 light-years away. NGC 2070 is a star cluster located in the center of the Tarantula Nebula and provides the energy to ionize the nebula. It is estimated to be 550 LY across and is so bright if it were where the Orion Nebula, the Tarantula, would cast shadows at night. It also happens to be the largest emission nebula in the Local Group of galaxies of which the Milky Way is part of.

For those not in the know, the Tarantula is only visible below 21 degrees north latitude so it is best seen from the Southern Hemisphere. In order to produce this image I used data from Slooh Online Telescopes for Educators (https://www.slooh.com/). Slooh has graciously given our high school a trial year to use their astronomy curriculum which includes their telescopes. What Slooh is NOT is a remote astrophotography observatory like Deep Sky West or Chilescope which is devoted to astrophotography pursuits, rather Slooh is strictly for educational purposes and scientific research.

It is a really ingenious way to learn about astronomy. The way is works is a student or family member (if you get a family membership) will be assigned a quest where they would learn all about a planet, moon, the sun, a star cluster, galaxy, or etc. and as part of the 'Quest' they would have to go on a 'Mission' where they would schedule time on a telescope to image the phenomena - if they are awake they see it acquiring data live. When it is complete, a pretty decent image is produced by a program and saved as a '.png' file. Slooh as of this writing has professional grade equipment in Chile and the Canary Islands so the entire night sky is doable. Chile has two telescopes available and the Canary Islands has four night time telescopes and a fifth solar telescope.

I made a video using Slooh - link (https://www.youtube.com/watch?v=-WTz-uj-sVQ)

The reason it is not good for straight astrophotography purposes is you can only go on one mission (schedule time - 10 min) at a time. Also, you have no control over the exposure time, it is predetermined based on the object. For my image of the Tarantula, the 27 stacked sessions (missions) consisted 20 seconds for RGB band and 50 seconds for luminosity (i.e. each session was 110 seconds). In addition, I have no idea if flats, darks, or bias were even collected but if they were I did not see any of that data.

I scheduled sessions (missions) over 2-month period from March to May using the Chile Two Wide-field Telescope which consists of the following equipment:

Telescope: Planewave CDK17 ($22,500)

Camera: FLI Proline PL16803 Monochrome CCD Camera with 63.5mm Shutter ($12,900)

Filter Wheel: FLI FL-CL1-10 CenterLine Ten Position Filter Wheel ($3,900)

Filters: Astrodon Photometric Johnson/Cousins Filters (50mm) ($660)

Mount: Paramount MEII ($20,000)

You can see from the prices which I included just for giggles that Slooh is using top of the line equipment. I do know people that have this kind of equipment but for most backyard astrophotographers it is not feasible. I managed to collect 32 LRGB sessions over that time period but only used 27 of the best sessions after running it through Subframe Selector. The rest of the processing was straightforward - what I would normally do. As expected I was able to bring out more of the faint nebulosity with the stacked 27 frames than the single frame. Interestingly the stacked image was more red than the single processed frame which was more purple.

I am pretty happy with how it turned out especially for such a short total exposure (49 min. total LRGB). It shows what can be accomplished with bortle 1 skies. I don't know if I will do it anymore as I prefer to collect my data with my own equipment but it was really fun to do. I have always wanted to see and image the Magellanic Clouds and some of the other goodies down south so this is a good consultation prize.

Figure 1 - My Processed Image (27 sessions)



Figure 2 - Slooh Processed Image, same crop (1 session)


Figure 3 - Slooh Processed Image, original field of view (1 session)

Tarantula Nebula & NGC 2070 from CT?
Dates: 3-5-23 ... 5-16-23
Camera: FLI Proline PL16803 Monochrome CCD
Telescope: Planewave CDK17
Barlow: None
Focal Length: 2938mm (native)
F/6.8
Focal Reducer: none?
Mount: Paramount MEII
Filter Adaptor: none?
Filters: Astrodon Photometric Johnson/Cousins Filters
Focuser: FingerLakes?
Autoguiding: none ?
Exposure: Lum 27 x 50, RGB 27 x 20
Gain: ?
Offset ?
Temp: ? 
Processing: PixInsight, Photoshop, BlurXT, NoiseXT, StarX, GradientXT, Bill's Colormasks

https://www.instagram.com/astroquest1/
http://astroquest1.blogspot.com/
https://www.astrobin.com/users/kurtzepp/collections/
http://youtube.com/AstroQuest1

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