M42 Orion Nebula using iOptron SkyTracker in NYC

This is my first test of iOptron SkyTracker. Orion Nebula M42 is in the list of top 10 deep sky objects for amateur astronomers. So I choose it for first test. I tried exposer 15 seconds. For fixed tripod with Canon Telephoto Lens EF 200mm f2.8 L II USM it gives star trails. With iOptron SkyTracker even without precise alignment stars looks like points. Weather was good but NYC light pollution, plus it was 3 / 4 Moon near Orion nebula. So I use small ISO (Urban astrophotography). There are results:

M42 Orion Nebula one single file from NY City

Canon 60Da, Canon  EF 200mm f/2.8 L II USM Telephoto Lens, Exposure 15 sec; f/2.8; ISO 320, New York City

Using DeepSkyStacker stacked multiple images. Every Canon Row CR2 image first updated in Canon Row 7 saved as Tiff file and later stacked in DeepSkyStacker. Post processing after that was done in Photoshop.

Orion Nebula M42 from New York City Backyard - 8 photos iOptron SkyTracker Canon 60Da

Canon 60Da, Canon  EF 200mm f/2.8 L II USM Telephoto Lens;  f/2.8; ISO 320; Exposure 15sec x 8 - Total time 2 min, New York City

M42 Orion Nebula NYC 36 photos iOptron SkyTracker Canon 60da Canon 200mm

Canon 60Da, Canon  EF 200mm f/2.8 L II USM Telephoto Lens;  f/2.8; ISO 320; Exposure 15sec x 36 - Total time 9 min, New York City, Messier 42 or NGC 1976

iOptron SkyTracker Canon 60Da Orion Nebula M42 Astrophotography 204 photos

 Canon 60Da, Canon  EF 200mm f/2.8 L II USM Telephoto Lens;  f/2.8; ISO 320; Exposure 15sec x 204 - Total 51 min

Removing Light pollution Astrophotography Urban Astronomy

The moon and the stars no longer come to the farm. The farmer has exchanged his birthright in them for the wattage of his all-night sun. His children will never know the blessed dark of night.

 — Leslie Peltier in his autobiography

Comparison of original image and final one after removing of the light pollution – night photo of Golden Gate Bridge, San Francisco, California.

Light pollution Astrophotography Urban Astronomy

Photoshop instruction:

Step1: Select the Layers panel and then  duplicate the layer
Step 2: Filter -> Noise -> Median… (about 50 px)
Step 3: Filter-> Blue -> Gaussian Blue… (about 30px)
Step 4: Select original layer
Step 5: Image -> Apply image (Blending: Subtract; Offset: 40)
Step 6: Delete the duplicate layer

See for example video in my other post Comet 103P/Hartley 2 from New York City

Note, that Astronomy Tools has more sophisticated methods to remove light pollution, or you can do some variations of such methods (it depends from size of you original image). You also can apply it only for part of original image.

The other way to remove light pollution is using multiple images, see for example my other post M42 Orion Nebula using iOptron SkyTracker in NYC

Urban Astrophotography

Urban Astrophotography - NYC astronomy - Orion Constellation

Urban Astrophotography NYC - Lyra Constellation

Cassiopeia constellation - Urban Astronomy-  Brooklyn Astrophotography

Brooklyn astronomy - Manhattan panorama at night