M1 - THE CRAB NEBULA

Updated: Nov 20, 2019


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Messier 1 is a pretty iconic target, being the first deep sky object to have a spot in the Messier Catalog!


The Crab Nebula is pretty small, and not easy to image when you are a complete beginner.


We imaged this target with both our unmodified Canon t3i DSLR camera when we were just getting started in Astrophotography, and 3 years later with our ZWO ASI 1600MM-Pro CMOS camera, and a little bit more skill :) We used the same telescope for both attempts and we will show you the two different results in this post. We spent just a little over one hour of total exposure with each camera so that you can really compare both final images.


The Crab was born in 1054 when a star died, and the event was so bright that it was visible during the day for 23 days, and also to the naked eye at night for almost two years!

Although rather small, this is a great target for astrophotography, because it is colorful and full of details. It is also pretty iconic, as it is after this discovery, mistaken for a comet, that Charles Messier decided to start building his catalog of “non-comet deep sky objects”.



IMAGING THE CRAB NEBULA WITH A DSLR CAMERA

February 8th, 2016


We spent the night with a new friend, Mike, who we met online on an astrophotography forum. It was very fun because we were able to do some visual with his Dobsonian while our own telescope was busy imaging the target. It was also our first time seeing Jupiter, which looked awesome! 


Below is our main image of the Crab Nebula, taken with our unmodified DSLR camera. We included all the acquisition details to help you get an idea of how we got this final result. Note that we only spent an hour and a half on this, but we wish we had at least four hours to make the image more neat and detailed.




GEAR USED:

Camera: Canon t3i (600D)

Telescope: Orion 8" Astrograph f/3.9

Mount: Atlas EQ-G motorized Mount

Coma: Baader MPCC Coma Corrector MkIII

Guiding: Starshoot Autoguider - 50mm Guide Scope

Processing: Pixinsight

ACQUISITION DETAILS:

Total Exposure Time: 1.5 hours

Exposure Time per frame: 3 minutes

30 lights - 15 Darks - 15 Bias

ISO: 800


IMAGING THE CRAB NEBULA WITH A CMOS CAMERA

October 22nd, 2019


Three and a half years later, we decided to re-visit Messier 1, equipped with the same telescope but a better camera! For some reason, our guiding refused to work, for absolutely no reason. The guiding star kept being lost and playing with all the settings did not help. After much frustration, we started to image the Crab, unguided...


We did 2 minute exposures instead of three to reduce potential star trailing, and although we had to trash quite a few frames, we still ended up with exactly one hour of usable data. You can see the result below. Note that we also did not use any dark frames during the processing, mostly as a test. it didn't turn out too bad.


We'd like to thank our friend Adrian Plata for giving a helping hand that night when our equipment refused to work properly. We were able to reboot everything, star align and all that thanks to his help!




GEAR USED:

Camera: ZWO ASI 1600mm Pro Mono

Telescope: Orion 8" Astrograph f/3.9

Mount: Atlas EQ-G motorized Mount

Coma: Baader MPCC Coma Corrector MkIII

Guiding: N/A (Refused to work!)

Acquisition: ZWO ASIAIR

Power: Pegasus Astro Pocket Powerbox

Processing: Pixinsight

ACQUISITION DETAILS:

Total Exposure Time: 1 hour

Exposure Time per frame: 2 minutes

Filters: Ha (20 minutes) / SII (20 minutes) / OIII (20 minutes)

Gain: 139



Locating the Crab Nebula


M1 is located in the constellation of Taurus, the bull. It is pretty easy to find because it is very close by one of the bright stars of the constellation, Zeta Tauri. 


The Crab nebula is not visible with the naked eye, at least not anymore. It is very difficult to spot through binoculars, although possible if you manage to spot the difference between the nebula and the nearby stars. Messier 1 is easily visible with any telescope, but a 16” or bigger instrument will reveal details within the gases. 


If you have the chance to use a much bigger telescope, you might also be able to spot the Crab Pulsar, a magnitude 16 pulsar that spins more than 30 times per second.


Cool Facts
  • Supernova reported in China in 1054 AD

  • Only supernova remnant in the Messier catalog

  • Expands at a rate of 1,500 km/s


Single Shot & Processing of M1 - DSLR Camera

Processing the Crab Nebula is not too difficult, but we had to give it several tries before ending up with a version we liked. It is very easy to over process the details in the nebula, so be careful when bringing out the gases within it.


Also, we had a lot of shots of M1 when going back home, but several had to be trashed due to too much red in them (The hand controller from the mount was reflecting its red light towards the telescope's mirror, a mistake that we will never repeat!).


Below you can see what a single 3 minute shot of the Crab looks like (you can spot it in the bottom right corner). Note that it was an unguided shot, as you can guess when looking at the star trails.


Single Shot & Processing of M1 - DSLR Camera

Seeing how we only had 1 hour of total exposure on M1, we did not really have high expectations and did not care much when processing it. We didn't even bother taking darks for that one...


Well, it turned out slightly better than expected and the end result isn't too bad. We found that the processing was very easy (maybe because of the non-caring part?) and quick.


Below you can see the stacked images for each narrowband filter used: Ha, SII, and OIII.



Unlike most emission nebulae (M1 is a supernova remnant), all three channels show great details, with the Sulfur filter bringing out a little more out of the nebula than the two others.


Our Previous Versions of Messier 1

As we said earlier, we had to redo the processing of the nebula several times until obtaining a result we really liked. Below you can see our Version #1 of the crab (left) and our Version #2 (right). See our Version #3 (final with our DSLR camera) on top of this page!


Version #1 was processed after we cropped the stacked images to really focus on the nebula. While it does look good, you can see a ton of noise in the details, which really does not look good. The sky in the background is also pretty terrible looking.

Version #2 was processed without cropping, but using the same processing steps as Version #1. We used a completely different workflow for our final image.


Final Thoughts

Messier 1, the Crab Nebula, is a small but great target for astrophotography. We recommend attempting to capture it when you feel like you need a challenge, and have confidence in your processing skills. Although when reading this 3 and a half years later, processing is actually very easy on this target, so you might only find the processing part difficult if you are a complete beginner like we were back then!



This target makes for a wonderful image, if you are able to bring out the colors and keep the sky beautiful as well.


Also, you should spend more than just one hour on this one, which will allow you to get more of the faint gases, and an overall better image.




We might update this post a final time when we re-visit this target once more but this time while making sure our guiding works and spending at least 4 hours or more on this beautiful deep sky object.


Click on an image below to see a comparison between our Canon DSLR camera and our ZWO ASI 1600MM Camera!


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Clear Skies,

Galactic Hunter






Part of: The Astrophotographer's Guidebook

Description: Discover 60 Deep Sky Objects that will considerably improve your Imaging and Processing skills! Whether you are a beginner, intermediate, or advanced astrophotographer, this detailed book of the best deep sky objects will serve as a personal guide for years to come! Discover which star clusters, nebulae, and galaxies are the easiest and most impressive to photograph for each season. Learn how to find each object in the night sky, and read our recommendations on imaging them in a quick and comprehensive way. Each target in this guide contains our advice on imaging, photos of expected results, and a useful information table. We've also included a few cool facts about each target, a map to find it in the night sky, and more!


#astronomy #astrophotography #messiercatalog #messier #galaxy #nebula #cluster #stars #space #galactichunter #nevada #lasvegas #canon #orion #telescope #m1 #crab #crabnebula

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