Weird Science

M1 - Crab Nebula

Polish ver­sion is here

The Crab Nebula is also sim­ply known as the Crab. The object was first obse­rved by John Bevis in the early 1730s, who inc­lu­ded it in his work Ura­no­gra­phia Bri­tan­nica, which was a star atlas. As often hap­pens in science, the nebula was inde­pen­den­tly disco­ve­red by Char­les Mes­sier in August 1758 during his attempts to obse­rve Hal­ley’s Comet. This event promp­ted Mes­sier to cre­ate a cata­log of objects simi­lar to the one he had obse­rved to pre­vent future con­fu­sion with comets. This mar­ked the begin­ning of the famous Mes­sier Cata­log. Natu­rally, the Crab Nebula rece­i­ved the honor of being the first entry, which is why it is also known as Mes­sier 1 or sim­ply M1.

The nebula is asso­cia­ted with a super­nova obse­rved pri­ma­rily by Chi­nese astro­no­mers in 1054. Its distance from Earth is appro­xi­ma­tely 6,300 light-years, with a dia­me­ter of about 11 light-years. At the cen­ter of the nebula lies a pul­sar that emits fla­shes ran­ging from gamma rays to radio waves. It rota­tes rapi­dly, com­ple­ting about 30 rota­tions per second.

Obse­rva­tions

Sep­tem­ber 22, 2020, aro­und mid­ni­ght – Jaworzno (Poland), gar­den
urban con­di­tions, high level of light pol­lu­tion

I would like to pre­sent a pho­to­graph tha­t—de­spite being far from per­fec­t—bro­u­ght me a great deal of joy.

That night, I poin­ted the camera lens almost direc­tly east (with a sli­ght nor­thern off­set) so that its field of view encom­pas­sed an area appro­xi­ma­tely 20 degrees above the hori­zon. It was a ple­a­sant sur­prise to notice an elon­ga­ted and sli­gh­tly blur­red patch of light near the star Tian­guan, which repre­sents Zeta Tauri (ζ Tau), in a 10-minute expo­su­re­—re­la­ti­vely short for deep-sky objects.

At higher magni­fi­ca­tions, the cha­rac­te­ri­stic fila­men­tary struc­ture of the Crab Nebula beco­mes visi­ble. At the first oppor­tu­nity, I will attempt to cap­ture addi­tio­nal, and per­haps even bet­ter, pho­to­gra­phs of this object.

Photo 1 Para­me­ters:

  • Total expo­sure time: 12 minu­tes (stack of 24 RAW fra­mes at 30s each, using an appro­priate num­ber of dark, bias, and flat fra­mes)
  • ISO: 2500,
  • Lens: zoom type (used at fmax = 250mm),
  • Aper­ture: f/4 (the smal­lest pos­si­ble for the lens used),
  • Mount: equ­a­to­rial mount with trac­king, ali­gned using the drift method and con­trol­led by a custom-built sys­tem.

Marek Ples

Aa