[BAA Comets] C/2017 O1

[Juan Jose Gonzalez]

Rolando's LRGB image is a beautiful one indeed, showing a wide and 
diffuse coma.


Here is my recent visual estimate :

C/2017 O1 - ASASSN1:
2017 July 23.13 UT: m1=9.8, Dia.=5', DC=2/, 20 cm SCT (77x).

[ Brighter than expected. Diffuse object with faint outer coma.
Field stars checked in DSS. Altitude: 17 deg.
Sidgwick method. Tycho-2 comparison stars. SQM : 21.0.
Mountain location, very clear sky.].

( Alto del Castro - Aralla, Leon, Spain ).


Best regards,


J. J. Gonzalez


------------------------------------------------------------------------------------------------------------------


Nick James wrote:

> Given that most comets are discovered by professional surveys when 
> they are very faint it is most unusual that this comet has been 
> discovered by the ASASSN team at around 15th magnitude (although JJ 
> Gonzalez has reported it as bright as mag 10). It is currently in 
> Cetus, moving slowly northward. Details of the orbit were announced on 
> CBET 4414 issued this afternoon. The magnitude parameters would imply 
> that it has been brighter than 17th mag since the beginning of May but 
> it may be in outburst.
>
> I've put some preliminary charts and an ephemeris on the BAA website 
> here:
>
> https://britastro.org/node/10782
>
> The charts show the path from the beginning of May through to 
> perihelion in October when it will be tracking north through Perseus. 
> If the current orbit is accurate it will actually pass near the north 
> pole around Christmas.
>
> There is a nice image of it by Rolando Ligustri on Space Weather here:
>
> http://spaceweathergallery.com/indiv_upload.php?upload_id=137135&PHPSESSID=4ujl1oqqt9iqn7ujre9g8ccgh6 
>
>
> Nick.
>