[BAA Comets] C/2017 O1

[Nick James]

Juan,

I've imaged it tonight using iTelescope T32 at Siding Spring and get 
m1=10.9, dia=6' (UCAC-4 R)

https://britastro.org/node/10791

This is so bright it must be in outburst or it surely would have been 
discovered earlier.

An interesting comet to watch over the next few weeks.

Nick.

On 24/07/2017 22:51, Juan Jose Gonzalez wrote:
> 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.
>>
> 
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