Re: [BAA Comets] NEOWISE close-up
Nick James 20 Jul 2020 07:02 UTC
Here is my final processed image of the central 4 arcmins of the coma
from last night. I've tried to process it to avoid saturation and have
used a log stretch followed by a mild large scale wavelet filter. The
photocentre is indicated by a black square.
Nick.
On 19/07/2020 23:42, Peter Tickner - peter.tickner1472 at btinternet.com
(via baa-comet list) wrote:
> Nick
>
> That is very helpful information. My images on 17th were the longest exposures I took with a 200mm f/5 Newtonian (15s and 10s stacks) but I also collected data in twilight at 2s, 4s and 8s. I haven't yet processed most of that but a test of the 2s images when the sky was still very bright shows that the detail is too washed out.
>
> Tonight I am trying with an 80mm refractor to see what it can pick out with the same camera using 10s, 15s and 30s at unity gain. I'm about to lose the target soon to local obstructions. If the forecast remains good for Monday I will try the 200mm f/5 Newt again and use a range of shorter exposures with lower or zero gain to see if it helps with the coma detail.
>
> Peter
>
> -----Original Message-----
> From: baa-comet@simplelists.com [mailto:baa-comet@simplelists.com] On Behalf Of Nick James
> Sent: 19 July 2020 22:47
> To: baa-comet@simplelists.com
> Subject: Re: [BAA Comets] NEOWISE close-up
>
> Here is a stack of 34x10s frames at 0.65 arcsec/pix showing the central coma of C/2020 F3 tonight. The images are about as long as I can expose in 1x1 bin mode and avoid saturatuon. I haven't done much processing yet but there is clearly a lot of detail there.
>
> Nick.
>
>
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