Jul.20/21 observation

[Roman White]

It was a clear night it Poltava on Jul.20/21 so I was outside observing C/2007 W1 comet and possible NLCs.

Have captured an ISS pass at 01:10 EEST (-0.9mag). Low in Bootes, before it entered the shadow.

...and an Iridium flare at 02:44:47 EEST (Iridium 75, -3mag). Vega near the left corner


Have spent some time playing with the flashlight before observing C/2007W1... (tried to write "W1"; you can see me&telescope, Perseus and Aries in the background.)


Now it is about an hour between the comet W1 rises and the naut.twillight begins, but I had no sucess while observing. I was searching it with a telescope, I have seen the star TYC647-114-1 (7.4mag) not far from the comet and the limiting mag. was about 9.2-9.5 because the full Moon interferring (it shined right into my eyes! ). Binoculars also didn't help. Tried to capture some photos:
Eastern horizon at 03:11 EEST, it is 10 or 13 sec @ ISO800.

Upper image crop

It's impossible to see the comet - very much noise.

No NLCs on that night.

Have you noticed the absence of C/2007W1 observation reports in Comet-Obs ML since Jul.15? Recently I haven't heard that someone obseved it. The situation becomes scary ... I'm hunting this comet already for 2,5 months (including the perihelion).

Do we need to wait until the Moon escapes from the morning sky? ..but the comet fades every day.

[Steveo74]

Great images Roman! especially shots #2 & 3. Very creative with the torch 

[martinastro]

Great report Roman!. That Iridium flare is quite a beauty. Nice shot with the sky writing. I also noticed the lack of visual observations on cometsml and found this very curious indeed for such a bright comet. I have been trying hard every clear night lately to track Boattini down using 10x50mm binos and an 8.5" F/7 reflector with no success. I blamed the street light beside the comet for this but after reading your report I'm beginning to wonder if W1 has rapidyl faded?. More than likely it's the Moon which is hampering observation. The BAA said the coma is large and slightly diffuse so I would suspect the comet has a low surface brightness and will be overlooked in a bright sky. I expect to read about successful observations once the Moon wanes. Let's hope we see it soon!

[Roman White]

Thanks Steve and Martin

Capturing an Iridium flare is a hard enough job because it lasts for a few seconds only and I need to push the shutter button in 17 (+/-3) seconds before the flare (12sec timer + 10...15 sec exposure), in that reason I have oftenly failed to photograph these flares, this one is the first sucessful.
It is really something happening if you hadn't seen the W1 Boattini with your 8.5" F/7 refractor. The Moon/comet conjuction will be on Jul.26-27, so after Jul.29 the Moon will not hamper the comet observations.

I've forgot to say that I have observed 2 meteors on that night (1 from Cassiopeides, 1 possibly from Capricornides).
I'm going to observe meteors on the next night Jul.22/23

[brianb]

It is really something happening if you hadn't seen the W1 Boattini with your 8.5" F/7 refractor.

Hmmm, I've noticed that diffuse comets sometimes show up better in a finder, or binoculars, than they do in a medium to large scope - the contrast gradient is steeper. I found Holmes was visible in binoculars for about three months after the last time I saw it in a scope - the integrated magnitude was 4 to 5 at the time but there was no way a scope would show it!

C2007/W1 Boattini certainly was diffuse before perihelion - I'm not giving up until the next Moon period - the dark period between New Moon and waxing gibbous is perhaps the best opportunity - approx. Aug 1-10.