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undetectable?
#1
Hi,

I have tried generating the ephermeris in ST4V adn ST3P and they both say that comet C/2020 F3 (NEOWISE) is undetectable or not visible.

Odd.

I'd see it on the camera, in the binoculars, and with my Mark I eyeballs.
cheers,
Blake

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#2
Hi Blake,

It shows up as magnitude 5 and visible to the naked eye for me.

1. Make sure that you have downloaded the latest Current Comets.

2. Open the comet in the Object Info. On the right side it should say:
"Observations (Mag, D, DC) as of 2020 Jun 20."

3. Make sure you have the date set correctly. Something like this happened once and it turned out that the date was a year off.

4. It should currently be mag 5 with a 6.8" coma
Clear skies,
Greg
Head Dude at Skyhound
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#3
I was all set to image C/2020 F3 (NEOWISE) with my DSLR this morning, but when I woke up at 3:50 AM it was cloudy.
Clear skies,
Greg
Head Dude at Skyhound
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#4
I'm pretty sure everything's right...

Here's the settings from ST3P...

And 4 Visual.

Never mind...

I had the time setting wrong.


Attached Files Thumbnail(s)
       
cheers,
Blake

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#5
Hi,

In the first ephemeris, you are sampling the comet every night at midnight. It is below the horizon until later in the month. This is the main problem. Enable the Alt/Az columns to see the altitude.

You also have a different telescope selected, which explains the differences between ST3 and ST4.

Solution: you aren't using the right ephemeris. Use the Nightly Observing Ephemeris (which I think may be the best thing I ever did). This will automatically determine the best time to observe each night, and the data will be for that time. Nobody ever talks about this feature but me, but how useful is that?
Clear skies,
Greg
Head Dude at Skyhound
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#6
Hi Greg,

I'm running ST4v (4.0h) with the Current Comets updated 5 Jul 2020. On the NP both C/2020 F3 (NEOWISE) and C/2017 T2 (PANSTARRS) are listed as 'Undetectable' for 9 Jul 2020 at 40°N in the 13" scope. In the OI's Visual Difficulty tab C/2020 F3 (NEOWISE) is reported as 'Undetectable' in every instrument (up to a 32") except a Takahashi TOA-150 and a Celestron RASA 11" where it's 'Obvious'. There does seem to be something going wrong somewhere. I just started ST4v this morning with no issues. I did notice the report of the comets as 'Undetectable', but wasn't going to report it until I saw Blake's post.

I didn't try the ephemeris for either object.

Phil S.
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#7
(2020-07-09, 02:31 PM)PMSchu Wrote: Hi Greg,

I'm running ST4v (4.0h) with the Current Comets updated 5 Jul 2020. On the NP both C/2020 F3 (NEOWISE) and C/2017 T2 (PANSTARRS) are listed as 'Undetectable' for 9 Jul 2020 at 40°N in the 13" scope. In the OI's Visual Difficulty tab C/2020 F3 (NEOWISE) is reported as 'Undetectable' in every instrument (up to a 32") except a Takahashi TOA-150 and a Celestron RASA 11" where it's 'Obvious'. There does seem to be something going wrong somewhere. I just started ST4v this morning with no issues. I did notice the report of the comets as 'Undetectable', but wasn't going to report it until I saw Blake's post.

I didn't try the ephemeris for either object.

Phil S.

I explained Blake's issue as the result of it being the wrong kind of ephemeris. I am not aware of any other problems with this comet... It would really help to know that have the latest comet data. What magnitude is it? Coma diameter? A screen shot of where it says it is undetectable would also be very helpful.
Clear skies,
Greg
Head Dude at Skyhound
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#8
In my case it occurs right in the Nightly Planner (NP). Also in the Object Info's Visual Difficulty tab.

Phil S.

Just started ST4v (4.0h) this morning. The NP still says C/2020 F3 (NEOWISE) is 'undetectable', but for 10 Jul 2020 C/2017 T2 (PANSTARRS) is 'Easy'. If I change the date to 9 Jul 2020, both comets are listed as 'Undetectable'.

Have not checked them in the ephemeris.

Phil S.
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#9
There is indeed a problem with F3 in the Nightly Planner as shown in the attachment. For some reason it only thinks it is visible for  about a minute in the evening sky and therefore becomer not visible. The Ephemeris gives the correct best time I think. The program seems confused now it has gone circumpolar.

Owen


Attached Files Thumbnail(s)
   
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#10
Yes Owen, my NP view is similar to yours for 10 Jul 2020. What happens if you change the date to 9 Jul 2020? What do you see in the Visual difficulty tab of the OI for F3? I saw mostly 'Undetectable' for 9 Jul 2020 even for a 32" scope. I'm at 40°N latitude.

Phil S.
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