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[vsnet-chat 4655] [vsnet-obs 34771] eta Car
- Date: Fri, 27 Jul 2001 11:31:10 +0200
- To: <vsnet-chat@kusastro.kyoto-u.ac.jp>
- From: "Berto Monard" <Lagmonar@csir.co.za>
- Subject: [vsnet-chat 4655] [vsnet-obs 34771] eta Car
- Disclaimer: The CSIR exercises no editorial control over E-mail messages originating in the organisation and the views in this message are therefore not necessarily those of the CSIR and/or its employees.
- Sender: owner-vsnet-chat@kusastro.kyoto-u.ac.jp
I tend towards agreement with most of Sebastian's statements.
If my house wasn't obscuring eta Car from view from the apogee platform, that telescope (20x120) would be ideal to look at such bright objects.
But in that case the homunculus light would be (at least partly) integrated with the direct starlight resulting in lower magnitude estimates.
For this reason, Sebastian's end statements "Try using binoculars if we can. These estimates have proven to be rather accurate compared with photometry." could eventually prove the referred photometry wrong.....
Regards,
Berto
>>> "Sebastian Otero" <varsao@sinectis.com.ar> 07/27/01 06:46AM >>>
> Visual observations of 25 July 2001
> observer: Berto Monard MLF, Pretoria, South Africa
>
> CAReta 010725.72 55 MLF * RASNZ seq
> * This observation fails to confirm the reported brightness of eta Car.
How much does telescope aperture play a rhole in distinguishing the light
from the actual star and that of the 'homunculus'. Using the lowest
magnification (at 64X) I still see the homunculus separate and its light is
not included in the estimate, which only compares the brightness (glare) of
eta Car to that of neighbouring stars.
That is true and that's why I mentioned that it is a difficult star to
estimate.
But the thing is: it is important to use the only optical aid needed for the
star to be seen in order to be accurate. I mean: I couldn't make an estimate
of eta Car even at the lowest magnification with my telescope (and it is 30X
!!!). Too small field, too bright image for my eyes to compare !!!
Stars brighter than 7th magnitude are very difficult this way, the brighter
the worse.
I always observe it through my 7x50's and this means: star plus homunculus.
This may explain the difference.
Try using binoculars if we can.
These estimates have proven to be rather accurate compared with photometry.
Regards,
Sebastian
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