#1  
Old 08-04-2018, 09:18 AM
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Merlin66 (Ken)
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Another Nova Cen????????

While testing a low res spectroscope last night I found an image of a 11 mag star which doesn't show on the UCAC4 catalogue.

RA: 14h37m27.98s
Dec: -60d53m08.5s

Close to UCAC4-146-159258 (Mag 11.3) and UCAC4-146-159279 (Mag 10.5)

Has anyone got images of this area around Alp Cen???????
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Last edited by Merlin66; 08-04-2018 at 10:09 AM. Reason: correction to coordinates!
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Old 08-04-2018, 01:54 PM
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Hmmm
Nothing showing on the DSS images......
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Old 08-04-2018, 05:38 PM
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Had a look in MPC too Ken. Simbad comes up with a target close to a NIR object.
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Old 08-04-2018, 08:01 PM
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Is it just me, or does it look slightly diffuse?
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Old 08-04-2018, 08:26 PM
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Markus,
I think you're correct.
This was a trial image with a grating spectrograph - the focus in the red I believe was compromised.

A comparison (non spectrograph) image needs to be taken for verification.....
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Old 09-04-2018, 09:07 AM
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I'm coming to the conclusion that it may have been a brightening of the NIR star IRAS 14336-6040. This would go some way to explaining the slightly larger (out of focus?) red stellar image.

(I was using a FULL spectrum modded Canon D1000 on an ED80.)
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Old 09-04-2018, 10:44 AM
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Yes, that was my conclusion too from the Simbad result.

I know the object was diffuse but didn't look like an optical light anomaly/reflection.

Have you asked anyone for a confirmation image Ken? Total cloud here for weeks.

Stu
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Old 09-04-2018, 08:11 PM
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Hi Ken, I imaged this field every night from 02 to 06 April and there was nothing showing at the co-ordinates you gave down to around mag 12.5. I missed the next two nights but tonight I imaged the field a bit more deeply and there's nothing showing down into the mag 14s.

However, I can't reconcile your co-ordinates with the image you posted, the stars don't seem to match up. In fact I can't really fathom what your field is - could you supply a scale & north arrow? Thanks.

EDIT: Hang on, my mistake, -60!!! Be right back!

Cheers -
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Old 09-04-2018, 08:25 PM
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Rob,
North to top.
The attached screen dump from CdC UCAC4 may help.
X marks the spot!
Ken
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Old 09-04-2018, 08:45 PM
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Yeah, got it Ken, something faint there, probably around 13.3 - 13.4 ~V. 10:52, 09 Apr 2018 UT, DSLR & 200mm lens, 5 x 15 sec, ISO 6400, F/6.3. Huge extinction at that location! On 6 Apr it's under a diffraction spike. On 5th April, something at limit of detection is visible at the location (55mm lens, limiting mag ~12.5). Earlier shots are indeterminate. Tonight's image attached.

Cheers -
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Old 09-04-2018, 08:50 PM
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According to this, extinction is somewhere 20-24 magnitudes in V-band, depending which system!!
https://irsa.ipac.caltech.edu/worksp...xtinction.html

Cheers -
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Old 09-04-2018, 09:01 PM
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Yep, ASAS J143728-6053.2 (IRAS 14336-6040) would be a good guess I reckon, very close to your given position.

Cheers -
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Old 09-04-2018, 09:30 PM
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Latest ASAS-SN light curve for this object is here (last 20 days):
https://asas-sn.osu.edu/light_curves...5-bf227de36370

On the rise.

Cheers -
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Old 10-04-2018, 08:38 AM
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Rob,
Thanks very much for adding that very useful data.

Simbad gives a 5.46 mag in the J band (1.05 - 1.34 micron) - this is a bit of a stretch for the Canon - The Full Mod, both internal filters removed.
This does allow recording to at least 8000A, where the 2nd order spectrum kicks in.
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Old 10-04-2018, 11:39 PM
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Good to be of help Ken.
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Old 26-04-2018, 05:00 PM
gary
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Quote:
Originally Posted by Merlin66 View Post
While testing a low res spectroscope last night I found an image of a 11 mag star which doesn't show on the UCAC4 catalogue.

RA: 14h37m27.98s
Dec: -60d53m08.5s

Close to UCAC4-146-159258 (Mag 11.3) and UCAC4-146-159279 (Mag 10.5)
Gaia DR2 5878471748912790016 is within a couple of arcseconds of the
given RA/Dec coordinates with a G-band mean magnitude of 19.37
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