Case 32 carbon star observed - 5/10/21

Hello, fans of carbon stars. 

On Tuesday 6th October 2021 I placed my William Optics 158mm F/7 apochromatic refractor in my Bortle 9 back garden. 

I had excellent seeing conditions and no Moon. 

Therefore it was high time to seek out an extremely faint carbon star in Cassiopeia. 

There was a 20 km/h wind blowing, but I refused to let that deter me from seeing Case 32. 

As I do have a mirror diagonal fitted my north is to the right and my east is down.   

The carbon star Case 32 has 2 other designations: GSC 04015-00768 or NSV 173. 

Guide 9.1 DVD states its magnitude is +12.3. 

Simbad gives +13.0. 

And AAVSO gives +13.5 V. 

So is Case 32 too faint for my scope?

Its Right Ascension is: 00 hours 29 minutes 08.24 seconds. 
The Declination is: +61 degrees 07 minutes 15.84 seconds. 

Its spectral class is C5. 

I did find it quite easy to star hop to its rough location starting with Beta Cassiopeiae (2.3 mag) through to 12 Cassiopeiae (5.4 mag). 

I had printed off a Guide 9 map which once again proved invaluable. 

There were 3 stars which pointed almost directly to Case 32. 

These were TYC 4015 3101 (10.1 mag), TYC 4015 1359 (10.2 mag) and TYC 4015 3037 (11.3 mag). 

There was also a 4th very faint star which is called TYC 4015 388 (12.4 mag) and it is 4 arc minutes east of Case 32. 

A 5th star, which is less than 3 arc minutes west-south-west of Case 32, has the designation 3UC303-011414 (on Guide 9) and its magnitude is +12.0. 

Therefore with the first 3 field stars observed with my 112X Pentax 10mm eyepiece, which gives me 27 arc minutes field of view, I felt I was ready to see if Case 32 was going to be visible to my eye.  

Of course it was not going to be all that easy to see it!

I had to increase my magnification up to 225X to see both TYC 4015 388 and 3UC303-011414, but they were still in the same fov thankfully. 

Indeed it took time to make out I was seeing both the 12.4 magnitude star TYC 4015 388 and 12.0 magnitude star 3UC303-011414 before I spotted Case 32. 

And so I discovered that the carbon star Case 32 is quite a bit fainter than what Guide 9 had suggested (+12.3). 

It was very clear that it was considerably fainter than both TYC 4015 388 and 3UC303-011414. 

I would suggest that Simbad's magnitude of +13 is correct.  

That is because of these last 2 field stars.

So I'm delighted to say I was successful in my endeavour in observing Case 32. 

And it is orange alright.

Indeed both 3UC303-011414 and Case 32 are 2 orange stars which sit side by side. 

How patient one has to be to see them both. 

Case 32 is my 21st carbon star in Cassiopeia and my 107th overall.  

Thank you for reading about my latest carbon star observation. 

Comments, corrections and images are very welcome. 

Clear skies, 

Aubrey. 

 

Fantastic report Aubrey. That seems like quite a wide margin between the Guide 9.1 figure and the AAVSO estimate, differing by a factor of 3... I think I remember mentioning that my faintest observation with the SE8 was a 13.9 star in Cygnus; that was around the time Boyajian's Star was causing a fuss and I was observing the area more closely than I would normally do with such faint targets. Anything below 12 is a superb effort from your Bortle 9 garden though.

Clear skies,
Finbarr.

Thank you, Finbarr. 

You are most kind! 

We most certainly can all have great fun seeking out extremely faint stars with our scopes.

I did find it a massive challenge to see Case 32 properly.
At first I thought the star right next to it - 3UC303-011414 was Case 32. 
But thankfully I waited very patiently for Case 32 to appear with my Nagler 5mm eyepiece. 

Can you tell us more about Boyajian's Star?
Why were you so interested in observing it? 

Clear skies from Aubrey. 

 

Aubrey, Boyajian's Star was revealed by the Kepler telescope in 2015 to be undergoing unexplained dimmings, which led to some pretty wild speculation that the cause may have been an alien megastructure.... subsequently proven to be a dust cloud. A good test of telescope optics though

Finbarr.

Ah yes, Finbarr. 

I remember that story now. Thank you. 

Aubrey. 

Hello Aubrey and Finbarr,

I very much enjoyed reading your posts. Like Finbarr said Aubrey, very well done on having the skill to observe that 13 mag star.

And a big congratulations on reaching carbon star number 107...that's some going! 

Kindest regards,

Darren.