Observations - 5/12/21

Hello one and all.

It was the night before Storm Barra. But the sky was clear from the late afternoon on Monday 6th December 2021. So I set up my William Optics 158mm f/7 apochromatic refractor. There was quite a strong wind whizzing around at some 30km/h. Sunset occurred at 16.07UT and I found Vega (Alpha Lyrae) at 16.12UT. Then I split Polaris (Alpha Ursae Minoris) at 16.30. Next came Schedar (Alpha Cassiopeiae) and Achird (Eta Cassiopeiae). I observed until 18.15UT. East is down and north is to the right – that’s because I have a mirror diagonal fitted at all times.  

I was very keen to observe these 3 doubles in Cassiopeia. All 3 are first timers for me – and all 3 are near Achird. Figures are from www.stelledoppie.it  

1. STF (F G W Struve) 43 came first. Magnitudes: A = 9. B = 9.5. Sep = 4.7”. PA = 168˚. STF 43 is a very nice double star. I was quite confounded to succeed in splitting it at 40x. I had the most slender of gaps between the 2 stars. It also looked good at 112x. Both stars were white. 

2. HJ (John Herschel) 1042 is an optical double. Magnitudes: A = 10.8. B = 11.8. Sep = 15.3”. PA = 64˚. The B star is so faint and my sky was not fully dark. Therefore I could only see 1 star at 40x. But 112x gave the perfect view. There was plenty of space between them as you might imagine. 2 white stars again here. 

3. Very nearby I observed a single K7 star called TYC 3667 1319. Other designations are: SAO 21624, HIP 3250 and HD 236496. The star’s magnitude is 8.8 and I could easily spot it at 40x. The star was visibly almond brown as my scope sees all these K7 stars as this colour. I observed it at powers 112x and 167x. The colour became stronger at the latter power.   

4. I knew J 220 was going to prove to be a rather difficult double star from the outset. Magnitudes: A = 10.5. B = 10.5. Sep = 3”. PA = 239˚. Even though the 2 stars were identical in magnitude I ended up using my 4mm WO eyepiece to split it. At 280x I saw the 2 stars pointing upwards with some sort of black gap between, but I could only use averted vision this time. How wrong I was to judge I ought to have separated J 220 at a much lower power. J stands for Robert Jonckhèere who lived from 1888 to 1974 - which means he died when yours truly was a 14 year old choirboy and he passed away in Marseille. J 220 is the second of his double stars I have successfully separated. J 735 being the first and it’s in Cancer. 

5. After I had printed off my Guide 9.1 DVD map over a week earlier, I noticed there was an open star cluster on it which was very faint. So I thought I ought to give NGC 189 a go. Remarkably there is an asterism right next to it which is shaped like a sideways version of Cepheus. This asterism is very easy to see at 40x as most of its stars are of 9th magnitude. However to see NGC 189 properly I needed to increase my magnification considerably. I glimpsed some of its brighter stars at 167x. My 5mm Nagler greatly improved NGC 189 at 225x. And my WO 4mm was most satisfying in making it more “alive” at 280x despite the strong winds. The brightest star is TYC 4016 229 (magnitude 10.9) and it is near the centre of NGC 189. Altogether I could see about 15 stars which includes some field stars surrounding it. Overall its magnitude is 8.8. Its diameter is 3.7’. It is a fair size and it does appear reasonably mottled with my aperture. 

Clear skies from Aubrey. 

Hi Aubrey, 

I hope you and Valerie are well after today's storm. Very well done on observing those three new stars. I don't think I've observed a brown coloured star before, so I enjoyed reading your description of one. Also, the open cluster and asterism sounded great too. 

Fair play for getting out last night, I on the other hand took an early night as I tried to spot Comet Leonard in the morning, but failed. 

Clear skies, 
Darren. 

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Thank you, Darren. 

These are very kind thoughts. 

Some astronomers are saying that Comet Leonard is a bit faint even though it's large. Good and powerful binoculars seem to be necessary combined with a dark sky to find Comet Leonard. A tripod is also a good idea.   

If you want to have a shot at observing an almond brown star with your 10" Dobsonian, Darren, why not have a go at Achird (Eta Cassiopeiae)? The secondary star is K7 and therefore it ought to be that colour. 

I was thinking of you specifically when I bumped into that Cepheus shaped asterism, Darren. And something tells me there is another Cepheus asterism somewhere else in the sky. 

Oh and by the way, A double star expert on www.cloudynights.com has said that J 220's magnitudes are fainter than they are stated on Stelle Doppie. A professional website called GAIA  suggests magnitudes 11.2 and 11.4. No wonder it was such a tough double to split. But generally speaking Stelle Doppie is very reliable.    

Valerie and I was very well health-wise. Thank you. 

Clear skies from Aubrey. 

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Hi Aubrey, 

Thanks for the recommendation - I'll check Achird soon...maybe tonight! 

Yep, I remember observing an asterism that resembles Cephus. I think it is close to M53... I must check over my notes. 

Also many thanks for your advice with Leonard. I was up late last night, but couldn't stay awake long enough for it to clear the neighbours house. I read that it could be breaking up, so combined with the weather forecast for the next couple of days it's unlikely I'm getting to get a look it

Clear skies, 

Darren

And I think I've been on the GAIA website. Apart from variable stars, I didn't realise there could be differences between magnitude recordings.