5 new doubles in Cassiopeia

Hello double star enthusiasts. 

It had been a mostly overcast day on Saturday 2nd October 2021. But as the Sun had set at 6.58pm local time very good clear skies started to occur. At about 6.30pm I was placing my William Optics 158mm F/7 apochromatic refractor in my back garden. My mount is a Berlebach Planet alt-az, and I have a mirror diagonal fitted. As a result my north is upper right and my east is lower right. I had a printed map from my Guide 9.1 DVD. I did all my observing from 9.15 to 10.30pm.  

www.stelledoppie.it provides the details of these 5 double stars in Cassiopeia.

1. HJ 1985 is an optical double. Magnitudes: A = 11. B = 11.5. Sep = 18.8”. PA = 147˚. Because these 2 stars are so dim I required 112X to see them, but I saw them very well. There was plenty of black space between them. 

2. STF 45 is another optical double, but the colours are most intriguing. Magnitudes: A = 6.9. B = 10.1. Sep = 19.1”. PA = 91˚. I had no problem splitting the 2 stars at 40X of course. But at 112X I was greatly admiring the colours. A is G9 strong yellow. I have not been able to find out what B’s spectral class is. But Guide 9 showed it as an orange-red star. And that’s precisely what I saw with my Pentax 10mm eyepiece. Today I visited this optical double star on Simbad. They seem to suggest that the star is of spectral class K3 or K4. Sissy Haas’ book says the star is blue – which cannot be right. Burnham offers no colours for B at all. However I very much trust that both Guide 9 and Simbad are spot on. Therefore I recommend STF 45 to you all. I found its colours remarkably similar to Eta Cassiopeiae (STF 60).  

3. BU 394 is a true binary and is very difficult to separate. Magnitudes: A = 8.5. B = 8.8. Sep = 0.9”. PA = 278˚. At 280X I could see the 2 stars distinctly, but they were not split. Out came my Nagler 3.5mm eyepiece which gives 320X and I could just about see the tiniest piece of black space between them. Success! Suddenly I noticed my seeing conditions had deteriorated significantly. I wasn’t seeing the black gap anymore. I used less powerful eyepieces and increased again. I must have spent a good 20 minutes studying BU 394 again and again. Eventually I did get the split at 320X in the end. The primary is certainly a G0 yellow star. 

4. There is a third companion to BU 394 which is very easy to observe. What is quite surprising is it is very much a true binary also. And it has a separate designation: TOV 223. TOV stands for Andrei Tokovinin. I’m not finding out much about him – other than he is or was a professional astronomer who has worked at the Cerro Tololo Inter-American Observatory in Chile. Back to TOV 223. Its magnitudes are: A = 8.5. C = 11. (B is included with BU 394). Sep = 105.5”. PA = 201˚. There was no hassle seeing the secondary at 112X. What’s also surprising is we have a real true triple star when combined with BU 394. 

5. Finally I have another toughie for you. ES 1202 is an uncertain double. Magnitudes: A = 10.8. B = 11.2. Sep = 2.2”. PA = 30˚. To separate the 2 stars I had to use averted vision to catch a glimpse of the secondary at 320X. I clearly was not going to be successful to blatantly see the 2 stars at any time. Users of larger telescopes will have a better time seeing the primary and the secondary of ES 1202. This double star lies extremely close to the border of Andromeda. There is a 5 star asterism to its west which is roughly square shaped and is across the border into Andromeda. 

Thank you for reading my latest report. 

I was very much pushing the limits of my William Optics 158mm refractor this time round.  

I did especially appreciate my time studying the colours of STF 45 and cleanly separating BU 394.  

Please come back to me if you have observed STF 45. Thank you. 

Comments and images are most welcome. 

Maybe next time I will seek out a carbon star in Cassiopeia 

Clear skies from Aubrey.          

Thank you for reading my report, Michael and Stephen. 
I always appreciate your thank-you's.

However I have one spelling mistake. 
Item number 4 should have the designation TOK 223. 
Humble apologies for that one. 
TOK stands for Andrei Tokovinin. 

Very best regards, 

Aubrey. 

Hi Aubrey,

Congratulations on observing those five stars - I know you were keen to bag them! 

And by the sounds of it you were made to work for them, particularly BU 394 and ES 1202. 

Your description of BU 394 highlights how important seeing conditions are to splitting doubles. So, it must have been a nice feeling to observe it at 320X. 

Also, I really liked reading the contrasting opinions that other observers hold of STF 45 and its colours. Considering it is seems like an easy split, maybe I should have a go at observing the colours too. Hopefully, I can get back out with my scope soon as I miss being out under the stars - and, planets and the Moon, and the ISS : )

Clear skies to you,

Darren.

Super to hear from you once again, Darren. 

I am seriously reckoning as many as possible ought to give STF 45 a shot.
It is so effortlessly easy to split and very near to the border of Andromeda.
Therefore figuring out the colours should be reasonably easy for anyone to figure out. 

Rumour has it we have clear skies on Tuesday night. 

Clear skies from Aubrey. 
 

Hi Aubrey,

Apologies for the delay replying...it has been a bit of a mad week. Consequently, I've had little to no time for astronomy.

Thankfully, we're nearly done with the week, and with somewhat of a clear sky, and the leg feeling much stronger I might take the scope out for a bit tonight. If I do I'll be sure to check out STF 45.

Clear skies,

Darren.

Well, well...what fun I've had trying to locate STF 45. 

The fun started before I even looked through an eyepiece. For instance, trying to find out how to get to STF 45 was problematic because Starry Night 7, which is the software I use, does not recognise the STF catalogue. Maybe it does, but when I entered 'STF 45' into the search function it came back blank. So, I checked Stellarium. Similar story there.

Where to next, Google would surely, help right? Wrong! What came back among other things was a recent post on Cloudy Nights, where the original poster had the title of the post 'STF 45 Cassiopeia and environs.' However, in his post he seems to use the Greek letter Sigma to denote STF 45.

I discovered that Sigma Cassiopeiae is a completely different star...nice by all accounts, and close to a beautiful open cluster, but not our STF 45.

After much searching, I was to discover that STF also goes by the name HIP 3045...BINGO! Starry Night likes HIP numbers. So back to Starry Night 7. Searched for HIP 3045, and there it was. Now the real fun was to begin...

Do I star hop from 'Shedar' or M110???

I decided to try M110, out to HIP 2900, and then Pi Cassiopeiae. Several attempts were made, but no joy. I was in and out of the house like a yo-yo; charting out my route on the PC, back to eyepiece, back to PC, sliding doors opening and closing. At this stage the wife was wondering what was going on down stairs.I really need to start printing out maps.

After several failed attempts I did try going from 'Shedar', but again, no joy! So, back to the PC, back to M110, and took note of a very distinct arrangement of stars to use as a point of reference. This grouping looked liked a mini Taurus, but reversed. Staring at the PC in sheer embarrassment I realised where I was going wrong...Instead of moving towards Cassiopeia I was moving away from it . Oh my - what a week!

So, I went back to Andromeda and made my way to HIP 2900, then I'd keep an eye out for Pi Cassiopeiae and then head in a NE direction towards STF 45 /HIP 3045. 

With my 2" 30mm eyepiece, which provides 42X, I could see those two little stars. All I could say was 'there they are, there they are!' I pushed the magnification to 50X, and 139X

To me the primary star displayed a 'Wheat' / light yellow. type of colour, whereas its companion seemed to be a darker shade of orange. 

To ensure I can locate STF 45 next time I used the 10 X 50 finder scope to take note of bright stars in the FOV. Beginning at Shedar, I'll head to Zeta, then pass through Nu and XI, to reach the three nice stars of Omicron, HIP 3478/68 Cas, and then to Pi, before heading out to STF 45/ HIP 3045. I tried this route several time after locating STF 45, and it was a doddle.

Aubrey thank you very much for providing me with such a fun evening. Hunting down STF 45 is a night I'll always remember.

Clear skies pal,

Darren.