Observations - 29th March 2020

Good evening, everyone.

Can you believe it?
3 Sunday nights in a row with clear skies!
This time very little wind and very cold temperatures of about 2 degrees Celsius at the end of the night
.
So I set up my William Optics 158 mm F/7 apochromatic refractor on its Berlebach Planet mount in my back garden. I observed from 6 to 7 pm. Had a break for dinner.Then went out again from 7.45 to 11 pm.

Sunset occurred at 19.55. That's Irish Summer Time.

1. Amazing! I could see Venus with my unaided eyes at precisely at 6 pm. Her magnitude was -4.5. Her distance was slightly less than 100.5 million kms. She was 48.5% illuminated and she was 24.9" in angular diameter. From 112X up to 225X I could see her southern cusp is brighter than the northern cusp. Both cusps are still slightly extended. There was not much shimmering at 225X. The planet is now a good size. I recommend the female planet to you all.

2. Next up was the 5.4 day old crescent Moon. Our nearest neighbour was 392,000 kms away. Its magnitude was -8.7. Its angular diameter was 30.4' wide. I picked out Mare Crisium, which is comparable to the size of Great Britain, Proclus (crater 28 km), Theophilus (crater 100 km). Straight away I could see 2 central peaks, one of which reaches 1400 metres. Rupes Altai looked wonderful but not quite complete. Other craters I saw were Piccolomini (88 km), Beaumont (53 km), Madler (28 km), unusually pear shaped crater Torricelli (28 km), Isidorus (42 km). Capella (49 km). Fracastorius with its northern rim missing (124 km). Vallis Capella goes down through the Capella crater. Its length is 110 km. You can't miss it. Later 2 more shorter in height peaks had appeared in Theophilus at about 8 pm. All these features I had observed before. However one I hadn't were Rimae Gutenberg which are 330 kms long. I found these 2 rilles to be wafer thin and very difficult to see.

3. A decently bright star called Ain (Epsilon Tauri) was occulted by the Moon This occurred at 8.14 pm and I observed it live. The star's magnitude is 3.5 and its light was snuffed out in a flash. Very nice to see. Occultations are great fun!

4. I observed Castor again and found my way to M44 the Beehive star cluster. Of course Tegmine was split yet again at 167X.

The rest of these doubles' figures are from www.stelledoppie.it

5. Epsilon Hydrae is a true double star. B is not visible. Magnitudes: A = 3.5. C = 6.7. Sep = 2.8". PA = 310 degrees. Split at 112X and very good at 140X. A is yellow-white. B has a slight blue tint.

6. I was asked by an observer on Cloudy Nights to check out the uncertain double Stf 1267 again. A has a slightly red hue. I'm happy with that. Its spectral class is simply M. Its secondary is extremely faint at 11.5. I could only get glimpses of it at 225X and 280X. The separation is wide at 10.9". Its PA is 61 degrees. Trust me - it's not easy.

7. Up I go to the constellation of Lynx. Stf 1333 is a true gem! Magnitudes: A = 6.6. B = 6.7. Sep = 1.9". PA = 50 degrees. Both stars are white. Excellent tight split at 112X. 140X is also excellent. One I had not observed before.

8. The true binary 38 Lyncis I had observed before. It's still so stunning! Magnitudes: A = 3.9. B = 6.1. Sep = 2.5". PA = 70 degrees. Superb split at 112X. Why go higher? Of course you can. But I didn't.

9. Stf 1339 is an uncertain double. Magnitudes: A = 9.2. B = 9.9. Sep = 1.5". PA = 65 degrees. So what magnification did I need? 140X. That's all. A wondrous sight! 167X is extremely good too.

10. I finish with an optical double in Cancer which is not in any way stunning: 53 Cancri. It was one I did not study before. Magnitudes: A = 6.5. B = 11.7. Sep = 43.7". PA = 335 degrees. A big gap between the 2 stars at 167X. I needed that power to see the very faint secondary.

11. The much nicer optical double Stf 1288 is further north. Magnitudes: A = 10.2. B = 10.2. Sep = 7.7". PA = 259 degrees. A is slightly yellow. Split at 112X. 2 identical stars like two eyes.

So all in all a brilliant night of observing. The date is also an anniversary of a Total Solar Eclipse I observed with binoculars in northern Nigeria on 29th March 2006. My 3rd and Valerie's first. 

Thank you for reading.
Comments are very welcome.

When will the clear skies return?
Answers on a postcard for that one. LOL!

All the best from Aubrey.

It has been a great spell of dry and clear weather Aubrey. Last night was the coldest night of the winter in S Limerick; dipping down to -4, quite unusual for the end of March. I was observing C/2019 Y4 ATLAS in Camelopardalis; still not showing any signs of 'greatness' to be honest as it hovers around 8th magnitude. But it will get 3 times closer to the Sun than it is at present and we still have an observing window of 7 weeks or so.

Clear skies,
Finbarr.

You have always been the man for comets, Finbarr.
I have been following your observations and those on Cloudy Nights.
Let's hope Comet ATLAS does continue to brighten more and more.

Clear skies,

Aubrey.

Hi Aubrey, 

What a wonderful session you had. Four hours - that's something else!

I very much liked your reading your lunar observations. And congratulation on the catching the occulation of Ain.  I spent an hour with the Moon on Friday the 27th, but more about that tomorrow.

Also, very well done on splitting Stf 1267 at 225X and 280X - what a scope!

Having not spent time in Hydra, and Lynx, it was so nice to read your reports on them. From your descriptions these constellations seem to contain some lovely objects, so many thanks for bringing them to life for us.

It seems to be pretty clear out there now, so I'm going to spend a little time under the stars.

All the best, 

Darren.

Fermidox wrote: It has been a great spell of dry and clear weather Aubrey. Last night was the coldest night of the winter in S Limerick; dipping down to -4, quite unusual for the end of March. I was observing C/2019 Y4 ATLAS in Camelopardalis; still not showing any signs of 'greatness' to be honest as it hovers around 8th magnitude. But it will get 3 times closer to the Sun than it is at present and we still have an observing window of 7 weeks or so.

Clear skies,
Finbarr.

Hi Finbarr,

Very many thanks for providing an update on Comet 2019 Y4 Atlas. Keen to hear more about it over the coming weeks, so keep us posted!

Clear skies,

Darren.

There may not be much more to hear about it Darren, unfortunately it seems to have already disintegrated -

www.astronomerstelegram.org/?read=13620