Saturday, July 1, 2017
Thursday, May 18, 2017
Messier 61 /NGC 4303
Messier 61 is a barred galaxy , part of the Virgo Cluster.
To find M 61 we may start at Porrima /Gamma Virginis , itself a beautiful double star worth of close examination.
From Porrima we should navigate toward West to the next naked eyes bright star Zaniah or Eta Vir.
From Zaniah we should change course toward North to 16 Virginis a fifth magnitude star.
Once we get there ,we are close to Messier 61.
Insert a low power ocular , let say of 25mm focal length and look for the star asterism adnotated below as ''a-b1-b2-c-d1-d2''.
Choose the star raw at East , namely b1-c-d1.
Follow the direction from ''a'' to ''d1''.
Go twice this distance further North and you will find a pair of stars.
The brighter is bearing the code HIP 60224 and it have a dimmer star to the North-East.
Imagine a right angle triangle having the right angle corner in the dimmer star.
At about twice the distance between HIP 60224 and the ''corner star'' , toward East-South East it lie Messier 61.
The above screen-print from Aladin Lite is not rendering well the brightness difference between HIP 60224 of 8.15 mv and the ''corner star'' which at 10.35 mv is much dimmer ,with more than two magnitudes.
The magnitudes quoted above are from Stellarium.
Stellarium is rendering better this brightness difference between the two ''guide stars''.
But of course ,the galaxy looked much , much fainter in the Revelation 9 mm Plossl ocular ,at 96x in my 125mm F/7 Dobsonian.
My first observation of M61 happened on May 14 and the second last night ,on May 17.
I saw just a dim ,hazy ,round patch of light , a very ,very dim one.
No structure , no shape , no central condensation.
For all this I will have to come back latter ,with a bigger telescope.
But I'm happy and grateful I was blessed with the view of this galaxy considered as big as our Milky Way and located at 53 million light-years.
Note :
The screen-prints are made from Aladin Lite and Stellarium and the notes were added with Paint.
To find M 61 we may start at Porrima /Gamma Virginis , itself a beautiful double star worth of close examination.
From Porrima we should navigate toward West to the next naked eyes bright star Zaniah or Eta Vir.
From Zaniah we should change course toward North to 16 Virginis a fifth magnitude star.
Once we get there ,we are close to Messier 61.
Choose the star raw at East , namely b1-c-d1.
Follow the direction from ''a'' to ''d1''.
Go twice this distance further North and you will find a pair of stars.
The brighter is bearing the code HIP 60224 and it have a dimmer star to the North-East.
Imagine a right angle triangle having the right angle corner in the dimmer star.
At about twice the distance between HIP 60224 and the ''corner star'' , toward East-South East it lie Messier 61.
The above screen-print from Aladin Lite is not rendering well the brightness difference between HIP 60224 of 8.15 mv and the ''corner star'' which at 10.35 mv is much dimmer ,with more than two magnitudes.
The magnitudes quoted above are from Stellarium.
Stellarium is rendering better this brightness difference between the two ''guide stars''.
But of course ,the galaxy looked much , much fainter in the Revelation 9 mm Plossl ocular ,at 96x in my 125mm F/7 Dobsonian.
My first observation of M61 happened on May 14 and the second last night ,on May 17.
I saw just a dim ,hazy ,round patch of light , a very ,very dim one.
No structure , no shape , no central condensation.
For all this I will have to come back latter ,with a bigger telescope.
But I'm happy and grateful I was blessed with the view of this galaxy considered as big as our Milky Way and located at 53 million light-years.
Note :
The screen-prints are made from Aladin Lite and Stellarium and the notes were added with Paint.
Tuesday, May 16, 2017
Enigma din R Crateris / The R Crateris Riddle
The telescope I'm using most often is pretty old at 20
years but not a ''classic'' because it is home made.
It is a Dobsonian with a 125mm F/7 very good primary mirror made by late Gavril Beches.
Currently the mounting is under refurbishment ,some parts gave up after two decades of stargazing.
The book where I got the target for the observation below is a classic , ''Pleasures of the Telescope'' by Garrett Putnam Serviss.
For
a long time my pet targets were double stars.
But since more than one year I'm addicted to a Deep Sky craze.
The second week of May being around Full Moon , there were not chances to see many galaxies in my small telescope...
But since more than one year I'm addicted to a Deep Sky craze.
The second week of May being around Full Moon , there were not chances to see many galaxies in my small telescope...
On 10 and 12 of May I was looking for another type of targets.
Like trying to see Messier 68 , a globular cluster but without success.
Like trying to see Messier 68 , a globular cluster but without success.
Serviss suggest , while being in that part of the firmamant , to have a look to Delta Corvi which is a double star and to R Crateris ,a variable red star.
I
started my star hopping with Algorab or Delta Corvi , an old friend because is
the starting point when searching for Messier 104 ''Sombrero Galaxy''.
This time ,thanks to Serviss , I looked a bit more careful and ... yes , Delta Corvi is a not so easy double star of very unequal stars ,separated by 24'' , split at 35x , if you look carefuly.
The dim companion is better seen at 69x /University 12.5mm ortho.
This time ,thanks to Serviss , I looked a bit more careful and ... yes , Delta Corvi is a not so easy double star of very unequal stars ,separated by 24'' , split at 35x , if you look carefuly.
The dim companion is better seen at 69x /University 12.5mm ortho.
From
Delta Corvi , I navigated toward West to Gienah Corvi /Gamma Corvi.
And here my science ended , I was not able to manage alone on the bright Moon lit sky ,among those dim and rare stars.
The Toshimi Taki atlas helped me to notice a triangular asterism located to the West of Gienah , composed of 31 Crateris -Eta Crt-Zeta Crt .
The lower side of this triangle ,namely 31 Crt- Zeta Crt is pointing toward Gamma Crt.
From Gamma Crt the next step is bringing us to Alpha Crateris or Alkes.
R Crateris is in the same field at 69x with Alpha Crt.
Here is a finder chart made using Stellarium and Paint.
And here my science ended , I was not able to manage alone on the bright Moon lit sky ,among those dim and rare stars.
The Toshimi Taki atlas helped me to notice a triangular asterism located to the West of Gienah , composed of 31 Crateris -Eta Crt-Zeta Crt .
The lower side of this triangle ,namely 31 Crt- Zeta Crt is pointing toward Gamma Crt.
From Gamma Crt the next step is bringing us to Alpha Crateris or Alkes.
R Crateris is in the same field at 69x with Alpha Crt.
Here is a finder chart made using Stellarium and Paint.
R
Crateris is the middle star of a boomerang shaped asterism of three stars.
The color of the star was ruddy and R Crt was the brighter in the asterism.
Serviss is not mentioning that R Crt is also a double star.
Stellarium is stating R Crt have a separation of 63'' and PA= 268 degree.
I haven't searched in big data bases but I believe the companion is the small star of 9.9 mv we see in this print screen from Aladin Lite.
Checking with Stellarium,the position angle of the small star fit very well : R Crt is to the East of Alpha Crt .
The 9.9 mv star is located between R Crateris and Alkes which lie to the West of R Crt .
This mean a PA of about 270 deg against 268 degrees listed by Stellarium.
The difference in RA between R Crateris and the supposed companion is of about four seconds of time which mean 60'' against the separation of 63'' listed by Stellarium.
Again ,data agree well.
The color of the star was ruddy and R Crt was the brighter in the asterism.
Serviss is not mentioning that R Crt is also a double star.
Stellarium is stating R Crt have a separation of 63'' and PA= 268 degree.
I haven't searched in big data bases but I believe the companion is the small star of 9.9 mv we see in this print screen from Aladin Lite.
Checking with Stellarium,the position angle of the small star fit very well : R Crt is to the East of Alpha Crt .
The 9.9 mv star is located between R Crateris and Alkes which lie to the West of R Crt .
This mean a PA of about 270 deg against 268 degrees listed by Stellarium.
The difference in RA between R Crateris and the supposed companion is of about four seconds of time which mean 60'' against the separation of 63'' listed by Stellarium.
Again ,data agree well.
According
to Simbad , R Crateris is a ''Helium burning asymptotic giant branch star'' :
However ,there is something that I don't understand.
Stellarium is stating R Crt to be of 8.95 mv.
According to Vizier the maximum brightness of R Crt is of 9.8 mv.
Stellarium is also showing the 9.8 mv brightness in the row about range of
variability.
But visualy ,R Crt was the brightest in the trio of stars shown in the screen-print.
Much brighter I dare to say...
Much brighter I dare to say...
So ,the ''riddle'' I found in R Crateris is this : how can a star of 8.95mv have a range of variability from 9.8 to 11.2 ?
Is this due to the different photometric systems used ?
Well
,it was fun to take a look at this giant red star.
But in the stellar world the red giant stars are pretty cool .
So ,should I say it was ...cool ?
Thursday, May 11, 2017
Observatii din primavara lui 2017/Observations Spring 2017-Part III
The Moon and Jupiter on the Eastern sky on March 30.
Mizar-Alcor-Sidus Ludoviciana in the 90mm RFT refractor.
Dubhe -Alpha UMa and optical companion.
Mu Bootis- Alkalurops as a double star.
At 100x the dim star prove to be a tight double star itself.
The Moon and Jupiter on April 10 through the lens of Coolpix S3300 camera and SVBony ''Moon&Skyglow Filter''.
The Moon and Jupiter through the same camera and a green filter.
Jupiter,the same evening , in the constellation Virgo at end of March,as recorded by the Coolpix S3300 camera , between Spica and Theta Vir.
On 10 of April I was taking - at least I was trying - afocal pictures with my 90x600mm ''zoth'' RFT refracting telescope.
Here we see the 90mm RFT refractor on my DIY ''Penelopa'' pipe-mount with LV 30mm 2'' ocular.
Arcturus and the star 22 Boo.
Delta Boo and companion.
Dubhe -Alpha UMa and optical companion.
Mu Bootis- Alkalurops as a double star.
At 100x the dim star prove to be a tight double star itself.
The Moon and Jupiter on April 10 through the lens of Coolpix S3300 camera and SVBony ''Moon&Skyglow Filter''.
The Moon and Jupiter through the same camera and a green filter.
Life is not always smooth !
The broken arm of right hand ocular of the Sakura 9x60mm binocular.
But we are still looking confidently to the future !
Saturday, April 29, 2017
Observatii Ianuarie-Martie 2017/Observations January-March 2017-Part II
Observations January-March 2017- P II
The Moon on 10 February through the lens of Coolpix S 3300 , mounted on a Velbon tripod.
Afocal pictures on 23 February 2017 : TS 100mm F/14 Maksutov - Cassegrainian at 56x / Sirius Plossl 25mm ,Coolpix S3300 , DIY pipe -mount.
The region of Merope in Pleiades
Messier 44 or Praesepe
Mizar ,Alcor , Sidus Ludoviciana
Regulus A+BC
Sigma Tauri
Sirius and Venus on 25 of February , only Coolpix S3300 :
Sirius
Venus
Venus on 27 February , surrounded by a halo.
In the picture ,the diameter of the ''Venusian'' halo is smaller than what I saw visually.
Visually ,the diameter of the halo was about half the length of a brick also visible in the picture.
Knowing the distance to the wall and the dimensions of a brick and using the ''arctan'' function I found for the halo a diameter of 0,32 degree or 19 minutes of arc.
On 28 February Venus was close to the two days old Moon.
This is a ''day light'' picture of the Moon taken with only the Coolpix S3300 camera.
In the dusk of the same day the Moon , Mars and Venus were lined on the Western sky .
On 4 March the Moon was in conjunction with Aldebaran as recorded below by the Coolpix S3300 camera.
For visual and afocal pictures of the Moon I used that night my trusty RFT 90x600mm refractor made by ''zoth''.
The Moon in my RFT 90x600mm refractor at 24x /Sirius Plossl 25mm.
Arcturus spying through the branches ,at left !
The Winter Triangle :
The Moon on 10 February through the lens of Coolpix S 3300 , mounted on a Velbon tripod.
The region of Merope in Pleiades
Messier 44 or Praesepe
Mizar ,Alcor , Sidus Ludoviciana
Regulus A+BC
Sigma Tauri
Cor Caroli /Alpha Canum Venaticorum
Sirius and Venus on 25 of February , only Coolpix S3300 :
Sirius
Venus
In the picture ,the diameter of the ''Venusian'' halo is smaller than what I saw visually.
Visually ,the diameter of the halo was about half the length of a brick also visible in the picture.
Knowing the distance to the wall and the dimensions of a brick and using the ''arctan'' function I found for the halo a diameter of 0,32 degree or 19 minutes of arc.
On 28 February Venus was close to the two days old Moon.
Trying to capture the Winter Hexagon with Coolpix S3300 , I missed Capella.
On the 3-rd of March I took afocal pics of the Moon in the day light using my 90X600mm RFT refractor at 24x / Sirius Plossl 25mm +Coolpix S3300 + SV Bony Moon&Skyglow filter.
In the dusk of the same day the Moon , Mars and Venus were lined on the Western sky .
On 4 March the Moon was in conjunction with Aldebaran as recorded below by the Coolpix S3300 camera.
For visual and afocal pictures of the Moon I used that night my trusty RFT 90x600mm refractor made by ''zoth''.
The Moon in my RFT 90x600mm refractor at 24x /Sirius Plossl 25mm.
On 13 March the Full Moon ,known as ''Worm Moon'' ,accompanied by Jupiter to the South , put up for a nice and colorful show !
On March 15 I was finally successful at recording the Winter Hexagon and the Winter Triangle.
Just in time !
The full Winter Hexagon :
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