Arcturus Sketch

Hi All,

It is great to read your reports from around the country during this uncertain time. There's great comfort knowing that so many of us are out with our scopes, having shared experiences, and recording our observations on this wonderful forum.

With this in mind, here is my small contribution...

As some of you know I recently spent time in and around Bootes, and planned to sketch an object or two from this part of the night sky. M3, and M53 are not great from my location at the moment thanks to light pollution, but Arcturus shines bright. Because I have a Newtonian reflector, the star has four pretty diffraction spikes radiating from its core, and it creates a lovely starburst effect. For this reason, I decided that I wanted a permanent record of it.

In addition to sketching Arcturus, I also observed M3, M53, and Izar. You'll be glad to know Aubrey that I did split Izar using 37.5X. Both stars looked very nice. I detected bright blue, and yellow / orange tones.

Other details from last night's sketching session include:

Object: Arcturus
Date: 19/03/2020
Location: Dundrum - Bortle 8
Time: 11:56 UT
Seeing: 7pk
Transparency 4
Instrument used: f/8 150mm Newtonian Reflector
Eyepiece: Orion 32mm Plossl
AFOV: 52°
TFOV: 1.39°
Materials used: 2B, 2H graphite pencils, and a blending stump. The image was sketched at the eyepiece and inverted using GIMP 2.0

As always many thanks taking the time to read the above, and your comments and feedback are always welcomed.

Clear skies to all,

Darren.

Lovely Sketch Darren, I like the colours of the stars too

There's a value in those diffraction spikes, they add a beauty to the brightness of the star

Keith..

Do I see Picot 1 in your sketch, Darren?
Upper left from Arcturus?
If so, you are sharing with us the increasingly popular asterism.
You are only missing one star in it.
Your Arcturus colour is extremely good.
It is a K class star. So Golden-orange to me.

Regarding Izar, I am utterly amazed you are splitting it at 37.5X.
I have never split it at 40X.
Sometimes I do get success at 112X.
But more often 140X.
Its current separation is 2.8". PA is 347 degrees.
That would be 5 o'clock in your telescope.

But if you did split it at 37.5X, you are making a world record!

Kind regards,

Aubrey.

Hello Keith and Aubrey, 

Very many thanks for your comments. 

Based on your point Aubrey I must have made a rookie mistake...Could it have been Delta Bootis that I split on Thursday at 37.5 power? That is also a double...right?

In terms of Picot 1, great spot! There is star left out of 'Napoleon's Hat' in the sketch I submitted yesterday.

Interestingly, I worked quite differently during the digitising phase of my sketch. Rather than scan the original sketch, which had all seven stars marked on it, I created a second sketch for digitising purposes. I was not entirely happy with how my original diffraction spikes turned-out once I digitised the sketch. What's more, I could not fix (add colour, blur, or straighten) them using the original sketch. So, I went to the Internet to see how other astronomical sketchers add diffraction spikes to their drawings using GIMP - the programme I use to digitise my sketches.

I spent a number hours learning, practising, and pulling-out whatever hair I've left to add in the digitised diffraction spikes. Thankfully, I got there in the end. However, it meant I had to create a second sketch. Among other things, I had to (1) remove my original diffraction spikes - the ones I sketched at the eyepiece - (2) create a new digitised brush that looked like the diffraction spike that Newtonian reflectors make, and (3) plot each star again.

As the primary goal of my second sketch was to include diffraction spikes that better reflected what I observed, I ended up missing one of the stars in Picot 1 when I plotted the other stars that were in the original sketch because I was mentally worn out at that stage

In addition, the image I submitted is a lower resolution picture. Consequently, the digitised diffraction spike ended up looking nowhere near as good as the initial higher resolution image that I created using GIMP.

Unfortunately, I could not upload that to the forum as we are limited to a certain size. Of course, I could do what some astrophotographers do and create a flicker account and submit a link to the better quality image in my post, but my preference is to limit the time spent at the post-processing stage. 

Thus, I'm going revert to my old way of working: submit my original sketch - the one I did at the eyepiece - leaving more time to obsere the stars. 

As they say 'lesson learned'. 

Kindest regards and clear skies, 

Darren. 

BTW, I had wrestled with idea of explaining how I created the diffraction spikes in my original post, but I figured it is fairly long-winded and estoric, so I decided to leave it out. 

Thank you, Darren, for this response.
You will greatly admire Picot 1 the next time.

Yes, Delta Bootis is a very wide double star.
It is a true binary too.
Its separation is 105".
PA is 78 degrees.
A is a good yellow-orange star.
That must have been the double you observed.
Still - you can tick that one off.

Please do keep up your sketching work, Darren!
They are very good.

The weather folk seem to be promising clear skies on Sunday night.

Kind regards,

Aubrey.

Hi Aubrey, 

Very many thanks for providing those details about Delta Bootis. That must have been what I viewed... I'll have to give Izar a go next time, and I'll be sure to use a more powerful eyepiece. 

I was struck by the shape of Picot 1 when I observed Arcturus on Thursday, but I was not sure what it was until today, so thanks for that too. 

Let's hope for another clear night tomorrow. 

Clear skies, 

Darren.