Pencil

[Richard N]

I’m new and I have started sketching. I’m  having great problems seeing pencil marks under red light. Any tips?

[markse68]

Maybe try a green LED? I’ve read conflicting info but some say the red led thing is a bit of a myth as our eyes are less sensitive to red so you need a brighter light. Our eyes are most sensitive to green so you can use a dimmer light and preserve dark adaption better. Or even a very dimmed white light?

Mark

[Franklin]

Black paper, white pencil?

[mikeDnight]

I use a dimmable red torch to see the paper unless there's plenty of moonlight, but I rarely ever make a completed sketch at the eyepiece. Instead, I make a rough sketch at the telescope then complete a cleaned up version once I'm back in the house. Like most visual observers who sketch, I'm sure you will soon develop a sketching method that you understand, so that you can later use the information to produce a beautiful finished sketch. Some of my eyepiece sketches can look quite chaotic but I understand the scribblings and numbers I use for brightness estimates of various areas. You'll need to use a dark enough pencil to see the pencil lines in low light.

 

 

[Spile]

Now I wonder?

https://www.instructables.com/Pencil-with-LED-lighting/

[Pixies]

@markse68 I've been hearing reports that an amber lamp is better than a red, because you can use it at a lower setting than just a plain red. Shame all my lamps are red LED. I'll need to find a white one and use some kind of orange tape/paint.

 

Although I'm quite new to sketching, as  @mikeDnight says, it's more a case of 'note-taking' at the telescope and then completing the sketch proper later indoors. But if you are sketching star positions, it's important to get it accurate at the time - in which case use a soft pencil (4B say) which is pretty dark.

Here's an example of the 'notes' I was taking for sketching Mars last year. However, one isn't so worried about dark-adaption with planets. In fact, it makes it worse!

 

[globular]

Short answer:  My tip is to close your observing eye when it's not at the eyepiece.  And use your other eye for everything else under a dim light of whatever colour you find works best.

 

Long answer:

I've read all sort of stuff about what colour light is best.
I concluded that I needed to try them all for myself.
So I tried lots of different things... different colours at different intensities... and concluded that I preferred red.... but the best thing was to observe with my right eye at the eyepiece... and use my left eye (with the right closed) for sketching / changing EPs / etc under a dim red light.
It took some getting used to but I find even very dim light (of any colour) spoils dark adaption.

Some of my colour 'research'...
*  the aim is to use a light that can seen by our cones, because these are the only receptors with enough resolution, but at the same time preserve and avoid bleaching out the more sensitive rods. Red light is the best wavelength for this.
*  red / orange lighting need to be brighter to be useful than white or green light. Lower lumens is more important than the colour.
*  most light sources are not monochromatic - except red which are typically 630 or 660 nm.  A red light is therefore more likely to reduces the sensitivity in only the red cones, leaving the blue and green dark adapted.  Other colours, unless very carefully filtered, will impact all cones. 
 
*  a low level blue-green light in the 520 nm range, which is the area of the maximum sensitivity of the eye, will allow 'good' vision at very lower levels which will not decreasing the sensitivity of the eye too much