Sketching With Ethos
Posted 19 August 2010 - 06:15 PM
I've had a question on my mind to do with extremely wide FOV's and sketching. Is it a good idea to sketch with wide field eyepieces like Tele Vue Naglers and Ethos? I can't see how you could do a sketch of an object with a 110 degree field like on the SX. There's no way to zoom in on an object, I think it would be so small compared to the size of the field it'd look like a star compared to everything else, unless you'd be using a 10" circle.
Am I right or am I wrong?
Posted 19 August 2010 - 06:40 PM
The widest field I work with is 70 degrees with my Pentax 10mm, which is a far cry from 110 degrees. However, even with narrower views, compact galaxies and planetary nebulae can still be very small compared to the field. So if you're sketching in even a reasonably large circle--say 6 or 7 inches, the object can still be quite small. It's really hard to create and refine details in something that tiny. The solution I use is to first create a full field-stop view of the object and star field. Then I create a second sketch--no circle involved--where I focus on just the object and make it as large as I need to include all the details.
Despite that challenge, I think a really wide field gives you a great opportunity to sketch a much broader context around the object, or include other interesting objects nearby. Some good advice David Moody gave me is that you don't need to sketch in a circle. (I still prefer to use the circle whenever possible : ) However, there are still a lot of times when it can really help to ignore the field stop, particularly if the field of view is either too big...or too small.
A couple examples...
Posted 20 August 2010 - 05:08 AM
Excellent advice from an experienced and talented observer (Jeremy Perez). I also normally use a field no larger than 70 degrees, as Jeremy, and as stated the object may appear small at even this field size. You may want to divide the field into quarters and slowly develop the observation (rendering). The best of luck in your observations.
Posted 20 August 2010 - 06:32 AM
3 of my 4 eyepieces are Nagler. But I almost never sketch the whole FOV. Mostly I sketch what I can see at "once" (to see the edge of my Naglers I have to look "around the corner"), or take a small portion of the scene (like the details of Jeremy). I think there are no rules... Take the freedom to sketch what you want!