Theory of Distance and Visual Limits

Early on in my astronomy career, I was looking at a rather nice astronomy book and it had wonderful high quality large photo prints.  They were obviously at the Hubble level, and they showed an excellent amount of detail.

I had left the book on my bed propped up, and upon my return, I noticed something.  I stood back a few feet, and noticed that there was less detail than being up close to it.  It seems like a rather oridinary thing, but I studied this for a while, and I started to formulate a scientific theory.

This theory states that there is a limit at which the human eye can detect color, and this varies to the person.  Plain and simple, at a certain distance, you can no longer detect color in an object.  I believe that this is possible in not just photographs, but as well live objects.

Step 1: Acquire a large, visual, preferably not very filtered astronomical picture.  The Orion Nebula and Andromeda galaxy are perfect.  Prop them up on a chair outside.

Step 2: Walk up to the photograph, and note the definite color and detail in the deep sky object.  Note and remember what you see.

Step 3:  Now walk back 10 feet, and study the photograph.  It now appears smaller, and with less striking colors and details.  What were beautifully detailed and cloudy objects are reduced to a smoother, mottled appearence.Note and remember what you see.

Step 4: Walk back another 10-15 feet and study the picture now.  It has most of it’s defined detail gone.  Now, when I got to this point, I came upon a problem.  Galaxies and nebulae emit their own light, and a photograph does not.  The solution I found was to have the picture be printed on a translucent piece of bendable plastic.  Now take a light, and shine it through the back, but scatter the light with a thin fabric sheet to make the light distribution equal over all diameters.  I probabily should have told you this before, so my apologies.

Step 5:  Now walk back again and again, repeating the process until which there is no more color detected by your eye.  This distance varies for everyone and generally, the view will be very similar to the view through a telescope.  You have now found your visual limit; but now what?

I am no math wizard, so there must be some kind of number system for the visual limit.  And if so, the object, distance of that object for real and the exposure time must also be accounted for.  This requires one big equation that I am definitely not up for.


This experiment actually works too! I tried it and there is something to this, try it yourself, it should only take a few minutes.  If you can’t have it printed on translucent plastic, another possible method is to print it out on regular paper or a poster and tape the paper to the plastic.  A decent astronomy poster that is somewhat large can be had for under 10 dollars on amazon.

Good luck and clear skies.





All Night Observing 9/15/12

Me and my dad had been thinking about doing a run up to Mount Baldy and we finally got everything ready to go.  The 14 inch and 70mm refractor easily fit into the car, as well as all of our accesory cases and star charts.  Just before we left, my Dad showed me his new 5x 2 inch barlow.  We had seen this on ebay and I did know of such a lens.

Anyway, we were all excited to go up there to get away from all the lights.  You know it’ll be good seeing when your going up the mountain and seeing the smog and lights from the city below.  It is an awesome view, and I was going  to take a picture of it, but I forgot the camera.   We made it all of the way up there, and we were just about to turn onto Glendora Ridge Road and it was blocked off.  It was probably because of the extreme heat lately and they didn’t want to risk a fire of some sort.

We came down the mountain looking for an alternate spot.  When were pretty much all the way down, we found a nice parking lot to view in. There were cars going by every once in a while, but no site is perfect.  We got everything all set up and we were observing for not more than 45 minutes when were told to leave.  I guess the police don’t want people around there after dark.

So we had to pack everything up and go home.  Once we got back, we could either take out the scope in the backyard or put it away.  We took it out.  I will try to list all of the objects I saw, but I might forget some.  I saw so many, if you can think of any decent object, I probably saw it.

I saw:

M13 globular

M57 planetary (as well as the central star)

M56 globular

M11 open

M27 planetary

Cat’s eye nebula (NGC 6543)

Blinking planetary (NGC 6826)

Stephan’s Quintet

M2 globular

M15 globular

M22 globular

M8 lagoon nebula

M20 Trifid nebula

M31 Andromeda galaxy

M42 Orion nebula


I stayed up pretty much all night.  I got to be the first one to see the Orion nebula in the 14 inch.  When you view it with that much aperture, you can see structures of clouds and dust going in multiple directions and the nebula extends out very far.  In the 10×50 binoculars the whole region is nebulous.  I also saw M31 which came out really awesome in a sketch I made.

Shortly after viewing it, I found out there was an area on the edges of the galaxy called NGC 206.  I would definitly seen it had I known it was there.  One of the other highlights of the night was Jupiter.  It was absolutely amazing in the 14 inch, and this is where I got the most use out of the Rini 5x.  I was getting clear focus, even when it filled nearly the entire field.  I must have spent about 45 minutes on it, and returned to it several times.

I also managed to sketch the Blinking planetary.  Also, I was able to pick out several very dim objects with the 70mm, such as the blinking planetary, the Cat’s Eye Nebula and the Saturn Nebula (NGC 7009).  I came in around 4:30, and it was still dark.  I guess it technically wasn’t all night, but it’s the longest observing run I’ve ever made.  I also tried imaging M45 with the digital and they came out OK, you can see the blue stars but not much more.


All in all, one of the best nights I’ve ever had out with the telescope,  I need to find a way to stay awake longer though.

Less than Transparent Skies

The growing dilema in amateur astronomy is light pollution and other related sources.  In the mid city, forget about all of the NGC’s or IC’s you’ll be lucky to see all of the Messiers.  I have faced this problem everytime I go out with my telescope.  The LA county fair is in full swing right now, and that pretty much rules out the entire southern sky.

I don’t have any problem with the fair, it’s just that it turns an already not transparent sky into something that can’t be described without seeing it firsthand.  If you live far away in the country, you don’t have much problem with this.

Anyway, I am finishing up the Mesier project, 70 objects are very close now! I need only about 15 more Messiers, but this is hardly any compared to how many I have observed.  Pretty much all of these were observed in town, in badly polluted skies.  Before going out with the telescope, I look at the color of the daytime sky.  If it is a deep blue, it will be a decent night.  However, if it is pale blue and the area above the horizon is a dirty smog color, it will not be worth going out for deep sky.  I have been limited to planets and the moon on nights like that.

I can’t wait to see dark skies, even acceptably dark sites like Mount Baldy are well worth the trip.  By the way, the blog appearence and theme has been changing a lot lately and I have finally found a look that I am satisfied with.  I haven’t observed too much as school is really in full swing now.  I have also been blogging less, like one to two posts a week.

If you ever get the chance to pull the trigger on one of Astro league, programs, it is HIGHLY reccomended you start one.  Mesier one is awesome for learning and taking notes on these bright and detailed astronomical objects.

Clear Skies

1 Year Anniversary of the Observer 70

Yesterday (September 9) was the 1 year anniversary of owning and using the observer 70mm.  The telescope came in one big box while I was at school.  Strange because this was my sisters birthday, wish her a happy one.

Don’t have too much time.  Had a killer observing run on Saturday til’ about 1 in the morning.  Saw Capella, Auriga, and even Orion in the pollution.  I also logged some more Messier objects, it’s winding down, I am planning to finish up by the time the moon gets big again.

The highlight of the evening was seeing the arrival of Jupiter.  It was big and bright, and still is to this day, my favorite planet to observe.  Hoping to do a more complete blog sometime this week.


Astronomical Sketches: Old And New

I’ve been going through some of my old observing notes lately and pulled out my very first astronomical sketch book.  I took a few minutes and looked through every page.  If you’ve seen my recent sketches, they are perfect representations of what you would see through the eyepiece, except they are negatives.  All of the sketches in my first book were all made with #2 pencil.

My first sketches were made on lined paper and the sketching circle representing the field of view in a telescope eyepiece was just merely hand drawn.  These first sketches were crude, and they were not descriptive or an accurate sketch either.  I the went to taping circular pieces of sketching paper which proved much better.

I was still not very satisfied with my results, and wanted more oomph from the sketches.  I read Steve Coe’s Deep Sky Observing, which is one of the best deep sky/ sketching books I have ever read.  Then came the perfect set up.  I has ample room for notes, including dates; times; and telescopes used plus a 3 inch circle complete with North and East markings.  These could be made on the computer and were used with ease.For an example of what these sketches look like versus the real thing: I have a picture of the real object and one of the sketch I made.











This object is a planetary nebula- the Dumbbell Nebula (M27).  See the Dumbbell? The sketch was made using my small 70mm Refractor, and the view would have been much more impressive from a darker sky.  For those who live in light polluted skies, you feel my pain and know what I am talking about.  There is one other type of deep sky object I like to sketch: globular clusters.  At first I thought this was not possible but once again, referring back to Deep Sky Observing, it shows how to sketch these stellar nodules of stars in space.

The view through a small telescope is dramatically less impressive than looking at a high quality photograph.  A strip of 35mm film can capture much more light than your eye.











You can really see the difference in globular clusters obviously.  By the way, Hi Digi Com and Media!

Observing Multiple Sky “Medias”

As many people who own telescopes, one usually has a regular that they use more often than not.  Mine has obviously been the 70mm f/10, which I have talked about on many occasions.  In the night and daytime sky, I have best found a way to classify each type of object groups as medias.

A media is a group of one kind of objects, like the deep sky for example.  This group could the be broken down in to smaller subgroups such as star clusters, nebulae, etc.  Solar system media includes solar observing, planetary observing and lunar observing.  This could also be yet divided again into more subgroups such as certain types of craters on the moon, the list goes on and  on.

I was observing 2 medias last night, the deep sky group and the lunar group.  For the majority of the night, it was the deep sky which was observed as the moon is in its waning phases currently.  First on my list was M22, a prominent bright globular cluster in the constellation of Sagittarius.  It is very bright with a distinctive oval shape.  Even with the blinding lights from the LA county fair glowing bright, many stars were on the edge of resolution and some were individually picked out.

After M22 came M11, the famous compact open cluster known as the Wild Duck Cluster.  Many objects were viewed last night and the list is too numerous to mention.  Just when I decided to bring it in, I noticed most of Cassiopeia peaking over the roof of the house and swung my scope over for a look.   The Double Cluster was still too low, and the light from the moon was coming in the east.  I decided to choose NGC 457, an open cluster that many people see an owl or “E.T.” from t.he hit movie.  I never saw the owl shape but the E.T. shape came right out instantly.

Just before I went in, the moon also came up high enough and just for the blog I took a picture:

Clear Skies.