Check out Comet Lovejoy!

Get up early and look out to the East to find comet Lovejoy, a brightening comet about 4.5th magnitude. From light polluted skies it should be easy with binoculars. I plan to go check it out myself and do a sketch. Here’s a finder chart for the next few days. Happy hunting!
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Amazing resolution with 6 inches

The 6 inch reflector, possibly the most common mirror size manufactured and used in telescopes.  I has been considered the “serious” aperture for many years.  At least that’s what it was like back in the day, meaning the 1950s and 60s.  That has certainly changed in today’s light pollution and advancements in telescopes, including Go-To telescopes

I can remember my grandpa telling me that he used to sketched moon craters and similar objects with his homemade 4.25 inch reflector.  He tried to have some of his sketches put into Sky and Telescope>, and unfortunately, they were never put in. I just got Sky and Telescope, and I don’t see any sketches in it.  Perhaps I’m wrong though.

I recently made an excelent detailed sketch of M42, on of the best nebulae you can view.  M42 is good in most any telescope, but it was great the other day.  Why? Because staying up late was worth it.  Even with a Waning Moon some 40 to 50 degrees away, it was still really good.  One of the only other times I’ve seen Orion- the constellation in general was at a PVAA star party at Mount Baldy.  I mean, this was really good seeing.

On a recent sketch from Astronomy Sketch of the Day, there is a nice sketch of M42-43, with a telescope with aperture of somewhere around 10 inches.  The sketch is great, I tip my hat to them, but notice that the seeing when it was sketched was 3 out of 5.  Most or all deep sky objects generally react well to darker/more transparent skies, so if you see my sketch below, notice that there is more structure and also notice more stars in the “Trapezium”.

Observed with a Star HOC 6-5 EQ; Orion Sirius Plossl 7.5mm eyepiece

Notice that I can pick out the “E” and “F” stars in the Trapezium cluster; this was previously only attainable by the using the Orion XX14, or a 12″ Meade Lightbridge at Mount Baldy.  I could not believe this much structure and defined detail in such a small telescope.  There is an interesting article on Belt of Venus regarding sketching and how much can be seen in a small telescope.  This article included seeing very detailed view of M101 with only a 50mm refractor.  Read this really cool article.

So the moral of the story is that even 6 inches can take you very deep in the sky, giving there’s decent viewing.  One thing to remember is that the light pollution usually is less so after midnight as lights turn off and freeways and highways become vacant.  I believe that most of the light pollution in La Verne is due to the 210 freeway that runs right through town.

When it comes to observing the deep sky, the more you look the more you’ll see; an experienced observer with a 4 inch telescope will see much more detail/structure in all objects than an inexperienced observer with a bigger telescope.

Keep looking up!

More Mirror Grinding: Books

When I first got the idea of actually building a telescope in my mind, the first book I read was Amateur Telescope Making.  To many this represents the pinnacle of telescope making books/guides.  However, there are more out there than I once thought.

For example, here is the book on mirror making that my grandpa wrote back in the 60s.  It was typed with a typewriter and the drawing were all made by him, which were really great drawings.  This book is the simple way on how to build a 3 inch F-12 reflector.  But don’t search for this book, because I have the only one.

Another good book for telescope making is Building Your Own Telescope, by Allen Thompson.  I have not read it myself but many have said it is a very good reading, and can had for around 10 dollars (here).  Look around, you’ll find countless books on this subject, they are not very recent, but still have the same valuable information to build a telescope from the ground up.

So, the question is, which book to buy?  This depends on how far you want to go as far as precision for the telescope.  I reccomend a simple technique that does not require the foucault test, because it just makes telescope making a whole lot simpler.  Plus, a mirror’s figure does not need to be perfect in order to observe celestial objects with satisfactory results.  It has been said time and again that a considerably less than perfect mirror will perform as well as a perfected mirror, it is just a matter of conscience.

Before I got really serious about building my telescope, I was demanding for perfection.  I had to do the focault test, had to have a parabolic surface, and I wanted at least a 6 inch diameter mirror.  It turns out that I did not do/get any of those, and that is fine with me based on what it said in Amateur Telescope Making.  Sometime in the near future, I will be putting my grandpa’s book on this website as a page, along with all of the pictures, sketches, and references.

This weekend, I had been pushing some glass myself- only 2 more grades of abraisive left to go!  I ground through the 12 micron today, and and hour was enough.  Last weekend (and the previous post), I had thought of something that would be simple and effective in cleaning house for the next finer grade of abraisive.

A simple idea really, all I did was cover the top of the grinding stand in clear plastic wrap, then set the tool in place as normal.  I tried it, and it really works!  Cleanup was easy as ever, all I had to do was simply pull up the tape, and lift the wrap off.  Then the new wrap can be laid on and taped, ready for action.

As I am progressing through these finer grades, the glass has started to lighten up a bit, and it is not as frosted as it previously was when I ground the first grade (#80 silicon carbide).  I have been told that when the final grade has been finished, the glass should almost be transparent, though not quite, as polishing will remove the final grade of pits.

While progressing through the project, I’ve been planning ahead for gathering the finishing materials (diagonal, diagonal mirror, mirror cell, etc) and found a place to get mirrors aluminized cheap, as well as pretty inexpensive secondary mirrors, and other components.

On Friday morning, I was able to take out my 70mm refractor for a good hour and a half.  I was able to get an extraordinary view of the Orion Nebula, which is saying something, because I have seen this diffuse cloud through a 14 inch reflector, so I know what I am talking about.  I’d say that the view at 56 power is pretty close to the view through a 6 inch reflector.  I hope to have this sketch on Astronomy Sketch of the Day, just like when I had my M31 sketch on there.

Here is my sketch of M42 :

All I can say is, I hope to be sketching this through my 4 inch soon.