Book Mania

Wednesday, November 27, 2013

An LED Gun Sight Telescope Finder

Monolux 60mm Telescope
Recently, before the fall weather turned rotten, I finally got a chance to do a bit of observing. The summer had provided little opportunity, given a copious amount of windy and cloudy weather, which was followed by a very busy fall that occupied my time. So my previous observing session had been some time ago.

I was pleasantly surprised when my adult son, who has rarely shown any interest in my hobby, wanted to go out and observe with me. Because of his inexperience, I decided to use my handy Monolux 60mm refractor, pictured at left. On its more than ample pipe mount, it handles easily, and makes a very simple telescope to use.

We went out early, given that it was already dark even at 6:00. I sometimes level the tripod so that I can use a calculator assist program for locating objects, but on this evening I decided to just go for some targets I could easily find. I selected a range of target types, so that my son would get an idea of what I enjoy about the hobby. Did I say hobby? Perhaps obsession is a better word.

Ptolemaeus Region Through ETX 90
We started with the 1st quarter moon. The terminator running down the center of the moon provided ample craters and shadows to keep us occupied for some time. The Monolux delivers the moon with wonderful clarity.

I enjoyed Albategnius and Ptolemaeus as I often had before. But as shared viewing with a novice often dictates, I spent most of the time finding new targets for my son and repositioning the view, given that the telescope was on an unguided mount.

After the moon, we took in the Pleiades (M45), which the FOV of the 700mm focal length Monolux was nearly able to reveal in its entirety. M45 was pretty low in the east, so not as magnificent as when viewed higher in the sky.

Next was the double double in Lyra. Because of the unguided mount, I chose not to go much above 100x, so we really didn't clearly split all components. I have split them with the Monolux before, but splitting the double double with the Monolux requires more magnification and some viewing experience.

So I moved on to the Ring nebula (M57). With a quarter moon and a 60mm telescope, I wasn't sure if we'd be able to actually see the Ring nebula, but we could. It showed up as a small but discernible smokey ring. I was impressed.

The next target was M13, the wonderful globular cluster in Hercules. It was discernible also, but being so low in the west it wasn't spectacular. With the 60mm, it showed as a patch of fog, and individual stars could not be detected. It did, however, give me a talking point as I tried to explain what a globular cluster was.

I contrasted that with the double cluster in Perseus. The side by side open clusters are a favorite of mine, and the relatively large FOV of the Monolux allowed both to be seen in the same field. It was a bit disappointing, however, as I recalled my oft views of the sight with my 6 inch f/5 Newtonian. Naturally, the Newtonian presents the double cluster with more pazazz.

After that we took in a view of the Andromeda Galaxy, M31. Again, it was easily visible in the 60mm telescope, but certainly less than spectacular because of both the telescope size and the competing quarter moon. It was, however, another good talking point, as I was able to explain that all of our other targets for the evening had been local Milky Way objects, but M31 was some 2.5 million light years away, far beyond the confines of our galaxy.

f/5 Newtonian Rich Field
To complete the evening, I moved the telescope over to Eta Cassiopeia. It's a somewhat challenging double star for the 60mm, with the companion star being rather dim. But it still gave us the opportunity to round out our target types.

Time For A Bigger View

A couple of nights later, I wanted to show my son the same sights through my favorite telescope, my f/5 Newtonian Rich Field. As shown, it sits on a sturdy equatorial mount, and has a clock drive. I thought the clock drive  would make observing a bit easier for my son, because the targets would stay in view.

I went out during the day and used my collimation eyepiece to check the telescope's mirror alignment. It had been many weeks since I'd last used the Rich Field instrument, after all. I was pleased to see that it had held collimation very well, and needed no adjustment. As a short focus instrument, for good image quality, accurate mirror collimation is essential.

Enter Murphy's Law

Rigel Quick Finder
That evening when darkness arrived, I headed for my workshop/observatory to get the Newtonian so I could set it up, only to find that the last observer had apparently been the infamous Murphy, of Murphy's law fame.

Murphy's presence became apparent shortly after I retrieved my trusty Rigel Systems Quick Finder. It's a super handy 1x finder that projects a red reticle into the night sky, making finding objects a snap.

Mine came with 2 bases, so I had installed a base on both my 6 inch f/5 Newtonian, and my 6 inch f/10 planetary DOB. That way I could use the finder on either telescope.

But on this evening, when I tried to insert the finder into its base, it wouldn't snap into place. After several tries, I looked more closely to see what was wrong. And Murphy's work became apparent.

On the back side of the finder, as shown at the bottom of the image at right, is supposed to be a flexible foot that clips into a slot in the finder base. As you can see, there is no longer a foot, just a hole in the base where the foot was.  The foot had broken off.

So, there would be no using the Newtonian that evening. While I could have found the moon without a finder, the other objects would have been virtually impossible to locate.

And what was so frustrating, was that not only was the 6 inch Rich Field out of commission, but so was my 6 inch Stargazer Steve Planetary DOB, since I used the Quickfinder on both.


That evening we still went out, but had to settle for views through my handy Meade ETX 90. It has excellent optics, and a clock drive to boot. So it was a step up over the Monolux of the previous observing session. But for star objects, not a very big step up. Besides, with the small elbo finder available on the ETX, finding dim objects like the Ring Nebula and the Hercules Globular Cluster were very difficult. So the moon looked great, but the other targets didn't give the punch I was hoping for.

Rolling With The Punch

I was a bit down about the broken Quickfinder. I tried a repair, but it didn't work. I was about to order me another one (I love that finder), when I remembered that some time ago my older son had given my a couple of inexpensive rifle sights that projected a red dot onto the target. My son had nabbed a couple of the NcStar Tippmann Red Dot Reflex Sight devices for half price, and then decided he didn't need them. He thought I might have a use for them.

Red Dot Gun Sight

So I finally found where I'd cleverly stashed them. I noticed that they were very similar to the sight on my Celestron NexStar 5SE, except that the Celestron sight had an adjustable intensity control for the reticle. My inexpensive Red Dot finders didn't have that adjustment, but did have adjustments for azimuth and elevation.

I decided that for the price (free), it was worth a try to see if I could find a way to use the sights. I had two telescopes that were short a finder, and two Red Dot sights, how perfect could it be?

The Red Dot finders are designed to fit on a Weaver Rail. They have a slot on the bottom (see arrow) and clamps on either side of the slot that can grip the rail. I thought that it shouldn't be too hard to fabricate something that would mount to the scope and fit in the slot along the bottom of the Red Dot sight.

Gun Sight Mounting Block
What I came up with was the simple wood block shown at left. It was cut from a 2x4. It was cut to the length of the slot on the Red Dot, and has a tongue along the top just wide enough to find snugly into the slot on the bottom of the sight.

I cut it out with my table saw, but this piece is so simple one could do it with a hand saw and a little patience.

I used rough grit sandpaper to form a curve on the bottom of the wood piece that would let it sit properly on the telescope tube. That left only drilling a couple of holes in the tongue part to accomodate the Red Dot sight.

Fastening The Sight

Gun Sight On Block

The image at left shows how the sight sits down on the tongue along the top of the block.  All that was left was to mark and drill holes that would align with the sight holes, and fasten the sight on with screws.

I didn't even need to use the clamp pieces, since the tongue was cut to fit snugly into the sight base. A bit of black paint and a screw to mount the block to the telescope finished the project.

Gun Sight On Telescope
The finished product is shown at left. 

So how does it work? Better than I'd have thought. The projected dot is rather bright, and I can't actually see stars through the view window. But, using both eyes, one eye looks through the sight and sees the dot, and the other looks past the sight and sees the stars. So I see a dot imposed upon the background of stars. After picking a bright star and tweaking the alignment knobs, I was easily able to find all of the targets on our original observing list.

I read one online article that suggested one could put a drop of fingernail polish on the LED to dim it down a bit. I haven't tried that solution yet.

On the evening my son and I used the Newtonian, he got to see rather astounding views of the Pleiades, the double cluster, and the Andromeda galaxy. What a difference 4 inches of extra aperture makes.

What's left to do? Just mount the other Red Dot onto my planetary DOB using the same technique, and everything will be back in order. Perhaps Murphy will take the hint and go bother someone else for awhile.

Saturday, June 29, 2013

My Celestron NexStar 5SE Review

My Optical Arsenel
At left you see a composite image showing much of my collection of telescopes. Starting at top left, you see my 60mm Carton refractor, my ETX 90 RA, my  NexStar 5SE, my 6 inch Newtonian, and my Stargazer Steve Dobsonian. Not included are a couple of small refractors.

I show these because they are the telescopes the represent the greatest variety. The favorites of these at the moment are the 60mm refractor and the Newtonian. I have fun with the collection not only because of the range of sizes and portability they provide, but they are each quite different optically. One refractor, one Maksutov Cassegrain, one Schmidt Cassegrain, one Rich Field Newtonian, and one long focus Dobsonian. It is that diversity that gives me enjoyment, with each of the collection offering views with particular characteristics. And, I imagine you can see, none of the instruments are expensive to own.

I purchased the Celestron NexStar 5 SE Telescope  used from an astronomy egroup friend. It hasn't made it's way into "favorite" status yet, but it may well edge out one of the others in that category. Since getting it, I've been using the NexStar side by side with others of my arsenal to see how it measured up. I wanted to find out how good the optics were, and how convenient (or not) the mount was.

The NexStar is a computerized telescope. Once it's aligned, just use the controller to select an object to view. I'm still getting used to it. For years I used a calculator program to tell me where to point my non-computerized telescopes. Now, I use a cell phone and the Star Pointer web site utility. It provides handy computer assist to any telescope, altazimuth or equatorial, that has setting circles.

Optics-wise, with my early trials of the NexStar 5SE I was favorably impressed. While I'm not sure I'm a fan of the GOTO mount just yet, the optics of the telescope are excellent. On early observing trials, I was just using Polaris as an alignment star. Peeking into the eyepiece, I noticed a quite obvious companion of Polaris. The companion I spotted is within the range of a number of my telescopes, yet I'd never noticed it before. The NexStar virtually stabbed me in the eye with the companion.  I was impressed.

On that same evening, I had the opportunity to observe the Plato region of the moon, and it was fortuitously  illuminated for good detail. Again, the NexStar virtually poked me in the eye with the view of about 3 craterlets on the floor of Plato. I've hunted for Plato floor craterlets before with other telescopes, and usually came away without success. But there they were, clearly visible, their impact splashes easy to discern. I looked with my 6 inch f/5 Newtonian, and sure enough it also revealed the craterlets. But, they were not as obvious as when observed through the NexStar.

More recently I decided to do comparisons between each of the telescopes you see in the arsenal by looking at Saturn. I started out one evening by looking with my 6 inch Stargazer Steve DOB. It's especially designed, at f/10, to be a superior lunar and planetary telescope. It has a Pyrex mirror, an over sized tube to help ventilate, a small secondary to minimize diffraction, and a very steady mount.

It showed Saturn superbly. The Cassini division was easy, as was the lighter colored equatorial band around the planet. Also easily detected were 3 of Saturn's moons: Titan, Rhea, and Dione. Stargazer Steve's telescope delivers. The only issue with the telescope is that because of its size, it is a bit more clumsy to use, and it's ultimate capability is usually limited by the atmosphere. It's always a bit of a disappointment when I endure the longer setup time the telescope requires, only to see that on that evening a smaller, easier to set up telescope would have sufficed.

Next I tried the NexStar 5SE on Saturn. To my surprise, the image was nearly as good as the one produced by the planetary DOB. The view was just not quite as bright, with Rhea and Dione a tad more difficult to see. The only other difference is that the Stargazer Steve low center of gravity mount was steadier than the NexStar mount.  But those were about the only differences. Again I was impressed with the optical quality and contrast capability of the NexStar.

The next evening I paired up the NexStar 5SE with my 6 inch f/5 Newtonian. I'd recently bought a Celestron Collimation Eyepiece to more precisely align the optics of the short focus Newtonian. Once I used the collimation eyepiece, I released that probably about 75% of the time, I'd been using a marginally or poorly aligned telescope. With the collimation eyepiece, I knew that the alignment was spot on.

Looking through the Newtonian first, I saw a nice image of Saturn, with the Cassini Division and the same 3 moons easily visible. But when I looked through the NexStar  5SE, the image was even sharper. It was slightly outperforming the short focus 6 inch Newtonian. I was happy with the NexStar, but a bit disappointed that the Newtonian, even with meticulous collimation, had a slightly softer image. None-the-less, the rich field Newtonian still makes a super star telescope.

Saturn Through ETX 90
A few nights later I viewed Saturn with my trusty old ETX 90 (now superseded by the Meade 3514-04-15 ETX MAK 90-Millimeter Telescope), whose images always astound me. The view looked a bit better than the 2012 ETX 90 photo of Saturn shown at left. Other moon and planet photos taken with the remarkable ETX 90 are shown on my ETX 90 Astro-photo web page.

Except for the brighter image that the NexStar 5SE delivers because of its larger aperture, the ETX 90 view of Saturn was surprisingly close. The Cassini Division was easily visible, though not quite as stark as shown in the NexStar, and the same 3 moons were visible. However, seeing Rhea and Dione with the ETX 90 required some time and considerable use of averted vision. A pleasing view, however. Was the NexStar view better? On that evening, just a bit. On evenings with a more cooperative atmosphere, I think the NexStar's potential would be more noticeable.

And finally, I got an opportunity to check out Saturn with the modest sized 60mm refractor. Some of you who jumped into the hobby with larger telescopes than the Venerable 60mm probably think that comparing a 60mm view with the likes of the other telescopes in my collection would be pointless. I beg to differ.

I've looked at Saturn many times over the years, and for awhile I was using an early version 90mm Chinese made Meade refractor. Try as I might with that 90mm, I could never quite make out the Cassini Division. I understand the currently made Chinese refractors are much better, but my early version didn't deliver the quality of images I expected.

But on this Saturn trial, with the excellent Carton 60mm lens at the business end of my telescope, I was able to see the Cassini Division. I could also see the planetary equatorial band, though with less contrast than seen through the bigger telescopes. The view was very nice indeed. As to the moons, I was only able to see Titan for certain, thought it seemed that at times I'd glimpse either Rhea or Dione.

So, what did I learn? The main thing I learned was that the NexStar 5SE has the potential to become one of my workhorse telescopes. The optics are very good, and the computerized mount fairly easy to use, if just a bit shaky. I think the NexStar is a keeper, and hopefully some planetary photos through the NexStar will be forthcoming. For the first summer of use, I struggled a bit with a flaky power switch on the NexStar, but I found that Celestron has a market place for parts, and I was able to find the exact replacement circuit card with the power switch. Now with a new switch, the NexStar works flawlessly.

I also rediscovered what I already knew, that comparing views through different telescopes, especially different types of telescopes, is a real blast. In this little project, I was able to compare views of Saturn not only through some different sized telescopes, but different types as well. The long focus refractor, the Maksutov, the Schmidt Cassegrain, the short focus Newtonian, and the long focus Newtonian each provided a pleasurable viewing experience.

Finally, I learned that both the quality 60mm and the ETX 90, as others have said, run out of light before they run out of image quality. The NexStar 5 SE, like the two 6 inch reflectors, tends to run out of seeing before it runs out of light. But the ease of setting up the NexStar suggests that it's still a great candidate for a first choice grab. It's as easy to set up as any telescope I have, is as portable, and provides excellent performance.

What's left for me to evaluate is whether I can adjust to using the Celestron computerized mount. I'm so used to manually movable telescopes, both altazimuth and equatorial, that having to do all telescope movements through a keypad still seems awkward to me. Now a Celestron 5 inch SCT on an equatorial mount -- that would peak my interest.

Sunday, February 17, 2013

Hello Spring Moon

Lunar Stofler Region - ETX90 Photo
Well, the winter of 2013 is easing off, so I'm getting mentally prepared for another observing season. I know -- if I wasn't so frail of spirit, I'd have observed through the winter on nearly every possible occasion. But I just couldn't get worked up to brave the cold this year.

I'll start lightly, by observing one of my favorites, the moon. I love looking at the ever changing views of the craters, like those of this photo from my ETX 90 photos page. The lighting variations of the countless craters bring up fantastic details each time I look. But this year will be special, at least for me. We just lost one of my most admired space pioneers in 2012, that being Neil Armstrong, the first man to set foot on the moon. He along with Buzz Aldrin and Michael Collins were the courageous astronauts that rode Apollo 11 all the way to the moon, with Armstrong and Aldrin descending to the lunar surface.

If you're old enough, you likely remember where you were and what you were doing on that momentous occasion. I remember precisely what I was doing. I had just graduated college with my science degree, and was thinking what a lucky break it was that just as I was poised to begin my career, we were landing on the moon. I thought my science future looked exceedingly bright.  Ah, the lamenting of youth.

My parents only had the one TV, and it was black and white at that. But they knew how much the moon landing meant to me, having bought me telescopes and astronomy books since my grade school days. So they let me watch the entire landing broadcast. I was glued to the set, and took a few Polaroids of the TV screen as history unfolded.  I'll never forget it -- it was one of the biggest thrills of my life.

I don't think I'll be able to look at the moon again, now that we're moving past that exciting era, without thinking of Neil Armstrong and his crew.  Those memories will definitely heighten my excitement each time I take on the wonders of our nearest neighbor, whether it be with my modest 60mm telescopes, or my six inch reflectors.

If you haven't looked at the moon in awhile, I suggest you study up a bit on the Apollo 11 mission and the excitement it caused, then see if you aren't a bit more inspired to get out there and give your eyes the unparalleled treat of the moons mountain ranges, craters, mare, rilles, and shadows. You can start that study of Apollo 11 with the following excellent book:
Moonshot: The Flight of Apollo 11 (Richard Jackson Books (Atheneum Hardcover))