Telescope Buggy for a Dobsonian

As described in one of my earlier reviews, I recently purchased an Orion 12 inch XT dobsonian telescope. It did not take long for me to realize that moving such a large scope across my backyard, even just 15 feet, could be a real undertaking. Flipping through my issues of Sky and Telescope, a couple of options jumped out. These scope buggies (one of them is even called the Scope Buggy) have similar features: large tires, adjustable width, and a way to pull it. Unfortunately, I was looking for something a little cheaper and, being taller than average, I also wanted something to lift the telescope up about a foot. The commercial versions all rested low to the ground, to improve stability and prevent rocking. Most of the commercial versions ran between $250 and $300, but I had less than $100 available.

Living in an old house, I spend a lot of time at home repair stores. Browsing through the Garden section, I found a solution. Lowe's had a 24" x 48" garden buggy with 10 inch tires for about $90. Measuring the distance between the 3 feet of the dobsonian, I realized that the Scope would just fit on the buggy. Plus, this would raise the telescope to a comfortable position for me.

Now that I have had a couple of chances to test this out in observing sessions a couple of points become obvious:

n because the telescope is raised up about a foot off the ground, I placed a couple of cinder blocks on the front axle to add a little weight and stability.

n The Scope itself is placed on the very back, and when you position the Scope for observing, you point the front in the direction you are least likely observe. This allows you to stand beside the eyepiece in about 280° range.

n Pay careful attention when you lay the guide bar down. Speaking from experience, this thing can be a deathtrap in the dark!

Overall, this has been an awesome accessory for observing. Parked in a shed, the Scope is already mostly cool down, and I just wheel it out and check collimation, and I'm observing. Obviously this solution is good for dobsonian owners, but not tripod users. Also, if you are short one of the commercial options would probably be better suited for you. But for me, I keep the garden buggy.

Review: Orion 12 inch XT dobsonian

After deliberating for several weeks on a scope upgrade, I chose to get an Orion 12 inch XT dobsonian. I selected this scope for a number of reasons: it was the most Aperture I could afford for the money, dobsonian mounts are quick and easy to set up, and I had previously had very good experiences with this vendor (Orion has good customer service). Also, it was on sale because it was from an open box floor model. Ultimately, it seemed the best match of price, performance, and quality that fit within my needs. I ordered it through Astronomics, and, as always, they were very helpful with my questions and the package arrived quicker than expected.

My first thoughts (and I guess I'm not alone in this) was "Wow that's a big box!" But in fact it comes in three boxes: one containing the tube, one containing the primary mirror, and one containing the base assembly. They are bulky but well within ability of an average adult. I feared putting the mirror into the tube because let's face it, if there's one thing to not screw up, it is the mirror. However, this turned out to be much simpler than expected. The base assembly took about 20 or 30 minutes, but might take longer, since in my case, all of the holes were already established because it had been assembled as a floor model. Total assembly took about an hour, with quite a bit of that dedicated to mount the mirror and collimating.

I had been warned that this size solid tube dobsonian could be a lot to handle. It is. I found it difficult to gently place the tube in the cradle of the base, and the jarring certainly didn't help my mirror alignment. In general, I found it difficult to maintain proper mirror alignment which resulted in constant recollimation, but part of this is due to my continued problems with my secondary mirror alignment. The included laser collimator greatly helped with this problem, so even if it got knocked around only a couple of minutes were required to get things back in order. As for carrying it inside and out, I have found a better solution for that. (I'll post pictures and a short write up later).

My impressions for the remainder of this write up are based on two nights of observation. The first night conditions were windy and cold, with a first-quarter moon blowing out most of the sky. The second night both seeing and transparency improved, and moon had moved to third quarter, which gave me four good hours of dark skies.

Mechanically, this scope is a snap to move around. On the first night the bolt holding the base together gave too much resistance when turning the scope, but I loosened it before the second night so that it became much easier to turn. The supplied finder scope is a large right angle version, and while it is much easier to use of the original straight through finders, I did struggle to get used to it. The focusor clearly improved over the old model, and is far more pleasurable to use.

On the first night of observations, I stuck mostly to bright objects. My initial impression set around the number of stars visible. The 12 inch definitely seems to go deeper for those faint stars than in my old model, an original 8 inch XT. Even with the moon out, things looked good. Because the wind continued to pick up, I decided to check out the moon and then called it a night. A word of warning: a telescope this size will produce a painfully (painfully!) Bright image of the moon if set at a lower power without any kind of filter. With a 10 mm plossl, the number of small craters and craterlets really stood out as being significantly more than I had noticed in the past.

With weather conditions much better, and my transportation issue solved with the scope, the second night involved a four-hour observation session focused on hunting down some of the Messier objects I needed for the Astronomical League Messier Observing List. I cruised through Cassiopeia, Perseus, Orion, Taurus, Canis major, Gemini, Hydra, and Monoceros before the moon came up and cold (32°F) sent me packing. I used the two Sirius eyepieces that came with the scope, a 25 mm and a 10 mm plossl , as well as a 2 inch Q70 32 mm eyepiece, and a three element 1.25 inch Barlow. I'll write more on the Q70 another day, in short I ended up using a 25 mm and the Barlow almost exclusively.

My targets included a few nebula, but mostly open clusters. On M1, The Crab Nebula , the view surprised me. With smaller scopes I had had trouble locating this object, even though at magnitude 8.4 it should be visible. With the 12 inch, not only was it easy to find, but it appeared significantly brighter than I would have expected. It actually made me wonder if an optimal observation site with a good weather would allow me to use the scope to pick the Pulsar in its center (although I'm pretty sure that it is far dimmer than the limiting magnitude of this scope) still, that is how pleased I was. Jumping over to the Orion nebula , M. 42 and M. 43, dust lanes seem to flow against the bright background and filamentary detail filled the field of view. For the first time, each of the six stars of the Trapezium stood out, although the F Star winked in and out with the atmosphere. And my last target in Orion also surprised me. M. 78, a reflection nebula north of the Alnitak region, proved difficult for me to find with the scope' s finder, but once there, the offset nebula stood out well as a pair of two tenth magnitude stars stared back at me. Sue French' s book definitely helped find this one. Several open clusters followed, with M. 35 revealing over a hundred stars (estimated) and the intervening NGC 2158 standing out , despite the fact that I did I know to look for it.

Rolling the 12 inch back to its shed, I cannot help but be extremely pleased with the scope. I cannot imagine how I could do better than this for visual observation for $700 (remember, mine was discounted). Even at the regular price, I would still consider a 12 inch dobsonian a great bargain for anyone who focuses on visual observation of deep sky objects. But remember, this is a Large Scope! Hopefully I can have pictures of a poor man's scope buggy up soon.

Downloadable observation and sketch amateur astronomer log

I have put together a printable sheet to use as an observer's log. At the top, I have included the Seeing and Transparency Scales from the American Association of Amateur Astronomy. On the left-hand side, under the eyepiece column, just write the type and size of the eyepiece you are using. In the circles, use a pencil to sketch in what you see at the eyepiece. This can really help develop visual observer skills as well as increase your experience at the telescope. It can also be frustrating at first. I can only load images here, so I have saved it as one. Enjoy!

RIP: George MacDonald Fraser, 1925-2008

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2008/01/03/db0304.xml

Cheap Man's Observatory

While I live in a rural part of our county, and the skies are startling crisp at the Zenith, I am located near an intersection that features a safety light, store light, and neighbors on each side of my property. Up to this point, much of the glare from these sources has been avoided by setting the telescope up in the shadow of my storage building. But light is still slipping into some of my photos as a gradient and if I take one step the wrong direction I lose my dark adaptation. Since a permanent Observatory housing for my telescope is not feasible at the moment, I wanted to try a low cost solution to block out a lot of the stray light.

My plan is this: find something to act as 10 foot poles that would extend from each corner of my building. Between my building and these poles, I will hang tarpoleun to act as a temporary wall. This will hopefully block out extraneous light while having the advantage of being quick to assemble and disassemble as necessary.

Project Materials:

3 8x10 tarps (I could only find 10 mil thickness, colored gray on one side and Brown on another)

2 PVC 10 foot long pipes

2 cinder blocks

1 roll of duct tape

1 box of eye hooks

Project Materials Needed Later:

1 roll of twine

2 cans of matte black spray paint

4 camping tent stakes

First, I measured up the PVC 8 feet and screwed in two eye hooks at a 90 degree angle from each other. Next, on each corner of my building, I measured up the same height and screwed in an eye hook on each side. Now I can use the reinforced eye holes in each tarp to hang my temporary walls.

Now I only needed to secure the poles and I should be set. To do this, I liberally applied duct tape to the base of each pole and a cinder block. In hindsight, not the best idea I never had.

The PVC turned out to be too weak to really hold each tarp, so I had to break out the twine and tent stakes to string up some guide wires opposite the directions of tension created by each tarp.

This created my enclosure and after each session I could unhook the tarps and be done with it. Now to test it!

Once settled in after sundown, I noticed a significant reduction in glare. Two problems were obvious though. First, the caution light at the intersection was just high enough to slip over the edge and create some glare on the top foot off the glossy tarp. To fix this, I took some matte black spray paint and coated areas that were affected. Problem solved (mostly anyway). Second, because the tarp was not as thick as I would like, my neighbors safety light created a soft glow of against one side. Another application of spray paint should fix that!

In the end, I achieve the desired effect of greatly reducing the effect of my neighbors' lights. Is it the best solution? Definitely not. Is it much cheaper than a dedicated Observatory? Absolutely. Will my dog rip it down when my back is turned? Almost certainly.

Book Review: Digital SLR Astrophotography

Book review: Digital SLR Astrophotography
ISBN number: 9780521700818
Price: $45 US
Author: Michael A. Covington
Publisher: Cambridge University Press

Astrophotography has always involved a skill set requiring precision, patience, and a lot of trial and error. The learning curve has been steep, to say the least, but with the advent of Digital photography a larger and larger number of amateurs face this learning curve. Unfortunately, Digital photography also demands a different set of skills not documented before. With the exception of the few books that have tackled the subject in one way or another, amateur astronomy using DSLRs still lacks one good all-around, comprehensive introductory text for beginners. A few books have concentrated on the processing aspects of Digital imaging, and a few older books have updated sections on film photography with mention of Digital cameras, but Covington's work here is one of the first to approach DSLR astrophotography as its primary focus. Digital SLR Astrophotography does a good job of introducing the interested amateur to the subject while providing enough information to allow a beginner to advance in the hobby.

Astrophotography's 217 pages are divided into 14 chapters. In the first part of the book, Basics, Covington spends four chapters discussing DSLR options, technical issues unique to this format, problems associated with using electronic sensors in the cameras, and a few simple projects to introduce the reader to some immediate success using the camera. Throughout this section Covington mostly refers to Canon or Nikon cameras, which are the two main brands currently on the market, but he pays little attention to other options aside from a brief mention. His treatment of software is similar, however, he does mention freeware options which any beginner is well advised to try before investing in an expensive processing package. Most examples used in the book refer to Adobe Photoshop or MaxDSLR.

In part two, Cameras, lenses, and telescopes, Covington uses a chapters to explain how to couple the camera to the telescope and how different configurations how different effects on the final image, modifying the light path with focal reducers (Meade or Celestron), the pros and cons of using camera lenses piggybacking to a telescope, issues and solutions to focusing Digital cameras, the necessity of tracking the sky and how to go about it, keeping power to the camera and finally, different types of Digital sensors in the cameras and their response to various wavelengths with and without filters. Throughout this part of the book Covington references Meade and Celestron products but with one or two exceptions, ignores what has come to be the third major supplier of telescope products, Orion Telescopes. Covington does a good job of providing illustrations that clarify some of the technical issues he discusses in the text. These are generally excellent, and go a long way towards clarifying the various lenses and focusing options. Covington also does a good job for presenting the reader with the various choices and amateur astronomer has to make, including guiding options and focusing aides. Unfortunately, in the case of the latter, Covington mentions that it is easy to create a Hartmann mask but fails to deal instructions, instead referring the reader to his earlier book Astrophotography for the Amateur.

Part three, Digital image processing, covers a topic that can be most confusing to new astrophotographers. Covington explains the difference between dark, bias, and flat frames well but consistently uses MaxDSLR for his examples. This obviously works well for readers already using that particular software package, but may not be as clear for beginners using some of the free software packages. Nevertheless, this section is a real strength of the book, and will definitely aid the beginner in understanding some of the complexity involved in serious DSLR astrophotography.

An appendix of about 10 pages briefly mentions WebCams and their use for planetary photography. The inclusion of this seems odd, and out of place, as if, after having read the entire book, a beginner decides DSLR photography is not for them and perhaps they would be interested in WebCams instead.

Overall, Covington has done a good job of providing an introduction to the topic that also presents the reader with some of the options they can face in the hobby as well as potential solutions to problems that will inevitably occur. As a primer the book is first rate. Covington's strengths are evident in his handling of some of the more confusing topics; he explains them well. The diagrams provided are clear and informative. However, a serious drawback of the book is that photographs (all black-and-white} are often unhelpful and in some cases confusing. Perhaps due to the black-and-white nature, this can be annoying and for a book that cost $45 may leave the reader feeling less than inspired. For example, when discussing the pros and cons of modifying an DSLR to be more sensitive to hydrogen alpha emissions, side-by-side photos are given to display the difference. Now, Covington's point is to show how well an unmodified camera can do, so some similarity is expected, but I have yet to detect any difference between the two photos. Secondly, for a book whose purpose is astrophotography, it is criminally bereft of any striking photos that typically inspire beginners into the hobby in the first place. Covington would have been well served by including even a small section of color plates illustrating some of the superior photos being taken with relatively inexpensive equipment by amateurs using DSLRs. Still, Digital SLR Astrophotography fills a much needed role as an introductory text on the subject.