TRO Blog

A New “Thing…”

AAVSO Spectra database logo

Technology is a wonderful thing! It has provided the means for an amateur astronomer to do high level scientific research. Enthusiasts can do imaging from their backyards with a small telescope that only professionals could do with a large telescope just a few years ago. One of these amazing areas of science opened up by technology is spectroscopy.

At a conference in 2009 in Big Bear California I met Oliver Thizy from France. He was there promoting spectroscopy for small telescopes for his company Shelyak. (https://www.shelyak.com/?lang=en)  One of the products featured at that time was the “Star analyzer” a 100 line per mm blazed grating maximized for low resolution spectroscopy with amateur equipment. While there I bought the “introductory priced” Star Analyzer.

This opened a new world of observing and imaging. Though you can use the grating visually, it really works best when coupled with a camera. Though spectra are mostly portrayed in color, a mono camera is preferred for imaging, but not required. In fact you can use a web cam or video camera, color or mono, as well as more traditional types of astronomy cameras. The main difference is sensitivity, since mono cameras are approximately 3 times more sensitive than a color camera. Plus, when measuring the lines with software, color does not matter.

From Robins astro pages on spectroscopy. http://www.threehillsobservatory.co.uk/astro/spectroscopy.htm

http://www.threehillsobservatory.co.uk/astro/spectroscopy.htm

The above image and link shows the type of work that is possible using a simple grating, telescope and camera. The Three Hills Observatory site is filled with useful info and links. With a simple setup it is possible determine the spectral classification of a star as well as velocities and variability in many instances. The article linked below shows how the velocity of a quasar can be obtained using a small telescope with a grating! http://www.astrosurf.com/buil/us/quasar.htm

Here is a mono spectra of a quasar from the above link.

In recent months the American Association of Variable Star Observers has premiered a new spectroscopy data base. It is already features hundreds of spectra from a number of observers. This type of effort opens up new possibilities of research when combined with light curves from the same or similar type stars.

https://www.aavso.org/new-spectroscopic-database

A “must have” program is Tom Fields, RSpec.  The web link below is loaded with information about amateur spectroscopy as well as a download page where you can download RSpec and try it out for a month before you buy. RSpec is easy to use, low cost, has thorough documentation as well as tutorial videos, and is geared to the basic amateur astronomy user. In fact with a Star analyzer grating (which is available for purchase on the website) and a DSLR you can take useful images of star spectra.  Tom Field, the developer, is very accessible and accommodating. Often he is available for a live chat when you are on his website. Here is the link.

https://www.rspec-astro.com/

Using an 8″ Schimdt-Cassegrain LX200 telescope and a Meade DSI Pro mono camera I obtained the spectra of 13th magnitude stars.  Using the 8″ I reproduced the results of the article from Christian Buil’s website using  3C273 with a magnitude of 12.9. With this spectra and RSpec it was easy to measure the red shift and come up with a velocity very close to the professionally derived value. Unfortunately, that data (and much, much more) went bye-bye when a hard drive crashed or I would include it in this post. Still it goes to show the possibilities for the amateur astronomer.

Amateurs are just beginning to scratch the surface of this growing field of research. In the years to come as prices of components fall and usage begins to grow it will be interesting to see what kind of new ideas and discoveries will come to light.

The Strange Tale of Barnard’s Star…Update 2019

Since an earlier post astronomers have detected a star around Barnard’s star! Here is a link to the article. https://earthsky.org/space/astronomers-discover-cold-super-earth-in-second-closest-star-system-barnards-star

This has been a long time coming! Here is a link to my original post from last fall.

http://templeresearchobservatory.com/2018/06/the-strange-tale-of-barnards-star/(opens in a new tab)

It’s Been Awhile…

There are two givens in life…Death and taxes! Everything else is uncertain. One of the most uncertain segments of life is the weather. The summer in Lexington, Missouri is no exception. Because of clouds, fog or rain the observatory has not seen light for over a month. Plus my wife and I were out of town for a couple of weeks. I think Mid-July was the last time I opened up the observatory! Obviously there is little to report when the clouds are out!

Before this long hiatus I did some observations on a nova and sent them into the Center for Backyard astrophysics and the AAVSO. These are always fun since you know that your observation is helping to do science. While visiting Toronto Canada, I was able to visit with Dr. Brian McNamara and Dr. John Percy. McNamara is one of the world’s leading experts on black holes and Percy is a an expert on variable stars. These were very interesting conversations.

We are in the process of buying the house we have been renting and when(or if) that goes through I will begin working on upgrading the facilities for TRO. I would like to pour a concrete pad and add my 8″ LX200 to the other scopes. This one would primarily be for spectra and would sport an ST-7E Camera and Star analyzer grating. However, after buying the house it may be awhile before I can afford to upgrade the observatory. Meanwhile I will be waiting for a clear night!

The Joy of Doing Science!

Bright Dwarf Nova TCP J21040470+4631129 Maxim DL5 screenshot

It is a lot of fun to take images of the sky. Pictures that only professionals, with professional equipment, could take, are now possible for just about anyone with a telescope. People are using cell phones held up to simple mounted telescopes to image all sorts of objects. As much fun as this is, my passion goes a little deeper.

When I was about 8, I remember reading astronomy books and dreaming of owning a large telescope. The pictures in magazines beckoned me with a Siren’s call that was hard to resist.The Sears catalog would automatically open to the telescope page.  Of course not having any money of my own I could only dream. Until one Christmas when I was 9 and I got a Tasco, 50mm, spotting scope. To a 9 year old it didn’t get much better than this. The passion began.

Sometime around age 13 I decided to join the American Association of Variable Star Observers and be a citizen scientist. So like Leslie Peltier, I sent off for beginner charts hoping that my parents would fork over the money to actually join later on. Every day I waited for the mailman then would rush to the mailbox to look for my charts. Two long weeks after the initial letter was sent they arrived.

Looking at the charts was puzzling. Where was the star? There was only a cross in the middle of it. Being a kid I had no clue how to interpret the field of view, much less getting the right orientation in the eyepiece. After a couple of nights I gave up. At the time I never even thought about trying to find an astronomy club.

Fast forward a few years. With a wife and 4 kids it did not look like there would ever be a time when I could buy a telescope bigger than 60mm. Enter the low cost Coulter reflectors. Even though the Coulters were pretty cheap, I still couldn’t afford it! So I called up the Coulter factory and asked if they had any “second” optics. They did! So a mirror and diagonal was obtained to build an 8″ telescope. Amply titled the Bargain Bucket, it cost 25 dollars to build over and above the 50 dollars I paid for the optics. The focuser was a .965″ from an old Sears 60mm refractor that broke. The eyepieces were from the Sears scope as well. The best view I ever had of the Orion Nebula was on a -5 degree night using a cheap, poor quality, 4mm eyepiece!

This led to a desire to actually do science, like I wanted to do when I was a kid! In Sky and Telescope was an ad for ground observers for the Hubble Space Telescope. I contacted the organizer and volunteered my scope. I even tried to get time on larger telescopes but after broken telescopes, assistant observers leaving the observatory a month before the observation, rain delays and clouds I never got any observations done. So I joined the AAVSO to try and continue doing science. This time I had no problem finding the variables!  At last, citizen scientist!

It is very exciting to contribute to the knowledge base of astronomy. To realize that your work and studies will be used by amateur and professional alike to study stars is very rewarding. Technology has made the tools way more accessible and affordable. At present I have running almost every clear night an 11″, a 4″ refractor and am working on setting up an 8″ to do Spectroscopy. These telescopes use software to remotely control them from computers or even my cell phone!

Below is a Light Curve of a bright Dwarf Nova. This shows the fluctuations of light as well as a steady decline in Brightness. The last image is of the results of the worldwide effort to record this star!

Dwarf Nova TCP J21040470+4631129
A light curve from the AAVSO database showing 20,000 plus observations of TCP J21040470_4631129

The Triumph of Temple 28!

“Why in the world did you name a telescope after yourself?” I get that question a lot, either verbally or from the way that people look while I am talking! Well it is simple, a friend of mine named them for me. He called me one day and said “Temple 20 is finished, come up and have a look.” I responded “Temple 20? What is that?”  He just started using this designation so I stuck with it. Temple Research Observatory got it’s name because everything else I could think of was already being used!

Around 5 years ago Temple Research Observatory acquired Temple 28, an 11 inch Celestron CPC on a homemade wedge. So for the last 5 years there has been an epic struggle to get it up and running like it is supposed to run. There has been maladjusted gears, the telescope falling over and various other hardships. After trying for 4.5 years to follow the “conventional thinking” of how to set up a Celestron CPC the results forced a change to unconventional thinking.( Links to previous articles)

The balance point had been changed to accomodate a heavy camera before I got it. So instead of trying to achieve a neutral balance, like you normally do, I weighted the front. Added more weight to the West side, not the east! Added a lot of backlash in Declination…lots of backlash! Cranked up the amount of movement in each Declination pulse as well.  Stopped trying to get PHD to work and stayed with Maxim DL 5 to guide. Went with an external guider (Orion ST-80 telescope and ZWO 120 mm camera) instead of the internal guider. The internal worked but it had trouble finding guide stars especially when filters were used. No problem finding a guide star when you have an 80 mm short tube telescope as a guider! After getting the tracking and guiding fixed the image would migrate from the left to the right of the image over a night. So after several hours using PHD drift align it was Polar aligned.

All of this is counter to the “common” wisdom of setting up a telescope for imaging. The learning curve is already steep but when the solutions run counter to this wisdom then it really takes a long time to figure it out. Dean Koenig of Starizona really helped with balancing techniques and advice. My astro buddies from the west have always been very encouraging and patient as well!

M 27 with Temple 28

Above is an image that was taken 7-01/02-2019 at TRO. It features Temple 28 with the ST-8E camera, clear filter and control with CCDCommander. It is 50 images of 120 seconds each stacked and processed in Maxim DL 5. After 5 years of frustration it was all worth it!

There still needs to be better cable control, as well as new dew heaters made for the guider scope. Temple 28 is still very rough looking and though I don’t care as long as it works, it could use a bit of sprucing up. Overall, the results of the last few nights lead to “The Triumph of Temple 28!”

Temple 28

Where is the dark?

Snow Lake in the Gila Wilderness of New Mexico has one of the darkest skies in the region. Accessed primarily by a 4 wheel drive road, guarantees that this location will continue to be a quality site for years to come.

In amateur astronomy a lot of time and energy is spent “going to dark sites.” These are places with minimal light pollution and the quality of that experience often depends on where you live. Just observing from an unlighted golf course or park in a city can enhance the observing experience.

Temple 10 (AR102 refractor) and Temple 28 (11″ CPC SC) at TRO Lexington.

In my current location, smack dab in the middle of a small town in Missouri, the presence of a historic cemetery behind my backyard improves the seeing. Though the site does not compare with any of the former TRO observatory locations in New Mexico, it allows imaging of at least 17th magnitude stars with an 11″ telescope. Even with businesses on the highway in front of my house, it is dark enough to see the milky way from the observatory location. However, if you move towards the road, away from the cemetery, the milky way fades away until you can only see the brightest stars. So location is important even in your own backyard.

The North and South rims of the Grand Canyon have some of the darkest skies I have ever experienced. When you suddenly realize there are so many stars that you can no longer distinguish the individual constellations, that’s when you know it is dark. We get used to light polluted skies and limited seeing, so that when we get to a dark clear site it can be daunting to find your way around the sky!

This give you an idea of what to expect at the Grand Canyon Star Party!

The Tucson Amateur Astronomy Association has a Grand Canyon Star Party every year. It is definitely worth the trip. Even with some of the South rim light pollution,this area is still premiere for observing. The high altitude, low humidity and clear skies combine to give a great experience. The north rim of the canyon is 1000 feet higher and is even darker than the south but is harder to get to.

View from the lodge at the North Rim of the Grand Canyon.

My big issue was stamina. After all the hassle to get the time off, the trip up, as well as daylight sightseeing, fatigue was a real issue! At about 2:30 am I was falling asleep at the eyepiece and had to go to bed.

Snow Lake from Dipping Vat Campground.

Snow Lake in the Gila Wilderness area of South Central New Mexico had the darkest sky I ever experienced. I was able to go and spend a few days in September 2009. It is a small lake at 7,313 feet. My first night there featured thunderstorms in the first part of the evening. Around midnight the sky cleared and the stars came out. Wow, what an experience. I had brought “The Bargain Bucket,” an 8″ Dobsonian reflector. With no lights of any kind within 30 miles of that location and only small cities at 45 and 60 miles away there was virtually no light pollution to mar the skies. Seeing was pushing magnitude 6.5 and objects that I had never seen before in a telescope were easily viewed. To top it off, there was no one else at all in the campground, except a herd of over 150 Elk!

The POD, 8″ F/4 reflector and the author south of Deming, New Mexico.

The final location that I will highlight is 30 miles north of the Mexican border and a few miles south of Deming New Mexico. We moved out of Deming into the desert in 2011. Even when we lived in central Deming, I could see the dust lane in the milky way from my driveway! After the move, a friend gave me a POD (Personal Observatory Dome) that was set up in the backyard. It was not unusual to image 18th magnitude stars with an 8″ telescope. With over 300 days of clear night sky each year, this is a hard location to beat.

Wherever you can get a view of the sky is a win for astronomy. If you can escape your light pollution from time to time or even better, move somewhere dark, it is ideal. Still, there is a lot that can be seen even in the midst of the most light polluted city. Take of advantage of where you are to observe what you can and find the the dark wherever you can!

Prepping a Celestron CPC 1100 for Imaging: A Lesson in Troubleshooting! Part 2

The 11″ CPC with the ST-80 guide-scope mounted.

A year or so ago in Astronomy Technology, I wrote an article about my 4 year struggle to get my 11″ Celestron CPC up and running. When the article was written everything seemed to be in order. I used several images from recent runs but still had a lot of reject images during these runs due to bad tracking. However, the final images came out ok  so I didn’t worry about it. I had not gone back and looked at the number of rejected images due to smeared stars. One of the curses of being busy!

The telescope was running remotely as I finished the article for the magazine on my office computer. In the morning, the images were uploaded with Teamviewer 13. With a cursory glance using the “large icons”settings in windows, everything seemed to look good from that run. Problem finally solved, article finished and sent off.

A month later I got around to analyzing that last set of images. What a disaster. With the large icons setting, they looked good, but when they were examined at full resolution, not so much. Out of around 100 images only 30 or so were usable to stack. This was worse than before the backlash and balance were adjusted!

Here is the link to the original article and one other blogpost on the subject!

http://templeresearchobservatory.com/wp-content/uploads/2018/10/Prepping-a-CPC-1100.pdf

3 Steps back 2 steps forward!

It was too late to retract the article and rewrite it so it went to print!  After 4+ years this scope still didn’t work right! So out of frustration I took off the SBIG ST-8E camera and moved it to the AR102 refractor mounted on the Sirius mount. This yields a large field of view and does a good job of photometry. Being ready to take a sledgehammer to the CPC,  I decided to give it a few months before I even thought about trying to fix it again. The link to 3 Steps Back 2 Steps Forward gives more details of some of these post break tests.

The “Great Nebula” in Orion. ST-8E and AR 102.

After a few months, the temperature finally went above freezing one day so the ST-7E went on the 11″ CPC until I could figure out why the telescope wouldn’t work right. The ST-7 camera is identical in weight to the ST-8 and would be a good substitute. Of course I couldn’t find the filter wheel for the CFW-8 so it wasn’t exactly the same weight. I did find the filter wheel…it was in the ST-7 case so I wouldn’t lose it. Then the wait on weather and schedule began!

Of course the weather has been just awful. Wettest year in 30 + years. Clouds, rain, fog, snow, hail, freezing rain and sleet, all since the article was written. On most clear nights I just ran the AR102 instead of the 11″ CPC. You just don’t waste clear nights on experimentation if you can help it in the midwest. The AR102 ran flawlessly, soothing my bruised ego a bit!

The first issue I ran into when trying to troubleshoot the CPC was that the ST-7E kept icing up! So I looked at the plug and realized that it was also a dummy plug! Somewhere I have 2 usable desiccant plugs but I can’t find them. Probably the same place as the filter wheel! So I took the dummy plug and drilled a hole in the aluminium stopper placed in the plug. I had an idea of putting in a small desiccant pack instead of the set up the current camera uses. When I turned it upside down, desiccant fell out! Apparently, these non-functioning plugs are non-functioning because they solder in an aluminium stopper, leaving desiccant inside. Seriously? That’s just crazy. To buy a desiccant plug today it will cost you 160 dollars from Diffraction Limited or 70 dollars for the Farpoint version of the plug. After some work I popped out the aluminium plug, pried off the cap, cut a small piece of fine metal mesh to hold the desiccant in, filled the cavity with desiccant material, then put the cap back on with some super glue. Took about 30 minutes. After a short time in the oven, problem solved!

The tracking issue had still not been solved. Went back and read every article I could find on adjusting a CPC. Called Dean Konig at Starizona. Even after following his sagely advice (one of the most knowledgeable about telescopes and imaging I have met!) the telescope was tracking worse than ever. Good grief what else could I do? Several times I went to Astromart contemplating selling this turkey.

So on a night of very marginal conditions I tried out some things. Remember, when you get so few good nights you don’t want to waste them with experiments! First I put my Orion ST-80 on the CPC to use as a guider scope. I moved the ZWO 120 MM camera to the ST-80 for better guiding and a wider field than the Meade DSI Pro I had used in the past. This helped a lot to steady out the tracking but it still didn’t really solve the problem.

Finally, a clear, (kind of) warm day, dawned. The cover was removed on the telescope and work begun. My first task was to replace the ST-7E with the ST-8E then make sure the wiring was routed correctly. Even though there is one stripped set screw this was accomplished easily.

All of the articles and advice had stated that you need to adjust out the backlash as much as possible and make sure the scope is perfectly balanced. After some thought I rebalanced the scope to a slightly nose heavy  configuration. Early in working on tracking, I had tried a tail heavy configuration, which is easy since the camera weighs so much. This really made it unstable in DEC. So for this try, a weight was added up front to make it slightly nose heavy instead.

On both RA and DEC I went back and adjusted the gears until there was at least 2-3 mm of slop when you moved the motor assembly. Totally counter intuitive! When the skies cleared enough to try out all of these changes I was shocked! The tracking errors were all below .70 of a pixel. This was on a hazy night where clouds kept cutting off the guide star.

A couple of weeks later (first almost clear night) I was able to get good tracking (below .40 of a pixel) for a half hour and a number of images. The weather went south after just a few promising minutes and ended the session. Still the results looked good. Unfortunately I had been here before only to be disappointed on the next run.

Another couple of days went by, the weather cleared and I was ready to try again. After a full night of imaging M 87, 125 images in all, only a couple were ruined by poor tracking.  These were due to high clouds blurring the guide star early in the morning (the dreaded “guidestar faded” in Maxim) thus throwing off the tracking. Still, even with this handicap, those images would have been usable for photometry.

M 87 with the 11″ CPC, ST-8E camera, 125 images in Sloan infrared Z.

M 87 cropped and enlarged showing the jet shooting out of the side. The jet is coming out of the black hole that was recently imaged by the Whole Earth Telescope!

The above images do not show up very well in this web format but there are numerous galaxies in the full resolution image. Even in the full sized image the jet can be seen. With this success the future for “Temple 28″(11” CPC) looks a little brighter!

Why was this telescope so hard to adjust? I think it was because a friend had “refurbished” the scope into a professional level instrument. This entailed moving the balance point and making a carbon fiber tube. The counterintuitive settings are probably due to this change in configuration. The second factor is a constant lack of time. It seems that I have very small windows to do my hobby and this leads to trying “shortcuts.” The mantra of firemen is “to do something fast you need to slow down!”Only time will tell if the problems are truly fixed and Temple 28  is ready to go to work! After 5 years that would be a welcome outcome!

The Tight Gear Caper

Never trust the internet! Virtually every site that I researched said “tighten your worm gear up until the motor strains and then back it off slightly.” Sounds like a great way to eliminate or reduce backlash doesn’t it? Well on my scope that advice doesn’t work!

After writing the article on preparing a CPC 1100 for imaging, (see an earlier post), I decided the telescope was still not tracking as good as it could. So I took off the gear covers and had another go at eliminating the backlash in the dec gears.  After 2 adjustments using the rule of thumb listed above it would no longer move much in DEC when tracking. Not much of an improvement. So I moved the ST-8E camera to the AR102 refractor on the Sirius mount and ran with it on clear nights. Now that was only a few nights! The weather has been atrocious this winter.

With a few clear nights in a row coming up it seemed prudent to work on the 11″ CPC again. The first task was to see if I could get it to move correctly in DEC while tracking.  RA was spot on, but DEC was way off. In fact it seemed the gears would not move at all mimicking severe backlash. After trying Maxim DL tracking then PHD with an external guider it just wasn’t working. So I pulled the cover off the fork arm and did something counterintuitive. Loosened up the gears until there was significant play in the system. Tried using PHD and it worked!

I used the PHD Polar Drift Align to get the alignment close. I have found that the built in Celestron routine seldom gets the PA closer than a degree or two. Though it was still off it was a lot closer. Last night I used the drift align feature in PHD to tweak both axis. Now it is as close as you can probably get.

There was still significant errors in guiding and about 50% of the images were trailed. There is also a movement after 100 images off the right side of the image. My guess is flexure from the external guider. The guider started off exactly lined up with the images on the chip. After an hour or so it was completely off. Smells like flexure to me!  Using an external guider makes finding mechanical issues way easier. So tonight I will switch to the internal guider chip and see if that will make a difference in the quality of the images. The big negative about using the internal guider is the small field of view that makes it hard to find a suitable guide star. The positive is the lack of flexure.

The next step after testing is to put the ST-8 back on then shoot an actual T-Point model. It would be nice to be able to get back to doing my Central Stars project and do regular stars with the AR102. The field of view is too large on this short focal length scope to be able to measure the Central Stars of Planetary Nebula accurately but it is great for doing regular variable stars.

M 53 using an uncooled ST-7E, no filters and using PHD to guide. It uses 79 images stacked in Maxim and lightly processed.

The second image is M 95, 114 by 60 seconds also stacked in Maxim and lightly processed.

 

 

 

 

 

 

Endless Winter!

Endless Winter!

There has not been weather like this in Missouri for at least 5+ years! According to weather records it was 2011 the last time we had any weather like this. Actually it seems that the 90’s were probably the last time we really had this type of weather pattern. School canceled, churches and businesses closed, these are the norm for this winter. In 2018 we barely even had snow at all!

One of the first things I noted upon moving from New Mexico to Missouri was the lack of clear skies! In New Mexico opening up the telescope every night for 2 straight weeks was not unusual. Opening up 2 nights in a row is very unusual here in Missouri. You make an adjustment on the telescope and it may be 2 weeks later before you get to try it out!

Since October there have only been a handful of clear nights and many of those those saw significant cloud cover by night’s end. The pattern has been ice and snow on Wednesday night with ice and snow on Sunday as well. One storm rolls out and a few hours later another storm moves in, with lots of high clouds in the hours between.

To add to the issue is the effect of all of this weather. My 2 telescopes are covered by heavy, weather resistant, tarps. Surprisingly enough, they work well. However, I had to cut short the last actual telescope session. It turns out the wind on the tarp loosened a knob and knocked the scope out of polar alignment. We did have a clear night at 7 degrees with a 25 mph wind but opening the telescope and polar aligning was not high on my list!

I also found that my cables get too stiff and hinder tracking when the temperature goes below 10 degrees. My current cameras are parallel port CCDs that use a heavy, stiff cable. This is enough to hinder tracking especially when the wind blows. In fact when my german equatorial mount would track, the power cable got so stiff that it would unplug itself. Obviously this required much more thought in routeing the cabling! None of this includes the ground heave during cold weather knocks the scopes out of alignment!

If these cold weather issues had ever confronted me before it would be easier to deal with them. A heat tape wrapped around the parallel cable is on the summer agenda of telescopic fix ups. Redoing the tripod foundations to minimize ground heave will also be a warm weather project. Hopefully getting some more clear skies will also be helpful!

3 Steps back 2 steps forward!

Have you ever worked on a problem and gone backwards? You have an Ah-Ha moment where you know that you have the problem solved and then when you implement the solution it’s worse than it was before? Well that has been my experience with Temple 28, The Celestron 11″ CPC.

In earlier articles you find out about the struggles with a welded, non-adjustable wedge, loose gears and balance issues. Each solution should have led to a better working telescope but it didn’t. In fact Right before Christmas 2018, I just gave up in frustration on this scope, set up my AR102 refractor on the Sirius mount and began using it. Temple 10, the AR102 and Sirius combination, works really well! Since then I have obtained data on 2 close binary stars that no one has recorded since the original survey was done. At least I feel like I have accomplished something.

After much thought and research we finally had a day above freezing so I went out and began to work on Temple 28 again. Looking at online images, I noticed that all the images of the worm gear assembly differed from mine. There is a backlash adjustment screw with a spring on it that is easily observable in the online images. In everyone else’s pictures the spring was at least 1/4 of the way up the shaft, with several being compressed to 1/2. The springs on Temple 28 were fully extended and rested against the spring stop.

So I pulled off the RA cover and began to adjust the spring. It is pretty easy to adjust the spring if you remove the 2 small screws that hold the flexible coupling to the worm gear and swing the motor out of the way. However, I did not want to introduce that level of change. When problem solving, it is often best to only change one thing at a time. So adjusting just the spring was the best way to proceed at this point.

After adjusting the spring about 1/4 of the way up the adjustment screw I loosened the screw slightly. This is to make sure that the worm does not bind on the gear. After testing the motor I then did the same thing to the Dec axis. This was more of a challenge since it is in an awkward place to adjust.

Temple 28 in all of it’s duct taped glory! Wiring has been rerouted and the guide scope removed since this image was taken last summer.

After removing the the SBIG ST-8E, then putting it onto Temple 10, I needed a heavy camera to counterbalance Temple 28. I dug out my old SBIG ST-7E. This camera is an exact duplicate to the ST-8E but with a smaller chip. The ST-7E also does not have the SBIG CFW-8 filter wheel installed…since I can’t find the actual filter wheel for it!

A rear view of Temple 28 showing the extended weight that is a necessity if you want to balance this beat!

Balance…always an interesting experience, in life and on a scope! When Temple 28 was first re-worked the tube balance point was moved to allow a heavy SBIG camera to be used. This means that what other people do on their CPC’s is not workable on Temple 28! Eventually, after much work I put two flat weights on the nose of the scope, the bottom 2.5 pound weight half way down the tube and strapped it all on tightly with hose clamps. Hose Clamps? Well they are cheaper and work just as well as 80-200 dollar rings or balance bars!

Well, the proof of the pudding is in the eating! So how did this newly adjusted system work out? Better, but not great! There was star trailing on about half of the images. For the type of photometry that I do it would probably still work in most instances but it is annoying none the less. In all fairness, when using the internal guiding chip, any fog, high cirrus clouds, corrector dew or frosting easily throws off the tracking. The conditions for this latest test were bad! High clouds, heavy dew on the corrector and forming fog in the sky. The a dew heater on the scope actually works fairly well. The presence of dew anyway says a lot about bad atmospheric conditions. So this test needs to be repeated when the conditions are better! In Missouri however, especially this year, any clear night, needs to be utilized regardless of conditions.

M 42 with Temple 28. SBIG ST-7E, no filters, 47 images of 60 seconds exposure. Around half of the images were rejected for stacking due to trailing stars. Still it is better than not imaging at all! The big spikes are blooming. This camera has no anti-blooming. You don’t want anti-blooming for photometry.

So what is the next step? Well the first thing is to find the filter wheel! I put it in a box during our move to Missouri where I could find it and haven’t located it since! This would bring the weight of the camera to match the ST-8E and facilitate an easy camera swap. It also makes doing photometry practical since the results are better if you use the right filters.

Screen shot of Maxim DL5 showing all the rejections due to star trailing.

Second, is to take the RA worm assembly completely off, clean and polish the worm and gears, then re-adjust the whole thing. You can do small adjustments with the backlash adjustment screw but the large adjustments are made by moving the entire assembly, then tightening down 2 screws. When you read the posts about this whole saga, it becomes apparent that this should have been done on day 1! Quoting from the movie contact ” This is the way it’s been done for billions of years. Small moves, Ellie. Small moves.”