Telescope Reviews: Thinking of Buying a C6-RGT As Your First Scope?

Thinking of Buying a Celestron C6-RGT As Your First Scope?

Before you purchase:

The scope is an excellent performer for the price and I am very happy with the purchase. But before you buy, there are several things you should be aware of:

1. Viewing positions in a large refractor are often very uncomfortable. Many interesting objects are directly overhead – given the low eyepiece position, viewing them requires laying on the ground – particularly unpleasant in the winter.
2. The scope is large and heavy though none of the pieces is unmanageable by itself. The mount and tripod (without weights) weighs about 35# and is easily moved with the legs at their shortest position. The OTA, although long, only weighs about 20# (25# after modifications) and is easily carried by the dovetail. Assembly requires 4-5 trips outdoors – tripod and mount, then balance weights, then OTA, then power unit and accessories and finally a viewing chair.
3. Slewing to position is noisy – equivalent to a power drill on medium speed. The noise is enough that I fear it is bothering the neighbors when I am out late at night. Fortunately, the motors are whisper quite during tracking.
4. Save at least 50% of your budget for accessories. The scope is only the beginning of the purchase – by the time you pick up the items you need to make viewing a pleasant and interesting experience, you will spend at least another 50% of the original purchase price in add-ons.

You will probably read books and articles suggesting a DOB for a first scope. Although I ignored the advice, in retrospect the suggestions were valid. I believe an 8” DOB is the best scope for someone just starting out. The scopes are very good performers at a reasonable price. Setup is simple, they are easy to transport to a dark-sky site, viewing positions are much more comfortable and the user can quickly move the scope to look at any object in the sky. The Skyquest XT8 Intelliquest from Orion is an excellent buy at $497.

You may find the DOB meets your needs for many years. If not, they are easy to sell or can be passed down to a younger family member. You can always pick up the large refractor at a later date if your interest in the hobby holds. And if you purchase your accessories wisely, they can move with you when and if you upgrade scopes.

When To Buy:
Depending on your location, winter can be a difficult time of year to get your first scope. Winter skies do have a number of wondrous sights, and seeing conditions can be quite good on clear, cold nights but freezing cold weather, dew, rain, fog and cloudy skies can quickly frustrate a novice astronomer. Learning to use your equipment correctly, and learning the layout of the skies, requires time and patience. Warm spring and summer nights make the experience much more relaxed and comfortable while you are learning.

Purchase and Shipping:
There are a number of excellent on-line vendors. I purchased my scope from Anacortes Bird and Telescope. The purchase experience was perfect. They stayed in touch by email during the transaction and advised me when the unit shipped - including links with the tracking numbers for all boxes. The scope was shipped in 3 boxes – 2 of which arrived on one truck (the tripod and mount) and a third 5 hours later on a second truck (the OTA).

The pieces were well packed and suffered no damage in shipment. The packing attention paid off because 2 of the 3 boxes suffered significant compression damage at the hands of the shipper but the scope was unscathed.

Assembly:
Assembly is fairly straight-forward. Read the manual carefully before starting. The instructions are adequate although the assembly drawings don’t supply as much small detail as I would have liked. A couple of things to note.

1. Tripod Alignment Bolt
The tripod ships with the alignment bolt between the legs. Some people feel this can lead to instability when the weights are installed and prefer that the weights be over a tripod leg. There are several threads on the internet discussing the pros and cons of each position. If you wish to move the bolt, it simply unscrews and can be easily screwed into the alternate position over a leg. I elected to move the bolt and find the mount to be very stable in that configuration.

2. Mounting Bracket
The instructions tell you to locate the small scope mount bracket which will be used to install the scope to the mount. You can ignore these instructions. The scope comes with a dovetail attached to the rings and the dovetail is inserted directly in the mount. The spare mounting bracket can be used if the mount is used with another scope.

3. Mounting Platform Safety Screw
Several people have suggested that the DEC index marks are 180 degrees off since the mounting platform safety screw points down rather than up. In my case, I elected to use the factory marks – the safety screw will still function as intended and keep the dovetail pressed into the mount should the main tension knob fail. If a failure occurred and the dovetail were to slowly slide in the mount, I believe the safety screw and dovetail retaining bolt would ensure that the dovetail could not slip completely free of the retaining bracket.

Accessories:
If you decide to order the scope, following are suggestions for several accessories that I found will improve the scope’s overall performance. The majority of accessories are under $100 and many are under $50. Don’t feel you have to add them all at once. Astronomy is a very enjoyable hobby that will likely keep you interested for the rest of your life. Add a few accessories each year as your budget allows.

1. Red Light (~$25)
If you don’t already have a red flashlight, protect your night vision and get one. The Rigel Systems Skylight is an excellent unit with 2 red and 2 white LEDs. The unit is well-made, reliable, very skimpy on battery use and brightness is continuously variable with a large control-wheel.

2. Planisphere (~$10)
The alignment process is highly dependent on accurately centering the scope on 3 selected stars. The large version of “The Night Sky” by Chandler is easy to read and plastic coated for protection against dew. Be sure to select the version designed for your latitude range.

3. Celestron Powertank (~$60)
The scope comes with a long power cord with an auto lighter adapter. You need a 12v power source to plug the adapter into in order to run the scope’s motors and electronics. I purchased the Celestron 7ah Powertank - fully charged, it will handle the scope’s power needs for 4 hours or more. Celestron also makes a larger 17ah unit that is useful if you intend to also run a dew heater. One note – the power cord shipped with the scope has a quick-blow fuse in tip of the auto adapter. If your scope won’t function, replace the fuse (Radio Shack carries them – part #270-1054 3A-250v-5mm x 20mm-Fast Acting) or try the shorter power cord that comes with the Powertank (some people feel the scope also operates more reliably with the shorter cord).

4. Right-Angle Mirror Diagonal (~$130)
With the exception of viewing objects near the horizon, don’t try to view without using a 90 degree diagonal. The diagonal that ships with the scope is adequate for the first few weeks but a good diagonal will enhance the quality of the scope’s performance. I elected to purchase the William Optics New Generation 90 degree diagonal. The product is very well made, includes a 2” to 1.5” adapter and adds needed weight to the rear of the scope to aid in balancing. Additionally, the unit uses a brass retaining ring to securely hold lenses in place.

Note: The diagonal is fairly heavy – I don’t recommend replacing the stock diagonal until after the visual back is replaced.

5. Right-Angle Finder (~$80)
Just as a right-angle finder is a necessity for the scope, it is also mandatory for the finder. The Celestron 9x50 finder works quite well but is inaccessible at many viewing angles. Save your back and get the Orion 90 degree RACI (right-angle correct image) finder. It is well made, offers the same power as the Celestron unit, is a perfect color-match and the included bracket fits the same dovetail as the stock finder.

6. Focus Knobs (~$30)
The focus knobs that come with the scope are completely inadequate and give the scope a cheap feel. I ordered the 2” brass focus knobs from focusknobs.com. The knobs are very, very well machined. They fit perfectly, look beautiful and give the focuser a much more professional look. In addition, the larger, heavier knobs give a much better feel to the sticky focuser mechanism and help shift the balance point lower.

7. Visual Back (~$35)
The 2” visual back that ships with the scope has an inexpensive feel and uses a single retaining screw to hold the diagonal. Mercury Systems supplies a well-machined replacement that uses a brass retaining ring to hold the diagonal securely. The unit installs easily by simply unscrewing the old back and screwing on the new one. Check mercurysupportsystems.com and look for part #SFA2. Highly recommended.

8. Fringe-Killer (~$70)
The scope is not an APO and will have some degree of chromatic aberration (CA) on bright objects. Fortunately, several manufacturers make inexpensive filters which can minimize the affects. I elected to purchase the Baader Fringe Killer. The filter removes 60-70% of the CA while maintaining a natural color rendition. You will only use the filter on a few bright objects such as Mercury, Saturn and the moon. On deep-sky objects, the scope’s performance is excellent without a filter installed. For those of you that can adjust to an overall color-shift in the image, the Celestron (Baader) Contrast Booster will completely eliminate CA at the expense of a noticeable shift to a yellow-brown image. Personally, I found the Fringe Killer a more acceptable compromise between CA and natural coloration. The Baader Moon and Sky filter, used in combination with the Fringe Killer, seems to enhance the image further.

9. Polarizing Filter (~$25)
Orion makes a very nice 2 part rotating polarizing filter. The filter is particularly useful on the moon. The moon is very bright when viewed through an EP and will quickly erase your night vision. The polarizing filter will allow you to dial the brightness to a comfortable level while leaving the color neutral. In addition, the filter will dramatically reduce the CA.

10. Eyepieces (~$180)
The 20mm Plossl that comes with the C6R is an adequate performer but additional EPs will be needed to take full advantage of the scope. EP selection is highly personal but, in general, it is best to buy quality EPs as you will likely keep them for many years. Start with a high-power EP for planetary work and a low-power objective for wide angle views.

For wide-sky viewing, I selected the 30mm Celestron Ultima. Be sure to get the latest model that has the machined retaining groove. The EP is of very high quality and offers beautiful views of objects such as the Pleiades.

For planetary work, I ordered a 9mm HD Ortho from University Optics. Again, a well-made high-power EP that offers sharp contrasty views of the moon and planets. I have since added a 7mm HD Ortho, a 12mm HD Ortho and an 18mm Ultima. The 18mm is now my favorite EP.

Televue Naglers and Panoptics offer superb wide-field performance and are well worth consideration if your budget allows. Televue Plossls are also high quality EPs offered at a very reasonable price.

11. Barlow (~$105)
A good Barlow lens will double number of magnifications you will have access to. Don’t skimp – the Barlow will be used to increase magnification near the limits of seeing and optics. You don’t want to introduce any distortions at high magnifications when you are looking for contrast and detail. Celestron makes a highly rated Ultima 2x Barlow that works quite well (in contrast to the low quality Barlow that ships with the scope). I elected to spend a little more to get a Televue 2x Barlow – superb optics and it uses a brass retaining ring to hold the lens in place – rather than a retaining screw which will scratch the lens barrel.

12. Chair (~$160)
Although the purchase of a chair threw me well over my intended budget, it quickly became a mandatory purchase. Using a large refractor, you will find yourself in a variety of uncomfortable viewing positions. A good quality, adjustable chair makes all the difference between taking a quick look and spending 30-60 minutes watching shadows along the terminator on the moon. Starbound makes an excellent chair that is lightweight, strong and easily adjustable.

13. Telrad (~$40)
The Telrad is a strange looking box that makes finding objects a breeze. The Telrad will get you in the general area, then the finder can be used to center on the object. Get one – after a few days, you’ll find it an invaluable addition.

14. Dew Shield (~$45)
Many users have elected to remove the stock dew shield and replace it with a lighter foam shield made by AstroZap. Again, this is one of many incremental changes owners make to reduce weight on the forward-end of the scope to aid in balancing. For time being, I decided to stick with the stock shield. Although a bit heavier than the AstroZap product, the steel tube provides protection to the large lens element.

15. Polar Scope (~$50)
A polar scope is not necessary to obtain an alignment adequate for visual use but is a nice addition to the mount. If you do decide to buy a polar scope, skip the Celestron scope and buy the Orion model designed for the Skyview Pro. Simply remove the entire polar scope mounting ring from the AS-GT and the Orion scope screws directly into the same hole. The Orion scope is etched with Casseopia and the Little Dipper for precise alignment on the North Celestial Pole.

Note – the Orion scope comes with a plain aluminum ring around the polar scope. If you like the current numbered Celestron ring (I did – it looks more scientific), the rings can be easily switched by removing 2 very tiny screws and unscrewing the front retaining ring from both the polar scope and Celestron polar mount.

16. Sky Atlas (~$65)
The sky is a target rich environment a good sky atlas is critical if you are going to locate DSOs. The Sky Atlas 2000 by Wil Tirion is one of the best (this is a different book than the Cambridge Star Atlas by the same author). The book comes in 6 versions – white stars on black, black stars on white, black stars on white with color and then laminated versions of each. Personally, I like the Sky Atlas 2000 2nd Edition Desk Laminated version which shows black stars on a white background. Although the color version is nice, the cost is over $120 laminated and some of the objects can be difficult to see at night under a red light. The laminated versions cost a bit more but will protect your investment when the book is outside on dew filled evenings. Additionally, you can make notes on the laminate and wipe them off when you move on to a different section of the sky.

Viewing Height:
My only serious frustration with the stock scope has been the low eyepiece location when viewing objects high in the sky. Although the brass knobs and WO diagonal helped add weight to the rear of the scope, the ultimate solution was to add a 3rd mounting ring close to the eyepiece and bridge the 2nd and 3rd rings with a heavy steel plate. The plate makes a perfect home for the Telrad.

AllMetalsInc (http://www.allmetalsinc.com/crflat0375.html) sells small steel plates (~$3-4 ea) in a variety of sizes that can be painted to match the scope. The addition of a 3/8” x 2-1/2” x 8” CR plate with ring, bolts and Telrad added another 2-1/2 lbs to the rear of the scope and allowed me raise the scope several critical inches.

Note: If you do make modifications to the OTA, keep an eye on the total weight. With all the changes to date, the OTA/finder/diagonal/Telrad/eyepiece combination now weighs 25.8 pounds. This is well below the 30 pound mount capacity and allows for the use of a heavier eyepiece such as a Nagel or a mid-range camera for astrophotography.

Alignment:
Warning: The scope’s computer is not very smart and it will select slews that force the OTA into the tripod legs. Should the scope impact the tripod, you could cause significant damage to the drives. You can press any of the directional arrows to immediately stop the slew. Be cautioned when pressing “undo” to skip a star during alignment - if you are near a leg, the scope may abruptly change direction and impact a leg before you can react. I’ve found it preferable to use the arrows to slew well away from the legs before selecting the next alignment star.

I found the alignment process initially frustrating because the accuracy of the GoTos varied from night to night. Assuming it was primarily my fault, I took the following steps and find that the process has become much more reliable.

1. Level the tripod - CAREFULLY
If the tripod isn’t level, the mount has no way of making an accurate determination of position as it skews. The bubble balance in the tripod may not be accurate. Check it at least once with an external level.

2. Locate Polaris in the polar scope
If you don’t have a polar scope, carefully center Polaris in the polar scope mounting hole.

3. Align the RA index stickers and lock the clutch.

4. Loosen the DEC clutch and center Polaris in a 20mm eyepiece. Lock the DEC clutch. Ignore the DEC alignment stickers.

5. Before starting the mount alignment procedure, be sure that the Telrad and finder scope are aligned with the OTA.

6. Enter the correct time, date, time zone, daylight savings setting, longitude and latitude for your viewing site. Be as exact as possible. You can find the time and lat/long settings for your address at various sites on the internet.

7. Select “Auto 3 Star Align” rather than “Auto Align”. The scope will allow you to select 3 stars from a list (2 will be on one side of the Meridian and 1 on the other side). When selecting stars from the list, try to pick stars which are between 30-60 degrees above the horizon, are NOT within 5 degrees of Polaris and are far enough apart to form a broad triangle. Do not attempt to center the star until the scope asks you to do so – this may be a few seconds after the scope appears to stop slewing.

You will probably find that the slew to the first star is off by several degrees. The second and third star should be visible in the finder. Be sure to verify that you are centered on the correct star – centering on the wrong star will lead to grossly inaccurate GoTos.

8. Center the scope carefully on each star using the Telrad to be sure you are in the correct vicinity, then narrowing in with the finder and EP. A 9-12mm Ortho EP works well for centering since the field of view is fairly narrow. If you are uncertain if the star is centered, take it out of focus and center the larger unfocused image. A 9-12mm illuminated reticle eyepiece will obviously help make this process much easier and exact if you have access to one.

When centering on a star, make all final adjustments using only the RIGHT and UP arrows. If you need to use the LEFT or DOWN arrow, overshoot the mark by a wide margin (1/2 the FOV in the eyepiece) then use the RIGHT and UP arrows to make the final adjustments. This will minimize the effect of backlash in the gears and enhance the accuracy of the alignment.

9. Once all stars have been centered, the scope will perform its calculations and advise if the alignment was successful. Several people have suggested that a shorter calculation period (5-10 seconds) indicates a more accurate alignment than a longer calculation period (15-20 seconds).

Note – Celestron periodically releases firmware updates for the mount (the software in the hand controller is only upgradeable at the factory) At the time of this writing, the current version is 5.06. If you are on an earlier version and experiencing runaway slews or other problems, you should consider upgrading (the version can be checked through the menus). A Celestron port expander and programming cable are required for installation of the patch.

Future Plans:

1. Mount Extension
Despite the changes I’ve made so far, the viewing position is still 6” too low for comfort. Since the AS-GT mount is apparently very similar to the Orion Skyview Pro mount, I will probably pick up the 16” extension Orion offers for the Skyview Pro and see if I can have it machined to a 6” length.

2. Focuser
If I decide to keep the scope long-term (My dream scope has always been a 115-120mm AP or Takahashi APO), at some point I will replace the focuser with a better machined unit. Although the stock unit is adequate, it is a bit jerky when trying to achieve fine focus at high magnification. I imagine that this is partially due to the Synta-glue clogging the stock unit but is also attributable to the poor mechanics of the focuser. I have also noticed that the focuser shifts axis slightly when changing rotation direction of the focus knobs. Both Moonlight and Feather Touch offer high-quality, well machined replacement units. I am currently leaning towards the Moonlight since it’s a directly bolt-up to the existing screw holes – the unit’s 3 lb 8 oz weight will allow the scope to balance slightly lower than the stock focuser.

3. Cases
I would like to start taking the scope to dark-sky sites once or twice a month as time and weather allow. Before I do, I plan to pick up a soft case for the tripod and mount and a well-padded case for the OTA. Orion sells soft, padded cases for $60-$80 which fit the scope nicely (#15164 for the OTA and #15175A for the tripod). An extra foam rubber camping pad inserted in the case will give the OTA additional protection.

Summary:

The CR-RGT is a great scope and I’m glad I bought it. I appreciate the light gathering capacity of the 6” optics and have really enjoyed making minor enhancements to improve the usability of the scope. The mount seems very stable for visual use and the price for the mount/OTA combination is unbeatable. If you decide to purchase the C6R, have fun personalizing it to meet your needs. But most of all, take time to enjoy the skies!

Ask almost anybody thinking about buying their first scope how they intend to use it and they almost always say the same thing - "Well, I want to look at the moon and planets, and see DSOs - and oh yeah, I also want to use it to take photos and by the way, it should cost under $1000". I know because I said the same things myself several months ago. The reality, of course, is that it is difficult to find one scope that does everything well, particularly when dealing with a restrictive budget. After weeks of research, I ended up with the C6-R and hoped that it would handle each of the 3 areas I was interested in an acceptable manner. Well, after owning the scope for 4 months, I decided to take a few moments and record my latest thoughts:

C6R OTA
Overall, the scope has performed quite well and fully meets my expectations for a 6" achromatic refractor. I have spent dozens of enjoyable hours out under the stars (between the never-ending rain clouds) and have memorable views of the moon though it's various phases, Saturn's rings, Jupiter's bands, M42, M45 and a number of globular clusters. I have also split many close doubles and have spent hours examining craters, searching for faint stars in the trapezium and locating tiny moons around Saturn. CA is present but well controlled by a filter - the only times I really notice it are on Jupiter, the full moon and splitting doubles on bright stars like Rigel. Crater detail on a waxing or waning moon is breathtaking and stars generally resolve into tiny pinpoint white dots.

AS-GT Mount
The AS-GT mount has also fully met my expectations. The 2" steel legs on the tripod are very steady and the scope settles down in a couple seconds after a bump. I experienced some initial difficulties with gotos but, as I suspected, they were my fault, not the mount's. Be sure to carefully level the mount, align on Polaris and enter a precise time - stars will rotate out of the selected location if you are off by a minute or so due to the natural rotation of the earth. I also found that an illuminated reticle EP is a worthwhile investment - since acquiring a 10mm, my gotos have been flawless and every object appears close to center in a 13mm Nagler.

I also confirmed that the mount does learn. The first night after a reset, the scope will miss the alignment stars by a wide margin. By the second night, the mount will learn how much adjustment was required on the previous night and will be much closer to the alignment stars. By the third night, the alignment stars are nearly centered. If you make an error and have a bad alignment, I found it helpful to use the menu "reset" command to clear the computer's memory. Please be aware though that you will have to re-enter the site and date/time information.

Finally, the tracking is excellent. Although I don't recommend it, I have left the mount tracking and gone out to dinner - returning to the back yard a hour or so later, the object was still in the EP. WARNING - if you leave the scope on, ALWAYS be aware of the scope's projected path so that it doesn't accidently contact a leg. I only do this on objects well below zenith.

One final note - do yourself a favor and get a new power cord. Scopestuff sells a heavy coiled cord just long enough to reach from a Powertank to the mount - $12.00 including shipping - fused auto-adapter on one end and Celestron plug on the other - even has a red led on the auto-adapter to confirm the cord is getting power. Well worth the money!

Astrophotography
Besides enjoying time at the eyepiece, one of the main reasons I purchased the scope was to dabble in astrophotography. I am pleased to report that it is possible to take very nice photos using the scope BUT it does have its limitations:

1. Weight
In general, a scope used for astrophotography should weigh less than 50% of mount capacity to minimize jitter - the C6R exceeds that recommended limit by a wide margin. As a result, there is some jitter on exposures over 2 minutes long.

2. Chromatic Aberration
Yes, CA is a problem on bright objects. While you may not notice the CA when using the scope visually, the blue fringe will be quite evident in a long exposure. For example, on a 2 minute exposure, bright stars will have a broad blue band around them whose width is equal to approximately 50% of the star's diameter. Fortunately, much of it can be adjusted away in post-processing using Photoshop CS or Elements.

3. Aperture
At F8, the scope is fairly slow for photographic use. As a result, longer exposures will be required and the FOV will be smaller than a faster scope.

Limitations aside, taking photos through the scope is quite enjoyable. I do not have a webcam so I have not attempted to photograph Saturn or Jupiter but have taken numerous pictures of the moon, globular clusters, M42 and star groupings using a Nikon D70 DSLR. A few examples can be found at this link:
http://www.cloudynights.com/photopost/showgallery.php?ppuser=6252&cat=500

If you decide to go forward with photography, take a few minutes to read this article on the Televue site - it explains in easy to understand language the various ways to connect a camera to your scope.
http://www.televue.com/engine/page.asp?ID=236

Prime Focus
The telescope acts as approximately a 40x lens (1200mm flocal length / ~30mm chip diagonal) - the exact magnification will depend on the diagonal measurement of your CMOS or CCD (figure 43mm for 35mm film). To attach a SLR or DSLR, you will need a T-adapter and T-ring. NOTE: Not all T-adapters will fit the Mercury Systems visual back - I found that the WO T-adapter is machined to exactly the same size as the WO 2" diagonal and fits perfectly. Add a Celestron T-ring for your specific camera and you are good to go. To achieve higher magifications, replace the T-adapter with a TV 2x or 4x Powermate with a T-adapter ring attached.

Afocal Imaging
One of the problems attaching a camera for prime focus photography is the fixed magnification. Since I have a growing selection of high-quality EP's, I have been looking for a way to take photos through the EP at various magnifications. I have had good results holding a small digital camera to an 18mm Ultima but have had much less success taking pictures through various Naglers. Although I have not tried it yet, Scopetronix makes a product called Maxview II which allows any EP to be attached to the camera. Quality of results unknown.

Software
I'm not going to go into any detail on software packages used in astro-photography. Suffice it to say, 50% of any astro-photo is done at the camera - the rest is done at the computer. Expensive to purchase, Photoshop CS is the most popular software for photo-editing. The package has a steep learning curve but allows near total control over all aspects of the final image. I elected to purchase the less costly Photoshop Elements. Although less full-featured, the software was only $80 and reads the Nikon NEF raw format. Lots of good tutorials are available on the web for both packages.

Starbound Chair
This chair is fantastic - very comfortable and adjusts easily to any height - a must with a large refractor since the viewing positions cover such a wide range of heights. The only flaw is that the rubber feet on the chair need to be replaced every 2-3 months - the steel tube pushes through the rubber long before the rubber wears out. Fortunately, Ace Hardware in my area sells exactly the same feet - buy those made for 7/8" tubing - about $0.65/each. The feet will last much longer if you put a steel washer in the rubber feet before installing them. Buy a 1" OD steel washer and press it into the bottom of the rubber feet with a screwdriver - the washer will prevent the tube-end from cutting the rubber.

Mount Extension
The default low viewing position of the C6R-GT is one of the weak points of the package. Adding a WO diagonal, 2" brass focus knobs and Telrad mounting plate helped a great deal but I have continued exploring ways to raise the raise the viewing position. I ordered the Orion 16" extension for the Skyview Pro mount but returned it a few days later - although it did mate reasonably well to the AS-GT mount and was very well made, it was too heavy, too long, had an overly-large azimuth bolt alignment hole and had a fairly flat bottom that barely engaged the tripod bolt.

I recently located a company named Astrosky that agreed to machine a similar extension in a shorter length (see picture in gallery link above).

The Positives:
The entire unit is 7" long and weighs about 3#. The end caps are well machined and mate well with the mount and tripod. The bottom end cap extends 3/8" into the tripod and engages approximately 8 threads of the tripod bolt. The top cap includes an Allen-head bolt with 2 washers and engages the bottom of the mount by 7-8 threads. Overall the quality of the machine work seems good - the caps fit tightly in the pipe and mate snugly with the tripod and mount. The caps are attached to the 4" pipe with 3 Allen-head screws on each end.

The unit feels very solid when installed and height is sufficient (with the other balance changes I made earlier) to prevent the scope from hitting the tripod legs when viewing at zenith. With the extension, I find that I am able to pull-in the lower leg extensions by approximately half of their length and still view objects directly overhead while seated in a Starbound chair. The mount doesn't feel tippy and seems quite stable with a 6" refractor installed.

Minor Quibbles:
(1) the bottom cap was manufactured much like the Orion bottom cap and the azimuth receiver hole is much wider than the peg - this allows the entire extension to twist slightly and could throw off a polar alignment if it shifted in use.

(2) the aluminum tube is painted a flat black - it actually looks kind of cool with the aluminum edges on the caps showing but doesn't match the pebbled finish on the tripod and mount.

Overall, the extension serves its purpose and is a bargain at a cost of around $60. James at Astrosky was good to work with and communicated well during the transaction.

Conclusion
The C6R-GT fully meets my expectations. The scope introduced me to a whole new world of astronomical observing and astro-photography - it has been a joy to use and great fun to modify. Although I intend to hold onto the scope for the next few years for visual use, I am planning to supplement it this year with an 80mm APO to expand my interest in astro-photography and allow me to take a scope on the road. Long-term who knows - at present I am thinking that the perfect combination may be an 80mm APO for travel and photography and a 12" DOB with Zambuto glass to reach those elusive DSOs.

Regards,