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Life with a C14

Posted by Clifton Loo   05/20/2005 07:00AM

As a teenager, I used to buy Astronomy or Sky and Telescope and be mesmerized by the big orange Celestron Schmidt Cassegrain telescopes, king among them being the C14. To paraphrase Ed Ting, everyone has thought about owning one of these beauties.

As is the story with many amateur astronomy buffs, I put the hobby on back burner for a long time. What ignited my interest again was the close descent of Mars in 2003. In an attempt to impress my wife, I pulled out my old 6” Newtonian and tried to give her the view of a lifetime of Mars, only to disappoint with a shaky mount, insufficient eyepieces and rudimentary skills. Out of the ashes of this train wreck came a renewed interest in astronomy. It occurred to me that I could spend a little money on my old and now new hobby. Two years later, a little money became a lot of money. While some purists complain about the quality of equipment coming from overseas, it allows the new amateur astronomer to get very good equipment at a bargain price. That, along with Astromart, becomes an explosive combination destroying a semblance of restraint and common sense in terms of budgeting for your hobby. In other words, one can easily justify curing your aperture fever.

About a year of renewed interest in the hobby drew me to one conclusion: the C14 is my ultimate scope. I had drawn this conclusion from various introspections and practicalities. The first conclusion is I don’t like dobs. I had a 12.5” and 12” dob and while I enjoyed the views, the constant nudging the scope and contortions to get in the right viewing angle took away from observing. Also, in a practical sense, I can barely get the solid tube 12” dob in my small car. Second conclusion is I didn’t care for the short focal lengths of the typical dob. I find my interests lie in planetary, lunar and deep sky objects that generally lend themselves to medium to high magnification, and the long focal lengths tend to do well with most eyepieces.

With my aperture fever running out of control, I found myself acquiring an old C14 for a bargain price. I decided to get rid of the fork mount and mount it on a CI-700. My first encounter with the C14 was a rough one. I found that there is a big adjustment to setting up 6” to 10” equatorially mounted scopes versus the C14. One of the biggest adjustments is carrying the mount or telescope any distance. After 15-20 minutes of emotional trauma, wondering if the telescope will slip out of your hand or one of those 25 lb weights falling on your foot, your appetite for observing diminishes. Ease of set up is directly proportional to observing time, and the value of any scope is the amount of time you log on it. I sold the first C14 simply because I felt it was not getting used.

However, the passion for the C14 didn’t die. With the permission of the comptroller (i.e. wife) I got a newer model C14 with CGE mount. I bought the set up with a bit of trepidation, wondering if I would quickly give this one up because of the sever costs of set up. I can say this C14 is here to stay. Here is my assessment of life with a C14.


Initial Impressions

The C14 tube has a nice finish with bright orange dovetail. In terms of ergonomics, one thing that helps out immediately is the set of two handles that are on the back of the C14 tube, near the primary mirror. My old C14 had no such handles, and I had to carry it by the visual back, which was very precarious. Even with the two handles, one has to cradle the tube, and it is still a bit of a danger carrying it any distance. The CGE mount is very heavy compared to the CG-5 I used to have, but it comes apart in very manageable pieces. Everything has a nice finish to it; nothing looks cheap. In some ways the mount is very similar to the old CI-700, but the electronics are more integrated and the knobs are much more ergonomic. I used to have a lot of trouble locking down the CI-700 quickly to prevent either axis from drifting when balancing or slewing, but this is not the case with the CGE. Also, the substantially bigger knobs on the saddle makes locking down the tube quickly an easy proposition, and the dovetail bar prevents the tube from sliding off the saddle. The tripod is adjustable, another improvement over the CI-700, and has a much better finish to it. All the electronic connections are on the pier connecting the tripod to the equatorial head, and the wires from the pier to the respective axis are surprisingly short and have yet to get tangled.

The Set Up

As opposed to my first C14 set up, I have a Pelican case for the equatorial mount and a JMI case for the tube. While these items seem like an afterthought, I find them a necessity. I keep everything in cases, and when I set up, it’s just a matter of rolling the cases onto the deck. It usually takes about 20 minutes to set up, but lately I’ve been closer to 15 minutes with more familiarity. First, the tripod is set up on Orion vibration suppression pads, which are a must. Then I roll out the equatorial mount in the Pelican case and assemble the mount and put on the counterweights. Then I mount the tube. My technique is to get down on one knee, grab the handle that’s farther from me with my right hand, and grab the front with my left hand. The dovetail is usually facing me. Once I get the tube out of the case, I place it on my thigh. Then, I rotate the tube so that the dovetail is facing down. Then I grab the handle farther from me and rest the tube on my arm on the mirror side, and my left hand cradles the front of the tube. I lift with my legs and find it very easy to control the tube. I can mount it fairly easily after that, even though it would be easier if the saddle was a tip-in. The reason I go into so much detail about how to mount the tube and the use of rolling cases is I find this the way to minimize set up time and strain. While this may be an afterthought for smaller scopes, planning and patience are necessities for bigger scopes.

Cooling and Collimation

Many amateur astronomers say SCTs are mediocre instruments, I’ve found this not to be the case. I have found that without care in collimation and cooling, SCT’s live up to their mediocre reputation. After set up, I found taking the visual back off and putting the tube in a position parallel to the ground cools most effectively, although I plan to buy a SCT cooler one day. I’ve gotten Bob’s Knobs to help me collimate, and have gotten good use out of these little accessories. Along with set up, cooling time is another big adjustment when compared with smaller scopes. These C14’s are the opposite of grab and go and require a lot of planning and patience not only for set up, but allotting time for cooling, and collimation if needed.

I have found that SCT’s hold their collimation much better than Newtonians, although I check for collimation every time out. As far as cooling goes, the images tend to be very good one hour after set up, if you set up when the sun is down. My experience is during the spring and summer months, for the fall and winter an SCT cooler will be a must.

Go-to and Tracking

I’ve had a CG-5 go-to and found it very accurate, as long as you had the time to accurately align the guide stars. The CGE is similar, except it requires less alignment stars. I’ve had one good go-to experience and one bad go-to experience. The first time I go-to’ed it was a little bit off. With some tweaking (this can be done with replacing alignment stars with found targets), the go-to was incredibly accurate. Hit the tour button one night not expecting much, and found most of the galaxies in the Virgo-Coma cluster. This is especially impressive because the long focal length (3910mm) creates a very tiny field of view and my skies are very light polluted (red on the light pollution map). My bad go-to experience is when the computer thought M3 was at the horizon, when it was closer to the zenith. I theorize this is probably because of a less than fully charged battery or some major set up error.

While the go-to has been hit or miss, the tracking has been impressive. I’ve had Jupiter at high powers and had to do very little adjustments. Yes, the scope will stop tracking when it crosses the zenith, but I think this is a good thing because it prevents the DEC axis and RA axis from hitting. Even my wife asked why we didn’t have to reposition the image when we were observing at Jupiter (that along with commenting how much bigger the image was!).


Optics

C14’s have a reputation for very good optics, and this one is no exception. My skills in star testing are nominal, but I think the optics are about 1/5 to 1/6 under-corrected. Of course, I find the best indicator of optical quality is performance on Jupiter and the C14 is impressive. The first few weeks I had the C14, I found the planetary performance was poor past 150x. I attributed this to seeing, but later found out it was a collimation error. When this error was corrected the performance of the cooled and collimated C14 on Jupiter was stunning. Previously, my best view of Jupiter was during opposition in 2004 with a 12.5” Discovery dob when I could get the magnification to 240x with no break down in image. In the C14, the image is razor sharp at 313x! I could see fine dark blue strings in between the two large equatorial bands. I’ve seen plenty of high magnification images where the detail was there, but the image was soft, but this image was exquisite! Even at 400x and 500x, the image reveals detail, but it is softer. The eyepieces used were simple Celestron Plossls sold in their accessory kit, and the image at 313x was from an old Kellner from the 80’s and 2x Barlow. I recently got a Televue Plossl, and am looking forward to the images rendered by that eyepiece. Saturn also performed well and I cannot wait until Mars reappears. It should also be noted that I have a very nice Williams Optics 2” enhanced diagonal and am sure this contributes to the stunning planetary images.

SCT’s are also underrated as deep sky instruments too. Most people prefer the short focus Newtonians, but we know higher magnification increases contrast by darkening the background. I’ve found that deep sky objects pop out in the C14, objects I didn’t think I could see from my house. As mentioned above, going through the Virgo-Coma cluster was a delight, one galaxy after another popping out. I didn’t see much detail in these images from my house (with the exception of the Sombrero galaxy), so I’m looking forward to taking the C14 to a dark site in a couple of weeks. The high magnification helps in contrast, but sometimes finding objects can be a little tough. I’d recommend getting a long focal length eyepiece (I have a 50mm GSO Superview that does great) and a Telrad. With these two accessories, I have not had much trouble finding things.

I would say the image shift is about 3-4 arcminutes, although I have not formally measured it. Many people add a motorized focuser or a SCT focuser, but I found there is enough snap-into-focus and these items are not necessary for visual use.


Overall Assessment

If you want to have just one scope, I’d highly recommend the CGE 14. It’s got the aperture and focal length to go deep, gives exceptional planetary performance and, with patience and planning, has reasonable portability. I think Celestron could improve on the package by adding a polar scope, vibration suppression pads, tip-in saddle, SCT cooler and possibly a dew shield or dew remover (of course, these things can be added with aftermarket products). The one downside of owning an SCT is that there are a lot of accessories that are necessities to maximize performance. On the other hand, it is not necessary to buy expensive, well-corrected eyepieces. The long focal length means most eyepieces will perform admirably. I’m looking forward to taking this big CAT on the road to a dark site. I’m sure the images will inspire another article!

Click here for more about this subject. -Ed.