First, I picked up a new Skywatcher Pro ED120 F7.5 OTA package just a little over a month ago, and until a few days ago I had only been able to use this scope on a mount built for an 80mm scope. To my eye the views were always very sharp, but the undersized mount would shake if I so much as breathed on it. Now that I have used this OTA on the new CGEM IMHO this OTA performs excellent views with virtually no hints of color on bright objects such as Rigel and Castor, and these can both be easily split with a moderate eyepiece.
In my opinion this beautifully painted metal flake OTA scope package (which is very similar to the Orion 120ED) provides not only excellent views with the FPL53 lens cell as has already been widely reported in other forums, but is also an amazing value at $1495 with an 8x50 finder, 2â€ dielectric diagonal, hard case, and 2 above average eyepieces. My personal experience has been that Joe Gordon (who runs Skywatcher USA) and all the folks at Skywatcher are simply great to deal with, and they provide the type of customer service experience most in this hobby expect and which has been sorely lacking at most of the competitive astro companies I have dealt with over the last few years. For more information on the Skywatcher Pro 120ED OTA package check out the link below. At this point I can only say that I have owned 6 other 80mm-102mm Chinese or Taiwanese FPL53 ED/APO equivalent refractors which I have already sold, but I have found the Skywatcher 120ED a definite â€œkeeperâ€.
Right after receiving my new Skywatcher 120ED, Santa visited and left a pretty new Canon 450D DSLR under the Christmas tree. Having never even used a DSLR and considering myself at the very best a total DSLR â€œNoviceâ€ I have been reading and â€œfumblingâ€ around with the new DSLR as time permits. I guess since at this point I am still pointing the camera with one hand, and reading from the userâ€™s manual with the other, one would suggest I have probably still not quite past the initial learning curve. As a point of reference like many others I have used an old analog SLR in the past, so I did have some very basic concepts of aperture and the former ASA, now ISO. I have also used an Orion SSDSI CCD a few times for some preliminary crude attempts at astro imaging. While I have bought and sold a few different GEM mounts, I have never had an EQ mount I considered to be capable of proper tracking for astro imaging so my astro imaging experience is just about non-existent.
I have previously owned 2 Celestron CG5 GOTO mounts and an Orion Atlas, but while I recognize these mounts have worked well for others, for various reasons none of these mounts really worked well for my needs. Since the announcement of Celestronâ€™s new CGEM mount and the â€œAll Star Polar Alignmentâ€ routine, I have thought that perhaps this mount might really work well in my environment. You see one of my constraints is that on my back deck where most of my observing is done I have a very restricted field of view, and I never have a view of Polaris. So when the UPS truck pulled up a few days ago with my new Celestron CGEM mount, I was anxious to see if the CGEM polar alignment would perform as well as I had hoped.
Iâ€™m a bit of â€œBottom Lineâ€ sort of person and suspect many other CN members might be as well, so Iâ€™ll skip to what I consider the most important attributes of the Celestron CGEM mount.
1. This is a reasonably heavy mount at 58 pounds with the tripod and EQ head, and has a real world payload of an honest 40 pounds.
2. The All Star Polar Alignment Routine worked perfectly, just like advertised.
3. GOTOs were right on, and preliminary tracking observations were excellent.
Please review the link below for more detailed information about this mount.
At the time of the announcement of the Celestron CGEM I had just sort of overcome the learning curve of my still relatively new Orion Atlas EQG mount, but my first thought was that the All Star Polar Alignment feature of the new CGEM mount made my Atlas EQG mount immediately antiquated for my needs. The good news to me was that my Atlas mount sold on another Astro forum the very same day I decided to sell it, but the bad news was that the new CGEM mounts were back orderedâ€¦
Like I stated above, the All Star Polar Alignment routine worked perfectly just as advertised, now let me explain the primary reason for my writing this brief report, as to me this feature alone is an amazing benefit. If unlike myself you have an unobstructed view of Polaris this feature might not seem to be very beneficial, but in actuality the accuracy of the polar alignment might really be more beneficial than realized.
In essence the All Star Polar Alignment consists of a basic alignment, and an additional Polar Alignment Routine and works like this:
Time/date/location data is entered as is typical of the alignment of virtually any mount, and then a simple 2 star alignment is performed as is customary, with the user provided many choices of various alignment stars. Both alignment stars must be on the same side of the Meridian and it seems default is to the West, and I chose Rigel and Aldederan which were both clearly visible from my location on the Western side of the meridian. The user can also opt to add multiple calibration stars on the opposite side of the meridian if so desired to increase pointing/GOTO accuracy, and I chose to use Pollox and Procyon for calibration stars which were on the Eastern side of the meridian. Each star was in turn centered in the finder and then aligned in the center of the OTA eyepiece. Following completion of the alignment, the mount calculates position data, and then displays alignment success.
The next step is to add the optional All Star Polar Alignment:
The user selects any star of their choice from the huge Nexstar database, and the GOTO feature of the mount slews to that star. I selected Rigel again, and the mount slewed to Rigel. The user then centers the selected star (Rigel in this example) in the eyepiece, and enters â€œAlignâ€ on the keypad, and then selects â€œAlign Mount Positionâ€ from the few drop down options provided. The mount then calculates the correct position of the true North (or South if you are "Down Under") polar axis, and prompts the user to hit enter to continue to Polar Align. The mount then slews to WHERE THE STAR (RIGEL IN THIS EXAMPLE) SHOULD BE IF THE MOUNT WERE PROPERLY POLAR ALIGNED.
The user then adjusts the CGEM mountâ€™s altitude and azimuth settings mechanically to center the Polar Alignment Star, and upon completion the mount is properly polar aligned. Please view the link below for more information and FAQ:
So Iâ€™m sure if you have plodded through all this rambling thus far you are probably wondering something like â€œWell does it all actually work?â€
In My Humble Opinion, the All Star Polar Alignment is one of the best astro features I have encountered to date. As I mentioned above, I do not have a clear view of Polaris from my back deck, and so have no ability to use a polar finder scope. I do not have an observatory, and just canâ€™t justify the time of a tedious drift alignment. My â€œfirst passâ€ of the All Star Polar Alignment took me about 10-15 minutes to both figure out and complete, and I suspect subsequent alignments should all take easily less than 5 minutes to complete. For what it is worth I pre-aligned the CGEM mount with accurate marks on my deck indicating the alignment path of the true North celestial pole, and set the elevation to 38 degrees for my latitude in Virginia consistent with the mountâ€™s user manual, as well as every other GEM user manual I have encountered. What was surprising is that while I suspected my alignment marks for the true North celestial pole were pretty accurate and in fact they were as the mount needed very little azimuth adjustment, the altitude needed a substantial adjustment of well more than 1 full degrees! Following the Polar Alignment, the mount now shows the latitude at closer to 36 degrees, and I have found that to be quite surprising. In case one is wondering, the bubble level on the mount was well centered, and GOTOs in all directions were really quite accurate consistently placing the selected object in the field of view. Time will tell as to the accuracy of the mounts elevation gauge and the bubble level, but certainly the initial results were what I would consider a very good polar alignment.
Now back to the resultsâ€¦
First, please no flaming attacks about my lack of imaging skills as they are not neccesary, my lack of skill in this area is readily acknowledged. I was interested in the results of the unguided tracking, and attached is a link to an image I posted on our local club site of what I think is the very first moderately acceptable image I took with the new Canon 450D DSLR, Skywatcher 120, and Celestron CGEM last Thursday evening, 1-29-09. Please note this image was posted just for what it is intended to be, a single unguided 45 second exposure.
If you can, please allow your mindâ€™s eye to picture a guy with a DSLR userâ€™s manual in one hand, a Celestron CGEM userâ€™s manual in the other, using a red flashlight to skim through the most appropriate reference materials trying to determine how to photograph a deep sky object he can barely see with his finder scopeâ€¦ This would have probably made for a hilarious YOUTUBE video, and that is pretty much what I was thinking as I was laughing at myself. Well I can tell you the Canon â€œLive Viewâ€ feature that displays your image on the LCD display is certainly much better than trying to peer through a view finder in the dark, but I will really have to work on my focusing technique as the first results were certainly less than impressive.
But the image in the link above is a single 45 second exposure of the familiar M42 Orion Nebula taken in the â€œRAWâ€ mode, and just cleaned up slightly with the 450D included utilities. This single image was taken with no guiding, and a simple prime focus attachment using the ED120 as a telephoto lens for the Canon 450D. I did try a few longer exposures of 90 seconds and it seemed the CGEM mount tracked perfectly and I suspect even longer unguided imaging can be expected, but my lack of focus skills and experience with the live view function on the 450D were much more evident, and I recognize focusing will require much more work in the future.
While this brief review is not intended to be an in depth technical analysis that many of the advanced astronomers here might appreciate, I thought other novice observers like myself might benefit from some of the results from my recent experience. In my novice opinion the initial performance results of the new Celestron CGEM mount are really quite promising, and I hope other amateur astronomers can benefit from understanding the functionality and benefits of the All Star Polar Alignment routine.
Please feel free to comment or ask any questions, Iâ€™ll do my best to help any way I can.
Keep looking up!