Instruments*
Updated as of: 05.19.2009
My observing environment has changed from nightly equipment moves to the end of the driveway into an observatory and fixed pier system at New Mexico Skies. Prior to this move however, I needed to move equipment, re-setup and re-align every night. There are 5 major sections below covering Mounts, Optics, Supports, CCD's, and Others. I have used the following major platforms: [for observatory dome information click here]:
As of April, 2009: RCOS 20"<Paramount ME Mount<Fixed Pier in Dome
Takahashi FRC300 + Televue NP101 < Paramount ME Mount < Particle Wave Monolith Portable Pier
Takahashi TOA130 < Takahashi NJP Mount < Takahashi Wooden Tripod
Takahashi FSQ106N < Takahashi EM-11 Mount < Takahashi Wooden Tripod
Takahashi Sky90 < Takahashi EM-11 Mount < Takahashi Wooden Tripod
Meade 14" SCT <
Meade 14" SCT < Meade LX200GPS Fork Mount < Meade Giant Field Tripod ... [All Sold]
Here are my observations regarding Mounts that I have used:
I am not a big fan of Meade products as I experienced defects with new equipment.
In my opinion they are generally of lower quality even at the upper end of
the product line. The mount was very difficult to align, not accurate, too
heavy and cumbersome to use. On the other hand, I have only good things to
say about the Takahashi NJP. It has worked perfectly in every respect. The
I have recently modified my opinions regarding the use of the Paramount in a nightly portable situation (movement to the end of the driveway). I have proven to myself that the ME is the preferred mount for me in a fixed pier, observatory location. After one year of learning, mostly through trial and error, I became equally comfortable using the ME or the NJP in my nightly driveway rollouts. My slow learning curve with the ME was complicated by the longer focal length of its OTA vs the NJP. This required precise physical positioning each night such that the ME will have essentially the same performance characteristics as if it were on a fixed pier. I have now mastered this task.
I can now equally recommend both mounts for a portable situation similar to mine.
Mounts |
Meade LX200GPS - sold |
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Ease of daily setup and a good polar alignment |
Very time consuming >40 minutes. Most Difficult to get right. |
Fast and easy! The Polar alignment scope is great! I can normally be within 30 arcseconds of perfect alignment in just 10-15 minutes. The job is simplified by the shorter FL of the TAK TOA130. View Sample. |
I bought this mount for traveling. It includes a built in Polar alignment telescope which like the NJP mount makes if fast and easy to use. | The biggest drawback with the ME was that I had a steep learning curve for fast polar alignment in a roll-out environment. View Sample. While not approved by anyone, I have finally found a setup procedure that gets me going as fast or even faster than the NJP setup in a roll out environment. See my Paramount quick-alignment blog. |
Rank [roll-out] | 4 | 1-tied | 3 | 1-tied |
Rank [fixed pier] | NA | 2 | NA | 1 |
Use with a remotely controlled observatory | I would not want to try it. | Probably would not work well or at all. | Probably would not work well or at all. | Excellent, and perhaps the only really good choice. |
Polaris required to be visible for alignment | Yes, if using Autostar alignment. | Yes, if using the polar alignment scope. | Yes, if using the polar alignment scope. | No, a big advantage in flexibility for the ME. |
Portability/weight |
Awkward and heavy - the worst with its combined fork and mount. |
Heavy but compact and luggable ~50lbs |
Much lighter and more portable than my other mounts. ~20 lbs |
Most heavy, ~65lbs before weights and not easily moveable without wheels. |
Pointing Accuracy. |
Worst. I could never really get it to be really accurate. I found and repaired drive gear damages. |
Outstanding accuracy. It works even better with TPoint. |
I have a USD-3 model upgraded to Temma 2 encoders. Overall the pointing accuracy is excellent. however see the other points below.
|
Pointing accuracy is excellent after a good TPoint model is available with over 200 points. |
Tracking Accuracy (Uncorrected) |
Worst, published tests show 15.0 arcseconds of error. I found drive gear damages on my system. |
Uncorrected peak-to-peak error measured at 2.3 arcseconds using 5th order fitting with PemPro. This is better than the advertised error of 4 arcseconds. View details. |
I have not measured the tracking accuracy. However, manual observations indicate peak error at about 2x that of the NJP. | Over six Worm Cycles yields an uncorrected 5.7 arcseconds of error using cubic drift fitting. A little worse than the advertised spec of <= 5.0 arcseconds. View details. |
Tracking Accuracy (Corrected) |
Worst, published test show 5.0 arcseconds of error after software corrections. |
TAK does not provide for software error correction, so 2.3 arcseconds of error remains. |
TAK does not provide for software error correction. | Measured at 0.8 arcseconds, View Details which is outstanding given that some of the error is from atmospherics, and it is less than .5a.s. in either X,Y direction. Error measurements and corrections made with PemPro. |
Tracking Accuracy (Corrected and Guided) |
Unknown | Usually < 0.3 pixels (X+Y) with 1000mmFL; and <0.1 pixels in RA using a 540mmFL remote guiding telescope | I have not measured the tracking accuracy. However, manual observations indicate peak error at about 2x that of the NJP. | Using a well aligned, fixed pier averages < .3 pixels combined (X+Y) error using a 540mmFL remote guiding telescope. |
Functionality |
Hand Controller or PC- with fully competitive capabilities |
Hand Paddle or Via Sky6 and limited options compared with others. No PEC |
Hand Paddle and limited options compared with others. No PEC | Joystick or Via Sky6. Rich functionality, PPEC, ProTrack and much more. |
Complexity |
Average |
Low |
Low | High |
Approx. Load Limits |
75lbs |
70lbs |
20lbs | 150lbs |
Documentation |
Good, Complete |
Very weak, limited in English (But complexity and functionality are low, so it is not as necessary) |
Very weak, limited in English (But complexity and functionality are low, so it is not as necessary) | Excellent, Comprehensive |
Other Points |
I would only recommend Meade if you are on a tight budget. |
Other than the long delivery lead times for telescopes (see OTA's below), I have been very satisfied with everything carrying the Takahashi label. |
I have experienced pointing go-to errors with the EM11. The problem was diagnosed and corrected as a loose locking screw on the RA encoder-shaft. | Software
Bisque the manufacturer of the
|
Availability | Immediate | 1 month | Immediate | 2 months |
Here are my observations regarding Optics:
There is really no comparison. Takahashi is vastly superior to Meade and better than others that I have used, IMHO. TeleVue is also very good. For larger apertures and longer focal lengths I have found that RCOS telescopes are the best instruments for me.
Optical Tube Assemblies |
Schmidt-Cassegrain |
Takahashi TOA130 Refractor |
Takahashi FSQ106N Refractor |
Takahashi FRC-300 Ritchey-Chretien (See a full review) | RCOS 20" Ritchey-Chretien |
Overall | Average | Great | Outstanding | Outstanding | Outstanding |
Image Quality | Average | Excellent | Superb | Spectacular | Spectacular |
Rank | 5 | 4 | 3 | 2 | 1 |
Aperture |
356mm |
130mm |
106mm | 300mm | 508mm |
Focal Length |
3560mm |
1000mm |
530mm | 2348mm | 4115mm |
Focal ratio/w reducer |
f10 / f6.3 |
f7.6 / f5.76 |
f5.0 | f7.83 / f5.9 | f8.1 |
1st Light | 2/2005 | 5/2005 | 12/2006 | 6/2006 | 4/2009 |
Quality of the optics |
Average |
Great |
Excellent | Excellent | Excellent |
Focuser | Primary Mirror | 4" Rack&Pinion | 2.5" Rack&Pinion |
Helical | Servo motor on Secondary Mirror |
Ease of Focus |
Difficult, needs continual refocusing |
|
Normal | Very Easy - Do it once and lock it in! Then detail focus with FLI-PDF | Very Easy - After a correct Backfocus distance is physically set, focus is controlled directly with TCC or FocusMax |
Back Focus | unk | 256mm | 120mm | 106.2mm | 381mm |
Spot free internals |
Good |
I expected better - only good |
Clean | Clean | Purchased Used and dirty |
Cooling and Heating | None Included | None Included | None Included | None Included | 3 tube air fans with dew heaters included |
Instrument Rotation | None - not needed | None - not needed | None - not needed | None - not needed | An Optional Add-on, but very necessary |
Temperature adjustments | None | None | None | Automatic within 5degC [refocus 2-4 nightly] | Carbon Fiber (Very Stable Focus) [refocus 1 nightly] |
Mirror |
Locks Manually - This is a big problem as the OTA continues to lose focus with movement or with temperature changes |
NA |
NA | Fully Locked, no flops | Fully Locked, no flops |
Obstruction | Yes, but unspecified | None | None | 25% | 16% |
Weight of OTA | Unknown | 22 lbs | 15 lbs | 66 lbs | 160 lbs |
Best Usage | Galaxies and deep sky | Nebulae, Planets | Wide Field, and Nebulae | Galaxies and Nebulae | Galaxies and deep sky |
Availability | Immediate | Immediate | Over 1 year | 7 months | 3 months |
Here are my observations regarding the Support Systems:
Tripods and Portable Piers | Mead - Sold | Takahashi | Monolith | Fixed Pier in Dome |
Stability | Poor | Excellent | Outstanding | Completely Solid |
Rank | 4 | 3 | 2 | 1 |
Portability/Weight | Heavy but easy to breakdown | Lighter Weight but more effort needed to breakdown | At about 50lbs, it is not particularly well suited for portability. Works fine with wheels. | Not meant to be portable |
Approx. Load Limits | 200lbs | 155lbs | 2,500lbs | 5,000+lbs |
Materials | Aluminum | Wood | Aircraft quality Aluminum | Steel |
Availability | Immediate | Immediate | 6 months | Custom Made 1-2 months |
My CCD manufacturer of choice is Finger Lakes Instruments (FLI). See my review comparing the FLI ProLine09000 and the SBIG STL11000 here, and see my comments below:
Camera | SBIG ST2000XM | SBIG STL11000M | Starlight Xpress Lodestar Autoguider | FLI ProLine 09000 |
CCD Sensor | Kodak KAI-2000 | Kodak KAI-11000 [Class-1] | Sony Exview [Class-1] | Kodak KAF-09000 |
Rank | 4 | 3 | 2 | 1 |
My comments | Internals were not clean on delivery. | Clean internals, but in my opinion my chip appears to have too much unwanted noise. SBIG responded that this is pretty normal. These apparent artifacts of the read out process can show up in images after reductions and I use Photoshop spot healing to eliminate the lines in the final images. This is not what I expected from this camera. When I wanted to improve my CCD, I ordered the FLI ProLine in part because of my disappointment with SBIG's response to my concerns. |
This Camera is designed to be an autoguider. With a low weight of only 50g (1/10 lb) it provides excellent capabilities without adding weight to the camera train and mount. It is a great companion to an FLI camera which has no internal autoguiding capability. My experience to date with this camera (placed in live operations in May, 2009) has been excellent. Connected to an OAG mirror, there has been no noticeable flexure. The electronics have worked as advertised, and the lack of cooling has not caused any problems. With its very modest chip size, accurate pointing from the mount and telescope is mandatory with longer focal length telescopes. For the same reason, the guide stars and Position Angles must be manually selected within the planning software before imaging. In my environment, the field of view is too limited to have the guiding software select its own guide star automatically. |
I love this camera. Before I received my new FLI CCD, Greg was very helpful by sending me a copy of the CCD's Bias image taken in the FLI lab. Now these are different chips, with Bias's taken at differing temperatures, etc, etc... but even with all the caveats the FLI Bias looks to me to have less noise and less concentrated noise than that from my SBIG. Most of this noise reduction is probably a result of the lower temperatures that I can achieve with the FLI cooling system, in my opinion. FLI has met or exceeded all of my expectations. Operational temperatures are reduced by nearly 60deg C from ambient. The chip's QE superiority and lower read noise are noticeable in my opinion. Downloading at 12 MHz is fast and almost fully noise free. |
Max Air Cooling | 30 deg C | 30 deg C | none | 55-60 deg C |
Actual Cooling achieved: Ambient/Operational |
+28/-5 C | +28/-5 C | none | +28/-30 C |
Bias Images [at my normal usage cooling temperatures] The images shown are illustrative only and are stretched .JPG |
at -9C | at -10C | not used | at -25C |
Approx download time for one Bin 1x1 image | 15 seconds | 20 seconds | 2/10 Second with USB 2.0 | 2-3 seconds at high speed 15 seconds at low speed (min noise) |
Chip size | 13.38 x 9.52mm 1640 x 1214 pixels |
37.25 x 25.70mm 4008 x 2672 pixels |
6.4 x 4.75mm 752 x 580 pixels |
38.6 x 37.76mm 3103 x 3086 pixels |
No of Pixels | 1.9 MP | 10.8 MP | .4 MP | 9.0 MP |
Pixel size | 7.4 µm | 9.0 µm | 8.2x8.4 µm | 12 µm |
Architecture | Interline | Interline | Interline | Full Frame |
Saturation | 40 K | 60 K | 50 K | 120 K |
Read Noise | 13.5 e | 13 e | 10-15 e | 7 e |
Peak QE | 45% | 50% | 65% | 69% |
Self-guiding | Yes (Internal) | Yes (Internal or optionally external) | NA | No |
Max Shutter Speed | .001 Seconds | .001 Seconds | No mechanical shutter | .01 Seconds |
Dark Current Doubling Temperature | 7 deg C | 7 deg C | NA | 7 deg C |
Availability | < 1 Month | <2 Months | about 1 month | ~ 5 Months |
Summary Recommendations:
In my opinion Takahashi is usually superior to the other products that I have used. It is expensive, and it is just plain good. I am equally pleased with the RCOS telescope. I am completely pleased with the Paramount ME and Takahashi NJP mounts. I strongly prefer Finger Lakes Instruments ProLine CCD with the Kodak 09000 chip over the SBIG options.
Finger Lakes Instrumentation Precision Digital Focuser, FLI's PDF. The focus control software is FocusMax.
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Other software recommendations:
PEMPro: (Return to Tracking section)
I have switched from PrecisionPEC to PEMPro for measuring and building PEC error correction tables for the ME's firmware. It is an excellent and comprehensive product.
*Legal disclaimer:
The preceding equipment analysis and recommendation are based solely on my
opinions and judgment. The recommendations are not based upon scientific,
demonstrable or documented evidence. So don't sue me just because you might not like my opinion.