Hardware Issues and Reviews


SBIG FW8G-STT (focusing)

Meade RA clutch lever

Meade vibration supression pads

Homemade electric focuser for the Meade LX600

Polar alignment telescope

Boltwood II vs. SkyAlert cloud sensors review

SBIG FW8G-STT - Issue # 1

Out of the box there was an issue, focus stars looked like donuts cut in half. No amount of turning the focus knob of the device would bring any improvement. In the autoguider image below, you can see a way out of focus star to the right.

I didn't think this would be a difficult problem to fix, but had a fear of voiding the warranty if I tried. Tim Puckett of SBIG was kind enough to call me and said crack it open, warranty will still be good. After opening it up, I found there was very little range of motion for the focus block.

The image below is of the focuser block all the way out.

Below is with the block all the way in. Like I said, not much range of movement.

Undoing the jam nut (not visible in the photo) and flipping the block over revealed the problem. A long screw is used as the "pivot point" for the autoguider shutter. This screw was nearly all the way out.


The fix was simple, turn the screw back in until snug, then back it out a bit so it doesn't bind the shutter.

The focusing block now has full range of motion, in the photo below it's all the way in.

Someone from Cyangon, Diffraction Limited, or whoever they are that bought out SBIG, said that the screw must have worked it's way out during shipping. I think that's nonsense. More likely the unit was assembled and never tested before shipping.


After reassembly and testing, problem is solved.

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Anyone who has ever actually used the stock clutch lever in the dark and/or in the cold knows that whoever designed this part never used it. It's very difficult to use with bare hands, and forget about it with golves on. To force it into actual usefulness, only a few modifications are necessary.

1. Remove it from the telescope.

2. Drill and tap a hole into it to fit whatever suitable screw you have handy.

3. Find a piece of aluminum to serve as an extension, and drill a hole in that.

4. Assemble and enjoy.

See photos below.



If you don't have a tap, you can do something simiilar by just finding a self-tapping metal screw and drilling the correct sized hole.



I had a piece of aluminum u-channel lying around, so I used that as the lever. About anything would work, but aluminum won't rust and you don't have to paint it.



To keep the bolt from working loose, I drilled a smaller hold and tapped a short piece of music wire into it.



I I put a spacer in to elevate the assembly slightly. This one isn't stainless steel, but I'll swap it out for one soon.



The finished product. No more broken thumbnails or having to use a screwdrive to loosen the RA clutch.

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They came with the telescope, so I foolishly assumed they should be able to support its weight.

After a couple of frustrating and wasted nights wondering why my tracking and pointing had gone south, I found these. They had been in place for less than six months. Why two of them broke is a mystery, my setup actually weighs less than the stock 12" LX600 with wedge, since I don't have the StarLock mounted.




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The Meade 12-inch LX600 - focusing issue and fix

I wouldn't want to leave anyone with the impression that I am not happy with Meade products. I could be happier with them, but for their flaws (which all have work-arounds), for the money, in my opinion, they can't be beat.

One of the issues that has come up with the f/8 LX600 is that with my imaging train (SBIG AO-8T, self guiding filter wheel and STT 1603 camera) things will not come to focus if I'm also using a crayford-style focuser. Not sure who to blame for this, as I've not heard that it's a widespread problem. In any case, the blame isn't as important as the fix. In that regard I can only thank Meade for finally fixing the mirror-flop problem in their later model SCT's.

In the past I've used the Optec crayford-style focusers, and have been very happy with them. But with the new f/8 version LX600, neither that focuser, nor the Meade crayford focuser, will come to focus with my imaging train. Time for another home-made solution, which, in short, is making an electric focuser that eliminates the need for an on-axis craford focuser, but still provides the convenience of electrical remote focusing.

Mechincally, the solution isn't hard to implement, but it does require a bit of electrical work. The focusing port on the telescope provides about 12 volts DC to the focuser, and when focusing is changed from "in" to "out", the telescope simply reverses the polarity. This is great if you have a 12 volt DC motor and gearbox you can couple to the focusing knob, but the motor/gearbox I had on-hand has a 3 volt motor. So I had to step down 12 VDC to about 3 VDC, and also provide not only positive but negative voltage to the motor.

Turns out the solution isn't difficult. A common voltage regulator is the NEC 956, which is an adjustable positive voltage regulator. Wiring up a simple circuit I was able to bring the native 12 VDC from the 'scope down to about 3 VDC, which made the gearbox motor much happier (since it's a 3 volt motor). The negative voltage issue was dealt with as simply, using an NEC 957 negative voltage regulator. This circuit now allows the focus to be adjusted either "in" or "out" by implementing the controls native to the LX600, and by using the focusing features in TheSkyX as well.

Some would argue that this isn't as good as a crayford focuser, and I would completly agree with them. But stuck with "not as good" is much better than being stuck with "nothing at all", and since mirror flop is greatly reduced in the LX600 (compared to the LX200), and things come to focus regardless of the temperature or filter, I'm quite satisfied with the solution.

Beta testing. The breadboard is tie-wrapped to the arm holding the focusing motor. No need to drill any mounting holes in the 'scope, is has unused tapped holes and screws that serve nicely.

The two trim potentiometers allow the voltage that controls the in and out speed to be independently adjusted.

The size of the pullys really isn't important, since the trim pots allow a wide range of voltage (speed) adjustments.

If you feel the need to go back to manual focusing, just slip the belt off one of the pullys, not much tension is requied to keep it on, so it slides off easily.

Just don't loose it in the dark. :-)

After testing is complete, all components will be soldered to a circuit board and housed in a weather-resistant enclosure.

Advantages of this system over a Crayford focuser is cost (my total investment in parts can't be over $30), and not being limited to a Crayford's narrow range of focus travel.

Disadvantages are that the mirror can't be locked down so mirror flop and focus shift is a possibility (but much less of one than in the XL200's). "Pretty picture" folks may find this objectional, but for variable star and asteroid work focus going slightly out of adjustment isn't a show stopper since the photometry software will easily compensate for slight focus shifts.

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Polar alignment 'scope

One real pain that any LX--- user goes through is getting a decent polar alignment. Necessity being the mother of invention, I've come up with my own way to make this process much easier.

The concept was this...find a polar alignment telescope with a polar alignment reticle, figure out how/where to permanantly mount it on the telescope, and make it super-easy to use.


The Polar Scope is mounted in two home-made rings. This did require drilling and tapping into the fork, but this wasn't that difficult. The 'scope rides in two ball bearings, and the usual adjustment screws are obvious. After getting the main telescope polar aligned to the best of your ability (using drift alignment or some other method), just adjust the polar 'scope to match the Big Dipper and the position of Polaris, lock down the adjustment screws, and you now have a way to polar align that doesn't involve being a yoga master or having back surgery.

The 'scope is a polar alignment 'scope out of a Meade LX something-or-other. The two ball bearings are just friction fitted with electrical tape.

When you look through the polar 'scope, this is (more or less) what you see. You simply rotate the 'scope until the Big Dipper and Cassiopeia are aligned as in the reticle (remember, it's mouted in ball bearings, so this is a very easy procedure), then mechancially adjust the main telescope until Polaris is centered in its circle. Of course this photo was taken during daylight, but you get the idea.

Advantages of this method is simplicity, no need to have a laptop or other imaging device, and price. I was able to make the rings from scratch out of cast aluminum, but it wouldn't be difficult to put a set of commercially-available rings on some extensions to lift them high enough so that the GPS antenna and other stuff doesn't get in the way. In any case it's cheaper than the $300 polar-alignment cameras on the market, and it does't require any imaging equipment.

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Boltwood II vs. SkyAlert cloud sensors review


This review of a side-by-side comparison of the Boltwood II Cloud Sensor from Diffraction Limited/Cyanogen , and the SkyAlert Cloud Sensor from Interactive Astronomy. Both units were purchased new by the author. The sellers were not made aware that I would be doing a review of their products, so no temptation was held to send me anything other than than a typical unit.


I have BS in Earth Sciences, worked in meteorology for the U.S. National Weather Service, upper-air meteorology for the U.S. Army, and aviation weather for both passenger and cargo airlines. I hold Commercial pilot with airplane single and mulit-engine land instrument ratings and a flight dispatcher certificate from the Federal Aviation Administration, and am a past member of the American Meteorological Society. In short, I have a vast amount of meteorological experience.

Astronomy was my first love. When I started looking through a telescope the CCD had not yet been invented. My path through astronomy started with visual observing and sketching, then film astrophotography, then to CCD imaging (staring with the home built CCD Cookbook camera). I traveled to South America to see Comet Halley in 1986, have viewed two total solar eclipses, discovered one asteroid and thirteen variable stars, and produced dozens of minor planet and variable star lightcurves for the Minor Planet Bulletin and the AAVSO.


Both the products discussed in this review are meant to serve as one line of a defense-in-depth against inclement weather wreaking havoc with an unattended telescope. Seemingly specifically designed to protect an observatory (whether local or remote) with a motorized roof, they also serve to keep the observer in touch with the weather at the telescope even if the observer is only a few feet away. While visual observers likely won’t find much utility is such systems, imagers that want to make the most of every minute of darkness will find such product near-indispensable.

In my case, I usually sit on a single target all night, taking image after image. Needing my sleep, I will usually go to bed long before the night’s imaging session is over. In the past that was an exercise in faith and hope, as the possibility of precipitation and high winds popping-up and doing bad things to expensive equipment was often in the back of my mind. With products such as these I can literally sleep better knowing that I can expect a decent warning before bad weather moves in.

Both these products sever as weather stations of sorts. What they lack is measuring wind direction and the amount of precipitation, i.e. a “rain gauge”, and for their intended use these features are not of particular value. A feature they have that’s normally not part of a consumer level weather station is the ability to measure the sky temperature, and derive the presence of clouds. This is done by comparing the ambient air temperature with the sky ambient temperature, performing the necessary math, and presenting the user with an indication of cloud cover.

These units also have moisture sensors that can detect liquid precipitation as well as snow, sleet and the like. It’s unknown if either unit can detect hail, but since the presence of hail is normally linked with rain, high winds and low clouds, sufficient warning should be available to the observer to take action, or to let the software of each product to close the roof of the observatory before significant damage may occur.


The author tested as may features as practical. Some features, such as software-commanded roof close, was not tested since the author does not have an observatory with motorized roof capability. Any information presented that was not personally tested or observed by the author was obtained from the user manual of each device.



Boltwood II


Sky Ambient Temperature (cloud cover) Yes


Ambient Air Temperature (1) Yes Yes
Wind Speed (2) Yes Yes
Wind Direction No No
Humidity Yes Yes
Dew Point Calculated from humidity sensor and ambient air temperature sensor vaules. Calculated from humidity sensor and ambient air temperature sensor vaules.
Atmospheric Pressure No Yes
Wetness/Rain Sensor Yes Yes
User can calibrate sensors No Yes
User configurable alerts Yes Yes
SMS Text Alerts No Yes
E-mail Alerts No Yes
Graph can be customized by user (3) Yes Yes
Audible Alert (4) Yes Maybe
Automotic roof close when alert is triggered (11) Yes Yes
Display can be viewed on a remote computer (5) Maybe Yes
USB interface to PC (6) (7) Through an adapter box 25 foot active USB cable
Power supply voltage (8) 24 VDC 12 VDC
Temperature limits for adapter box (9) - 0 degrees C to +40 degrees C No adapter box required
Sensors can be replaced in the field No Yes
Interfaces with other Software (10) Maybe ACP, CCD AutoPilot, CCD Commander and others.
Will command 'scope to park before roof close (11) No Maybe
Warranty 12 Months 12 Months
Money back guarantee No 30 Days
User Manual last updated August 2012 February 2017
Customer Service (12) Poor Excellent


1. Both units showed high ambient temperature reading during the day, especially when the sun is shining on the units. This is to be expected, since the units are designed for nightime use. With the SkyAlert a "Solar Offset" setting, which allows the user to adjust the ambient air temperature when direct sunlight is shining on the unit, is provided. The Boltwood II does not have this capabiilty.

2. The Boltwood II uses a “hot wire” type anemometer. It has no moving parts, but in my experience lacks in accuracy.

The SkyAlert has two wind speed options, the default thermal anemometer, or a 3 cup anemometer available as an extra cost add on. I have the 3 cup mechanical anemometer version, and no experience with the static sensor option. The mechanical anemometer can stop working during freezing rain.

3. The Clarity II software that comes with the Boltwood II allows a very limited ability to customize the graph (seven options). The SkyAlert Graph has dozens of customizable options.

4. This means an audible alert on the computer the software resides on. In combination with SMS or E-mail alerts set up on the SkyAlert unit, an audible altert can be heard when the SMS message is sent to a portable device (smart phone) depending on how the portable device is configured. The Boltwood II provides the option of different beep tones on the PC.

5. Per the Boltwood II Users Manual remote operation is possible with software the user must write, or obtain from a third party. The Users Manual also states that “running on via [sic] some form of remote console software from another computer, there can be problems”. SkyAlert has a free utility that can be downloaded from their web site to allow remote operation. The author uses this, and it functions as advertised.

6. Longer cable lengths are available from both manufacturers.

7. My SkyAlert would not connect when attached to a USB 3 port, but would to a USB 2 port.

8. The Boltwood II Users Manual says that the adapter box “should work at 12 V but has not been tested.”

9. The Boltwood II Users Manual gives the operational limitations of the adapter box as -0C to +40C, however in the WARNINGS section of the manual paragraph “g” states “The adapter box is for indoor climate only.” Indoor climate conditions are not defined in the manual. The Users Manual doesn't resolve the contradiction between +1C being considered "indoor climate conditions".

10. The Boltwood II Users Manual says that the device can “Provide the Cloud Sensor II’s data via a COM (ActiveX) or a file interface, to other software.” No list of “other software” is provided.

11. This feature is available if the user has the SkyRoof software installed and working with the SkyAlert unit. The Boltwood II software may command a roof close that in some circumstances could strike the telescope. This feature was not tested by the author. Both the Boltwood II and SkyAlert (with the optional SkyRoof software) will command a roof close after a power loss. Thus it is possible that the roof may close and strike the telescope even when no inclement weather is near. The SkyAlert needs the separate SkyRoof software to command a telescope park and roof close. This functionality of the SkyRoof software is not a part of this review, however SkyAlert documentation states that SkyRoof will attempt to park the telescope before closing the roof.

12. I've had occasion to contact each seller several times. In the case of Diffraction Limited (13 e-mail contacts and five fourm postings) in only two cases did I receive a reply in less than three days. I have had over ten e-mail contacts with Interactive Astronomy (SkyAlert) and in every case have received either an e-mail response or a phone call in less than three hours).

On 9 January 2018 I sent Diffraction Limited a technical support request, along with the appropriate log files, concerning an issue with the Boltwood II. As of this writing (19 February 2018) I've never received a call or email from their technical support.


Both units perform their basic functions as advertised, with the exception of the anemometer on the Boltwood II. It could be that the no-moving-part anemometer on the SkyAlert unit works as poorly as the Boltwood II anemometer. I don’t have that version so I can’t comment on it. The Boltwood unit would consistently show a 3 to 4 MPH wind while the atmosphere was completely calm,and would occasionally show an 18 to 20 MPH wind when the true wind speed was in the 12 to 14 MPH range.

Having been running the Boltwood II and SkyAlert units side by side for several weeks, the SkyAlert unit is, in my mind, clearly the better value. It can be used remotely with free software, provides graphing that can be highly customized, email and SMS alerts and allows the user to calibrate sensors. It has FTP functionality than can load a graph of weather conditions to a web page. All sensors are field replaceable. The Boltwood II has none of these features or benefits.

The SkyAlert has virtually all the functionality of a traditional consumer "weather station", except for the lack of a wind direction sensor. If the user can live without that, the SkyAlert can do double-duty as observatory protection and a weather station. Since the Boltwood II lacks not only wind direction data but also barometric pressue data, and has no method for ambient air temperature adjustement (it will most always report too high a temperature when in sunshine, see note 1) it's less suited for conventional weather station duty.

The SkyAlert unit comes with a 30 day money back guarantee. There is no money back guarantee with the Boltwood II. Once you take it out of the box and mount it, Diffraction Limited considers it in "no longer new condition" for which no refund will be given.

Probably of most benefit to a true “remote user” is the capability of SkyAlert (with the optional SkyRoof software installed) to send a park command to the telescope before closing the roof. To those using a rool-off roof observatory, where when in operation the telescope is above the roof line, this feature can move the telescope to a safe position for roof closing. The Boltwood II has no such documented capability, and could result in the roof striking the telescope during a software-commanded roof close because an alert threshold has been reached or a power failure has been detected (see note 9).

Best of all, the basic SkyAlert unit (without the 3 cup anemometer option) costs $749. The Boltwood II with the shortest cable option costs $1,795.

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Questions/comments, E-mail me at john at theastroimager dot com