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You can certainly do as you propose if you use the right sort of battery. I use one of these, but any sealed 12V AGM mobility scooter or golf buggy battery would do the trick: https://www.amazon.co.uk/gp/product/B07GDPPMNP/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1 Avoid any type of wet battery (traditional lead acid for example) as they're not good for transporting and can generate explosive gas when charging. Non-deep cycle batteries will die fairly quickly if used as astronomers tend to use them To charge up I use a cheap 'smart charger' - just connect the clips to the terminals and leave it plugged in when not using and it will keep the battery charged and in good condition. You do not want the battery to discharge too much as that will also kill it (and they tend to discharge over time): https://www.amazon.co.uk/gp/product/B01MY5UT1E/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1 I use a wheeled tool case to lug around all my astro gear, and the battery and charger are just fixed inside that. Just be careful that nothing metallic can sit on the battery terminals and short them out or it'll be a barbecue. You will definitely want a 12V fuse of the appropriate rating set in the positive wire as close to the battery as possible. Just add up the amps drawn by all your gear and go for the same or nearest rating up from that. Do ensure that the wiring is thick enough to take the current.

I'm working on setting up my new WO GT81 (the current 2019 version) with the WO FLAT6AIII flattener/reducer. I'm struggling a bit to understand the correct spacing as the diagrams and drawings provided by WO are pretty unclear and also inconsistent. I've got slightly elongated stars in one corner and edge which tells me that the spacing is not right and possibly a slight tilt somewhere in the train. So the setup is: GT81 -> FLAT6AIII (screwed directly the the M63 thread on focuser) -> OAG/EFW2 (screwed to M48 thread) -> ASI1600MM (screwed to M42 thread) The diagram below suggests that there should be 55mm between the back face of the 6AIII body and the sensor which is 6.5mm inside the front face of the 1600MM. I also need to allow a further 0.35mm to account for the 1mm thick filter (approximately) so the distance is actually 55.35mm. To get there I thus a spacing between the back face of the 6AIII and the front face of the 1600MM of 48.85mm (55mm - 6.5mm + 0.35mm). So having done that I have as close to the 55.35mm 6AIII to sensor spacing as I can get. I know it should be good since it's a straight swap of train from the M48 thread on the back of my SW80ED + 0.85x reducer to the M48 thread on the GT81 and FLAT6AIII M48 thread. The rear of flattener to sensor spacing for both setups is 55mm or so, and the ED80 setup was giving good results. Next I need to set the 6AIII adjustment per the table in the above diagram. The diagram below shows how to set the adjustment: This uses the Z81 (not GT81) as the example, but if you subtract the 55mm spacing from the 58.2mm spacing for the Z81 (both in first diagram above) you get 3.2mm (per the second diagram). So for the GT81 following the same maths you take the 60.1mm 'Backfoucus' value, subtract 55mm and thus set the adjustment to 5.1mm. All good, except there is a second diagram floating about showing different values: This diagram says the back focus for the GT71 is 64.1mm (not 62.1mm per first diagram), and for the GT81 it is 62.1mm (not 60.1mm). So in both cases it says another 2mm of adjustment is required. This is backed up by the 'adjust distance values of 9.1mm and 7.1mm respectively. I'm just wondering if anyone knows which of these two values (62.1mm or 60.1mm) is the correct one. I've currently gone with 62.1mm which isn't giving a great result (worse than my SW80ED and 0.85x reducer). Of course I can keep adjusting until I get it right, but due to the fact you need to screw the 6AIII in or out to adjust, it is painful as I need to unplug all the cables and remove the extension tube from my guide scope for each attempt, then reconnect it all and take a new sample image. I've got limited time and even more limited clear skies so was hoping for a bit of advice to try and get this nearer to right second time around? Thanks for any help you can offer.

With regard to the RA finder, the dew shield is usually totally inadequate, mine dews up very quickly. You could try making an extension out of some craft foam or similar, just cut a length, roll it up and use an elastic band to hold it on the end, or self-adhesive velcro for a better job. The eyepiece end is a total disaster, facing straight up at the sky usually with no protection. Keep it capped unless using it and ultimately yes you may need a dew heater for it. For the rest of the eyepieces, you can certainly use a dew heater, but keeping them in warm-ish pocket and swapping them regularly usually works for me. Some people make heated eyepiece boxes which do the same thing more effectively. For the XT8, it's probably only the secondary you need to worry about in most circumstances. That tends to get cold more quickly but to be honest I don't have many issues with my 10" Dob. The primary mirror in a closed tube Newt generally won't dew up unless conditions are extreme or you have been out all night since the tube acts as a giant dew-shield. You don't really want to be heating the primary since it can create a boundary layer of turbulence on the front of the mirror ruining the view. Some Dobs have built in fans to keep this layer moving and also cool the mirror. The moving air also prevents dew forming in the the bargain. Mine has one but I have never needed to use it (yet). Search for "Newtonian Fan" and you'll get the idea. Definitely do not heat the tube body, that will set up air currents that will ruin the views.

Placing the scope close to the house will delay the onset of dewing not make it happen sooner. The air contains a variable amount of gaseous water vapour, which will condense in to liquid water when the atmospheric pressure and air temperature meet certain conditions. We can't control the amount of water vapour or pressure, so primarily we care about temperature. When the temperature falls far enough, water condenses in to clouds or fog. In temperate latitudes with less water vapour, the air has to get quite cold for this to happen, but in the humid tropics, condensation can occur when it is much warmer. In the case of the telescope, if the lens or mirror cools enough, the adjacent layer of air also cools and water condenses on to the surface of the scope since it needs a nucleation site to start condensing. The mirror or lens mainly cools by radiation. Heat is lost to the environment in the form of infra-red radiation, but it is also gained from the environment by the the same means. The scope is radiating at + or - a few degrees or tens of degrees C, as is the ground and nearby objects like buildings. When the sky is clear at night, space is radiating at about -270 C. So there is a rapid net loss of heat from the scope to space. Placing the scope next to the house blocks some of the sky and will greatly slows the net rate of heat loss since the house will actually heat the scope by radiation. If you park your car next to the house, the windows facing it will dew/frost far less than those facing away since they experience a net heat gain whereas those facing the sky experience a net loss unless it is cloudy (clouds are warm vs. space). Placing the scope by the boiler vent would replicate the tropics, hot humid air, but otherwise the house is not the issue, quite the opposite. The keys are: - An insulated dew shield (e.g. foam) since this blocks the lens from seeing most of the sky (except the bit you are observing) and thus reduces the rate of net heat loss. Metal dew shields cool quickly so are less effective. - Cap the lens or tube until observing for the same reason. - Keep eyepieces in a closed, insulated box until using them. - Use a dew heater to offset the net heat loss. Heater is a bit misleading though, it should only be warm enough to keep the surface above the dew point. If it feels warm then it is too warm and will create local 'seeing' issues. - A bit of breeze is ideal, since air is a good insulator and if it is moving it won't stay in contact with the cold scope long enough to reach the dew point. You car won't dew up and (radiation) fog doesn't form on windy nights for the same reason.

Depends on how you are connecting the mount to the battery. If you add a 12V cigarette lighter socket wired to the battery you will probably be OK. The cigarette plug that may have come with the mount should have a fuse inside to protect against a short. (To change the fuse you usually unscrew the silvery ring on the tip of the plug). If you are running cables direct from the battery to the plug that goes in to the mount then I would add a fuse to the positive wire. You can get round fuse carriers and blade fuse carriers (that take standard car fuses) online. Check the mount's rating (in amps) and use the same value for the fuse or the next value up if not available. The thing to understand about batteries is that whilst the voltage is safe, they can supply a lot of amps, so if you get a short things can melt or even catch fire.

WO 61 definitely ticks all your boxes. Bought one for the Mrs recently and it is a delight to use; solidly build, focuser is super smooth, views are very good - no appreciable colour fringing on the Moon for example. Works well on the cheapo photo tripod as it is so light and compact. With dewshield retracted it is very portable, not quite a pocket scope, but definitely fits a moderately sized handbag. The only question would be mounting it for piggy-backing. It has a single tube ring with a vixen-style "foot" complete with a pair of tripod screw holes. Very handy for grab and go, but not so conventional for mounting on another scope.

The US legal system has the concept of punitive damages which isn't (generally) the case in the UK. So you can make a claim for way more than your actual losses and the court (or jury) can award them as a discouragement to others thinking of trying something similar. They generally get whittled down through a series of appeals after they are awarded, so initial claims tend to shoot for the Moon not expecting to get anything close to what is being claimed. Question is whether anti-trust regulators will decide to take a look at this whole mess and dish out fines or other sanctions. May be they'll consider the market to small-fry to bother with, but either way it is us consumers who suffer when companies behave like this.

Absolutely certain which is why I am just as surprised. Can only think there is a short somewhere or the pinout on the mount connector isn't as I'd assumed. Will figure it tomorrow when I open up the mount to see what's what. Suspect one or more of the chips will be fried though, so likely to require a swap out.

Ok well that was a complete disaster. Tested the mount output and found GND and 12V in the pins as shown in the AZ-GTi manual. Wired up the buck converter and tested fine. Was only getting 4.3V maximum on the output side after adjusting the trimmer. The battery pack was only putting out 11.4V so not too concerned. Wired the WiFi chip to the converter and TX and RX lines. Triple checked for shorts, solder bridges, etc. Plugged it in, powered on mount, small puff of smoke and now have a dead mount board (no response on both axes error). Will have a look in the morning when less annoyed, but cannot see what I got so wrong. Will take a look at the board tomorrow to see if anything can be repaired but doubt it, otherwise it's 50 quid for a new board and still no WiFi

I haven't taken mine apart, but other AZ-Goto users report that the RX and TX lines are connected on the mount board, so it's a half duplex setup. Hence my wondering about the potential flow control line as usually for bi-directional comms on half duplex you need a control line to ensure that both ends aren't trying to send at once. On the other hand the AZ-GTi wiring diagram suggests that only the power and RX/TX lines are actually connected. I do wonder if the AZ-GTi is full duplex, but I guess I'll find out soon enough.

Ah here we go, given AZ-Goto and AZ-GTi can use same cable, and presumably same pinouts at handset end, this thread (and manual) give the RJ12 pinouts. I'll give that a whirl and post a wiring diagram when I have it working. Cheers all. https://stargazerslounge.com/topic/327773-diy-ftdi-eqdir-usb-adapter-rj12-wiring/

Yes from what I've seen they're the same cable and pinout for the two. From what I can see so far (RJ12 connector, clip facing away, pin one one the left): Pin 1 not connected Pins 2 and 4 are RX and TX, which are connected inside the mount, so could connect one or the other to both RXD and TXD on the WiFi board. Have seen posts about people seeing outgoing commands reflected straight back, so presumably correct. Pin 3 is +12V so goes to IN+ on the buck converter. Pin 5 is GND so goes to GND on buck converter and WiFi board. Pin 6 is Flow Control (from other post). Not sure what to do with that one? Any ideas welcome.

I have all the parts in hand as the slow boat from China has finally arrived about a month later, but what I'm looking for is a pinout for the Skywatcher Az-Goto mount. The handset connects using an RJ45 (handset end) to RJ12 (mount end) cable and I need the RJ12 pinout. Can anyone point me the right way? Note that the manual and the web have diagrams showing the pinouts for the RJ11 handset to PC connector, but that is not what I am seeking.

Only up to the age of 50 or so. Beyond that you'll get down there, but probably not back up!

For the bright planets and Moon you won't be that affected by street lights provided you can position so you are not looking straight at or very close to one. So viewing them from the front garden is a good option assuming they clear whatever is on the other side of the road. Be prepared to bend down a long way to view things at low altitudes. You can make a solid wooden base to raise the scope a foot or two higher if you have some basic woodworking tools, or a chunky second hand coffee table or similar can be pressed in to use. For DSOs viewing higher and nearer the zenith gives the best views, though it can be rather tricky to aim a Dob straight up just because the mechanics mean that getting from one side of the zenith to the other often requires a 180 degree rotation of the base. With the tube pointing straight up you don't have a long lever to make the turn, so it can be an effort and rather jerky. Once you are down to 80 degrees or so from the zenith it's fairly easy. Don't let that put you off, it's still a million times better than a cheap/wobbly EQ or Alt-Az mount. Unless you have a flat horizon all around, and most of us don't, you have to plan ahead and be prepared to wait for the right time of year to view a lot of things anyway.

Heavens above has predicted and historic data for the ISS amongst other things. It is more helpful for finding ground tracks once you have identified a pass in in your data though: https://www.heavens-above.com/PassSummary.aspx?satid=25544&lat=0&lng=0&loc=Unspecified&alt=0&tz=UCT You need to set your lat/long (at the top right of page), you probably need to set it halfway between your location and GRAVES location to ensure passes that are mutually visible passes are included. You'll figure it out once you look at the ground track maps. Set passes to 'all' rather than 'visible' since we don't care about daylight or illumination by Sun. Then you can use the arrows at the top of the list of visible passes to go back in time. Once you see a pass that corresponds to your capture you can then click on the pass, and on the detail page there is a link to a ground track map. Just take care with timings and time zones/daylight savings. The data gives times local to the observer's location not UT, and of course your 'location' may be in Europe not UK. Also Spectrum Lab times tend to drift quite badly for my setup, many minutes out so you need to exercise some judgment to correlate passes and captures. Still it can be interesting - here's a slide I made overlaying two passes and ground tracks, showing the effect of different ground tracks and rates of change of radial velocity/return frequency for example:

Key points: - If you go for OSC the (typical) RGGB Bayer filter will mean that only the R pixels receive any signal (as the Ha wavelength is in the red). Thus three quarters of your pixels will be more or less black. So mono for Ha solar imaging. - A larger sensor is helpful in framing targets, but equally consider the size of the sweet spot of your scope. There is no point in spending on a large sensor if you're going to crop out a lot of the image due to it being off band. - Consider the resolving power of the scope (Dawes limit). If you use a Barlow to increase magnification beyond the resolving power of the scope, you're wasting your time. - Consider the camera pixel scale (arc seconds covered by one camera pixel) vs. the resolving power of your scope. You want your pixel scale to be half the resolving power (Dawes limit) of the scope to fully sample the image, but it may ve better to have a larger pixel scale and get the whole target in the frame than fully sample a smaller part of it. - Cooling is really not necessary for Ha solar, but if you're going to use it for deep sky too may be worth the cost. I use a 174MM with a Lunt LS60 which allows both full disk and 2x Barlow for more close up views.

Just to add another data point, once I had a free replacement posted from Bresser, I got a friend to clean the original one using an ultrasonic cleaner. It worked a treat - 30 minutes in the water bath and good as new without the use of any chemicals or razor blades. I think the only other point to note is that the bath has a plastic basket rather than a metal one, so no risk of scratching the filter. Cheap ones go for about £30 on Amazon; not worth it for this one job but useful if you already have one or know a friend who does.

Just to add another data point, once I had a free replacement posted from Bresser, I got a friend to clean the original one using an ultrasonic cleaner. It worked a treat - 30 minutes in the water bath and good as new without the use of any chemicals or razor blades. I think the only other point to note is that the bath has a plastic basket rather than a metal one, so no risk of scratching the filter. Cheap ones go for about £30 on Amazon; not worth it for this one job but useful if you already have one or know a friend who does.

I built a DIY pipe pier for my NEQ6. The whole observatory build process is documented in detail here (parts 2 and 3 cover the pier): https://www.blackwaterskies.co.uk/series/a-small-imaging-observatory/ Bear in mind this was for imaging, so I only built the pier using a 1 metre length of 6 inch steel pipe delivered from eBay (as was the rebar), filled with bags of ready-mix concrete. You'd probably want a longer pier (and thus more diameter) for visual. A plastic pipe would certainly work if you can find an appropriate length and diameter. Sourcing long, large diameter metal pipes from eBay is a challenge since they're hard to deliver and so tend not to go much over 1 meter in length. One option I've found is mild steel flue pipe. It is in no way strong enough to act as a pier on its own, but would be ideal if painted and filled with concrete and rebar. You can buy it in 1 metre lengths which are formed to slot together to make whatever length you need, and being thin mild steel wouldn't be too hard to cut one pipe down to make the exact length you want: https://www.ebay.co.uk/itm/STEEL-FLUE-PIPES-ELBOWS-COWLS-FROM-4-INCH-UP-TO-8-INCH/172496012877?var=471340394224&hash=item282990464d:m:mOsMuGoz-8fF5kPxl3LXjrw You'd probably want 2 x 180mm or 200mm, 1 metre lengths. For the pier head adaptor, I went with an off-the-shelf NEQ6 extension tube: https://www.firstlightoptics.com/sky-watcher-mount-accessories/skywatcher-eq6-extension-tube.html This is designed to fit the NEQ6 mount head perfectly, and my blog posts describe how to drill out the bottom plate of the extension tube and fix it in to the concrete pier using stainless steel studding (again bought from eBay). Hope this gives you some ideas.

You can: - Disable all driver updates in the system settings, just Google for it, but it's a very blunt instrument and you probably don't want to go there as new devices and software will often work better if you are using latest drivers. - If you're using Win 10 Pro then you can use the group policy editor to disable driver updates for specific device IDs, but not possible in home editions. - You can go in to device manager and select the properties of the device, then choose 'roll back driver' after it has auto updated. This may prevent it re-updating for a while, but I never had much luck and would regularly have to roll back or reinstall the working Prolific driver. In the end, you don't want to be wasting limited clear skies chasing these gremlins and personally I just bit the bullet and bought an FDTI cable which works flawlessly. The Lynx ones also look more professional and better made, I was always worried with the hi-tec ones that one accidental yank and the cable would part company with the plastic box housing the board.

See this: http://www.prolific.com.tw/us/newsdetail.aspx?news_id=35 I don't know what version of Windows you are using, but if Windows 10 that chipset doesn't have a supported driver and Windows 10 will update (break!) drivers automatically. Is it the Hitec Astro EQDirect cable by any chance? If so you're definitely going to have problems with Win 10 and possibly earlier versions of Windows. Prolific produced the original chipset but it was then ripped off by loads of far-east chipmakers who basically cloned the chip, sold it cheaper but used Prolific's drivers so both stealing their IP and the money they invested in writing, testing and updating drivers. In the end Prolific released an updated driver that tries to detect the clone chips and stops working. You used to be able to get around the problem by finding and installing the older driver version, but with Win 10 it would happily re-update to the later driver next reboot unless you went through a bunch of shenanigans to prevent it. The upshot is that you'll save yourself a lot of grief by moving to a new EQDirect cable with an FDTI chipset, e.g. the Lynx Astro models.

Might be worth having a look at this if you're using PI, or even if you're not, to understand the general principles of weighting. https://www.lightvortexastronomy.com/tutorial-pre-processing-calibrating-and-stacking-images-in-pixinsight.html#Section5 Bottom line is that if you combine two stacked masters containing 20 subs each, simplistically you'd weight them 50:50, but what if 10 of the subs in the first master are "poor" and only 2 of the subs in the second master are "poor"? Would you now think 50:50 is the correct weighting? The only practical way to ensure correct weighting is to stack everything in one go.

Regarding "Zooming in", up to a point it's purely a display issue (i.e. adjusting FC to show a smaller frequency range), but after that point zooming further just increases the height of each frequency bin without actually gaining resolution, same as for a digital image once the individual pixels become visible. To understand more I'd suggest you read this: https://www.qsl.net/dl4yhf/speclab/fftinfo.htm The basic idea is that at some point, you will have to start trading off resolution in frequency vs. resolution in time. To decrease the size of the frequency bins (i.e. the span of frequencies covered by one waterfall line) the FFT process needs to collect a larger block of samples, which takes a longer time, thus increasing the time span covered by each waterfall update. The point at which this becomes an issue is a function of the sampling rate of your dongle and the processing power of your PC, but once you reach it you have to make that trade off. The settings that control this are mostly here: https://www.qsl.net/dl4yhf/speclab/settings.htm#fft_settings Don't be afraid to play about with a copy of your working configuration - you might find it easier to tune in to the test beacon or an FM radio station to see the effects of each tweak rather than waiting for meteors.

The offset up and down buttons change the offset, the display up and down buttons change the frequency scale by nudging the VFO, so you can use both to get the right combination for your dongle. Once you are happy, right-click the Tune to Graves button to amend the VFO value it tunes to permanently and save your settings. If I recall the chosen offset will remain set in the config file until you change it. I'm away from my equipment so recollection may be faulty here!