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SimM

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About SimM

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    Nebula

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    Hampshire UK
  1. Lenovo sell a car charger to USB Type C. Many newer laptops can be powered by this type of input. 7Ah battery is at the low end but expect better from your car battery. Even if you can get it to work it would be best to see if the laptop can be powered but not charged and in a low power mode. If that’s not possible then a battery that powers your scope and dew heater etc. isn’t going to last. Trying to invert a battery to 240AC and then using a charger isn’t a viable thing from a small battery. Simon https://www.digitaltrends.com/computing/charging-via-usb-c/
  2. The App has a night mode, but the advert is not switched to red! On my iPhone I set the colour filters on and accessibility shortcut to Colour Filters. Three clicks and the screen switches between colour and red. The intensity and spring properties of the advert are eliminated. Similarly, in an App like Sky Safari, the menus are not switched to red and any switch to another App will be in colour - until the “three clicks” which affects all parts of any App.
  3. I have a “collection” of four old eyepieces - no undercut. On the diagonal there are two screws (bolts) with v. fine threads. New OTA and a new EP with an undercut. At first I thought this would be a problem but I realised that it takes 9 half turns to fully undo the screws but 2 half turns to retract the screws so that the screw is retracted into the mount and the EP slips out. So I settled on 3 half turns is all that’s needed to retract the screws.. So two screws and an undercut looks to be a simple solution but also a more reliable one. I haven’t handled a twist to lock or compression style fixing but the size of these doesn’t seem to be standardised. Since some of them push a ring sideways the EP isn’t held as securely as the two screw method. I can see this style being difficult to release because the mechanism eventualy sticks/twists. So the old method of two screws doesn’t seem to be bettered? It doesn’t look sophisticated but it doesn’t seems to cause problems either? Simon
  4. I realise this isn’t a real test. I did a polar align and some error numbers drop to 0. The RA now varies only around 2 seconds. Seeing the numbers change was a worry but it’s only by a tiny amount. Nowhere is M Az M El explained.
  5. Decision made/ordered/anticipated... I had some more thoughts and decided to get B-P Hyperion eyepieces and an (ideally BH) case. The target OTA is my EdgeHD 800 and not my Newtonian. I won’t be buying a 2” diagonal just yet. The “thought process” for me isn’t entirely straightforward and perhaps I have a tendency to over think things a bit too much? My “need”is satisfied by 8mm, 13mm and 21mm (high) (medium) (low) and coincidently about 3/4 x F/10, 1 1/4 x F/10 and 2 x F/10, that’s sometimes suggested as a “guide”. I also “want” a wider view satisfied by 24mm (wide) which has an exit pupil 2.4mm (for my tired “old” eyes). For the moment I don’t want to replace my diagonal with a 2” one, so a true low wide TFOV EP isn’t a priority. Depending upon UK seeing conditions I can appreciate that the 10mm would sometimes give better viewing than trying to use an 8mm so also adding this to the “mix” would be worthwhile. I can’t see a reason for getting the 5mm as it is about on the seeing limit of 3/4 x F/10 x 2/3 and in the UK not worth the trouble. The 17mm would be quite nice (a Morpheus 17.5 would be even nicer). Excluding the 5mm I found it cheaper to buy 5 eyepieces and a case but add the 17mm later it becomes more expensive than the full kit. Common sense says buy the 5 eyepieces (and avoid the temptation) later to add the 17mm or 17.5mm. My credit card reveals something else because (clearly I can’t justify that) it shows that I bought the full set. I don’t plan to use all the eyepieces in an evening. More likely I will pick a low, medium and high that’s skewed a bit lower, normal or higher, if that makes sense, especially as UK skies are very variable too. Simon
  6. It’s been a while, so you have probably figured this out - but for anyone else wondering what’s going on... The D type connector found on some EQ mounts is serial, but it’s not RS-232. The interface for both types is “serial” but the EQ mounts uses either 3.3V or 5V. The RS-232 standard is 12V. Plugging two PCs together with RS-232 “works” because both are using 12V and see the correct voltages at the receiving end. Connecting the mount’s serial connector to the a PC is probably not going to work because the voltage thresholds won’t be reached. If an interface doesn’t work, then lowering the serial bit rate (speed) can work. But if it’s in any way flaky then it’s best avoided. Using the wrong voltages won’t necessary “fry” the electronics because they can protect their inputs e.g. limit currents and RS-232 works. RS-232 can work in one direction when voltages are different because a higher voltage can be tolerated. In the other direction it may not work because the full 12V swing is expected and crossing the threshold from zero to one’s doesn’t occur. RS-232 is not just one standard. Although the speeds are common the operating characteristics vary. When PCs were in their infancy and it was possible to make stuff on a breadboard, two types of chip were available, parallel and serial chips. These were TTL compatible chips and the serial chip could send/receive data but couldn’t generate the 12V required. For this, there were converter chips. Actually receiving was OK because the voltage swings can be detected (resister dividers). Maxim chips did this and were popular. TTL chips were soon replaced by CMOS and the voltage became less important. Later when processor speeds increased, lower voltages were used. So now it’s very common for chips to work on 3.3V. In the mount the electronics could be 5V but more likely it will be 3.3V. The inputs to these chips are protected against higher voltages so damaging them is unlikely. On most laptops there probably are USB ports and no RS -232 ports. There are cables available which convert USB to RS-232. The type you need is not converting to 12V so a “generic” one is the wrong choice. It’s like connecting a PC to your mount, which doesn’t work. A flaky link is something to be avoided. Cables for conversion from an Astronomy shop have advantages: they can support longer cables, be flexible and work at lower temperatures and at the USB end they use better chipsets. USB need a Windows driver and the better ones keep the same COM port e.g. setup becomes consistent and plugging into any serial port works. I have theHEQ5 Mount, it doesn’t have a serial mount input. Instead it relies upon a port on the hand controller. MyHC is the latest type so only has a USB port. I could use a USB cable to the mount and skip the HC completely. I will be using the HC in a PC direct mode. Here it talks to a PC USB to USB and passes this through to the mount. In effect the HC is an expensive USB to serial (low voltage converter. Since it has no other job to do in this mode, it can be expected to work very reliably. SW don’t do themselves any favours because they don’t update the documentation. Most people assume that they still include a serial connector on the HC base but they don’t. To see the V5 HC search for ORION handcontroller. Technically any Mount has serial input because the ports include serial on some of the pins, but to use them requires a special cable. Simon
  7. I have read all the tips - thanks. It seems to be take it outside and then take the cap off, take the cap off before taking it out. Always put the cap on before bringing it inside and when it's done, leave the cap off to circulate the air before putting it away. Best is to keep it close to the outside temperature e.g. from the house to the garage to the back yard. Also learned hat some of these rules don't always apply e.g. different seasons and the house temperature vs outside.
  8. John - Greetings from up top! I was originally looking at an Alt/Az mount e.g. an 8SE or Evolution 8. But I realised that although I don't particularly like equatorials, this is the way to go for any type of in-depth photography. My dislike of equatorials comes from a misunderstanding. My old mount can be setup as Alt/Az by removing the wedge but I tried to point the equatorial mount like a Dobsonian and it (obviously) just didn't work. I now want a mount that has GOTO so the complexity of driving the equatorial has been removed. Also with modern astronomy Apps and at least half an hour and a cup of tea, one can see how things work and it's no longer the mystery it was. When I was comparing scopes, I include WiFi to compare like with like e.g. adding it to an 8SE and having it on an Evolution. Now that I have a new mount HEQ5 and an OTA EdgehD 800 I'm not so bothered by not having WiFi. My HEQ5 has USB on the HC and a Direct PC mode that allows a computer to control the motor directly. This means I can update the HC (already done this) with my PC. Also many programs can talk through either Serial (but now USB) to the scope. With the WiFi adapter - if you use an iPhone or iPad - isn't there a restriction that you can only talk to it one App at a time so it require two devices (so I read) but not for Android. I was planning to use Sky Safari to control the scope. But as I work out what my workflow will be, I may use Sky Safari to setup an observation list, but it's not much trouble to instruct the HC to move through my list. I like having the App with the compass enabled or AR to see around the sky whereas a few decades ago I would have resorted to a planisphere. So aligning to a particular star isn't a challenge because I can see the constellations and brighter stars in real time. Waiting for a clear sky is more of a challenge though. I also have a jump start battery. I bought one and it's a low cost option. I have a 17 Ah battery in a plastic case. It's important that the scope is driven with a good power supply that's well regulated and doesn't dip out. The starter unit gives this because the battery output is directly accessible. My SynScan allows 2 or three star alignment and then a Polar alignment without needing a polar scope/. I have the polar scope and know what to do, but for folks standing on their head e.g. down under I understand the stars you look for are dim and it's not so easy to find them. So this method must appeal to you. Simon PS if we have all the clouds then you must be having excellent night skies?
  9. I asked R.V.O. which dovetail would be added to EdgeHD 800 and they say if it's a Vixen mount then the bolts/holes are setup for a Celestron Vixen bar on top. Or if's Losmady then one of the Celestron Losmady bars can be used. However, when I check the position of the free bolts/holes e.g. to the right of the finder (above the shiny label) the holes doen't line up. I thought it's odd that they don't line up but I also noticed that centre of two bolts/holes at the back of the OTA are lined up with a bolt/hole at the from of the OTA. I have the Vixen mount, but of I had the Losmady equivalent, then they may be using these three holes e.g. getting stability across the width of the dovetail at the back and support at the front? This would make sense because the same front/back OTA covers could be used for the other type of mount e.g. flip it over and put the Celestron stickers on. So perhaps the knowledge at R.V.O. is the exact opposite of what's required. e.g. need Losmady on top if it's Vixen underneath? I ask the question because I was considering mounting a DSLR and a long telephoto prime lens piggy backed on a top rail. I'm now thinking I could use a smaller dovetail and replace the OTA with just the DSLR and telephoto for occasional use. Simon
  10. Is this the norm? I unpacked EdgeHD and placed it on my mount - it's in the sitting room awaiting clear skies without rain! I can "do" a 2 or3 star alignment and "pretend" that the stars are already centred and complete the alignment. Afterwards if I monitor the position e.g. display RA and Decl, I don't see these being completely stable. Is that normal e.g. get it outside and polar aligned and referencing "real" stars and that shouldn't happen? I have the OTA balanced on the mount - 10Kg about 1 1/2" from the side of the mount e.g. bar pushed up inside and locked. Simon
  11. The search for EP goes on... astronomy.tools has a good tool for estimating AFOV etc. Thanks for all the help. I'm leaning towards some combination of Hyperion but I'm also eyeing up a more concentrated set of Morpheous with perhaps one Hyperion. I'm not too bothered with eyepieces for Newtonian. BST StarGuiders from FLO are not expensive but they don't have sufficient eye-relief for my tired old eyes! My choice for Morpheous would be three eyepieces: 17.5mm (116x) + 14mm (145x) + 9mm (226x). The 6.5mm (313x) wouldn't be viable for UK sky conditions. The 12.5mm (163x) is perhaps too close to the 14mm (145x). For Hyperion it would be 5 eyepieces: 21mm (97x) + 17mm (120x) + 13mm (156x) + 10mm (203x) + 8mm (254x). The 5mm (400x) wouldn't be viable for UK sky conditions. The 24mm (85x) has a simliar AFOV as the Celestron Plossyl 40mm (51x) that's in with the OTA). So 3 Morpheous EP would provide a cleaner and wider FOV compared to 5 Hyperions which are more tightly grouped and overall slightly less expensive. I could add the 24mm Hyperion to either setup. If I was adding it to the Hyperions then I would simply buy the 7 eyepiece set as it's no more expensive than 6 EP to get a case. The 4 eyepiece set has 3 EP that I could use e.g. 10mm, 17mm and 24mm as the 5mm isn't really viable. Later I might get a 2" diagonal and one/two wide field eyepieces but that's for the future. Simon
  12. I like the Baader Hyperion eyepieces because they have good eye-relief. For an 8" SCT the 5mm is perhaps too short as seeing conditions rarely allow 400x but the other EP are a good selection of sizes 8mm - 24mm. Their boxed smaller set of 4 EP are 5, 10, 17 and 24mm of which I would only make use of are three: 24, 17 and 10 giving 200x, 120x and 85x. I can also see value in the other three EP that are 21, 13 and 8mm giving 250x, 150x and 100x. I looked at the resulting AFOV at astronomy.tools and it would be nicer to buy them all except the 5mm! The larger boxed set is also very tempting because the closer spacings can be better matched to seeing conditions. Perhaps the 5mm could also be used to split binaries or to aid 2/3 star alignment (almost as good as having a reticle eyepiece)? Although I don't need a 2" diagonal until I buy one or two really wide/long eyepieces e.g. the 35mm Aero mentioned or APM UFF or similar mentioned, the supplied Celestron 1 1/4" diagonal has some drawbacks. Eyepieces are screwed in which is fiddly and prone to damaging them. The diagonal is also held on with screws which might not be the most secure mounting. If I did look at a 2" diagonal it would be one with an integrated SCT attachment so that the light path through the bigger diagonal was about the same as a 1 1/4" with the 7cm visual back. Celestron have two, the XLT coated one (compression ring with a screw to secure the eyepiece 93527) and a better one with a dielectric diagonal with true twist locks (93573). Compared to the 1 1/4" equivalent version this would be more future proof. Of course with the shorter SCT connector the eyepiece is also closer to the back of the SCT - but I think it would be OK. Perhaps unscrewing the SCT coupling isn't ideal but using a push fit on a long visual back with screws is also not ideal too? A 2" diagonal would be nice and I really would be interested to know if the focal point is retained when switching to this type e.g. the length of the 1/4" visual back is optimised for the SCT and the more direct SCT coupling compensates for the bigger 2" diagonal - the blurb says "using the SCT adapter provides a solid and secure connection whilst limiting additional optical distance" - suggests that it's "close" rather than exactly like the "optimal" focal length e.g. with a 1 1/4" diagonal and "long" visual back. It's suggested that it's better to use the 1 1/4" adapter rather than risk putting a Baader Hyperion EP directly into a 2" diagonal and risking touching the mirror. The adapter doesn't interfere (vignette) the smaller (1 1/4") eyepieces. Simon
  13. I have the HEQ 5 mount which has a Vixen compatible saddle. Three questions about what “scope knows”, user comfort and PEC... I want to mount an 8” SCT and I’m confused by the position of the mount knobs and declination lock. In the HOME position I can put the counterweight vertically down so that it’s in-line with the north tripod leg. When I mount the OTA, the two bolts for holding the dovetail can be either on the LHS or RHS with the declination lock on the other side and the counterweight in front of me. Am I right to think that the scope and/or the mount “don’t care” if the locking knobs and declination are to either side because the GOTO “learns” that in the HOME position, the OTA points up and the counterweight is down? But for the user standing behind the mount, the orientation makes a difference to if the Declination locking knob is UP or DOWN but is obviously reversed for EAST or WEST of the meridian when using it. The mount manual shows two scopes with the saddle reversed for each type e.g. refractor and Newtonian. So regardless of the mount e.g. HEQ5 or other, is it better the setup the Declination lock on the LEFT or RIGHT when mounting an SCT? If the PEC was configured, switching the side wouldn’t matter because it’s only about the “internals” but may need to be redone if the mount is moved e.g. putting the scope back and balancing with nothing else changed would not invalidate the PEC? Simon
  14. Why do you need a usb serial cable? My HC has a USB connector - so any old "printer" USB cable would connect PC to HC. There is a Direct or Passthru mode in the HC to control the mount.
  15. I should use one because there is lots of visible coma however I probably won't get one because the main intent is to use new eyepieces e.g. Baader Hyperium with the F/10 scope where it's not critical. With the newtonian (that I find unwieldy and too heavy), I have some ancient Televue Plossl EP that work quite well. I can see that it would be nice to get all the above EP (except the 5mm) but I think later on I might start to regret getting them too soon. There is also the Aspherics as well and a 2" diagonal (Celestron have a new on that I like)... Simon
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