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ronin

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Everything posted by ronin

  1. Should have bought the jacket. Simply you may think the world revolves around astronomy but I suspect your wife does not. Very likely she will think her gift was wasted. And there is SG Lite which is free.
  2. By rights if you put a blue filter in front of the red led nothing should get through, the filter should be blocking red and green and passing only blue. Same if you put a green filter in front as it should pass only green and block red and blue. It all depends on how good or narrow the filter is, the speactra passed tends to spread out a bit. Also depends on how pure the red wavelength is but an led tends to be narrow/pure. A red filter would pass the red led output and also pass the red component of the white led, so with a red filter you should get red light coming through on the eyeball side of the filter. At a guess/estimate you would need say a white led 10x brighter then the red led to "see" about the same at the eye. As the red filter should pass all the red led output but block the blue and green and assorted other bits of the output from the white led, so reducing the final apparent "red" brightness.
  3. The astrophotography side is the problem. To do both it first cost money - I would say the least expensive, but reasonable, AP option is around £1200. This would consist of a Goto EQ5 (£600), a small 70mm ED refractor (£400), flattener for the scope (£150) and some pennies for the assorted attachments. The mount needs to be equAtorial. Now that will get you going but at some time it will be a better scope, that means a better mount, guiding is extra cost and extra weight so a bigger mount, mono is very good but that is a dedicated camera, a filter wheel and nice £100+ filters (minimum 3 or 4 of). If the idea is simply to dabble at the initial AP stage then EQ5+70+bits will be fine. Many do as all they want is to get some images but not win AP of the year. You can get the EQ5 add a visual scope say a 102 Bresser and go looking then later buy a small imaging scope for imaging. Or buy a bigger mount now HEQ5 in preparation for the future. Pure visual will depend on you, a simple 150P or 200P dobsonian will do visual but before you get ideas forget any AP with one. It is simply the wrong scope on the wrong mount for any AP. The minute people ass AP into it as a factor that one aspet causes complications. Add a location, there are clubs around, just no idea of where you are, nearby town is adaquate. Suggest a town as a county means you could at a county border so have access to clubs in the next one. Also do not get a nice big sounding visual package and expect it to do AP, very little cross over in reality. An 8SE on its mount is again not really suited to AP (wrong scope and wrong mount) but it is a good visual one. I would say EQ5+102 Bresser (achro) or 150P reflector, and later buy a small 70ED for a bit of AP. So in effect 1 mount and 2 scopes eventually.
  4. The TV's are good, they do cost a bit new, and although used sounds nice I suggest you put a Wanted ad up. If you wait for someone to advertise some for sale you have to both wait and be the person that gets in there first. TV plossl's go down to 8mm, Al stopped there and I can half understand why, eye relief gets a problem below that and I suspect field curvature, at either the object or image plane, does also. Alternatives are likely the Vixen NPL's. Always reported as good - except for the outer housing which some compalin of feeling plasticky. Which as I suspect they are a hard plastic moulding and the optics as a tube assembly are inserted into this kind of makes sense. Watch the costs as even the Vixen NPLs are getting to match the BST's, and the BST's may lose out on overall sharpness and clarity but they are close and they are comfoprable easy to get along with eyepieces. It will depend on what you want, and it may not be simple. Also may take a few eyepieces to come to a conclusion.
  5. Why a focal reducer and a barlow, one reduces the focal length then you go adding a barlow to increase it. I would have expect the 2 item to not work overly well together, they were sort of not intended to, so anticipate a poorer image. Generally the less glass in there the better, they all add to the aberrations. I would forget the barlow and the 4mm, maybe a 10mm as you think or a 12mm.
  6. Taken from Wiki: The curve (2) is for a doublet - basically a parabola. The curve (3) is for a triplet (Cubic) The distances away from the ideal focal plane indicate the difference between a double and a triplet and the plot Agema give is that of a triplet not a doublet. Which gives me concern for the data supplied.
  7. Have Skysafari on a tablet and it has never caused a problem immaterial of the brightness of the screen. The tablet does "sense" the ambient light level and adjust accordingly. Think there is a night or red mode on it, tried it once or twice, but the detail and usability seems worse, so it is just left as normal. Half the reason is I want to be able to see and read it and the usual display is best for that. Doesn't seem to really destroy any night vison, or if it degrades it then it is for a few seconds. Sometimes think we take aspects too seriously, we are after all just hobbyists looking through a telescope for an hour or so when a convenient clear night appears magically over the horizon.
  8. Interesting chromatic focal shift, they seem to have fixed the focal plane for 3 seperate wavelength in the visible spectrum, Fraunhoffer G which is 430nm, e line of 546nm and around 680nm (guess B line of O2). Yet that requires 3 lens to accomplish as in a doublet design you can only work with 2 wavelengths. The plot is also not parabolic, which is the output of a doublet. Going to be interesting what people find with it, as they appear to have controlled 3 wavelengths with 2 lens.
  9. As it reads it is not debayered then the sensor+mask will be a row or RGRGRGRGRGRGRG, then a row of BGBGBGBGBGBGBG. With a Ha filter in then a row of BGBGBG gets in effect no illumination on it and would remain a dark band, even the RGRGRGRG gets just alternative pixels illuminated. Since it is still fundimentally a general purpose camera for holidays, landscapes, nature and sports shots it makes me wonder how the software of the camera gets around all this. One sort of option is that the internal software is just trying to boost the level to get the G and B row of pixels up but it will do some to the R so possibly making the banding worse. What is the result without any NB filters, just simple OSC use ? I do wonder if getting a DSLR, modifing it, swapping filters and then debayering it and still it is uncooled and remains a DSLR with whatever limitations is really more economic then just buying a ZWO or Atik that is built for the purpose.
  10. 1: Yes you are interested in DSO. Reason is there are 3 planets and they are not there all the time, what are you expecting to do when not there? The underside of the clouds are boring, eventually. 2: Immaterial of everything a good refractor will give the best planetary views. They are also likely the best for AP. AP requirements are differnt to visual. 3: Don't say that. A good refractor can be 5x the maximum you have indicated, and that is just the refractor. 4: No idea, 5: Goto you will require. It is very useful and it has tracking as a default and the tracking is about 400% relevant to virewing and 1000% relevant to AP. Dump the packages you list, all packages are aimed at visual, although I will say have a look at the ETX for another reason. I would say go get a good mount, equitorial and goto. Not sure whose however. Get a mount equal to the Sky Watcher HEQ5 - not sure of the equivalent in the US. Scope - if ES do a 102ED (triplet) then consider one of those. The FCD models are good the FCD-100's are better. Think ES do a 125 ED FCD-100 but cost leaps but it has had excellent reviews. With the mount you have the option to use mount and say a less costly Achro for visual, Bresser 102 or 120 maybe, and later get a smaller AP scope - ES 80ED maybe. That way you spread the purchasing cost and can do either. The ETX 125: I read somewhere that the OTA can be removed easily and so another put in its place. Must be a design change as on the old models this was not simple. If this is possible then you could use the supplied scope for visual and planetary imaging and then swap to, say, a 72mm ED for some AP. A lot will depend on how serious the AP will get. But the HEQ5 match should cover about it all for a long time. Other mounts are the iOptron, but their reviews are mixed. Add a location as I guess you are US based and people will point you at UK retailers and equipment.
  11. The usual way for planetary imaging is to get a video of the offending planet, load the video into AS2 or Registax and then select the best 200 frames or something like that, then stack these and the do a little processing. Seems from comments that AS2 is a bit better at stacking and registax a bit better at the processing. The processing is faairly minor. For Registax I have heard 3 "options. First was move all the wavelet sliders to the centre, second was move the first a little, the second a bit more and so on all the way to the last, the other was slide No 3 or 6 all the way to the right and leave the rest. So I suggest you ignore the previous and just use trial and error. Half an hours playtime. So whichever of the 2 imaging options will give you an AVI file for processing would be best, and I suspect that will be the webcam.
  12. Is that a Red one or have WO added a Bronze ?? Didn't they used to have a thermometer on the focuser - close to totally useless but it was a talking point .
  13. They are presently unlikely to effect the view you get. If you think about it the modern telescopes are multi mirror construction and the gaps between them have no effect. I would take the mirror out, have a good look at it and probably give it a clean, you can ask how to do it properly on the forum. Then have another look. Some marks may get removed others reduced, some unchanged. What you are bothered about are ones that are oxidation of the aluminium layer as that means the SiO layer has been penetrated. Seriously suspect that you will find no degration of your view. One of the strange properties of the incoming collimated light is in effect the sprad of the "data" - it's everywhere. Add a location as there is another mirror coater in the N. London area - Vacuum Coatings I think. All depends on where you are. Galvoptics (Essex) used to coat mirrors but I think they have pulled out, however may be worth an email enquiring. Half guess they still have the equipment and so may do one. The other aspect is find out the complete cost of it all, trhinking that if the coating is penetrated then the mirror may need a minor regrind to remove any significant pitting. There is the possibility that a new mirror may actually cost less - TS optics sell the GSO range of mirrors.
  14. Long Perng do make an ED Doublet 90mm: http://www.longperng.com.tw/goods.php?act=view&no=7 Not going to guarantee the link going to the right page. Trouble is you need to find you imoports and sells them. They ahve a new one that is a 90mm Triplet and uses 2 bits of ED glass also.
  15. Only one I know of is the Primaluce Airy 90 which is a copy of the WO Megrez 90. You do not see many Megrez 90's for sale, no-one seems to let go of them. Myself included. Likely someone does make a 90mm but it maybe a triplet, wasn't there a Raptor 90 from either Astro Tech or Stellarvue think a triplet, and if the idea is imaging then get a triplet. An ED is good but still a doublet and people do report CA, and imaging is harder on the optics. WO have a 61 and a 73 now. Just wondering if the old 80 ED and then the Megrez 90 may make a reappearance . How about the new WO 73?
  16. Not entirely sure what you are thinking of. As far as I was aware Afocal is scope with eyeiece and camera with lens. The scope and eyepiece are set as "normal" to deliver collimated light as the output. This means the "image" exiting the eyepiece is at infinity. So the the DSLR and its lens "simply" focuses this infinite object as normal on to the sensor. Go draw out the ray trace of the system. If you used the camera body and just the eyepiece you simply get collimated light out of the eyepiece and no actual image. The camera lens or your eye forms the image. So adding using macro lens is just the same as normal Afocal imaging. Just a bit of a different lens on the camera. Hold a piece of card up to the moon and look at the card - no image just light falling all over it. That light is the collimated light from the moon. It holds the data to create an image but in itself is not an image. You need an eye or a lens to create the image.
  17. Only to answer, kits are rarely worth it. Baaders seem tempermental, they sometimes work but at other time don't. ES are safer. Start this as a new topic, best not to hijack anothers as answers get mixed.
  18. Binoculars - 8x42's. They are the most popular in the birding fraturnity and they are so because they do everything pretty well. I have Bushnell's but any good set will do you. Don't go mad on an expensive pair unless you want them specifically and likely for something else such as serious birding. My approiach is that with binoculars you look around you do not so much look at. Eyepieces, I tend to think most will consider additional eyepiece fairly quick. Part of looking at the skies is to get the best enjoyment you can from it and the supplied items are not great so not so much enjoyment. Ignoring the pair you have then consider 30mm, 20mm, 12mm and maybe one shorter at 8mm. I have used some of the BST focal lengths here are they are popular. I have a set and a half of them. They are £50 each however, equally so is a good plossl these days - Vixen NPL's. Vixens go in 5mm steps more or less, so 30, 20, 10, 8 (yes I know 8mm is not 5 away). If BST's then 25mm, 18mm, 12mm, 8mm. You could possibly leave the 18mm out for a while. I do not use a barlow. If you got the 25mm, 12mm and 8mm and a barlow you do not gain much. The 12mm is the 25mm barlowed and the 8mm barlowed may be too much. So in a way only the 12mm barlowed produces anything. May as wekll just buy a 6mnm eyepiece. You could go buy the GSO = Revelation plossl's. They are less cost and generally fairly good. But the BST's will last you a lifetime. If you waear glasses then plossl's have drawbacks.
  19. Not sure if it has been mentioned but when aligning the finder to the scope you will need to point the scope at something distant, distant being around a mile or two away. You may have a problem making sufficent adjustment up or down, sometimes people have to make a small shim to pack one end or the other up a bit. Skywatcher make a variety of scopes and I suspect they use a "standard" finder so the finder and scope are not a perfect match to one another in all cases. Next is simply convenience, looking at the images the eyepiece is straight up ant the horizontal, people usually stand there and look into the eyepiece by bending slightly, they in effect look down into it. Yours is in a position that will prove uncomfortable. I suspect you will find it better to revolve the scope so the eyepiece is at about a 45 degree angle between horizontal and vertical. With the weights either on or off take care as gravity will either drag the weights down if you remove the scope or drag the scope down if you remove the weights. Either way something plunges towards the ground fast. As has been said start with the 20mm, unfortunately the 10mm is not great but give it a go when you are a bit more familiar with it all. Try the moon, astronomers complain of the moon but it is a regular and good object. It is not a big an you think. Do you know the main constellations? If not learn a few of the basic ones: The Plough (asterim), Orion, Cassiopeia, Auriga. Nice scope and a good first scope, it will do just about everything on the visual side you are likely to need. The PL means a "Long" one which is nice, eventually (probably next Tuesday) consider an extra eyepiece or two. Everyone gets extra eyepieces. Reasonable plossl eyepieces will work well but set and tell people a budget per eyepiece. Eyepieces ranges from say GSO ploss's at £25 to TV Ethos at £500.
  20. Couple of things to take into account: The finders need to be set up and they may also need you to make a small shim to prop up one end or the other. Unfortunately the finders are not specific to a scope and so need time spent with/on them. Place all hammers well out of reach. Next problem is your brain . It is playing tricks on you, equally everyone elses does the same. Do you know Orion (hopefully Yes), head out (now) with just a pair of eyes, no scope, and find Orions Belt, then look below it for the Orion Nebula. Take a good look at it, then swing over to the right and look at the moon. Which is the bigger? For reference the Orion Nebula is between 1.0 and 1.2 degrees in size, the moon is 0.5 degrees in size. The moon is half or less the size of the "little" fuzzy thing just below Orions Belt. That is your brain playing tricks. The moon is fairly small, just being bright the brain for some reason interprets this as big. Start with the 20mm and likely only the 20mm, I think it safer to say do not use the barlow. Not sure but I think the scope design is not a good one for barlow usage. As it is the moon one option you have is aim scope at moon, just sight along the tube itself, remove eyepiece and standing back a bit try to get the moon in view down the focuser, then drop the 20mm in. You get a nice wide view without the eyepiece, hopefully enough to get the moon visible down it. Do any movement slowly as the image will move the wrong way.
  21. As you say you don't want an ED or apo for imaging then why are you considering one for visual? Just seems an odd way of doing things. If you got the ED100 then I would expect you to try the ED100 for imaging, then almost certainly use that most of the time afterwards and so use the 120ST for visual. The initial post seems to read you using the (possibly) better ED for visual (and also upgrading the focuser, another good move for imaging) and the not so good ST for imaging, which seems at odds with general practise. If you actually want the ED for imaging then get the ED, otherwise get the Altair and save the money.
  22. Remained cloudy (just) until around 19:00, then half the sky was clear, the other half cloud. Eventually it all "cleared" but only the main/bright stars stood out. Appeared to be a slight very high cloud layer. Was up at around 04:30 and it was CLEAR. Just too late to do anything and it was cold.
  23. The handset should remember the Longitude, Latitude and Timezone. These should be on the display when you power on the handset for a few seconds. Think you may have to press Enter to confirm the settings. Not sure what happens if you do not press Enter - that is if you have to. What it does not remember is the Date, Time and DST, these you have to reenter at each use. Is there any chance that you are being asked form Date and Time and DST and presuming that all dta has been lost ? I suppose there may be an internal battery for the positional data, but I have not heard of one. However if there such an item and it is dead then the data would be lost. Needs a question either in the moubts section or maybe direct to the (a) retailer who may know more, even OVL the importer.
  24. It very basically amounts to you getting a lomg exposure set of images then stitching them together. Many will aim the camera at the NCP (North Celestreal Pole). HOWEVER there is software to do it. do not ask why!!! Which I think is called "Star Trails". With that I think you take more shorter exposures and it will stitch the images together and fill in the gaps. I say don't ask why as the person who talked about it to us one night was really really impressed and couldn't stop singing its praised. I sat there thinking how useless it was. Who wants star trails. Different point of view I suppose. Star trails do show the star colours up very nicely however.
  25. Looked up "Scope Nights" see it is not on Android. Equally I see it gives updates at 3 hour intervals which I suppose is my arguement/point. Say the "Clear" prediction was made at 09:00, soon to be 12:00 and what if the 12:00 prediction indicates a bit more cloud then "Clear" impliied at 09:00, then at 15:00 more cloud again, or maybe back to clear. A weather forecast that can alter every 3 hours is likely worse then no forecast at all. Do I throw the scope bag in the car now and charge up the batteries for them or not? I simply would question if an update at 3 hour intervals is really much use. If they said clear most times but at 18:00 swap to cloud and cloud appears then you have wasted preparation and expectation time and they can still say they were accurate. Just no use to you at all.
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