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PEMS

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About PEMS

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    Nebula

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    Bedfordshire
  1. Will say that you still need to turn them off when speaking to people. They may be red but when you look at a person they are still close to blindingly bright. And basically uncomfortable to the person you are shining them at from close quarters. This is often forgotten. Seems that the assumption is that they are red so it is OK to shine into someones eyes from 2 feet away. Being honest it is not. That is one area where a torch wins out. You can forget about a head torch, you cannot with a hand torch.
  2. Which Nikon? The F mount has a flange distance of 46.5mm, the S mount has 34.85mm, the I mount has 17mm and the Z mount has 16mm. So 4 options and all different . Going to assume that it is an F mount and is therefore 46.5. You need to supply the Nikon camera type or name or whatever, D5n00 usually, To get to 55 you need another 8.5mm, which is not a lot. Need to know the thickness added by the M48 adaptor. If that is greater then 8.5mm then you cannot get the camera sensor at the correct position of 55mm from the appropriate face of the flattener., since camera body and M38 adaptor already exceed 55mm. If the M48 adaptor adds less then 8.5mm then subtract the M48 thickness from 8.5mm and set the flattener to that value. So if it adds say 6mm you set the flattener to 8.5-6 = 2.5mm. If the M48 adaptor is greater then 8.5mm and you are having problems that i likely the reason. If you have one of the newer mirrorless cameras then I would expect you need a selection of spacers to move the camera sensor back sufficently. Really need the camera model and the M48 thickness that it adds.
  3. I suggest getting the scope and ignoring the "photo's taken with it" bit. They very probably were not. It is the wrong scope for imaging. If 70mm and 700mm then a 30mm plossl will give you around 23x in magnification and that delivers a field of close to 2 degrees. Unfortunately a little too small to see all of the Andromeda galaxy in one go. You really need 3 degrees for that and you will find that 4 degrees is better. A 4 degree field comes out as around 12x and so a very long 58mm eyepiece. Which does not exist as well as I am aware. Andromeda is often wanted and asked about but the size of it means that relatively few scopes will fit it all in in one view. Using inexpensive eyepieces you need a magnification of around 12.5x for 4 degrees, and with the "long" 30mm plossl that means a scope focal length of 350-400mm maximum. The advantage of a scope is you can purchase, and so change, eyepieces to get the best magnification and field to suit more objects. A set of 20x binoculars will not realistically show Jupitier's banding where in the scope indicated a 12mm eyepiece will. 12mm giving 58x. Advice here is do not go thinking that a 5mm will do more as the image will be bigger but very likely the image of Jupiter will be poor. For 20x binoculars you will also need a tripod or monopod for stability. Small additional expense but an expense.
  4. I honestly that simply means that the people posting their great understanding of things on Youtube leaves a lot to be desired concerning their actual knowledge. Some are or were bad, one was nicknamed "The Coffee Grinder". So yes there are bad ones. Nothing recently has received that bad a name. You can check out the gear meshing and adjust. Would suggest that most people should do so. They are after all mass produced item and not to often talked of delicate, accurately set up items they get described as. The other is as said the noise comes at the fast slew rates, reduce the maximum slew rate down by 2 steps. Makes a huge difference. Finally if they were seriously quiet astronomers would complain they cannot tell if the mounts are actually doing anything.
  5. It seems that as a genarallity the mono ones have an anti reflection coated glass cover and the colour ones have an IR cut filter as standard. Makes sense as your OIII should not be passing IR through to the sensor, and if you wanted to obtain IR images then you do not want an IR cut filter in place. lso saves ZWO money I would expect.
  6. Any particular side of the M25, just curiosity. I would check that everything you have still works if you haven't already done so. If something has gone to the great observatory in the sky, then you consider replacing that first. Also means that you have something to start from or use or build on. Keep it simple and use the Star 71 - is it the Mk1 or !! ? If all is operating I would suggest you consider the camera as being the one to replace. Yes CMOS has taken over. But there are differences and you will have to learn or appreciate those. The one that is in a way biggest is that you do not need 600 second exposures, you will likely find that 120 or 180 second exposures will do as good. You may still need a similar total capture time. Seems however that the now old CMOS exposures are still suggested and really no reason. I suggest that if you replace the camera you plan on some relearning and expect changes. The Star 71 was a little tempermental it seems, so check the quality of the stars in images. Just thinking something may have moved and it needs some attention. The Mk1 of 5 elements was sensitive. No idea about the Skywatcher, seems big for imaging. So really your decision on that. Clubs would be the next aspect but we are not allowed out at night, it would seem.
  7. I will suggest a different line. Search out a reasonable 80mm achro refractor, I suggest not the short tube ones that are 400mm focal length, they introduce too much chromatic aberration (colours around bright objects). Bresser in the UK does one called a FirstLight. It is 80mm diameter and 640mm focal length, so f/8 in technical terms. They come with a Nano mount and tripod, reasonable on stability. But at the lower cost end they save money by a slightly questionable mount/tripod. Also search out FLO offerings and Rother Valley offerings, the same basic scope can occur under different vrand names. Reason is they are simple and easy. Another plus is that the owner can fit a full aperture solar filter and look at the sun. Something different to do in summer. The scope mentioned if they get into the hobby more can be "enhanced" by purchasing something like the Skywatcher Az GTi goto mount. An 80mm will just be OK on one, no bigger then 80mm however. Then they have a goto system. Learn about the pros and cons of one before that occurs. So you start with a simple and easy scope, can make a small addition for solar viewing, and if they get into the hobby easy to add a small goto later. You end up with a reasonably do everything system. Would be visual only but that is not a problem. Many suggest keeping visual and any imaging separate entities. For a first entry in to this something easy to use is usually better. Cost I think is around £160 so fits the budget fairly well.
  8. Get the 25mm, 12mm and the 8mm. I had expected to use the 5mm more but it is rarely used in a scope. The 25mm is to find targets, the 12mm and 8mm do the job of magnifing whatever. Don't worry or think about the worst as for some reason people need to identify the worst. And on the BST's I think I have read just about the 25mm, 18mm, 15mm and 5mm as being given as the worst. So best idea is just forget that classification. I find they work well at f/5, like it would seem all eyepieces they produce better result in slower scopes. However as said all eyepieces seem to do that. Better is something like the ES ranges and thay are close to 3 times the cost. Except for the ES52 range that is, but you lose field of view for the same focal length in eyepiece. With the three above a barlow is of limited use. It would likely only be useful on the 12mm. So maybe search out a 6mm somewhere - ES52's do I think offer a 6.5mm. Actually a usefule focal length if you later decide on a 5mm BST. A 6.5mm would sit nicely between the 5mm and the 8mm.
  9. I would say both Yes and No. Seems little in this hobby is straightforward. The wifi on the Az GTi works fine, you will find it better with an Android phone or tablet and if you purchase Skysafari (the Plus version is adaquate). iPhone systems operate it seems slightly differently and you may find you need one for the Synscan app and another for the Skysafai. The basic steps are to set up the mount, connect with the Synscan app and align, bring up Skysafari, connect, then run from the Skysafari interface. That is a quick idea. So that is the good side. Not so good side is that both mount and phone or tablet need power. Not a great problem if only out for an hour or two. After that one runs down. Next is the phone or tablet needs to stay connected to the mount. Again fine if at home but if at a club or event it would mean leaving the phone or tablet with the mount if you went elsewhere. I would have thought the 127 was at the heavy end of the mount capacity and the general narrow field of view could create additional work at alignment and even getting objects in view. Your field of view would be limited. One simple option I suggest you keep in mind it obtaining a simple 80mm achro of say f/8 and having that available to swap out the 127 at times. Would mean 2 scopes but I would keep it as an option.
  10. Rather unfortunately if you want to do astrophotography then the mount needs to be equitorial. Also getting to a reasonable set up can be costly. Can be done at lesser cost but compromises are to be made. The Evostar 90 will be a nice general visual scope, not ideal for astrophotography. Just a bit too big. A scope for astrophotography tends to be small and usually an ED is the start. Could you swap to a 72ED. They will cost more. Mount would need to be something like an EQ3-2 but a goto. Astrophotography needs a driven mount. In honesty an EQ5 would be better, much better all round. Just more expensive all round. Can I suggest a simple scope like the Evostar 90 and use that for visual. A slightly smaller one would be the Bresser Firstlight 80mm 640mm refractor on their Nano mount. I think it is a better mount. Again for visual only to look around and see things and get familiar with everything. Like finding targets. Then consider astrophotography as a separate aspect. In a way the minimum is around a goto EQ5 and a 72ED scope, or 80ED. You could use a 72ED and an EQ3-2 but it is back to making compromises again and the EQ5 is overall safer. Wait until we can all go out, find a club and look and talk to people. Where are you, if possible add the approximate area to your details.
  11. I assume you refer to the 72ED. If so the focuser travel is limited. Will say the Az GTi is not recommended for DSO AP. It is not intended for that use and will I expect deliver poor results. Or need a lot of work to get results. Exposures will need to be short even with a 72ED. 420mm focal length I understand.
  12. Looking at the adverts it is a reflector on an Eq mount. So in a way a high eyepiece sounds and looks right, at least right in assembly terms. Have you set the tripod legs up as short as possible as in fully retracted? That seems about all that could be suggested. The eyepiece will be the tripod height plus the EQ head height plus around half the scope OTA length. That all adds up. If when the legs are fully retracted, fully spread to lower a little more then if eyepiece still remains too high I cannot think of a great deal that can be done to reduce the final height. An alternative tripod comes to mind but most would have a similar problem. The Skywatcher Az GTi tripod is short but I have no idea if the Eq head you have would be a straight and simple swap.
  13. One question: Are you only intending to look at planets? The 90 Mak will show Jupiter and Saturn and the moon. it is very likely too small for Mars in any detail. In a way that is 3 objects. There are 110 Messiers, same Caldwells and many double stars. Would it not be more applicable to buy a scope for the majority of objects. A 90mm Evostar will show Jupiter and Saturn and the moon. The negative of an achro is the presence of chromatic aberration. However the Evostar is a 90mm 900mm focal length so at f/10 should be reasonable in the CA aspect.
  14. Any standard type lead acid battery has the problem that they are intended for what could be described as a short intense discharge - starting a car engine. For astronomy use you want one that is intended for a long slow discharge. Standard lead acid batteres will discharge to around half capacity then the internal plate damage by possible deformation or caking on the surface. After which they damage more and quicker. Batteries for mobiliuty scooters and golf trolly's are better but both cost more. One I did read of was a Lithium Motor Cycle battery. Small and I think the capacity was 4Ah so somewhat smaller, cost was reasonable however. May be an option to search for slightly larger ones but I would expect the cost to rise rapidly. A normal lead acid would be OK if you could go out and after a set time pack up even if the sky was good everything running fine. In effect a good night and you pack up early, Unfortunately that doesn't happen. Having reread the initial post are you only observing or imaging also? 90 minutes seems short and even the mentioned motor cycle Lithium I would have expected the same or longer as a reasonable amount of time the HEQ5 should be just tracking. I have noticed the term "Deep Cycle" used on many however it seems a little suspect as some read a AGM and that may not be 100% a deep cycle.
  15. I would have said you need to do some level of polar alignment. An equitorial mount is intended or meant to be polar aligned so has to benefit from some polar alignment. For a quick observing it would seem to be of use to at least aim the correct leg at Polaris, level the mount at least slightly and if polaris is in view then at least place it in the polar scope circle. In the centre it will be close enough for visual and would add minimal additional time to the general setup. If the mount is a goto then at least set poaris in the centre. Otherwise the system may be too far out for it to run.
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