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htj

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About htj

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    Nebula

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    Mostly visual, though occasionally I do a bit of photography.
  • Location
    Denmark
  1. I believe Orion EON (the US version) was discontinued. The Equinox still looks readily available in shops though.
  2. The reducer does NOT increase the aperture. It makes the light cone steeper (f-ratio, important for photography), and flattens the field. As it has been mentioned, it is designed for imaging, not visual use. The maximum field is defined by the field stop of the inner parts of the telescope. I think it is around 46 mm for a C8, but it will probably vignette significantly towards the last mm at the edges. The reducer actually limits the field that can be seen. Do not use the reducer for visual use. A 2" diagonal will by the big mirror and big connectors always have a very long optical path. Very long optical paths can cause loss of aperture on Cassegrains, though this is mostly an issue with binoviewers. However a feather touch focuser (though a nice piece of equipment) and a 2" diagonal may actually start to cause loss of aparture. For a C8 loss of aperture will probably start at around 150 mm optical path. Give or take 10-20 mm. The recommended Baader T2 diagonal is also what I recommend for a diagonal with shorter optical path. It has a 35 mm field stop, though you can probably go to 36-37 mm field stop on your eyepieces without noticing. A 1 1/4" diagonal will have a field stop of around 27 mm. A 2" around 46 mm. You cannot "adapt" a 2" eyepiece to a 1 1/4" without making the field of view narrower. This assumes that the eyepiece has a field stop over 27 mm though, but almost all 2" eyepieces has this, as that is the main reason for making them 2". Some Nagler and Ethoses are exempt as they are physically large and needs the support that 2" gives.
  3. I don't think a 180 mm Mak is going to do significantly better than your C8 to make it worthwhile to buy it. Also note that cooling a 180 mm Mak can take quite a while, and it basically needs to be stored relatively cool. See the note on FLOs homepage. To get significant better experience for the solar system objects you probably need to step up in aperture, like a C9.25, C11 or a 10"/12" dob. However most of the time you will be limited be seeing, even with your C8. Seeing is really the limiting factor most of the time. To beat the seeing you really need to spend more time at the eyepiece really. Both in order to practice, but also to catch the nights / moments with excellent seeing. Binoviewing usually make for a more relaxed seeing experience, so that could be an option. More time at the eyepiece -> good. Also make sure that the collimation of your C8 is spot on and that it is properly cooled. This is free and quite important to get good results. Eyepieces tend to be rather personal thing. Orthos and Plossls provide very sharp and scatter free, but have limited ergonomics. I have the Pentax XW 7 and 10, which are very good and have excellent ergonomics, which means I can relax when observing and hence spend more time observing.
  4. You would be facing the sun for 14 days straight... however the other 14 days should be pretty good. I would like to get closer to Jupiter and Saturn and at a place with less Atmosphere. Olympus Mons on Mars perhaps. Not sure how much light the two moons would reflect though.
  5. I have the Baader Aspheric 36. It behaves quite well at f/9 and slower. In f/6 the edge performance takes a bit hit. It would probably do a bit better at f/7, but I would not expect good edge performance. For long, wide angle eyepiece I think the price is quite good though, and it is relatively light compared to similar eyepieces. Have not tried the aero, so I cannot compare the two.
  6. The maximum I've pushed it to is 86x. And thats with a scope that weighs less than half of the Skymax 150 and is slightly shorter. I really wouldn't go over 100x with it. The main "problem" with the mount is generally acknowledged to be the tripod (I mostly agree with this), and the thin aluminium legs, which have very poor dampening characteristic. There are some options for improving this. The most harsh is to get a wooden tripod, but this increases both price and weight. Someone over on cloudynights filled the legs with expansion foam (the stuff used for isolation), with quite good results. This adds a little weight, but is quite cheap. Still, I wouldn't put a Skymax 150 on it. Sorry.
  7. Hi I have the Vixen Porta II mount, and would not put a 150 Mak on it. I tried putting an Intes M500 mak (similar to the Skywatcher 127 in size), and that didn't really work. It does work quite well with my little Megrez 72 (which is what I got the mount for), but it still start to suffer at high magnifications. I would be looking into the AZ4 mount for a 150 Mak. As minmum. A 150 mak is also a scope that will mostly be targeted towards high magnifications due its long focal length, so a stable mount is really needed. In fact, I'd consider a tracking mount for that scope, as magnifications will typically be on the high side, which means an awful lot of manual tracking, but you may be okay with this. Something to think about at least.
  8. Hi I agree with the AZ4 as mount for this class of scope. I use a 100ED with an AZ mount myself (a more substantial one than the AZ4 though), and I am quite happy with it, though aperture feber has struck. The scopes you list are somewhat different. Two of them are triplets (the APM & FLT). There are two Altair 102 f/7 scopes, one is a doublet, and one is a triplet, so I don't which one you a referring to. The Vixen is a doublet though. Triplets will usually have tighter stars and less CA, but I doubt you will see much difference for the scopes you have listed. The triplets will take longer time to cool down, which may or may not be an issue for you. The FLT98 has great optics, but it is expensive and is largely considered an imaging scope. It will also have the most field curvature of the three scopes (shortest focal length). You could get an Equinox 120ED for less than what the FLT98 costs. Have you considered the Skywatcher Pro/Equinox 120ED? The APM should have a very nice focuser and has the biggest aperture, which is in its favor (but it comes at a price), but I am not sure I'd go for a triplet here.
  9. Those are two very nice pictures. While the M42 certainly goes bam-pow! the second shows almost impossibly small and round stars, and a very high detail level in the galaxies. Great job.
  10. htj

    M42 HaRGB

    I like the colours. Lots of details in the core.
  11. As several people have mentioned having the focus plane far back (as with a binoviewer) on a cassegrain, means that mirror has to be moved forward which increases the focal length. However this also decreases the effective aperture of the system as some of the light from the primary will not hit the secondary. Furthermore this will decrease the contrast of the system, as the central obstruction will have a relatively larger size. If you are using a 2" diagonal, I would suggest trying a 1.25" diagonal or one of the Baader T2 prims/diagonals, which adds very little length to the light path (but will only work if you binoviewer has a T2 thread for mounting). There is no similar focal-length changing effect on newtons and refractors since their focal length is decided by the primary mirror or front elements, and not a combination of two mirrors. The 20 mm -> 12 mm effect sounds like too much. The image with binoviewers is often perceived as larger and wider, than a corresponding single eyepiece, so juding this can be tricky.
  12. The LVW 22 has a field stop around 25 mm, so they will vignette. Only you can tell if it will bother you. If you have one already, you can try it out in the binoviewer when you get one and see how much it vignettes. Then you can decide to sell it or get another. A cheaper alternative to the Panoptic 19 mm could be the Explore Scientific 68 20 mm.
  13. There are around 4 or so Baader T2 diagonals: T2 Prism. Shortest one. Also comes in versions with SCT and 1 1/4" connectors. Around 100€. Seems to be sold out everywhere. Optical length 47.5 mm T2 Maxbright Prism. Has a prism from Zeiss. Not really a clone. Around 200€. T2 Maxbright mirror. Around 200€. T2 Amici prism. This one should give upright images, but probably also the worst image quality. I'd stay away from it for astro usage. Around 225€. Housing on the last three appears to be the same so the are probably all around 54 mm optical length I think. Regarding the calculation, the result is right, but the GPC changes the light cone of the telescope to have a longer focal length, so the calculation is more on the order of (925*1.7)/8=196 Remember that the GPC 1.7 only gives 1.5 when inserted between the diagonal and binoviewer. The GPCs will also put out the eye relief a bit since they function as barlows.
  14. Hi As several others have remarked, the Maxbright binoviewer can be combined with one the Baader T2 diagonals for a system, which has a shorter optical length, which can often make the difference between being able to focus and not. The optical length of the binoviewer is 110 mm, and 47.5 mm for the Baader T2 prism an 54 mm for the T2 Maxbright prism/mirror. The typical length for a 2" diagonal is 105-110 and around 80 for a 1 1/4" diagonal. The T2 prism is the cheapest option, but appears to be sold out everywhere currently. The field stop when the light cone enters the Maxbright binoviewer, is 23 mm, but is reduced to 21 mm internally, a eyepieces with a field stop of 21 mm will give you the maximum field. Options could be ES68 20mm, LVW 17, BST18, 25 mm Plössl. I'd avoid to short (say under 12 mm), as they will greatly enhance any collimation error in the binoviewer, making it harder to merge the pictures or will make the viewing less relaxed. The advice about barlowing with the GPC instead is sound. The prism in the binoviewer will offset the focus point a bit. In order to fix this a glass path correcter (GPC) should be used, but it is only needed for high magnifications. The GPC will also function as a barlow, and move the focus point outwards, which can be hand. When used it will also act as barlow. Baader provides three different GPCs with varying magnification factor. Note that the GPC 1.7 is really a mislabelled 1.5. The GPC factor is for when inserted between the diagonal and binoviewer, however it also possible to position it between the diagonal and scope. With a T2 diagonal the 1.25 GPC will roughly be 1.45 and the 1.7 GPC will be an actual 1.7. Changing the GPC is a bit of a hazzle, so two different set of eyepieces can be a good idea.
  15. Regarding cooling, some of the Intes Micro (the deluxe models I think) has a cooling fan, which greatly aids cooling. If the Intes has this, it is a huge plus over the Skywatcher IMHO. Storing cool or semi-cool is preferable though. Typically it is from 7 inches and up that cooldown really starts taking a long time Mak-Cass. I haven't seen a Skywatcher Mak-Cass, but I can attest to the Intes Micro being a very nice piece of hardware. Collimation can be a bit of challenge though. While the Intes keeps its value pretty well, finding a buyer can require a bit of patience (been trying to sell an M500 for a month or so now).
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