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Steve Milne: I do have a reasonable mount, so this is not a problem now, it is not a high end, but it is not very cheap bad one, i saw a lot using it with amazing nice results so it is capable one even it is not in AP/Paramount level, it is SW AZ-EQ7. I want longer a bit focal length to have more coverage, i have Canon lenses which will give me wide field easily, also i can afford many scopes for wide-field in the future, so i wasn't worry about wide field at all, i want to start with difficult and slightly harder to get or slightly expensive than cheap wide field scopes, many targets i like really really like were taken by longer field, i am not that much blown away by so wide field images, they are nice and i like them, but i want to jump higher, many started with wide then upgrade, i don't want to do that, i start with upgrade, and i mentioned i want to have that scope in 500-700mm range, i found one that i am thinking to buy, not Esprit, i was hoping to buy TMB92SS brand new but this is gone, later when i have enough practice or shots with this 500-700mm scope then i can buy something for 300-450mm, but you forgot that with 500-600mm i can use a reducer so it can go wide and fast, so it is like i buy 2 scopes in one, it will not be a good idea to have 400mm scope then i add an extender to go up to 500 and speed getting much slower, and maybe the extender will magnify the issues too, so i know what i am looking for as field of view, harder or not isn't gonna stop me, astrophotography is all about challenge, in fact i am also buying a Newtonian later too that is in 1000-1200mm range, so i will have selections of scopes in different focal lengths, and i know bigger or larger/longer scopes will be big challenges, i like challenges, people done amazing with those difficult heavy scopes even with reasonable scopes, so i can do as well, i don't like in windy crazy weather country, so all these will help me, i will take time ofcourse and being patient, i don't want to buy one scope then later upgrade, i may buy 300-400mm now then i want to upgrade very soon but i can't due to budget, but sounds if i buy a scope of 500-700mm i may not think to downgrade any soon, so it will be like one time purchase, i looked at images and i know which focal lengths i need. My camera is QHY163M |
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| Hi Tareq. An important thing to consider is the imaging resolution. Indeed, in deciding what is and is not possible, imaging resolution might be a more relevant consideration than focal length. Your camera has a pixel size of 3.8 µm. So, at 500mm you would be imaging at around 1.57" per pixel. At 700 mm you will be imaging at 1.12". At 1.12", your mount would need to give a total guide error of around (PHD RMS) 0.56", for you to get consistent results. That is quite tough. (For comparison, my QSI683/Tak 106 combination gives an imaging resolution of 2.1".) |
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Steve Milne: Doesn't matter, i will face many errors in my journey anyway, at the end this shouldn't stop me, if i have to worry a lot about the weight and errors and focal lengths then it means i better use my camera lens wide angle or 60-70mm telescope and only few targets i may not feel interested to shoot more again and again wide field and then i will stop astrophotography, there is nothing nice for me than accepting the challenge and face difficulties then succeed, the scope i will get is 650mm one, and i will guide too, and i will do my best for polar aligment, then we will see how much errors we will get, i used my ST80 with full errors and not good polar alignment at all and i managed to have images, the exposures were drifted noticibly but managed to stack and align it, so i shouldn't worry much about errors really, i will work hard to minimize those errors, i saw people using heavier scopes than the one i will get on EQ5 even with nice results, or even on AVX, so AZ-EQ6 won't be less performance, and i am buying a reducer for this scope so i can go wider to around 500mm something and faster, then my camera won't be much problem then. Forgot to say, no winds here, and light pollution is bad but the sky is clear. |
