Hi question about choosing 2nd hand telescopes.

[landmiiines]

I already have my very first telescope which is the Celestron Astromaster 130EQ. Well I was not quite impressed with the telescope especially after I researched that this telescope cannot take astroshots because of focusing problems. (Correct me please if this telescope can be used for astrophotography) Now I am thinking about buying a 2nd hand telescope to maybe compensate for my expectation on the celestron astromaster 130EQ.

These are my choices: (please don't mind the prices because these are in Peso)
1st choice:
4.5" Telescope Imager Orion
4.5" Telescope Imager Orion Philippines - 4032684

2nd choice:
Vixen 4" reflector telescope
Astronomical Telescope Philippines - 5142414

3rd choice:
Meade 390 series refractor
Meade Telescope 390 Series OTA with Vixen Polaris Mount Philippines - 5778792

I am planning to maybe take pictures of DSO's. Don't mind the mount because I am planning to use my astromaster mount. Please look at the links and maybe help me on choosing which one to buy. Because I don't know which one is better. Please help me. Any help or suggestion or recommendation would be great. By the way these are my only choices because shipping telescopes from the US to Philippines is quite expensive.

[sada]

I am no pro when it comes to AP, am not there yet.But a think all reflectors have problems when it comes to focusing because of the focuser itself.it intrudes itself on to the mirrors of the scope.A problem that refractors & mak-cass scopes dont have. am sure one of the guys will correct me if am wrong.so if your asking me what scope to pick out of the choices you have give me for AP then its got to be the refractor.good luck my man.

[landmiiines]

I am no pro when it comes to AP, am not there yet.But a think all reflectors have problems when it comes to focusing because of the focuser itself.it intrudes itself on to the mirrors of the scope.A problem that refractors & mak-cass scopes dont have. am sure one of the guys will correct me if am wrong.so if your asking me what scope to pick out of the choices you have give me for AP then its got to be the refractor.good luck my man.

Ohhh thanks for the reply. All reflectors have problems when focusing? Let's wait for more replies. Thanks again for the reply . By the way do you know what multicoated means? Because the refractor here has a description that says it is not 100% multicoated anymore.

[Olsonsview]

If a seller tells me a scope lens is not multicoated "anymore" I see many red flags. I think that someone tried to clean a lens and used a solvent that wiped off the coatings from a lens surface. SOme reasons for such drastic cleaning may be a fungus growth that seriously attacks coating, or lack of skills properly maintaining optical instruments. I would steer quite clear of this opportunity. Re-coating optics is do-able, but not cheap.
A lay answer to your question about the definition of "multi-coating". The reason you need coatings, and the latest best choices are the multi-coatings, are that they allow a lens to transmit light through it and on the proper path, to give you the best possible image. Light that gets reflected back from an uncoated polished glass surface, instead of going through the lens, will muddy, fringe, and otherwise negatively affect the final image. Coatings are needed, and are among the best modern features of a fine lens. I am a newbie to astronomy, but a long time pro photographer who has enjoyed the blessings of multi-coating for many years. Good luck!

[sada]

Ohhh thanks for the reply. All reflectors have problems when focusing? Let's wait for more replies. Thanks again for the reply . By the way do you know what multicoated means? Because the refractor here has a description that says it is not 100% multicoated anymore.

IT DEEPENS if its the lens or mirrors its different coated polish they put on to stop or reduces things like stray light or help sharpen the view they use things like magnesium fluoride & other stuff.the more coated the better.If its the OTA,THEN I THINK ITS DIFFERENT coating's of special paints.so if it is no longer multicoated it means that some of the coating has been damaged.

[landmiiines]

If a seller tells me a scope lens is not multicoated "anymore" I see many red flags. I think that someone tried to clean a lens and used a solvent that wiped off the coatings from a lens surface. SOme reasons for such drastic cleaning may be a fungus growth that seriously attacks coating, or lack of skills properly maintaining optical instruments. I would steer quite clear of this opportunity. Re-coating optics is do-able, but not cheap.
A lay answer to your question about the definition of "multi-coating". The reason you need coatings, and the latest best choices are the multi-coatings, are that they allow a lens to transmit light through it and on the proper path, to give you the best possible image. Light that gets reflected back from an uncoated polished glass surface, instead of going through the lens, will muddy, fringe, and otherwise negatively affect the final image. Coatings are needed, and are among the best modern features of a fine lens. I am a newbie to astronomy, but a long time pro photographer who has enjoyed the blessings of multi-coating for many years. Good luck!

Soooo when it is not multicoated anymore I cannot get clear images? The seller didn't indicate that it is not multicoated anymore. This is his description in the issues: Owing and relative to its age the multicoating is no longer 100% but the optics is free from scratches nor molds. Multicoating don't even exist back in the days. And it doesn't even affect the optics performance. However, this will be sold at a low price as implied. Includes 5 year - warranty.

so which telescope do you suggest do you suggest in the three that I have included in this thread? Please if you have spare time please check the link and the telescope. I really need suggestions or opinions

[landmiiines]

IT DEEPENS if its the lens or mirrors its different coated polish they put on to stop or reduces things like stray light or help sharpen the view they use things like magnesium fluoride & other stuff.the more coated the better.If its the OTA,THEN I THINK ITS DIFFERENT coating's of special paints.so if it is no longer multicoated it means that some of the coating has been damaged.

Sooooo having maybe a little damage on the coating is not a good sign of buying the telescope? Please if you have spare time can you take a look at the links that I have provided and maybe suggest a telescope for me I cannot decide because I don't know which is better because the only refractor that he is selling has a problem which is Owing and relative to its age the multicoating is no longer 100% but the optics is free from scratches nor molds. Multicoating don't even exist back in the days. And it doesn't even affect the optics performance. However, this will be sold at a low price as implied. Includes 5 year - warranty.

[sada]

sooooo having maybe a little damage on the coating is not a good sign of buying the telescope? Please if you have spare time can you take a look at the links that i have provided and maybe suggest a telescope for me i cannot decide because i don't know which is better because the only refractor that he is selling has a problem which is owing and relative to its age the multicoating is no longer 100% but the optics is free from scratches nor molds. Multicoating don't even exist back in the days. And it doesn't even affect the optics performance. However, this will be sold at a low price as implied. Includes 5 year - warranty.

if he is selling with the warranty you could
buy it & see if it is affected & if it is you have the warranty send it back & tell them that a more experiences friend say's that there is something wrong with it. But i will have a look at it again.

[sada]

I CAN'T SEE ANYTHING WRONG WITH IT.SO ASK YOUR SELF DO I FEEL COMFORTABLE BUYING A 2ndhand scope that has a bit of damage but dose not affect the views or not.If you dont feel comfortable don't buy & look elsewhere.good luck.

[jerryTheC]

The problem with imaging, for a lot of visual Newtonian reflectors, is where the focal point of the scope ends up. For visual use, you need to put the focal point of the scope at the focal point of the eyepiece - that is, at or near the end of the eyepiece barrel. For a visual Newtonian, that's somewhere inside the barrel of the focuser; for a refractor, that's somewhere in the diagonal.

For prime focus photography - which uses the telescope as a big lens - you want to put your sensor (or, in the old days, film) at the focal point. For a DSLR, the sensor is some way back in the camera body (since it has to make room for the viewing mirror and shutter in front of it). With a refractor, this is usually possible, since you can get closer to the focal point by leaving the diagonal off, or designing the refractor with a removable tube section at the back. With a Newtonian, all you can do is rack the focuser in - there's no diagonal you can take off - and in many cases, you can't rack the focuser far enough in to get the focal point past the end of the focuser tube, which means you can't achieve focus with a camera - unless the scope was designed with imaging in mind (which means that you need a longer travel focuser, or an extension tube, for visual use - and since that puts the focal point further away from the main tube, and the main mirror closer to the secondary, you need a slightly bigger secondary too).