6" or 8" Newtonian for visual observation? What other extras required for decent planetary and DSO viewing?

[BogdanMD]

Hello everyone, complete newb here looking for advice.

Many years ago I bought a Celestron Powerseeker 70AZ and spent quite a few nights looking at planets from my light polluted balcony. I've never seen a DSO and never took it to a really dark sky.

For a couple of weeks now I've been looking for an upgrade. First I've looked at 8" Dobs but the bulky size and the near the ground mount made it not less suitable for some of my requirements (above average performance, compact design, light weight, budget priced +/- compatibility with AP in the future). Not asking much am I right? I then looked at 127 Maks, I was set on picking one but a good EQ mount would exceed what I'm willing to pay at the moment (750 euro).  

So the telescope that would fit my needs the best looks to be a EQ mounted Newtonian, the only model I'm looking at is the Skywatcher 150PDS or 200PDS on a NEQ-5 mount without GoTo. It's the only brand sold at a store which offers a suitable payment option.

I'll still be using it most nights from my balcony but I can also take it to the countryside a couple times a month so size and portability are important. I'm aware the assembled telescope will weight ~26 or 29kg, but disassembled it should be manageable.

I've been reading many discussions here and on other platforms, looked at sketches, videos so I think I have an idea what to expect I'll be able to see through the eyepiece which is nothing like the AP images, so tiny colored discs for planets and blurry, fuzzy grey streaks for nebulas. That's alright and enough at this point and price range, I'm sure it would still look impressive compared to my old scope.

I've set one of the requirements as being able to upgrade in the future for astrophotography at a basic level. My planned budget for that would be about 1300-1400 euros, enough to buy a HEQ-5 GoTo mount (1075 euro) and a cheap CCD camera (I haven't done any research on the camera so my plan might not be realistic). I want to use the Newtonian on the new mount.

A few things I couldn't decide on:

1) Since I'm starting with visual viewing for at least a few months, I can't decide if I should get the 6" or the 8" Newtonian. The 8" should provide a better image for my eye especially when it comes to DSO's but it might be too big for the HEQ-5 if I want to do AP in the future. The 6" would be best on that mount but if the visual viewing is poor, I'm afraid I might loose interest quickly. I'm somewhat inclined to go for the 6" half expecting DSO's not to be all that much more detailed on the 8" either, but sketches I've seen tend to prove the contrary. This chart also shows how much more powerful is the 8" mirror compared to the 6".

Did anyone else face the same dilemma and what did you choose? If you upgraded from 6" to 8", was the improvement noticeable?

2) Does the 150/750 Newt require a coma corrector? What about the 203/1000?

3) For planetary viewing, what other eyepieces should I get beside the one that comes with the scope (Apex 28mm)? (50-75 euro range if possible). I think I could also use the 3x Barlow I have from my old telescope.

4) For DSO viewing, what other eyepieces should I get beside the one that comes with the scope (Apex 28mm)? Should I get one with more magnification for small nebulas? (50-75 euro range if possible)

5) Do I need to buy filters? Planet filters, light pollution filters, ultra high contrast? I don't really know anything about filters and their usefulness.

Reading back what I've wrote it all sound really demanding for a single, budget scope but my old scope set the bar really low so I'm hopeful that I can put something together to have fun with in most situations.

Thank you for reading and I'm looking forward to hear your thoughts!

EDIT: For extra accessories I'm looking at:

Skywatcher Gold Line 6mm and 15mm or

Meade Zoom 8-24mm Eyepiece or

Skywatcher Ocular Planetary UWA 6mm 1,25"

Castell UHC filter

Baader MPCC Mark III (this is a quite expensive piece and I probably won't buy it now if it's only needed for AP)

Meade Laser collimator

I'm limited in my choice by both price and store availability (I won't post the store unless it's alright).

Edited May 17, 2020 by BogdanMD

[Dr Strange]

OK. So a few things. Astro Photography (AP) and visual astronomy are two different beasties with two different sets of requirements. For visual aperture is the most important factor. For AP it is the mount. In addition AP is a very complex part of the hobby and the telescopes you are looking at are capable of some amazing AP images but are not generally recommended for people just starting out in it. 

For visual the 150 is the recommended aperture recommended for a beginner to really "see" things. 203mm is better. 

For AP a 70-80mm APO refractor is what is recommended for a beginner. The APO has a very short focal length, doesn't require precise collimation, doesn't need a long cool down, or any additional items like a MPCC etc to use which  allows for the person to learn how to do AP well without as much complexity as the reflector (mirrored) scope adds.  

With that in mind I would suggest the Skywatcher AZ-GTi 130mm Newtonian. This is only £359 and will show you a lot more than the 70mm. It is also a fully GOTO mount. It will show you DSO and planets from a light polluted sky. And it is very transportable. It can be used for AP with a 70-80mm APO as well by adding a wedge to it. However the HEQ5 is the better AP option. At 359 it will let you conserve your money for the much more expensive AP equipment you will end up buying. Speaking of which buy once and cry once instead of buying something, becoming frustrated with it, then buying something else. A 70-80mm APO can be used for years for AP so you will not be upgrading any time soon after purchasing it.

The AZ-GTi is here: https://www.firstlightoptics.com/sky-watcher-az-gti-wifi/sky-watcher-explorer-130ps-az-gti.html

[bomberbaz]

I own this mount and cannot help but think that the mount is at it's limit with that scope (130ps). I use it with a 90mm/F10 celestron frac and it is at the limit there. It is my white light scope but I always remove the dew shield. Less for the wind to grab hold of and reduces wobble. 

That said, the mount is a brilliant bit of kit for use with lightweight scopes. I currently have three which I use with it and they all give me a lot of satisfaction in three different categories:  Solar white light, Solar HA, EEVA and use of my MAK. Sorry that's four. Anyway the mak is used for planetary and viewing stars (cluster, doubles etc).

Actually it's got a fifth use. I have taken a few images of various night sky wide views using my sony camera. It's an all in one type camera but has a lot off ubiquitous settings.

Another thing worth mentioning is the GTI can make use of the SW wedge which means it can be changed to an EQ mount, even more versatility. (Requires an upgrade to mount, done online, free of charge)

The AZ Gti mount is a great bit of kit for a lot of basic stuff. If you want something more advanced, expect your wallet to take a bigger hit.

Steve

Edited May 18, 2020 by bomberbaz

[BogdanMD]

On 18/05/2020 at 19:04, Dr Strange said:

OK. So a few things. Astro Photography (AP) and visual astronomy are two different beasties with two different sets of requirements. For visual aperture is the most important factor. For AP it is the mount. In addition AP is a very complex part of the hobby and the telescopes you are looking at are capable of some amazing AP images but are not generally recommended for people just starting out in it. 

I am totally expecting many nights of subpar results before I figure even the basic things out. That being said, I've seen a few albums of people starting AP with a Newtonian and they took some really amazing images, I don't know how much time it took until they were confident enough to post that first picture, but I'm hopeful anyway. 

For visual the 150 is the recommended aperture recommended for a beginner to really "see" things. 203mm is better. 

I went back and forth about the 203 but I came to the conclusion that it's just too big for my balcony.

For AP a 70-80mm APO refractor is what is recommended for a beginner. The APO has a very short focal length, doesn't require precise collimation, doesn't need a long cool down, or any additional items like a MPCC etc to use which  allows for the person to learn how to do AP well without as much complexity as the reflector (mirrored) scope adds.  

A "good" refractor (my current telescope is technically a refractor as well) is still something I'll keep in mind for my next telescope, but it's not something I want to invest into right now.

With that in mind I would suggest the Skywatcher AZ-GTi 130mm Newtonian. This is only £359 and will show you a lot more than the 70mm. It is also a fully GOTO mount. It will show you DSO and planets from a light polluted sky. And it is very transportable. It can be used for AP with a 70-80mm APO as well by adding a wedge to it. However the HEQ5 is the better AP option. At 359 it will let you conserve your money for the much more expensive AP equipment you will end up buying. Speaking of which buy once and cry once instead of buying something, becoming frustrated with it, then buying something else. A 70-80mm APO can be used for years for AP so you will not be upgrading any time soon after purchasing it.

The AZ-GTi is here: https://www.firstlightoptics.com/sky-watcher-az-gti-wifi/sky-watcher-explorer-130ps-az-gti.html

This is actually the exact scope and mount I had in mind when I started my research. I was really impressed with the user friendly mount and the scope was a big upgrade over what I have now. Then I wanted to go bigger and that mount can't hold a larger aperture. 

Thank you for you insight, I really appreciate taking the time to respond even though I've already ordered the 150PDS with the NEQ5 yesterday. I'm really excited to try it out over the weekend and hopefully take it to a dark sky next week. I'll start saving for the HEQ5 mount and a camera once I get used with the EQ mount and know my way around the sky. I'll keep doing my own research in the meantime.

19 hours ago, bomberbaz said:

Another thing worth mentioning is the GTI can make use of the SW wedge which means it can be changed to an EQ mount, even more versatility. (Requires an upgrade to mount, done online, free of charge)

Hmm, that is something I didn't know and wish I did. I still believe 150mm is the right aperture for me at this time. Anyway, I've already pulled the trigger on something else so let's see how that one plays out. Thank you for reaching out!

[Dr Strange]

Happy to help! And congratulations on the new purchase! I would suggest starting with visual and doing that for about 5-6 months so you learn your equipment, your night sky, and so on then jumping in on AP.  I tell my wife that the hobby keeps me out of the pub's so it is a win win and allows me to spend more than she thinks I should. ;)