Advice needed on new equipment

[Bluecloudyeagle]

Hi everyone,

I'm a 20 year old Astronomy hobbyist from India. 

I've been doing mostly visual observing using a celestron nexstar 8se and an alt-az mount for the last 4 years. I bought this primarily for visual observing, but The telescope and it's mount has had a lot of issues over 

the last few years (tracking issues, goto issues, coma, collimated many times but still images aren't sharp) and I've spent a while trying to fix these with little success, now I think I'd like a new telescope and an equatorial mount specifically geared toward deep sky long exposure photography. 

I also have an interest in planetary, and I really want to get a setup that can image polar caps of mars, cloud bands on saturn, small features on the moon etc. As for deep sky, I'm interested in galaxies and nebulas. (like M51, Helix nebula, dumbell nebula etc).

I have a canon EOS R full frame camera, and a 150-600mm sigma lens, so I thought that for widefield targets like M31, M42 etc, I can just use my camera + lens (+skyguider pro type tracker?) 

I'm also considering getting a dedicated astrophotography webcam type camera in the future (I have a neximage 5 already)

I live in a bortle class 8 city, but I hope to be able to travel with my setup to nearby darker skies in the near future. 

I've been researching a lot, and I was considering the Bresser Messier 152L refractor, 150mm apeture and 1200mm focal length, but I was wondering why not many people use it for Deep sky astrophotography considering its affordable price. I realised that it is a achromatic scope, and hence will suffer from chromatic aberration. I'm not sure whether this is a big problem or not, for planets and galaxies. (does using a mono camera + filter wheel help here?). An APO of an equivalent size is too expensive, and I thought that getting a smaller APO to fit in my budget won't have the focal length I require. 

I have also looked at Evostar 150mm ED, which is an APO, quite expensive (more so after import duties here in India) but I can consider it if it is worth it. 

One other thing I have considered is a newtonian reflector of around 10kg or less preferably with a high focal length, but I haven't looked into it too much so if you have any recommendation for a newtonian that will serve my purpose better than a refractor, then it is most appreciated. 

As for mounts, I was looking at the EQ6 R pro due to its high capacity, and I won't have to worry about upgrading due weight for a long time. if I get a smaller scope, I can consider a smaller mount also. 

Sorry for writing so much, but I wanted to give as much context as possible.  

Any advice is highly appreciated. 

Best regards,

Shivam

 

[Highburymark]

Hi Shivam, I’m not an imager so am sure more knowledgable members will be able to give you better advice, but it sounds like you’re after the ‘Perfect Scope’ (as we all are!), ie large aperture and decent focal length, visual and imaging, planets and deep sky, good quality without spending too much etc...., but in reality there is no single scope that will do everything. 
A 150mm refractor is a big instrument. The 150ed would be fantastic - a lifetime scope - but a lot of serious imagers and observers do very well with a 120ed. That is pretty close to a perfect all-rounder for many of us. The Bresser would give you the aperture you’re looking for, but even at F/8-ish, you might find the CA off putting on bright objects - I haven’t used one, so maybe someone else will chime in on this. I think many imagers might prefer a Newtonian - particularly if you already have a strong mount. 
I’ve had two SCTs, and I know that your issues with bloated stars aren’t unusual. While some owners take stunning images with their C8s and C9.25s, there is variation from one SCT to another. If you move to an ed refractor or a Newt, I’m sure you’ll see a transformation in star tightness.
No matter the difficult decision you have ahead, it’s a nice problem to have. Good luck!

[John]

I have owned a Meade AR6 152mm F/8 refractor and the false colour is quite evident. It's OK for visual observing but I don't think an imager would find it acceptable. Also they are very large scopes to mount steadily.

Have you considered putting your 8SE tube onto a sturdy equatorial mount ?

 

[Bluecloudyeagle]

On 27/05/2020 at 23:56, Highburymark said:

Hi Shivam, I’m not an imager so am sure more knowledgable members will be able to give you better advice, but it sounds like you’re after the ‘Perfect Scope’ (as we all are!), ie large aperture and decent focal length, visual and imaging, planets and deep sky, good quality without spending too much etc...., but in reality there is no single scope that will do everything. 
A 150mm refractor is a big instrument. The 150ed would be fantastic - a lifetime scope - but a lot of serious imagers and observers do very well with a 120ed. That is pretty close to a perfect all-rounder for many of us. The Bresser would give you the aperture you’re looking for, but even at F/8-ish, you might find the CA off putting on bright objects - I haven’t used one, so maybe someone else will chime in on this. I think many imagers might prefer a Newtonian - particularly if you already have a strong mount. 
I’ve had two SCTs, and I know that your issues with bloated stars aren’t unusual. While some owners take stunning images with their C8s and C9.25s, there is variation from one SCT to another. If you move to an ed refractor or a Newt, I’m sure you’ll see a transformation in star tightness.
No matter the difficult decision you have ahead, it’s a nice problem to have. Good luck!

Thanks for the Advice  I am leaning towards the 150mm ED refractor, but I'll do some more research.

[John]

Have you thought about the maksutov-cassegrain design ?

Shorter tube so easier to mount steadilly. Long focal length so good sized planetary images. Sharp optics and more aperture for your money than an apo refractor.