Looking for advise on scope for starting out in DSO

[bluesilver]

Hi,  a bit of a broad question i know,  but just looking for somewhere to get me started for now.

I want to get into astrophotograhpy and with that i am interested in the DSO,  so galaxies, nebular, that sort of area.

So i am basically just looking for some general advise on what sort of scope to go for at the moment.

I currently have at the moment the scopes i have are a Skywatcher 150ED Evostar  and also a Skywatcher 16" Dobsonian

I was originally planning to use the 150ED Evostar for DSO but have been advised that this isn't really the best scope for doing this with,  so might be possibly looking at moving this scope on and keeping the Dobsonian for visual observing.

So looking at DSO photography, 

I am planning to use a ZWO camera,  only have the ASI224mc planetary camera at the moment,  but also might be using a DLSR as well.

I have a guide scope,  a Orion 60mm guide scope
My guide camera is a ASI 290mm mini guide camera
Mount is a Skywatcher AZ-EQ6

1.  I am thinking at this stage that a triplet might possibly be the best option,  but looking for advise on this.

     I see that you can also get what is called SHARPSTAR 100Q-II APO QUADRUPLET f/5.8
2.  What brand should i be looking at?  William optics, Skywatcher, 
3.  Is it best to move away from Skywatcher to a more dedicated brand model?
4.  Size, should i be looking at something like a 80mm range or similar?
5.  I was thinking of staying with the refractor scopes,  but again always open to any advice

 I realize it is a broad question,  but hoping this will narrow things down a tad or at least get me in the right track

Also i guess when you look at what most of the scopes being used for DSO,  they are generally in the 80-100 mm rage

 Any advice would be greatly appreciated.
Thanks.

Edited January 7, 2021 by bluesilver

[Waldemar]

Hi Bluesilver,

The best advice for you is to buy Steve Richard's book:  Making Every Photon Count - Steve Richards | First Light Optics
Steve is a member of this forum with the name 'Steppenwolf' and the book will tell you all you need to know about imaging.
There is a follow-up on it too: Dark Art or Magic Bullet - Steve Richards | First Light Optics

This combo will provide you with invaluable information and will spare you a lot of money by guarding you against buying the wrong equipment

[Owmuchonomy]

Great advice above on the book. Don’t be hasty to move on the ED150. If you want to image galaxies it will be spectacular.

[KP82]

You already have most of the necessary equipment and I assume you have read and understood the general process of DSO imaging.

To answer your questions:

1. It doesn't have to be a triplet. Any scope with good colour correction and a fast focal ratio will do although triplets do offer the best control of CA among refractors. The sharpstar quadruplet is a petzval design with built in flattener. This will save you some time from working out the optimal spacing yourself. However if you plan to use the scope for both visual and imaging, pay attention to the backfocus distance in the specs of those quadruplets as some of them are specifically designed for imaging only and do not have the backfocus to accept a diagonal.

2. Brand name doesn't matter. Pick one with a focal length that suits the targets you plan to capture. Also it depends on your budget. In terms QA, SkyWatcher, William Optics, TS Optics, Altair, Sharpstar, etc are all about the same. Sharpstar manufacture their own scopes whereas the other four are just different brand names for scopes that come out of the same 1 - 2 factories (Synta, Longpern, KUO, etc.). Vixen is a good mid-high range Japanese manufacturer if you're after Japanese quality lenses. Finally there are the premium brands like Astrophysics, TEC, Takahashi, APM-LZOS and CFF which all offer some sort of minimum guarantee on the optical quality.

3. Skywatcher have their own dedicated series of imaging refractors, Esprit.

4. Most 80mm scopes have a focal length between 400 and 600mm which are suitable for many DSO targets. They are also fast enough (~ f/6) and can be made faster with reducers. They are much lighter than say your 150ED, so a lot easier on the mount. Your AZ-EQ6 will perform well effortlessly with an 80mm scope. Also the relatively shorter focal length will provide more tolerance for tracking errors in the mount.

5. Refractors generally do not have collimation issues and are easier to handle for beginners like us. So if you're more familiar and comfortable with them, stick to them. Dedicated imaging newts, hyperstar and RC while offering higher resolution or super fast focal ratio will require more effort to get good results, therefore are best left to the advanced folks.

 

BTW I'd strongly recommend using your DSLR over the 224mc for DSO imaging. You may want to get it astro modded unless you plan to get a dedicated cooled camera soon. I'd also advise you to read the books mentioned in the previous post and familiarise yourself with the capture and post processing software.

Edited January 7, 2021 by KP82

[bluesilver]

Thanks for the replies and advise.

I will be definitely looking in those books mentioned,  also was told to have a look at a book called The deep-sky imaging primer second edition by Charles Bracken

https://www.amazon.com/Deep-sky-Imaging-Primer-Second/dp/0999470906/ref=sr_1_1?dchild=1&keywords=The+Deep-sky+Imaging+Primer&qid=1610074674&s=books&sr=1-1

I have modified my DLSR ( Canon 600D )  and letter on down the track will possibly be looking at a dedicated cooled camera.

But first i think it is going to be taking a look at those books.

Appreciated.