Tips for a beginner with an SCT

[DarkAntimatter]

Hello, I'm getting my first scope soon, an SCT, after much research and using scopes of a couple of friends.  I also have a DSLR and I'm sure it won't be long before I want to try taking some astrophotos. 

I've read many (very many) posts explaining that an SCT is a difficult scope to start photography with, because:

1. The high focal length means longer exposures 

2. The high magnification of the high focal length means any motion errors from the mount, the alignment, etc. will be more severe than on a faster scope.

But since this is what I have (or will hopefully soon have) and I'm not in a position to buy an additional scope (maybe some day) I was wondering what kinds of objects might be reasonable to try for.  I live in a fairly light polluted area (yellow) so was thinking of some relatively short shots of something bright, like M42 that I could stack.  Or start by piggybacking the camera on the mount (ge) and trying some shots through the camera lens of some really wide fields?

I'd appreciate some advice from someone whose done this, for something that might be within the skills of a noobie.  Thanks for any help you can provide.  

[Alien 13]

I am sorry but I would stick to planets and the moon, an SCT and beginner doesn't go together and even an expert will struggle with DSO unless you have a top end guided mount.

Alan

[paul mc c]

I am fairly new to AP,and these were taken with an SCT,and all basic processing,so im sure you can get similar results.

[LightBucket]

16 minutes ago, Alien 13 said:

I am sorry but I would stick to planets and the moon, an SCT and beginner doesn't go together and even an expert will struggle with DSO unless you have a top end guided mount.

Alan

Sorry but completly disagree, i started with an 8” SCTand used it on a wedge and with a guide scope and guide camera got 15 min subs no problem, the secret with those scopes is getting very good balance. So it is doable....in my opinion, people seem very quick to discount SCT for imaging DSO’s, but they shouldn’t....

[DarkAntimatter]

7 minutes ago, paul mc c said:

I am fairly new to AP,and these were taken with an SCT,and all basic processing,so im sure you can get similar results.

Wow, that's a nice high bar from me.  I am getting that same scope (the 9.25), so maybe after a lot of practice...

What camera were these taken with?  (Hoping you say dslr and not some expensive CCD!)

[paul mc c]

Canon 1100d non modded,non guided.

[Davey-T]

Which particular SCT are you getting, it needs to be mounted on a wedge to convert to equatorial setup and autoguided using a separate guidescope or off axis guider, all adds to the expense.

DSLR pixels don't lend themselves to SCT imaging even with a 6.3 focal reducer you would be imaging at less than 1 arc second per pixel.

Field of view is restricted so you will only get the centre of M42 or the core of M31.

Having said all that it is quite possible to take images with this setup depending on your expectations.

One thing it would be good for is imaging the Moon, OK on Alt / Az mount and no guiding needed but you could invest in a dedicated camera for the purpose.

Dave

[DarkAntimatter]

22 minutes ago, Alien 13 said:

I am sorry but I would stick to planets and the moon, an SCT and beginner doesn't go together and even an expert will struggle with DSO unless you have a top end guided mount.

Alan

I'd like to try some planets, but with a DSLR won't the sensor be too large (ie. the planet will appear as a tiny round dot)?  This would be prime focus.

[LightBucket]

And here is my effort taken with a DSLR and 8” SCT

 

 

[Alien 13]

1 minute ago, DarkAntimatter said:

I'd like to try some planets, but with a DSLR won't the sensor be too large (ie. the planet will appear as a tiny round dot)?  This would be prime focus.

It would depend somewhat on the DSLR., the pixels size of modern ones is similar to dedicated planetary cameras but a DSLR can only do 7-8 frames a second against the 200 plus of a planetary camera, this technique relies on "lucky imaging" so the dedicated camera has a huge advantage. 

Alan

[HunterHarling]

I am very happy with me sct.

Always remember to turn the final adjustment for focus counterclockwise to reduce mirror flop.

You will also need a dew shield or the corrector plate will be soaked.

Sct telescopes are very capable for excellent deep sky images but I do recommend a good gem mount.

 

[paul mc c]

11 minutes ago, DarkAntimatter said:

I'd like to try some planets, but with a DSLR won't the sensor be too large (ie. the planet will appear as a tiny round dot)?  This would be prime focus.

Taken with said camera and 2x barlow,not the sharpest but not a tiny dot.

 

 

 

[MarsG76]

45 minutes ago, DarkAntimatter said:

Hello, I'm getting my first scope soon, an SCT, after much research and using scopes of a couple of friends.  I also have a DSLR and I'm sure it won't be long before I want to try taking some astrophotos. 

I've read many (very many) posts explaining that an SCT is a difficult scope to start photography with, because:

1. The high focal length means longer exposures 

2. The high magnification of the high focal length means any motion errors from the mount, the alignment, etc. will be more severe than on a faster scope.

But since this is what I have (or will hopefully soon have) and I'm not in a position to buy an additional scope (maybe some day) I was wondering what kinds of objects might be reasonable to try for.  I live in a fairly light polluted area (yellow) so was thinking of some relatively short shots of something bright, like M42 that I could stack.  Or start by piggybacking the camera on the mount (ge) and trying some shots through the camera lens of some really wide fields?

I'd appreciate some advice from someone whose done this, for something that might be within the skills of a noobie.  Thanks for any help you can provide.  

 

37 minutes ago, Alien 13 said:

I am sorry but I would stick to planets and the moon, an SCT and beginner doesn't go together and even an expert will struggle with DSO unless you have a top end guided mount.

Alan

 

21 minutes ago, LightBucket said:

Sorry but completly disagree, i started with an 8” SCTand used it on a wedge and with a guide scope and guide camera got 15 min subs no problem, the secret with those scopes is getting very good balance. So it is doable....in my opinion, people seem very quick to discount SCT for imaging DSO’s, but they shouldn’t....

I have been using and imaging with a SCT for a few years and I think it's very doable... I think it's a misnomer to say that a SCT is only good for planetary and lunar photography. I have been taking DSO images with a  8SE on a CGEM mount at upto f10/2032mm that turned out quite good... as a added bonus certain DSOs like for example the pillars of creation were magnified and more detail was extracted from the subs.

 

[MarsG76]

16 minutes ago, LightBucket said:

And here is my effort taken with a DSLR and 8” SCT

 

 

Another great testament to SCT imaging.

 

[DarkAntimatter]

9 minutes ago, Davey-T said:

Which particular SCT are you getting, it needs to be mounted on a wedge to convert to equatorial setup and autoguided using a separate guidescope or off axis guider, all adds to the expense.

DSLR pixels don't lend themselves to SCT imaging even with a 6.3 focal reducer you would be imaging at less than 1 arc second per pixel.

Field of view is restricted so you will only get the centre of M42 or the core of M31.

Having said all that it is quite possible to take images with this setup depending on your expectations.

One thing it would be good for is imaging the Moon, OK on Alt / Az mount and no guiding needed but you could invest in a dedicated camera for the purpose.

Dave

A Celestron 9.25.  For the mount, I was going to get the CGEM but I was very fortunate and someone put me in touch with a person who had a G11 that they were selling because they were upgrading and I got it (used) for the same price as the CGEM (new) and I was advised that a well-kept used G11 was a better choice than the CGEM.  At a star party last month there was a person who was doing 5 minute unguided subs with a G11 and a C8, although it took him a long time to align it well enough to do this and I probably won't have that skill until I get a lot of practice.  But I was hoping to get away with 1 minute subs or so after some practice.  

Since I'm getting the scope, have the camera, and someone is lending me a T adaptor and camera adaptor , I would like to try unguided because I wouldn't have to buy anything else for this.   We'll see if the bug bites after that and maybe I will save up for things like focal reducers and guide scopes!

[DarkAntimatter]

7 minutes ago, paul mc c said:

 

 

 

Wow, impressive.  You are giving me hope.  

[paul mc c]

again i am only a beginner,and have very little knowledge in AP,but for planetary images get a planetary cam,i have a ZWO 120mc and have had some very good images.

[Davey-T]

I used my 10"SCT with a Canon 450d for a while which fuelled my enthusiasm for astro imaging and resulted in spending loads of money in pursuit of better images.
Using a wedge and auto guiding I can do 30 minute subs using an Atik 314L CCD camera then wanting bigger field of view spent more money on other scopes / mounts / / cameras and not forgetting the computer hardware /software and still haven't stopped spending money so mind you don't get hooked as it's a slippery slope 

Dave

[paul mc c]

5 minutes ago, Davey-T said:

I used my 10"SCT with a Canon 450d for a while which fuelled my enthusiasm for astro imaging and resulted in spending loads of money in pursuit of better images.
Using a wedge and auto guiding I can do 30 minute subs using an Atik 314L CCD camera then wanting bigger field of view spent more money on other scopes / mounts / / cameras and not forgetting the computer hardware /software and still haven't stopped spending money so mind you don't get hooked as it's a slippery slope 

Dave

Never a truer word spoke....

[DarkAntimatter]

1 hour ago, paul mc c said:

Never a truer word spoke....

Therein lies the trap.

I've spent the budget getting the scope and mount so I'll have to be satisfied with what I've got for a while. Fortunately I see there is some pretty good free software for image processing. 

Thanks to all who replied. You give me hope there are some photos out there for me too. 

[Chris]

Tips for a beginner who is getting an SCT and wants to image DSO's:

1) buy a 0.63 reducer/flattener (you don't want to be imaging DSO's at f10, I've tried and it's sooooo slow!)

2) Dew control! SCT's are dew magnets, so a heated dew shield would be a great help.

3) Collimation and focus. You can change a lot of stuff in post processing, but you can't alter poor focus and collimation in software. Buy/make a focus mask to get optimal focus.

4) Best mount you can afford. The  focal length of the C9.25 will need it! 

[Sp@ce_d]

Adding to Chris's tips... My tips would be:

Have plenty of patience & plenty of long clear nights!

I wouldn't use the words beginner, SCT & DSO in the same sentence ? I wasn't a beginner when I tried but it made me feel like one or worse!

For DSO imaging I'm one of those who struggled to get satisfactory results during the year I had my c9.25 on the obsy mount. At best my images were just too soft. I had a constant battle with collimating & mirror flop/focus. I fitted a motorised Moonlite focusser & rotator but even with regular automated refocusing it just didn't do it for me. Very frustrating!

Planetary yes, visually it's one of my favourite scopes to use but DSO imaging I failed miserably & expensively with it.

Now, the RC8 I put on the mount after it is another story.. still there after 2 years

[Chris]

I've got to agree with the above, it's a challenging option for beginner in my opinion.

I had my C8 Edge HD @ 1400mm focal length reduced to f/7, all setup in an obsy with NEQ6 mount and pier. I found the Edge version to be quite sharp and flat as it places the internal flattener at the optimal position. However, I really really struggled with the focal length, although partly due to my NEQ6 being a terrible example which I ended up selling for next to nothing  

I got much better results with my WO66, ED80, and 130pds (faster and shorter focal length scopes which are easy to mount)