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#1 francov

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Posted 17 August 2019 - 11:02 PM

Hello everyone. Although I’ve been coming to the site for a while now, I’m new to posting so first, I wanted to thank everyone that participates in here because I’ve learned a ton from you in the last year.bow.gif

I’ve already taken my first steps in AP and now I feel ready to move up a little. So I hoping some of you will give me a couple of suggestions.

 

I started my journey accidentally by taking a long exposure with my DSLR  in a dark sky site and being amazed at the result. I moved on to a skyguider pro and I was hooked.  A few months ago I took your advice and spent everything I could afford on a mount. I got an EQ6-R and I mounted my old DSLR with a 400mm lens on it. I learned to PA (now doing it with sharpcap) and guiding with PHD2. I work with Photoshop for a living so stacking and processing were not the biggest challenge. But my DSLR is at its limit (5DmIII). I can do 4-min exposures but the sensor will heat up so bad that my images have noise in all sorts of colors.

 

So now that I have a mount and I have learned my way around it, I’d like to finally get a scope and a camera and I’m hoping you could share suggestions on a good combo. I’d like to keep my budget up to $2000-2500, but I could push it a little higher. I’m open to anything from a small refractor to an 8” RASA, as long as the EQ6 can handle it.

 

My target would be DSOs, but I won’t be doing this on my backyard. Instead, I’d drive out 2-3 hours to a dark sky site (bortle 2) for a couple of days every time I can, so my total integration time won’t be 30 hours (at least for now).

 

Thanks in advance!


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#2 Stelios

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Posted 17 August 2019 - 11:42 PM

It appears that you want a cooled camera, as well as a scope. This sort of excludes mono with a $2500 budget, but shooting from Bortle 2 an OSC should be OK.

 

The main choices for a camera are the ASI294MC-Pro and the ASI183MC-Pro.

 

As for a scope, an F/6 80mm refractor like the AT80EDT would be my recommendation. That would pair very well with the smaller pixels of the 183. Of course this would not be suitable for small objects, but then no one scope can do it all.


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#3 RedLionNJ

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Posted 18 August 2019 - 10:27 AM

If you can take 4 minute exposures just with the 5DmIII and a 400mm lens without significant sky background, there should be no good reason you can't get something like a 70-80mm APO (maybe f5 with a FR/FF) and hook the Canon up to that.

 

Individual 60-second exposures shouldn't overheat the sensor and any noise due to temperature should be greatly-reduced by correct use of darks.

 

There will be almost no end of targets for such a setup.


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#4 francov

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Posted 19 August 2019 - 12:24 PM

Thank you. That was the direction I was going for, but since I'm still new, I thought I'd ask just in case. I'm definitely open to splitting the purchase and getting first a scope, and later a dedicated camera (or first, a cooled camera and using my canon lenses, and getting a scope later) (but some people seem to find those EF adapters not very precise).

 

I think CCD cams are out for now, but I'm somewhat open to mono (ASI1600MM?). My concern with them is less about cost and more about time.



#5 nimitz69

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Posted 19 August 2019 - 05:16 PM

Have you done the calculation to determine at what sub exposure length you are swamping read noise with that camera? I would think that unless your skies are exceptionally dark you don’t need to be doing 5 min subs. With the EQ6-R Pro and your dslr just look into a nice 80mm apo triplet refractor and you're set.  You can do a lot of great imaging with that, particularly once you drop the exp time down to 60-90 secs ...



#6 francov

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Posted 21 August 2019 - 12:25 PM

Thanks nimitz69. I have not, but I have noticed that noise gets progressively worse. My few last dark frames end up with pretty significant color noise. With my limited knowledge, I assume this is heat not dissipating. I've compared my subs with those of a Nikon DSLR taken the same night and the difference was pretty substantial (I've read Nikons (Sony sensors) perform better anyway). I figured if I am going to invest, I should get a cooled camera that stays cool in the temperature swings of the desert.

 

The 80mm triplet apo is winning (is 102mm asking for trouble?), but he idea of a very fast RASA 8 is still appealing to me. It sounds like I could shoot more than one target in 2 nights. But if it will need collimation every time I drive out of the city, then I'm out...



#7 dhaval

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Posted 21 August 2019 - 03:50 PM

I believe at this stage a cooled camera will add more value than a scope given your limited budget. Remember, when you get a scope, you will most likely have to change the focuser on it - and that may not be something trivial (unless, of course, you get a scope that has a really good focuser, in which case the cost of such a scope will be high). 

 

I am also inclined to think that adding a mono camera with filters will take you further along, simply because you have a 400mm lens (and even if you buy a scope, you will most likely end up with a widefield scope), which will render itself as a widefield instrument allowing you to shoot most of the larger targets like nebulae. That also implies that you will most likely be shooting narrowband more so than anything else and hence using a mono camera will be more beneficial (this is not to suggest that an OSC can't shoot NB, but a mono camera will be much more efficient). 

 

CS!


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#8 nimitz69

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Posted 21 August 2019 - 04:46 PM

Thanks nimitz69. I have not, but I have noticed that noise gets progressively worse. My few last dark frames end up with pretty significant color noise. With my limited knowledge, I assume this is heat not dissipating. I've compared my subs with those of a Nikon DSLR taken the same night and the difference was pretty substantial (I've read Nikons (Sony sensors) perform better anyway). I figured if I am going to invest, I should get a cooled camera that stays cool in the temperature swings of the desert.

 

The 80mm triplet apo is winning (is 102mm asking for trouble?), but he idea of a very fast RASA 8 is still appealing to me. It sounds like I could shoot more than one target in 2 nights. But if it will need collimation every time I drive out of the city, then I'm out...

I started with a Nikon D5300 which has just about the lowest noise out there for a DSLR and. Then moved to an OSC which I currently have.  Aperture is not king in AP like it is for visual and larger apertures make learning AP much harder.  The nice thing about an 80mm is you get to do all the great wide field nebula stuff while learning and then if you need more resolution and want to go after fainter stuff you can move to a 127 or 130 or than the 8” RASA.  Crawl, walk, run is the best advise for getting started in AP.  Things that experienced imagers find straight forward to do, as a beginner you may find overwhelming.  While there is no argument that a c oiled mono camera will produce the ‘best’ results in light polluted skies there is a lot more to worry about in the Image Capture process with mono - you’ll need filters and a filter wheel.  Electronic or manual?  Do you have auto focus? Etc,

 

Also people when first starting out are usually trying to “buy the right stuff” so they don’t have to buy again but the truth is that as your skills and knowledge improve you’ll be changing equipment.  After the D5300 and now the ASI294 MC Pro I’m in the process of getting ready to move to mono but I’ve Ben doing it slowly.  First DSLR, then OSC, now I’ve added auto focus, next will be mono + filters.  The one thing I haven’t done is change scopes because I’m not looking to produce spectacular images at this point (not that my WO 81 GT APO isn’t capable of that) but I’m focused on the process of AP.  many beginners are so focused on producing  pictures immediately that they cut corners or jump to fast.   AP is a marathon not a sprint.  I’m not aware of any end date f or AP so we have all the time in the world ...


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